TW202106116A

TW202106116A - Controlling conversion efficiency in an extreme ultraviolet light source

Info

Publication number: TW202106116A
Application number: TW109110091A
Authority: TW
Inventors: 王海寧; 席爾多斯威爾漢默斯爵森; 羅伯特傑拉法斯; 亞歷山大安東尼夏夫根斯; 迪特瑪烏韋赫伯特翠斯; 丹尼爾約翰威廉布朗
Original assignee: 荷蘭商Ａｓｍｌ荷蘭公司
Priority date: 2019-04-01
Filing date: 2020-03-25
Publication date: 2021-02-01
Also published as: NL2025231A; EP3949692A1; KR20210141483A; WO2020205883A1; CN113661789A

Abstract

An extreme ultraviolet (EUV) light source includes: a vacuum vessel; a target material supply system that supplies targets to an interior of the vacuum vessel, the targets including a first target with an initial shape at an initial target region; a first optical source configured to provide a first light beam to a first target region, the first light beam configured to modify the initial shape of the initial target; and a second optical source configured to provide a second light beam to a second target region, the second target region configured to receive the modified target, the second light beam being configured to convert some of the target material in the modified target to a plasma that emits EUV light. The initial shape of the first target is controlled to thereby control an amount of plasma produced from the interaction between the second light beam and the modified target.

Description

控制極紫外光源中的轉換效率Control the conversion efficiency in extreme ultraviolet light sources

本發明係關於控制極紫外(EUV)光源中之轉換效率(CE)。The present invention relates to controlling the conversion efficiency (CE) in an extreme ultraviolet (EUV) light source.

極紫外(「EUV」)光，例如具有為100奈米(nanometer; nm)或更小(有時亦被稱作軟x射線)之波長且包括處於例如20 nm或更小、介於5 nm與20 nm之間或介於13 nm與14 nm之間的波長的光之電磁輻射可用於光微影程序中，以藉由在抗蝕劑層中起始聚合而在基板(例如矽晶圓)中產生極小特徵。Extreme ultraviolet ("EUV") light, for example, has a wavelength of 100 nanometers (nanometer; nm) or less (sometimes referred to as soft x-rays) and includes, for example, 20 nm or less, between 5 nm Electromagnetic radiation of light with a wavelength between 20 nm or between 13 nm and 14 nm can be used in photolithography procedures to initiate polymerization in a resist layer to build on a substrate (such as a silicon wafer). ) Produces minimal features.

用以產生EUV光之方法包括但未必限於：當在電漿狀態中時運用在EUV範圍內之發射譜線來轉換包括例如氙、鋰或錫之元素之材料。在常常被稱為雷射產生電漿(「LPP」)之一個此類方法中，可藉由運用可被稱作驅動雷射之經放大光束來輻照例如呈材料小滴、板、帶、串流或叢集之形式的目標材料而產生所需電漿。對於此程序，通常在例如真空腔室之密封容器中產生電漿，且使用各種類型之度量衡設備來監測電漿。Methods for generating EUV light include, but are not necessarily limited to: using emission lines in the EUV range to convert materials including elements such as xenon, lithium, or tin when in a plasma state. In one such method, often referred to as laser-generated plasma ("LPP"), an amplified light beam that can be called a driving laser can be used to irradiate material droplets, plates, ribbons, etc. The target materials in the form of streams or clusters are used to generate the required plasma. For this procedure, plasma is usually generated in a sealed container such as a vacuum chamber, and various types of metrology equipment are used to monitor the plasma.

在一個態樣中，一種極紫外(EUV)光源包括：一真空容器；一目標材料供應系統，其經組態以將目標供應至該真空容器之一內部，該等目標包括至少一第一目標，該第一目標在該真空容器中之一初始目標區處具有一初始形狀；一第一光學源，其經組態以將一第一光束提供至該真空容器中之一第一目標區，該第一光束經組態以修改該初始目標之該初始形狀以形成一經修改目標；及一第二光學源，其經組態以將一第二光束提供至該真空容器中之一第二目標區，該第二目標區經組態以接收該經修改目標，該第二光束經組態以與該經修改目標相互作用且將該經修改目標中之目標材料中的至少一些轉換成發射EUV光之一電漿。該第一目標之該初始形狀受控制以藉此控制根據該第二光束與該經修改目標之間的該相互作用而產生的電漿之一量。In one aspect, an extreme ultraviolet (EUV) light source includes: a vacuum container; a target material supply system configured to supply targets into one of the vacuum containers, the targets including at least one first target , The first target has an initial shape at an initial target area in the vacuum container; a first optical source configured to provide a first light beam to a first target area in the vacuum container, The first beam is configured to modify the initial shape of the initial target to form a modified target; and a second optical source configured to provide a second beam to a second target in the vacuum vessel Zone, the second target zone is configured to receive the modified target, the second beam is configured to interact with the modified target and convert at least some of the target materials in the modified target to emit EUV One of the light plasma. The initial shape of the first target is controlled to thereby control an amount of plasma generated according to the interaction between the second light beam and the modified target.

實施方案可包括以下特徵中之一或多者。該目標材料可包括一熔融金屬，且該供應系統可包括：一儲集器，其經組態以固持該目標材料；一噴嘴，其經組態以流體地耦接至該儲集器且將該等目標發射至該真空容器之該內部中；及一致動器，其機械地連接至該噴嘴。該初始目標區處之該第一目標之該初始形狀可藉由致使該致動器以多於一個頻率使該噴嘴振動來控制。該第一目標與一第二目標之間的一間距可藉由調整施加至該儲集器中之該目標材料之一壓力來控制，且該第二目標可在該第一目標之前由該目標供應系統供應。該第一目標之該初始形狀可基於該第一目標與一第二目標之間的該受控間距。Implementations can include one or more of the following features. The target material may include a molten metal, and the supply system may include: a reservoir configured to hold the target material; a nozzle configured to be fluidly coupled to the reservoir and The targets are launched into the interior of the vacuum container; and an actuator, which is mechanically connected to the nozzle. The initial shape of the first target at the initial target zone can be controlled by causing the actuator to vibrate the nozzle at more than one frequency. A distance between the first target and a second target can be controlled by adjusting a pressure of the target material applied to the reservoir, and the second target can be controlled by the target before the first target Supply system supply. The initial shape of the first target may be based on the controlled distance between the first target and a second target.

在一些實施中，該EUV光源亦包括經組態以將一第三光束提供至一第三目標區之一第三光學源。在此等實施中，該第三目標區經組態以接收該第一目標，且該初始目標區處之該第一目標之該初始形狀係藉由使該第一目標與該第三光束相互作用而控制。該第三目標區可能比該第一目標區及該第二目標區更接近該目標材料供應系統。In some implementations, the EUV light source also includes a third optical source configured to provide a third light beam to a third target area. In these implementations, the third target area is configured to receive the first target, and the initial shape of the first target at the initial target area is achieved by making the first target and the third beam mutually Function and control. The third target area may be closer to the target material supply system than the first target area and the second target area.

該初始目標區處之該第一目標之該初始形狀可為熔融金屬之一扁圓球，該扁圓球具有沿著一第一方向之一第一範圍及沿著垂直於該第一方向之一第二方向之一第二範圍，且該第一範圍對該第二範圍之比率係可介於0.6與0.8之間。The initial shape of the first target at the initial target area may be an oblate sphere of molten metal, the oblate sphere having a first range along a first direction and a direction perpendicular to the first direction There is a second range in a second direction, and the ratio of the first range to the second range can be between 0.6 and 0.8.

該初始目標區處之該第一目標之該初始形狀可為熔融金屬之一扁圓球，該扁圓球具有沿著一第一方向之一第一範圍及沿著垂直於該第一方向之一第二方向之一第二範圍，且該第一範圍對該第二範圍之比率係可介於0.75與0.9之間。The initial shape of the first target at the initial target area may be an oblate sphere of molten metal, the oblate sphere having a first range along a first direction and a direction perpendicular to the first direction There is a second range in a second direction, and the ratio of the first range to the second range can be between 0.75 and 0.9.

該初始目標區處之該第一目標之該初始形狀可為熔融金屬之一扁圓球，該扁圓球具有沿著一第一方向之一第一範圍及沿著垂直於該第一方向之一第二方向之一第二範圍，且該第一範圍對該第二範圍之比率係可約為0.8。The initial shape of the first target at the initial target area may be an oblate sphere of molten metal, the oblate sphere having a first range along a first direction and a direction perpendicular to the first direction There is a second range in a second direction, and the ratio of the first range to the second range may be about 0.8.

該經修改目標可具有藉由該初始目標區處之該第一目標之該初始形狀判定之一形態，該形態描述在三維中該目標之一形狀及/或一目標材料密度。該經修改目標可包括在該三維中之一者中的一側向範圍，該側向範圍可取決於該第一目標區與該第二目標區之間的一距離。The modified target may have a form determined by the initial shape of the first target at the initial target area, the form describing a shape of the target in three dimensions and/or a target material density. The modified target may include a lateral range in one of the three dimensions, and the lateral range may depend on a distance between the first target zone and the second target zone.

該第一目標材料小滴之該初始形狀受控制以藉此控制根據該第二光束與該經修改目標之間的該相互作用而產生之電漿之一量可包括：該第一目標材料之該初始形狀受控制以藉此控制該EUV光源之一轉換效率(CE)，該CE為供應至該經修改目標之能量對作為EUV光自該電漿發射之能量的一比率。The initial shape of the first target material droplet is controlled to thereby control an amount of plasma generated according to the interaction between the second light beam and the modified target may include: the first target material The initial shape is controlled to thereby control a conversion efficiency (CE) of the EUV light source, which is a ratio of the energy supplied to the modified target to the energy emitted from the plasma as EUV light.

該初始目標區可介於該目標材料供應系統與該第一目標區之間。The initial target zone may be between the target material supply system and the first target zone.

在另一通用態樣中，一種控制一極紫外(EUV)光源中之轉換效率(CE)之方法包括：藉由控制該EUV光源之一組件來判定一初始目標之一初始形狀；致使一預脈衝光束與該初始目標相互作用以形成一經修改目標；及致使一主光學脈衝與該經修改目標相互作用以產生發射EUV光之一電漿。該經修改目標與該主光學脈衝之間的該相互作用係與一轉換效率(CE)相關聯，該CE為供應至該經修改目標之能量對作為EUV光自該電漿發射之能量的一比率，且該CE係基於該初始目標之該經判定初始形狀而控制。In another general aspect, a method of controlling the conversion efficiency (CE) in an extreme ultraviolet (EUV) light source includes: determining an initial shape of an initial target by controlling a component of the EUV light source; The pulsed beam interacts with the initial target to form a modified target; and causes a main optical pulse to interact with the modified target to generate a plasma that emits EUV light. The interaction between the modified target and the main optical pulse is associated with a conversion efficiency (CE), which is a ratio of the energy supplied to the modified target to the energy emitted from the plasma as EUV light Ratio, and the CE is controlled based on the determined initial shape of the initial target.

實施方案可包括以下特徵中之一或多者。該EUV光源之該組件可包括作為一目標材料供應系統之一部分的一儲集器，且判定該初始目標之該初始形狀可包括在由該目標供應系統產生該初始目標之前控制該儲集器中之熔融目標材料上的一壓力量。控制該儲集器中之該熔融目標材料上的該壓力量可控制該初始目標與另一目標之間的一間距，且該初始目標之該初始形狀可基於該間距。Implementations can include one or more of the following features. The component of the EUV light source may include a reservoir as part of a target material supply system, and determining the initial shape of the initial target may include controlling the reservoir before the initial target is generated by the target supply system The amount of pressure on the molten target material. Controlling the amount of pressure on the molten target material in the reservoir can control a distance between the initial target and another target, and the initial shape of the initial target can be based on the distance.

該EUV光源之該組件可為耦接至一目標材料供應系統之一毛細管之一致動器，且判定該初始目標之該初始形狀可包括控制該致動器使得該致動器以多於一個頻率使該管振動。控制該致動器使得該致動器以多於一個頻率使該管振動可自一目標材料射流產生一聚結目標串流，且該方法亦可包括調整該多於一個頻率中之一者使得該等聚結目標中之兩者合併成一合併目標，且該初始目標係該合併目標。The component of the EUV light source may be an actuator coupled to a capillary tube of a target material supply system, and determining the initial shape of the initial target may include controlling the actuator so that the actuator operates at more than one frequency Vibrate the tube. Controlling the actuator so that the actuator vibrates the tube at more than one frequency can generate a coalescing target stream from a target material jet, and the method may also include adjusting one of the more than one frequency such that Two of the coalescing targets are merged into a merged target, and the initial target is the merged target.

該EUV光源之該組件可包括經組態以供應該初始目標及至少一第二目標之一目標材料供應系統，且判定該初始目標之該初始形狀可包括控制該目標材料供應系統使得調整該初始目標與該第二目標之間的一間距，該第二目標在該初始目標之前由該目標供應系統供應。The component of the EUV light source may include a target material supply system configured to supply the initial target and at least one second target, and determining the initial shape of the initial target may include controlling the target material supply system to adjust the initial A distance between the target and the second target, the second target being supplied by the target supply system before the initial target.

該EUV光源之該組件可包括經組態以提供一初始光束之一初始光源，且判定該初始目標之該初始形狀可包括控制該初始光源使得該初始光束與該初始目標相互作用，且該初始目標之該初始形狀可藉由使該初始目標與該初始光束相互作用而至少部分地判定。The component of the EUV light source may include an initial light source configured to provide an initial light beam, and determining the initial shape of the initial target may include controlling the initial light source so that the initial light beam interacts with the initial target, and the initial The initial shape of the target can be determined at least in part by making the initial target interact with the initial light beam.

上文所描述之技術中之任一者的實施可包括EUV光源、系統、方法、程序、器件或裝置。以下隨附圖式及描述中闡述一或多個實施之細節。其他特徵將自描述及圖式及自申請專利範圍而顯而易見。The implementation of any of the technologies described above may include EUV light sources, systems, methods, programs, devices, or devices. One or more implementation details are set forth in the accompanying drawings and description below. Other features will be apparent from the description and drawings and the scope of self-applying patents.

參看圖1，展示極紫外(EUV)光源100之方塊圖。該EUV光源100為EUV微影系統101之一部分，該EUV微影系統101包括輸出裝置199 (諸如微影裝置)，該輸出裝置199接收由EUV光源100產生之曝光光束198。目標串流121係由目標供應系統110產生且朝向目標區124_2行進。串流121中之每一目標皆包括在電漿狀態中發射EUV光的目標材料。揭示了用於藉由控制初始目標形狀來控制光源100之轉換效率(CE)之技術。初始目標形狀為在與光脈衝104_2 (其亦被稱作預脈衝)相互作用之前的串流121中之目標之形狀。Referring to FIG. 1, a block diagram of an extreme ultraviolet (EUV) light source 100 is shown. The EUV light source 100 is a part of the EUV lithography system 101. The EUV lithography system 101 includes an output device 199 (such as a lithography device), and the output device 199 receives the exposure light beam 198 generated by the EUV light source 100. The target stream 121 is generated by the target supply system 110 and travels toward the target area 124_2. Each target in the stream 121 includes a target material that emits EUV light in a plasma state. A technique for controlling the conversion efficiency (CE) of the light source 100 by controlling the initial target shape is disclosed. The initial target shape is the shape of the target in the stream 121 before interacting with the light pulse 104_2 (which is also referred to as a pre-pulse).

在圖1中所展示之實例中，初始目標121p (其為串流121中之目標中之一者)係在目標區124_2中。光脈衝104_2與初始目標121p相互作用以形成經修改目標121m。舉例而言，經修改目標121m可為與目標121p相比在x-y平面中具有更大範圍且與初始目標121p相比沿著z軸具有更小範圍的目標材料之圓盤形分佈。經修改目標121m可為在三維中與初始目標121p相比具有更大體積的粒子雲狀物或霧狀物。經修改目標121m與光脈衝104_1 (亦被稱作主脈衝)相互作用以形成發射光197 (其包括EUV光193)之電漿196。經修改目標121m具有判定或影響經修改目標121m中之多少目標材料轉換成電漿196的形態或形態特性。轉換效率(CE)為由光脈衝104_1供應至經修改目標121m之能量對作為EUV光193自電漿196發射的能量之量之比率。因為經修改目標121m之形態影響轉換成電漿196之目標材料之量，所以經修改目標121m之形態影響所產生之EUV光193之量且因此亦影響CE。In the example shown in FIG. 1, the initial target 121p (which is one of the targets in the stream 121) is in the target area 124_2. The light pulse 104_2 interacts with the initial target 121p to form a modified target 121m. For example, the modified target 121m may be a disc-shaped distribution of target material that has a larger range in the x-y plane than the target 121p and a smaller range along the z-axis than the original target 121p. The modified target 121m may be a cloud or mist of particles having a larger volume than the original target 121p in three dimensions. The modified target 121m interacts with the light pulse 104_1 (also referred to as the main pulse) to form a plasma 196 that emits light 197 (which includes EUV light 193). The modified target 121m has a morphology or morphological characteristic that determines or affects how much target material in the modified target 121m is converted into plasma 196. The conversion efficiency (CE) is the ratio of the energy supplied by the light pulse 104_1 to the modified target 121m to the amount of energy emitted from the plasma 196 as EUV light 193. Because the morphology of the modified target 121m affects the amount of target material converted into plasma 196, the morphology of the modified target 121m affects the amount of EUV light 193 generated and therefore also CE.

EUV光源100包括控制系統150，該控制系統控制初始目標形狀以藉此控制經修改目標121m之形態且因此控制CE。在以下論述中，最終目標為用於產生電漿196之目標。在圖1之實例中，經修改目標121m為最終目標。最終目標之形態描述例如在至少一個維度中最終目標中之目標材料的空間配置或形狀及/或最終目標中之目標材料的密度。在一些實施中，最終目標之形態描述最終目標在三維中之密度。The EUV light source 100 includes a control system 150 that controls the initial target shape to thereby control the shape of the modified target 121m and thus the CE. In the following discussion, the ultimate goal is the goal for generating plasma 196. In the example of FIG. 1, the modified target 121m is the final target. The shape of the final target describes, for example, the spatial configuration or shape of the target material in the final target in at least one dimension and/or the density of the target material in the final target. In some implementations, the shape of the final target describes the density of the final target in three dimensions.

初始目標121p為串流121中的在目標區124_2中但尚未與光脈衝104_2相互作用的目標。初始目標之形狀亦被稱為初始目標形狀。初始目標121p在真空腔室中所處之部位可被稱作初始目標區。在圖1之實例中，初始目標121p之形狀為初始目標形狀，且初始目標區為初始目標121p恰好在與光脈衝104_2相互作用之前的區。串流121中之各種目標可具有不同的形狀。舉例而言，串流121中之一些目標可為大體上球形小滴且初始目標121p可具有非球形形狀。因此，即使串流121中之一些目標為球形小滴，初始目標形狀亦可能為非球形。The initial target 121p is a target in the stream 121 that is in the target area 124_2 but has not yet interacted with the light pulse 104_2. The shape of the initial target is also called the initial target shape. The part where the initial target 121p is located in the vacuum chamber may be referred to as the initial target area. In the example of FIG. 1, the shape of the initial target 121p is the initial target shape, and the initial target area is the area of the initial target 121p just before the interaction with the light pulse 104_2. The various objects in the stream 121 may have different shapes. For example, some targets in the stream 121 may be substantially spherical droplets and the initial target 121p may have a non-spherical shape. Therefore, even if some targets in the stream 121 are spherical droplets, the initial target shape may be non-spherical.

控制系統150藉由控制初始目標形狀來控制最終目標之形態。控制系統150藉由例如以下操作來控制初始目標形狀：調整施加至儲集器118中之目標材料之壓力p；控制機械地耦接至目標供應系統110之調變器132振動之頻率以藉此在串流121中之個別目標之間引入相對運動，使得該等目標在到達目標區124_2之前合併以形成具有特定形狀之較大目標；及/或使初始目標與第三光脈衝(諸如圖2之光脈衝204_3)相互作用。在更詳細地論述此等各種技術之前提供對EUV光源100之綜述。The control system 150 controls the shape of the final target by controlling the initial target shape. The control system 150 controls the initial target shape by, for example, the following operations: adjust the pressure p applied to the target material in the reservoir 118; control the frequency of vibration of the modulator 132 mechanically coupled to the target supply system 110 to thereby Introduce relative motion between the individual targets in the stream 121, so that the targets merge before reaching the target area 124_2 to form a larger target with a specific shape; and/or make the initial target and the third light pulse (such as FIG. 2 The light pulse 204_3) interacts. An overview of EUV light source 100 is provided before discussing these various technologies in more detail.

串流121中之目標彼此空間上分離且彼此空間上相異。在光源100之預期操作條件下，串流121中之目標一次一個地進入目標區124_2。目標區124_2亦接收光脈衝104_2。光脈衝104_2與初始目標121p之間的相互作用形成經修改目標121m。光脈衝104_2與初始目標121p之間的相互作用可增強經修改目標121m吸收光脈衝104_1的能力。舉例而言，光脈衝104_2與初始目標121p之間的相互作用可改變目標材料之分佈之形狀、體積及/或大小及/或可縮減目標材料沿著主脈衝104_1之傳播方向之密度梯度。空間特性之改變亦可造成實體特性改變。舉例而言，若經修改目標121m在至少一個維度中大於初始目標121p，則目標材料在彼維度中散開，且在彼維度中目標材料之密度與初始目標121p沿著同一維度之密度相比較低。The objects in the stream 121 are spatially separated and different from each other. Under the expected operating conditions of the light source 100, the targets in the stream 121 enter the target area 124_2 one at a time. The target area 124_2 also receives the light pulse 104_2. The interaction between the light pulse 104_2 and the initial target 121p forms a modified target 121m. The interaction between the light pulse 104_2 and the initial target 121p can enhance the ability of the modified target 121m to absorb the light pulse 104_1. For example, the interaction between the light pulse 104_2 and the initial target 121p can change the shape, volume and/or size of the distribution of the target material and/or can reduce the density gradient of the target material along the propagation direction of the main pulse 104_1. Changes in spatial characteristics can also cause changes in physical characteristics. For example, if the modified target 121m is larger than the original target 121p in at least one dimension, the target material is scattered in that dimension, and the density of the target material in that dimension is lower than the density of the original target 121p along the same dimension .

目標區124_2係介於目標供應系統110與目標區124_1之間。經修改目標121m大體上沿著x方向漂移至目標區124_1且由光脈衝104_1輻照。經修改目標121m與光脈衝104_1之間的相互作用將經修改目標121m中之目標材料中的至少一些轉換成發射光197之電漿196。經由經修改目標121m與光束104_1之間的相互作用產生電漿196被稱作電漿產生事件。The target area 124_2 is between the target supply system 110 and the target area 124_1. The modified target 121m generally drifts along the x direction to the target area 124_1 and is irradiated by the light pulse 104_1. The interaction between the modified target 121m and the light pulse 104_1 converts at least some of the target material in the modified target 121m into a plasma 196 that emits light 197. The generation of plasma 196 through the interaction between the modified target 121m and the light beam 104_1 is referred to as a plasma generation event.

光197包括具有對應於目標材料之發射譜線之波長的EUV光193。EUV範圍可包括具有例如5奈米(nm)、5 nm至20 nm、10 nm至120 nm或小於50 nm之波長的光。光197亦可包括不在EUV範圍內之波長。處於不在EUV範圍內之波長的光被稱作帶外光。舉例而言，目標材料可包括錫。在此等實施中，光197包括EUV光且亦包括帶外光，諸如深紫外(DUV)光、可見光、近紅外(NIR)光、中間波長紅外(MWIR)光，及/或長波長紅外(LWIR)光。DUV光可包括具有在約120 nm至300 nm之間的波長的光，可見光可包括具有在約390 nm至750 nm之間的波長的光，NIR光可包括具有在約750 nm至2500 nm之間的波長的光，MWIR光可具有在約3000 nm至5000 nm之間的波長的光，且LWIR光可具有在約8000 nm至12000 nm之間的波長的光。The light 197 includes EUV light 193 having a wavelength corresponding to the emission line of the target material. The EUV range may include light having a wavelength of, for example, 5 nanometers (nm), 5 nm to 20 nm, 10 nm to 120 nm, or less than 50 nm. The light 197 may also include wavelengths that are not within the EUV range. Light at a wavelength not in the EUV range is called out-of-band light. For example, the target material may include tin. In these implementations, the light 197 includes EUV light and also includes out-of-band light, such as deep ultraviolet (DUV) light, visible light, near infrared (NIR) light, intermediate wavelength infrared (MWIR) light, and/or long-wavelength infrared ( LWIR) light. DUV light may include light having a wavelength between about 120 nm and 300 nm, visible light may include light having a wavelength between about 390 nm and 750 nm, and NIR light may include light having a wavelength between about 750 nm and 2500 nm. The MWIR light may have a wavelength between about 3000 nm and 5000 nm, and the LWIR light may have a wavelength between about 8000 nm and 12000 nm.

EUV光源100包括真空腔室109中之光學元件113。光學元件113經定位成收集光193中的至少一些以形成曝光光束198。光學元件113可為例如具有面向目標區124_1之反射表面116的彎曲鏡面。光學元件113亦可包括允許光脈衝(諸如光脈衝104_1)到達目標區124_1的孔隙(圖中未繪示)。反射表面116接收及反射光193中之至少一些以形成曝光光束198。反射表面116具有塗層或其他光學機構使得光學元件113反射在EUV範圍內之波長但不反射光197之帶外分量，或僅反射光197之標稱量的帶外分量。以此方式，曝光光束198主要包括EUV光且包括很少或不包括帶外光。微影裝置199使用EUV曝光光束198以曝光基板195 (例如矽晶圓)，以藉此在基板195上形成電子特徵。The EUV light source 100 includes an optical element 113 in a vacuum chamber 109. The optical element 113 is positioned to collect at least some of the light 193 to form an exposure beam 198. The optical element 113 may be, for example, a curved mirror surface having a reflective surface 116 facing the target area 124_1. The optical element 113 may also include an aperture (not shown in the figure) that allows light pulses (such as light pulses 104_1) to reach the target area 124_1. The reflective surface 116 receives and reflects at least some of the light 193 to form an exposure beam 198. The reflective surface 116 has a coating or other optical mechanism so that the optical element 113 reflects the wavelength in the EUV range but does not reflect the out-of-band component of the light 197, or only reflects the out-of-band component of the nominal amount of the light 197. In this way, the exposure beam 198 mainly includes EUV light and includes little or no out-of-band light. The lithography device 199 uses the EUV exposure beam 198 to expose a substrate 195 (such as a silicon wafer) to thereby form electronic features on the substrate 195.

光脈衝104_1為作為光束106_1之一部分的單一光脈衝。光束106_1為一脈衝列，該等脈衝中之每一者在時間上與鄰近脈衝分離。脈衝104_1具有有限時距，被稱作脈衝持續時間。脈衝持續時間可為在此期間光脈衝104_1具有非零光功率的總時間。其他度量可用以描述脈衝持續時間。舉例而言，脈衝持續時間可小於期間光脈衝104_1具有非零功率的時間，諸如脈衝104_1之半高全寬(FWHM)。光束106_1係由光學源108_1形成且由光束遞送系統105_1遞送至目標區124_1。The light pulse 104_1 is a single light pulse as a part of the light beam 106_1. The beam 106_1 is a pulse train, and each of the pulses is separated in time from adjacent pulses. The pulse 104_1 has a finite time span, which is called the pulse duration. The pulse duration may be the total time during which the optical pulse 104_1 has non-zero optical power. Other metrics can be used to describe pulse duration. For example, the pulse duration may be less than the time during which the light pulse 104_1 has non-zero power, such as the full width at half maximum (FWHM) of the pulse 104_1. The light beam 106_1 is formed by the optical source 108_1 and delivered to the target area 124_1 by the light beam delivery system 105_1.

光脈衝104_2為光束106_2中之單一光脈衝，其包括在時間上分離的脈衝列。光脈衝104_2具有有限時距。光脈衝104_2係由光學源108_2形成、沿著光束路徑107_2傳播，且經由光束遞送系統105_2遞送至目標區124_2。The light pulse 104_2 is a single light pulse in the light beam 106_2, which includes a pulse train separated in time. The light pulse 104_2 has a finite time span. The light pulse 104_2 is formed by the optical source 108_2, propagates along the beam path 107_2, and is delivered to the target area 124_2 via the beam delivery system 105_2.

光學源108_1及108_2為光學系統或光產生模組108之部分。舉例而言，光學源108_1及108_2可為兩個雷射。舉例而言，光學源108_1、108_2可為兩個二氧化碳(CO₂ )雷射。在其他實施中，光學源108_1、108_2可為不同類型之雷射。舉例而言，光學源108_2可為固態雷射，且光學源108_1可為CO₂ 雷射。第一光束106_1及第二光束106_2可具有不同波長。舉例而言，在光學源108_1、108_2包括兩個CO₂ 雷射之實施中，第一光束106_1之波長可為約10.26微米(µm)且第二光束106_2之波長可介於10.18 µm與10.26 µm之間。第二光束106_2之波長可為約10.59 µm。在此等實施中，自CO₂ 雷射之不同線產生光束106_1、106_2，從而導致該等光束106_1、106_2具有不同波長，儘管兩個光束皆自同一類型之源產生。The optical sources 108_1 and 108_2 are part of the optical system or light generating module 108. For example, the optical sources 108_1 and 108_2 can be two lasers. For example, the optical sources 108_1 and 108_2 may be two carbon dioxide (CO ₂ ) lasers. In other implementations, the optical sources 108_1 and 108_2 may be different types of lasers. For example, the optical source 108_2 may be a solid-state laser, and the optical source 108_1 may be a CO ₂ laser. The first light beam 106_1 and the second light beam 106_2 may have different wavelengths. For example, in an implementation where the optical sources 108_1 and 108_2 include two CO ₂ lasers, the wavelength of the first beam 106_1 may be about 10.26 micrometers (µm) and the wavelength of the second beam 106_2 may be between 10.18 µm and 10.26 µm between. The wavelength of the second light beam 106_2 may be about 10.59 µm. In these implementations, the _{light beams 106_1, 106_2 are generated from different lines of the CO 2} laser, resulting in the light beams 106_1, 106_2 having different wavelengths, even though the two light beams are generated from the same type of source.

光脈衝104_2可具有1皮秒(ps)至100奈秒(ns)之持續時間，舉例而言，脈衝104_2可具有1 ns至100 ns之持續時間及約1 µm或10.6 µm之波長。在一些實施中，脈衝104_2為具有約1 mJ至100 mJ之能量、約1 ns至70 ns之脈衝持續時間及約1 µm至10.6 µm之波長的雷射脈衝。在此等實施中，經修改目標121m可為大體上圓盤形目標。在一些實施中，脈衝104_2具有小於1 ns之持續時間及1 µm之波長。舉例而言，脈衝104_2可具有300 ps或更小、100 ps或更小、100 ps至300 ps之間或10 ps至100 ps之間的持續時間。在此等實施中，經修改目標121m可為目標材料之粒子雲狀物或霧狀物。The light pulse 104_2 may have a duration of 1 picosecond (ps) to 100 nanoseconds (ns). For example, the pulse 104_2 may have a duration of 1 ns to 100 ns and a wavelength of about 1 µm or 10.6 µm. In some implementations, the pulse 104_2 is a laser pulse having an energy of about 1 mJ to 100 mJ, a pulse duration of about 1 ns to 70 ns, and a wavelength of about 1 µm to 10.6 µm. In such implementations, the modified target 121m may be a substantially disc-shaped target. In some implementations, the pulse 104_2 has a duration of less than 1 ns and a wavelength of 1 µm. For example, the pulse 104_2 may have a duration of 300 ps or less, 100 ps or less, 100 ps to 300 ps, or 10 ps to 100 ps. In these implementations, the modified target 121m may be a cloud or mist of particles of the target material.

光束遞送系統105_1、105_2包括各別光學系統112_1、112_2。光學系統112_1、112_2包括能夠與各別光束106_1、106_2相互作用的一或多個光學元件或組件。舉例而言，光學組件元件或組件可包括被動光學器件，諸如鏡面、透鏡及/或稜鏡，及任何相關聯機械安裝器件及/或電子驅動器。此等組件可轉向及/或聚焦光束106_1。另外，光學元件或組件可包括修改光束之一或多個屬性以形成及/或修改光脈衝的組件。舉例而言，光學組件可包括能夠改變光束106_1或光束106_2之時間量變曲線以分別形成光脈衝104_1或光脈衝104_2的主動光學器件，諸如聲光調變器及/或電光調變器。在圖1之實例中，光束106_1及光束106_2分別與單獨光束遞送系統105_1、105_2相互作用且分別在單獨光學路徑107_1、107_2上行進。然而，在其他實施中，光束106_1及106_2共用同一光學路徑之全部或部分且亦可共用同一光束遞送系統。The beam delivery systems 105_1, 105_2 include respective optical systems 112_1, 112_2. The optical systems 112_1, 112_2 include one or more optical elements or components capable of interacting with the respective light beams 106_1, 106_2. For example, optical components or components may include passive optical devices, such as mirrors, lenses, and/or ridges, and any associated mechanical mounting devices and/or electronic drivers. These components can steer and/or focus the beam 106_1. In addition, optical elements or components may include components that modify one or more of the properties of the light beam to form and/or modify light pulses. For example, the optical component may include active optical devices, such as an acousto-optic modulator and/or an electro-optic modulator, capable of changing the time-quantity curve of the light beam 106_1 or the light beam 106_2 to form the light pulse 104_1 or the light pulse 104_2, respectively. In the example of FIG. 1, the beam 106_1 and the beam 106_2 interact with the individual beam delivery systems 105_1, 105_2, and travel on the individual optical paths 107_1, 107_2, respectively. However, in other implementations, the beams 106_1 and 106_2 share all or part of the same optical path and can also share the same beam delivery system.

EUV光源100亦包括將目標串流121發射至真空腔室109中之目標供應系統110。目標供應系統110包括目標形成結構117，該目標形成結構包括界定孔口119之噴嘴。在操作使用中，孔口119在壓力p下流體地耦接至含有目標混合物111之儲集器118。目標供應系統110亦包括壓力系統170。舉例而言，壓力系統170包括泵、氣體供應器、閥，及/或能夠增大、減低或維持施加至儲集器118中之目標混合物111之壓力p的其他器件。The EUV light source 100 also includes a target supply system 110 that emits the target stream 121 into the vacuum chamber 109. The target supply system 110 includes a target forming structure 117 that includes a nozzle that defines an orifice 119. In operational use, the orifice 119 is fluidly coupled to the reservoir 118 containing the target mixture 111 under pressure p. The target supply system 110 also includes a pressure system 170. For example, the pressure system 170 includes pumps, gas supplies, valves, and/or other devices capable of increasing, decreasing, or maintaining the pressure p of the target mixture 111 applied to the reservoir 118.

目標混合物111包括目標材料，其為剛處於電漿狀態中時具有在EUV範圍內之發射譜線的任何材料。舉例而言，目標材料可為錫、鋰或氙。其他材料可用作目標材料。舉例而言，元素錫可用作純錫(Sn)；用作錫化合物，例如SnBr₄ 、SnBr₂ 、SnH₄ ；用作錫合金，例如錫-鎵合金、錫-銦合金、錫-銦-鎵合金或此等合金之任何組合。目標混合物亦可包括雜質，諸如非目標粒子或夾雜粒子，例如氧化錫(SnO₂ )粒子或鎢(W)粒子。The target mixture 111 includes a target material, which is any material that has an emission line within the EUV range when it is in a plasma state. For example, the target material can be tin, lithium or xenon. Other materials can be used as target materials. For example, elements can be used as pure tin, tin (of Sn); as tin compounds, e.g. _{_{_{SnBr 4, SnBr 2, SnH 4}}} ; as tin alloys such as tin - gallium alloy, tin - indium alloys, tin - indium - Gallium alloy or any combination of these alloys. The target mixture may also include impurities, such as non-target particles or inclusion particles, such as tin oxide (SnO ₂ ) particles or tungsten (W) particles.

在圖1中所展示之實施中，結構117包括大體上沿著x方向延伸至孔口119之毛細管114。孔口119處於毛細管114之末端處且在真空腔室109中。毛細管114可由例如呈熔融矽石或石英之形式的玻璃製成。目標混合物111呈能夠流動之形式。舉例而言，在目標混合物111包括在室溫下為固體的金屬(諸如錫)之實施中，金屬被加熱至處於或高於該金屬之熔點之溫度且維持處於該溫度使得目標混合物111中之目標呈液體形式。因此，目標混合物111流動通過毛細管114且經由孔口119噴射至腔室109中。拉普拉斯(Laplace)壓力為形成氣體區與液體區之間的邊界之彎曲表面之內部與外部之間的壓力差。該壓力差係由液體與氣體之間的界面之表面張力造成。當壓力p大於拉普拉斯壓力時，目標混合物111作為連續射流125射出孔口119。In the implementation shown in FIG. 1, the structure 117 includes a capillary 114 extending generally along the x-direction to the orifice 119. The orifice 119 is at the end of the capillary 114 and in the vacuum chamber 109. The capillary 114 may be made of, for example, glass in the form of fused silica or quartz. The target mixture 111 is in a flowable form. For example, in an implementation where the target mixture 111 includes a metal (such as tin) that is solid at room temperature, the metal is heated to a temperature at or above the melting point of the metal and maintained at that temperature such that the target mixture 111 The target is in liquid form. Therefore, the target mixture 111 flows through the capillary 114 and is ejected into the chamber 109 through the orifice 119. Laplace pressure is the pressure difference between the inside and outside of the curved surface that forms the boundary between the gas zone and the liquid zone. The pressure difference is caused by the surface tension of the interface between the liquid and the gas. When the pressure p is greater than the Laplace pressure, the target mixture 111 is ejected from the orifice 119 as a continuous jet 125.

射流125根據液體射流之瑞立-高原(Rayleigh-Plateau)不穩定性分解成個別目標。在圖1之實施中，毛細管114之側壁115機械地耦接至致動器132。舉例而言，致動器132可為回應於所施加電壓信號而擴展及收縮以藉此造成側壁115之變形的壓電致動器。藉由使側壁115變形，在供應系統110中之目標混合物111中形成壓力波，且調變供應系統110中之目標混合物111之壓力。壓力調變控制射流125分解成小滴，使得個別小滴聚結成較大小滴，該等較大小滴以所要速率且具有某些特性而到達目標區124_2。舉例而言，可以特定方式控制致動器132之動作以控制串流121中之目標之初始形狀，如關於圖3及圖5更詳細論述。The jet 125 is decomposed into individual targets according to the Rayleigh-Plateau instability of the liquid jet. In the implementation of FIG. 1, the side wall 115 of the capillary 114 is mechanically coupled to the actuator 132. For example, the actuator 132 may be a piezoelectric actuator that expands and contracts in response to an applied voltage signal to thereby cause deformation of the side wall 115. By deforming the side wall 115, a pressure wave is formed in the target mixture 111 in the supply system 110, and the pressure of the target mixture 111 in the supply system 110 is adjusted. The pressure modulation control jet 125 breaks down into droplets, so that individual droplets coalesce into larger droplets, and the larger droplets reach the target area 124_2 at a desired rate and have certain characteristics. For example, the action of the actuator 132 can be controlled in a specific manner to control the initial shape of the target in the stream 121, as discussed in more detail with respect to FIGS. 3 and 5.

在圖1及圖2中，虛線指示包括資料及資訊之電信號流動所沿著的通信路徑或資料鏈路。該等通信路徑或資料鏈路屬於能夠傳輸資料之任何類型之連接。舉例而言，資料鏈路或通信路徑可為經組態以傳輸包括資料及/或資訊之電子信號及命令的有線及/或無線連接。目標供應系統110經由資料鏈路152耦接至控制系統150。控制系統150經組態以藉由經由資料鏈路152將命令信號129發送至目標供應系統110而控制目標供應系統110之各種組件。In FIG. 1 and FIG. 2, the dotted line indicates the communication path or data link along which the electric signal including data and information flows. These communication paths or data links belong to any type of connection capable of transmitting data. For example, the data link or communication path may be a wired and/or wireless connection configured to transmit electronic signals and commands including data and/or information. The target supply system 110 is coupled to the control system 150 via the data link 152. The control system 150 is configured to control various components of the target supply system 110 by sending the command signal 129 to the target supply system 110 via the data link 152.

舉例而言，在一些實施中，致動器132經由資料鏈路152耦接至控制系統150。在此等實施中，控制系統150產生被提供至致動器132之命令信號129。當將命令信號129施加至致動器132或施加至與致動器132相關聯之元件時，致動器132以藉由命令信號129之內容控管之方式移動。舉例而言，致動器132可為基於施加電壓來改變形狀的壓電陶瓷材料。在此等實施中，控制系統150產生經遞送至致動器132之電壓波形。施加至致動器132之波形之量值及/或極性係基於來自控制系統150之信號。歸因於毛細管114與致動器132之間的機械耦接，當致動器132移動或振動時，側壁115變形，且毛細管114中之目標混合物111之壓力經調變。For example, in some implementations, the actuator 132 is coupled to the control system 150 via the data link 152. In these implementations, the control system 150 generates a command signal 129 that is provided to the actuator 132. When the command signal 129 is applied to the actuator 132 or an element associated with the actuator 132, the actuator 132 moves in a manner controlled by the content of the command signal 129. For example, the actuator 132 may be a piezoelectric ceramic material that changes shape based on an applied voltage. In these implementations, the control system 150 generates a voltage waveform that is delivered to the actuator 132. The magnitude and/or polarity of the waveform applied to the actuator 132 is based on the signal from the control system 150. Due to the mechanical coupling between the capillary 114 and the actuator 132, when the actuator 132 moves or vibrates, the side wall 115 is deformed, and the pressure of the target mixture 111 in the capillary 114 is adjusted.

在一些實施中，控制系統150由資料鏈路152耦接至壓力系統170。控制系統150藉由將命令信號129發送至壓力系統170來控制壓力p。此外，控制系統150可耦接至致動器132及壓力系統170兩者及/或供應系統110內之耦接至致動器132及壓力系統170之組件，使得控制系統150經組態以控制致動器132及壓力系統170。In some implementations, the control system 150 is coupled to the pressure system 170 by the data link 152. The control system 150 controls the pressure p by sending a command signal 129 to the pressure system 170. In addition, the control system 150 can be coupled to both the actuator 132 and the pressure system 170 and/or the components in the supply system 110 that are coupled to the actuator 132 and the pressure system 170, so that the control system 150 is configured to control Actuator 132 and pressure system 170.

控制系統150包括電子處理器模組154、電子儲存器156及I/O介面158。電子處理器模組154包括適合於執行電腦程式之一或多個處理器，諸如通用或專用微處理器，及任何種類之數位電腦之任一或多個處理器。通常，電子處理器自唯讀記憶體、隨機存取記憶體(RAM)或此兩者接收指令及資料。電子處理器模組154可包括任何類型之電子處理器。電子處理器模組154之電子處理器中之一或多者執行儲存於電子儲存器156上之命令信號指令。命令信號指令管控命令信號129之形成。The control system 150 includes an electronic processor module 154, an electronic storage 156, and an I/O interface 158. The electronic processor module 154 includes one or more processors suitable for executing computer programs, such as general-purpose or special-purpose microprocessors, and any one or more processors of any type of digital computer. Generally, electronic processors receive commands and data from read-only memory, random access memory (RAM), or both. The electronic processor module 154 may include any type of electronic processor. One or more of the electronic processors of the electronic processor module 154 executes the command signal instructions stored in the electronic storage 156. The command signal instructs and controls the formation of the command signal 129.

電子儲存器156可為諸如RAM之揮發性記憶體，或非揮發性記憶體。在一些實施中，且電子儲存器156包括非揮發性及揮發性部分或組件。電子儲存器156可儲存用於控制系統150之操作的資料及資訊。舉例而言，電子儲存器156可儲存使初始目標形狀與最終目標之形態相關的資訊。The electronic storage 156 may be a volatile memory such as RAM, or a non-volatile memory. In some implementations, the electronic storage 156 includes non-volatile and volatile parts or components. The electronic storage 156 can store data and information used to control the operation of the system 150. For example, the electronic storage 156 may store information related to the shape of the initial target and the shape of the final target.

電子儲存器156亦可儲存諸如命令信號指令之指令作為指令或電腦程式之集合，該等指令或該電腦程式在經執行時致使電子處理器模組154產生命令信號129且與供應系統110通信。在另一實例中，電子儲存器156可儲存在經執行時致使控制系統150與單獨機器相互作用之指令。舉例而言，控制系統150可與位於同一工場或設施中之其他EUV光源相互作用。The electronic storage 156 can also store instructions such as command signal instructions as a collection of instructions or computer programs, which, when executed, cause the electronic processor module 154 to generate a command signal 129 and communicate with the supply system 110. In another example, the electronic storage 156 may store instructions that, when executed, cause the control system 150 to interact with a separate machine. For example, the control system 150 can interact with other EUV light sources located in the same workshop or facility.

I/O介面158為允許控制系統150與操作員、光學源108_1、光學源108_1之一或多個組件、微影裝置199及/或執行於另一電子器件上之自動處理程序交換資料及信號的任何種類之介面。I/O介面158可包括視覺顯示器、鍵盤及諸如平行埠、通用串列匯流排(USB)連接之通信介面及/或諸如(例如)乙太網路之任何類型之網路介面中的一或多者。I/O介面158亦可允許在無實體接觸的情況下經由例如IEEE 802.11、藍芽或近場通信(NFC)連接進行通信。The I/O interface 158 allows the control system 150 to exchange data and signals with the operator, one or more components of the optical source 108_1, the optical source 108_1, the lithography device 199, and/or an automatic processing program executed on another electronic device Of any kind of interface. The I/O interface 158 may include one of a visual display, a keyboard, and a communication interface such as a parallel port, a universal serial bus (USB) connection, and/or any type of network interface such as, for example, Ethernet. More. The I/O interface 158 may also allow communication via, for example, IEEE 802.11, Bluetooth, or Near Field Communication (NFC) connections without physical contact.

EUV光源100亦可包括感測器系統130，該感測器系統將包括與光197或EUV光193相關之資料之信號157提供至控制系統150。感測器系統130包括能夠偵測光197之一或多個波長之感測器135。感測器135可為能夠偵測或感測光197中之波長中之任一者之存在的感測器。因此，感測器135可為能夠偵測EUV光之感測器或能夠偵測帶外光之一或多個波長之感測器。在包括感測器系統130之實施中，儲存於電子儲存器156上之指令可包括在經執行時分析來自感測器系統130之信號157且使用關於光197之資訊以告知對串流121中之目標之初始形狀之調整的指令。The EUV light source 100 may also include a sensor system 130 that provides a signal 157 including data related to the light 197 or EUV light 193 to the control system 150. The sensor system 130 includes a sensor 135 capable of detecting one or more wavelengths of light 197. The sensor 135 may be a sensor capable of detecting or sensing the presence of any of the wavelengths in the light 197. Therefore, the sensor 135 may be a sensor capable of detecting EUV light or a sensor capable of detecting one or more wavelengths of out-of-band light. In an implementation that includes the sensor system 130, the instructions stored on the electronic storage 156 may include analyzing the signal 157 from the sensor system 130 when executed and using information about the light 197 to inform the stream 121 Instructions for adjusting the initial shape of the target.

圖2為作為EUV微影系統201之一部分的EUV光源200之方塊圖。該EUV光源200為EUV光源之另一實例。該EUV光源200與EUV光源100 (圖1)相同，惟該EUV光源200使用第三光脈衝204_3以控制初始目標121p之初始形狀除外。FIG. 2 is a block diagram of the EUV light source 200 as a part of the EUV lithography system 201. The EUV light source 200 is another example of EUV light source. The EUV light source 200 is the same as the EUV light source 100 (FIG. 1), except that the EUV light source 200 uses the third light pulse 204_3 to control the initial shape of the initial target 121p.

第三光脈衝204_3為由光學源208_3產生且由光束遞送系統205_3引導至目標區224_3的光束206_3之一部分。光束遞送系統205_3與光束遞送系統105_1及105_2相似，惟光束遞送系統205_3之光學元件具有允許與光束206_3相互作用之光譜特徵除外。目標區224_3係介於目標區124_2與孔口119之間。第三光脈衝204_3與目標221i之間的相互作用會修改在與光脈衝104_2相互作用之前的目標221i之幾何屬性。目標221i為串流121 (圖1)中之目標。在與脈衝204_3相互作用之後，目標221i與串流121中之其他目標一起朝向目標區124_2漂移。因此，第三光脈衝204_3用以控制或修改串流121中之目標之初始目標形狀。The third light pulse 204_3 is a part of the light beam 206_3 generated by the optical source 208_3 and guided by the light beam delivery system 205_3 to the target area 224_3. The beam delivery system 205_3 is similar to the beam delivery systems 105_1 and 105_2, except that the optical elements of the beam delivery system 205_3 have spectral characteristics that allow interaction with the beam 206_3. The target area 224_3 is between the target area 124_2 and the orifice 119. The interaction between the third light pulse 204_3 and the target 221i will modify the geometric properties of the target 221i before the interaction with the light pulse 104_2. The target 221i is the target in the stream 121 (FIG. 1). After interacting with the pulse 204_3, the target 221i drifts toward the target area 124_2 together with other targets in the stream 121. Therefore, the third light pulse 204_3 is used to control or modify the initial target shape of the target in the stream 121.

可藉由控制光束206_3之特性來控制初始目標形狀。舉例而言，可藉由控制與目標221i相互作用之光脈衝204_3之強度及/或時距來控制初始目標形狀。控制系統150耦接至光學源208_3及/或光束遞送系統205_3，且控制系統150可藉由控制光學源208_3及/或光束遞送系統205_3來控制光脈衝204_3之特性(例如光脈衝204_3之依據時間而變化的強度)。亦可藉由控制光脈衝204_3與目標221i之間的位置重疊來控制初始目標形狀，舉例而言，光脈衝204_3可經引導為撞擊目標221i之一側而非撞擊目標221i之中心。The initial target shape can be controlled by controlling the characteristics of the beam 206_3. For example, the initial target shape can be controlled by controlling the intensity and/or time interval of the light pulse 204_3 interacting with the target 221i. The control system 150 is coupled to the optical source 208_3 and/or the beam delivery system 205_3, and the control system 150 can control the optical source 208_3 and/or the beam delivery system 205_3 to control the characteristics of the light pulse 204_3 (for example, the light pulse 204_3 depends on time And the intensity of change). The initial target shape can also be controlled by controlling the positional overlap between the light pulse 204_3 and the target 221i. For example, the light pulse 204_3 can be guided to hit one side of the target 221i instead of hitting the center of the target 221i.

光脈衝204-3之波長可為例如約200 nm至約10 µm。光束遞送系統205_3相似於光束遞送系統205_1及205_2。光學源208_3相似於光學源208_2。The wavelength of the light pulse 204-3 may be, for example, about 200 nm to about 10 µm. The beam delivery system 205_3 is similar to the beam delivery systems 205_1 and 205_2. The optical source 208_3 is similar to the optical source 208_2.

參看圖3，展示用以控制EUV光源中之CE之實例程序300的流程圖。該程序300可藉由EUV光源100 (圖1)或EUV光源200 (圖2)來執行。Referring to FIG. 3, a flowchart of an example program 300 for controlling CE in an EUV light source is shown. The procedure 300 can be executed by the EUV light source 100 (FIG. 1) or the EUV light source 200 (FIG. 2).

藉由控制EUV光源之組件來判定初始目標之初始形狀(310)。初始目標形狀為當目標在與光脈衝104_2相互作用之前在目標區124_2中時的目標之形狀。為了控制初始目標形狀，控制系統150可控制EUV光源100或EUV光源200中之目標供應系統110。控制系統150亦可控制EUV光源200之光學源208_3及/或遞送系統205_3。此等途徑在下文中依次論述。The initial shape of the initial target is determined by controlling the components of the EUV light source (310). The initial target shape is the shape of the target when it is in the target area 124_2 before interacting with the light pulse 104_2. In order to control the initial target shape, the control system 150 can control the EUV light source 100 or the target supply system 110 in the EUV light source 200. The control system 150 can also control the optical source 208_3 and/or the delivery system 205_3 of the EUV light source 200. These approaches are discussed in sequence below.

在一些實施中，控制系統150藉由調整施加至儲集器118中之目標混合物111之壓力p來控制目標供應系統110。圖4展示控制系統150調整壓力p之實施。圖4為恰好在脈衝404_2 (其為光束106_2之脈衝)與初始目標421p相互作用之前及在形成EUV光發射之電漿496之電漿產生事件期間或不久之後的EUV光源400的方塊圖。在圖4之實例中，串流121包括目標421_a、421_b及初始目標421p。目標421_a、421_b及421p在大體上在x方向上之軌跡上自孔口119行進至目標區124_2。In some implementations, the control system 150 controls the target supply system 110 by adjusting the pressure p applied to the target mixture 111 in the reservoir 118. Figure 4 shows the implementation of the control system 150 to adjust the pressure p. 4 is a block diagram of the EUV light source 400 just before the pulse 404_2 (which is the pulse of the beam 106_2) interacts with the initial target 421p and during or shortly after the plasma generation event forming the plasma 496 for EUV light emission. In the example of FIG. 4, the stream 121 includes targets 421_a, 421_b and an initial target 421p. The targets 421_a, 421_b, and 421p travel from the aperture 119 to the target area 124_2 on a trajectory generally in the x direction.

如上文所論述，目標混合物111作為射流125自孔口釋放，且該射流125分解成個別目標，該等個別目標各自沿著行進方向(此實例中之x方向)與鄰近目標分離距離423。距離423影響串流121中之目標之初始形狀。EUV光源100定期產生曝光光束198使得可快速曝光基板195。因此，在EUV光源之操作期間規則地發生電漿產生事件。電漿496及/或由電漿496形成或與電漿496相關聯的其他物質係在真空腔室109中，而串流121中之目標朝向目標區124_2行進。電漿196及/或其他物質與串流121中之目標相互作用且可改變該等目標之初始形狀。由電漿496形成或與電漿496相關聯的其他物質可包括例如自電漿496發射之離子、由電漿496發射之光學光，及散射光(諸如來自主脈衝104_1及/或預脈衝104_2之散射光)。As discussed above, the target mixture 111 is released from the orifice as a jet 125, and the jet 125 is broken down into individual targets, each of which is separated from the adjacent target by a distance 423 along the direction of travel (the x direction in this example). The distance 423 affects the initial shape of the target in the stream 121. The EUV light source 100 periodically generates an exposure beam 198 so that the substrate 195 can be quickly exposed. Therefore, plasma generation events regularly occur during the operation of the EUV light source. The plasma 496 and/or other substances formed by or associated with the plasma 496 are contained in the vacuum chamber 109, and the target in the stream 121 travels toward the target area 124_2. The plasma 196 and/or other substances interact with the targets in the stream 121 and can change the initial shape of the targets. Other substances formed by or associated with plasma 496 may include, for example, ions emitted from plasma 496, optical light emitted by plasma 496, and scattered light (such as from main pulse 104_1 and/or pre-pulse 104_2). Of scattered light).

電漿496及/或其他物質之間的相互作用之強度取決於待塑形之目標與目標區124_1之間的距離及自電漿產生事件以來已經過之時間量。因此，增加距離423會縮減藉由與電漿496相互作用所造成的塑形之量，且減低距離423會增加藉由與電漿196相互作用所造成的塑形之量。增加壓力p會增加串流121中之目標之速度且增加距離423。減低壓力p會減低串流121中之目標之速度且減低距離423。按簡化形式且不考慮噴嘴處之壓降，以方程式(1)展示壓力p與距離423之間的關係：

方程式(1)；其中d為目標之間的距離(圖4之實例中之距離423)，T為EUV光193之產生週期(EUV光之脈衝經提供至輸出裝置199之頻率之逆)，p為施加至儲集器118之壓力，且ρ為目標材料111之密度。The strength of the interaction between the plasma 496 and/or other substances depends on the distance between the target to be shaped and the target area 124_1 and the amount of time that has passed since the plasma generation event. Therefore, increasing the distance 423 will reduce the amount of shaping by the interaction with the plasma 496, and decreasing the distance 423 will increase the amount of shaping by the interaction with the plasma 196. Increasing the pressure p increases the speed of the target in the stream 121 and increases the distance 423. Decreasing the pressure p will decrease the speed of the target in the stream 121 and decrease the distance 423. In a simplified form and without considering the pressure drop at the nozzle, the relationship between the pressure p and the distance 423 is shown in equation (1):

Equation (1); where d is the distance between targets (distance 423 in the example of Figure 4), T is the generation period of EUV light 193 (the inverse of the frequency of EUV light pulses provided to the output device 199), p Is the pressure applied to the reservoir 118, and ρ is the density of the target material 111.

為了控制壓力p，控制系統150產生經提供至壓力系統170之命令信號129。在此等實施中，控制系統150產生經提供至壓力控制器170以控制壓力p之命令信號129。舉例而言，命令信號129指示所要壓力p'且將一命令提供至壓力系統170，該命令致使該壓力系統將所要壓力p'施加至儲集器118中之目標材料111。所要壓力p'可為壓力p之相對較小改變。舉例而言，所要壓力p'可為壓力p之0.1%或更小的百分比改變。In order to control the pressure p, the control system 150 generates a command signal 129 which is provided to the pressure system 170. In these implementations, the control system 150 generates a command signal 129 that is provided to the pressure controller 170 to control the pressure p. For example, the command signal 129 indicates the desired pressure p′ and provides a command to the pressure system 170 that causes the pressure system to apply the desired pressure p′ to the target material 111 in the reservoir 118. The desired pressure p'can be a relatively small change in pressure p. For example, the desired pressure p'can be a percentage change of 0.1% or less of the pressure p.

所要壓力p'可基於例如儲存於電子儲存器156上之查找表或資料庫而判定。查找表可包括與正使用EUV光源100所根據之條件相關的資訊。對應於最佳CE之初始目標形狀取決於經修改目標121m之特性(諸如形狀及密度)。舉例而言，在脈衝404_2具有約1 µm之波長及約10 ns至100 ns之時距的實施中，經修改目標121m為大體上圓盤形，在x-y平面中具有最大空間範圍。在脈衝404_2具有約1 µm之波長及約10 ps至100 ps之時距的實施中，經修改目標121m為粒子及其他物質之雲狀物或霧狀物。因此，經修改目標121m之形狀及密度取決於脈衝404_2之特性。最佳初始目標形狀取決於脈衝404_2之特性及最終目標之所要形態而變化。因此，查找表可儲存使脈衝404_2之特性(諸如時距)與初始目標形狀及為達成彼初始形狀之對應距離423相關的資訊。可與脈衝404_2之特性、用於彼等特性之對應初始目標形狀及距離423相關聯地儲存所要壓力p'。The desired pressure p′ can be determined based on, for example, a look-up table or database stored in the electronic storage 156. The look-up table may include information related to the conditions under which the EUV light source 100 is being used. The initial target shape corresponding to the optimal CE depends on the characteristics (such as shape and density) of the modified target 121m. For example, in an implementation where the pulse 404_2 has a wavelength of about 1 µm and a time interval of about 10 ns to 100 ns, the modified target 121m is substantially disc-shaped and has the largest spatial extent in the x-y plane. In the implementation of pulse 404_2 with a wavelength of about 1 µm and a time interval of about 10 ps to 100 ps, the modified target 121m is a cloud or mist of particles and other substances. Therefore, the shape and density of the modified target 121m depend on the characteristics of the pulse 404_2. The optimal initial target shape varies depending on the characteristics of the pulse 404_2 and the desired shape of the final target. Therefore, the look-up table can store information related to the characteristics of the pulse 404_2 (such as the time interval) with the initial target shape and the corresponding distance 423 to achieve that initial shape. The desired pressure p'can be stored in association with the characteristics of the pulse 404_2, the corresponding initial target shape and the distance 423 for their characteristics.

回應於接收到命令信號129，壓力系統170啟動泵、閥及其他器件以將壓力p改變為所請求值。在一些實施中，壓力系統170包括量測壓力p之值之壓力感測器，且在控制系統150提供命令信號129之前將該經量測壓力p與所要壓力進行比較。舉例而言，壓力系統170可經由資料鏈路152將經施加壓力p之值(或經施加壓力p之值的指示)提供至控制系統150，或控制系統150可自壓力系統170擷取壓力p之值。In response to receiving the command signal 129, the pressure system 170 activates pumps, valves, and other devices to change the pressure p to the requested value. In some implementations, the pressure system 170 includes a pressure sensor that measures the value of the pressure p, and the measured pressure p is compared with the desired pressure before the control system 150 provides the command signal 129. For example, the pressure system 170 may provide the value of the applied pressure p (or an indication of the value of the applied pressure p) to the control system 150 via the data link 152, or the control system 150 may retrieve the pressure p from the pressure system 170 The value.

因此，可藉由控制作為EUV光源100之組件的壓力系統170來判定初始目標形狀。Therefore, the initial target shape can be determined by controlling the pressure system 170 as a component of the EUV light source 100.

在一些實施中，藉由控制致動器132來判定初始目標形狀。致動器132為目標供應系統110之一部分且因此亦為EUV光源100之組件。圖5為EUV光源500之方塊圖。該EUV光源500為EUV光源100之實例實施，在該EUV光源中，控制系統150經由資料鏈路152耦接至致動器132。控制系統150控制致動器132以判定初始目標形狀。In some implementations, the initial target shape is determined by controlling the actuator 132. The actuator 132 is part of the target supply system 110 and therefore is also a component of the EUV light source 100. FIG. 5 is a block diagram of the EUV light source 500. The EUV light source 500 is an example implementation of the EUV light source 100 in which the control system 150 is coupled to the actuator 132 via the data link 152. The control system 150 controls the actuator 132 to determine the initial target shape.

如上文所論述，致動器132之運動在目標混合物111中產生壓力波且致使射流125分解成構成串流121之目標。使致動器132振動或以其他方式致動之一或多個頻率判定串流121中之目標之各種特性。舉例而言，致動器132之振動可用以判定串流121中之目標到達目標區124_2之速率以及目標之形狀。As discussed above, the movement of the actuator 132 generates a pressure wave in the target mixture 111 and causes the jet 125 to decompose into the targets that make up the stream 121. The actuator 132 is caused to vibrate or otherwise actuate one or more frequencies to determine various characteristics of the target in the stream 121. For example, the vibration of the actuator 132 can be used to determine the speed at which the target in the stream 121 reaches the target area 124_2 and the shape of the target.

為了藉由控制致動器132判定目標之初始形狀，控制系統150將調變命令信號129提供至致動器132。致動器132之運動用以控制串流121中之目標之特性。如上文所論述，致動器132之運動會調變目標供應系統110中之目標材料111使得射流125分解成個別目標。致動器132振動之頻率判定串流121中之目標之特性，包括目標之初始形狀。In order to determine the initial shape of the target by controlling the actuator 132, the control system 150 provides a modulation command signal 129 to the actuator 132. The movement of the actuator 132 is used to control the characteristics of the target in the stream 121. As discussed above, the movement of the actuator 132 modulates the target material 111 in the target supply system 110 so that the jet 125 is broken down into individual targets. The frequency of the vibration of the actuator 132 determines the characteristics of the target in the stream 121, including the initial shape of the target.

控制系統150將命令信號129提供至致動器132。命令信號包括使具有至少在第一頻率及第二頻率下之分量的致動信號被施加至致動器132之資訊。致動器132可為例如壓電致動器。在此等實施中，命令信號129為包括在兩個不同頻率下之分量之電壓信號，或使與致動器132相關聯之器件產生在兩個不同頻率下之電壓且將彼等電壓施加至致動器132之資訊。回應於施加電壓信號，致動器132在第一及第二頻率下振動。控制系統150可包括一函數產生器，該函數產生器產生具有一振幅之電壓波形，該振幅在被施加至調變器132時足以使調變器132移動。電壓波形之頻率係由操作員經由I/O介面158控制及/或由儲存於電子儲存器156上之指令控制。The control system 150 provides the command signal 129 to the actuator 132. The command signal includes information for causing an actuation signal having a component at least at the first frequency and the second frequency to be applied to the actuator 132. The actuator 132 may be, for example, a piezoelectric actuator. In these implementations, the command signal 129 is a voltage signal that includes components at two different frequencies, or causes a device associated with the actuator 132 to generate voltages at two different frequencies and apply those voltages to Information of actuator 132. In response to the applied voltage signal, the actuator 132 vibrates at the first and second frequencies. The control system 150 may include a function generator that generates a voltage waveform having an amplitude sufficient to move the modulator 132 when applied to the modulator 132. The frequency of the voltage waveform is controlled by the operator via the I/O interface 158 and/or controlled by commands stored in the electronic storage 156.

第一頻率為高於第二頻率的頻率。在第一頻率下使毛細管114振動致使射流125分解成所要大小及速度的相對較小目標。第二頻率用以調變串流中之目標之速度且促進小滴聚結使得形成較大目標，其各自由複數個相對較小目標形成。在目標之任何給定群組中，各種目標以不同速度行進。具有較高速度之目標可與具有較低速度之目標聚結以形成構成串流121的較大聚結目標。此等較大目標與非聚結小滴相比彼此分離更大距離(諸如圖4之距離423)。在聚結之後，串流121中之目標大致為球形且大小為約30微米(µm)。The first frequency is a frequency higher than the second frequency. Vibrating the capillary 114 at the first frequency causes the jet 125 to decompose into relatively small targets of the desired size and velocity. The second frequency is used to modulate the speed of the targets in the stream and promote the coalescence of droplets to form larger targets, each of which is formed by a plurality of relatively smaller targets. In any given group of targets, various targets travel at different speeds. A target with a higher speed may coalesce with a target with a lower speed to form a larger coalesced target that constitutes the stream 121. These larger targets are separated from each other by a greater distance than the non-coalesced droplets (such as distance 423 in FIG. 4). After coalescence, the target in the stream 121 is roughly spherical and has a size of about 30 microns (µm).

可將額外頻率施加至致動器132。將額外頻譜分量引入至致動信號中會允許較佳控制聚結程序且可用以判定初始目標形狀。舉例而言，除了第一及第二頻率以外，亦可將具有例如30 kHz至100 kHz、40 kHz至60 kHz或50 kHz之頻率的正弦波施加至致動器132，及/或可將第一頻率或第二頻率中之一者調整為不同頻率及/或波形形狀使得將額外頻率分量施加至致動器132。施加額外頻譜分量會引入兩個鄰近聚結目標之間的相對運動使得該兩個鄰近目標在朝向目標區124_2行進時彼此接近。該兩個鄰近目標合併以形成未必具有球形之新的較大目標。以此方式，串流121中之到達目標區124_2的目標之初始形狀可藉由控制致動器132予以判定。Additional frequencies may be applied to the actuator 132. The introduction of additional spectral components into the actuation signal allows better control of the coalescence process and can be used to determine the initial target shape. For example, in addition to the first and second frequencies, a sine wave having a frequency of, for example, 30 kHz to 100 kHz, 40 kHz to 60 kHz, or 50 kHz may be applied to the actuator 132, and/or the first frequency may be applied to the actuator 132. Adjusting one of the one frequency or the second frequency to a different frequency and/or waveform shape allows additional frequency components to be applied to the actuator 132. The application of additional spectral components introduces relative motion between two neighboring coalescing targets so that the two neighboring targets approach each other as they travel toward the target area 124_2. The two adjacent targets merge to form a new larger target that does not necessarily have a spherical shape. In this way, the initial shape of the target reaching the target area 124_2 in the stream 121 can be determined by controlling the actuator 132.

因此，可藉由控制致動器132來判定初始目標形狀。Therefore, the initial target shape can be determined by controlling the actuator 132.

亦參看圖2，亦可藉由控制光學源208_3及/或遞送系統205_3來判定初始目標形狀。如上文所論述，目標221i與脈衝204_3之間的相互作用可塑形該目標221i。舉例而言，遞送系統205_3可包括電光調變器(EOM)，該電光調變器可控制以調整脈衝204_3之時距以控制目標221p在x-y平面中及/或在y-z平面中之範圍。在另一實例中，遞送系統205_3可包括使脈衝204_3相對於目標區224_3轉向之光學元件，諸如(例如)鏡面。在此等實例中，藉由將脈衝204_3引導至目標221i之特定部分來判定初始目標形狀。舉例而言，可將脈衝204_3引導至相對於目標221i之中心在X或-X方向上位移的目標221i之一部分。Referring also to FIG. 2, the initial target shape can also be determined by controlling the optical source 208_3 and/or the delivery system 205_3. As discussed above, the interaction between the target 221i and the pulse 204_3 can shape the target 221i. For example, the delivery system 205_3 may include an electro-optical modulator (EOM), which may be controlled to adjust the time interval of the pulse 204_3 to control the range of the target 221p in the x-y plane and/or in the y-z plane. In another example, the delivery system 205_3 may include an optical element, such as, for example, a mirror, that turns the pulse 204_3 relative to the target area 224_3. In these examples, the initial target shape is determined by directing the pulse 204_3 to a specific part of the target 221i. For example, the pulse 204_3 may be directed to a part of the target 221i that is displaced in the X or −X direction with respect to the center of the target 221i.

在判定初始目標形狀之後，形成最終目標(320)。最終目標為與脈衝104_1相互作用以形成電漿196的目標材料集合。在圖1之實例中，最終目標為經修改目標121m。藉由使初始目標(具有初始目標形狀之目標)與預脈衝相互作用而形成最終目標，該預脈衝為光束106_2中之脈衝(例如圖1之脈衝104_2)。預脈衝與初始目標之間的相互作用會改變目標121p中之目標材料之幾何配置以形成經修改目標121m。After the initial target shape is determined, the final target is formed (320). The ultimate goal is to interact with the pulse 104_1 to form the target material collection of the plasma 196. In the example of Figure 1, the final target is the modified target 121m. The final target is formed by interacting an initial target (a target with an initial target shape) with a pre-pulse, which is a pulse in the beam 106_2 (for example, the pulse 104_2 in FIG. 1). The interaction between the pre-pulse and the initial target will change the geometric configuration of the target material in the target 121p to form a modified target 121m.

起始電漿產生事件(330)。當主脈衝(例如圖1之脈衝104_1)與最終目標(諸如經修改目標121m)相互作用時發生電漿產生事件且電漿產生事件形成電漿196。電漿196發射光197。與電漿產生事件相關聯之CE取決於由主脈衝遞送至最終目標之能量之量及自電漿196發射之EUV光之量，此取決於轉換成電漿196的目標材料之部分。最終目標之形態影響目標材料之轉換效率，且最終目標之形態係藉由判定初始目標形狀來控制，如在(310)中所論述。因此，藉由控制EUV光源100或EUV光源200之組件判定初始目標形狀會控制CE。Initial plasma generation event (330). When the main pulse (for example, pulse 104_1 in FIG. 1) interacts with the final target (such as the modified target 121 m), a plasma generating event occurs and the plasma generating event forms a plasma 196. The plasma 196 emits light 197. The CE associated with the plasma generation event depends on the amount of energy delivered by the main pulse to the final target and the amount of EUV light emitted from the plasma 196, which depends on the portion of the target material converted into the plasma 196. The shape of the final target affects the conversion efficiency of the target material, and the shape of the final target is controlled by determining the initial target shape, as discussed in (310). Therefore, by controlling the components of the EUV light source 100 or the EUV light source 200, it is determined that the initial target shape will control the CE.

圖6A至圖6D展示與初始目標形狀相關之實驗資料。6A to 6D show experimental data related to the initial target shape.

圖6A為使最終目標形態與不同初始目標形狀相關的21個不同陰影圖之矩陣。在圖6A中所展示之實例中，預脈衝具有2 mJ至3 mJ之能量、1.064 µm之波長及10 ns之持續時間。Fig. 6A is a matrix of 21 different shadow maps that correlate the final target shape with different initial target shapes. In the example shown in FIG. 6A, the pre-pulse has an energy of 2 mJ to 3 mJ, a wavelength of 1.064 µm, and a duration of 10 ns.

該等陰影圖以行A至G配置，其中該等行A至G中之每一者在列1至3中之每一者中包括一個陰影圖。每一陰影圖在左下方部分中展示初始目標形狀以及最終目標。初始目標形狀經特性化為沿著x方向之範圍對沿著z方向之範圍之比率。初始目標形狀在行A至G中之每一者中係不同的。行A中之陰影圖係藉由比率約為0.6的初始目標形狀產生。初始目標形狀之比率自行A至行G增大。行G中之陰影圖係使用比率為1.8的初始目標形狀產生。初始目標形狀在行A中係大體上扁球形(在x方向上)且在行G中係長球形(在x方向上)。圖6A及圖6B中之x方向及z方向與在圖1中之x方向及z方向相同。列1至3中在行A至G中之每一者中的三個陰影圖具有相同的初始目標形狀且展示在三個不同時間收集之資料。The shadow maps are arranged in rows A to G, where each of the rows A to G includes one shadow map in each of the columns 1 to 3. Each shadow map shows the initial target shape and the final target in the lower left part. The initial target shape is characterized as the ratio of the range along the x direction to the range along the z direction. The initial target shape is different in each of rows A to G. The shadow map in row A is generated from the initial target shape with a ratio of approximately 0.6. The ratio of the initial target shape increases from A to G. The shadow map in row G is generated using the initial target shape with a ratio of 1.8. The initial target shape is generally oblate (in the x-direction) in row A and prolonged (in the x-direction) in row G. The x direction and z direction in FIGS. 6A and 6B are the same as the x direction and z direction in FIG. 1. The three shaded maps in each of rows A to G in columns 1 to 3 have the same initial target shape and show data collected at three different times.

如藉由逐行比較資料所展示，最終目標之形態隨著初始目標形狀改變而改變。此外，如藉由比較一行內之陰影圖而顯而易見，由具有特定初始目標形狀之初始目標形成的最終目標之形態相當一致。圖6A中所展示之資料指示最終目標之形態取決於初始目標形狀。As shown by comparing the data row by row, the shape of the final target changes as the shape of the initial target changes. In addition, as is obvious by comparing the shadow maps in a row, the shape of the final target formed by the initial target with a specific initial target shape is quite consistent. The data shown in Figure 6A indicates that the shape of the final target depends on the initial target shape.

圖6B為展示關於相似實驗之結果的陰影圖矩陣，其中預脈衝具有2 mJ至3 mJ之能量、1.064 µm之波長及12 ps之持續時間。結果再次展示出，自特定目標形狀產生之最終目標之形態相當一致，此指示最終目標之形態取決於初始目標形狀。Figure 6B is a shadow graph matrix showing the results of similar experiments, where the pre-pulse has an energy of 2 mJ to 3 mJ, a wavelength of 1.064 µm, and a duration of 12 ps. The results again show that the shape of the final target generated from the specific target shape is quite consistent, which indicates that the shape of the final target depends on the initial target shape.

圖6C展示作為針對具有5個不同基座能量之主脈衝的x範圍與z範圍之比率之函數的經量測CE(%)。基座為在時間上在主脈衝之初級部分之前但仍為主脈衝之部分的主脈衝之一部分。圖6C中所展示之CE資料係用於藉由運用具有1 ns至100 ns持續時間之1 µm預脈衝輻照最終目標而起始的電漿產生事件。Figure 6C shows the measured CE (%) as a function of the ratio of the x-range to the z-range for the main pulse with 5 different pedestal energies. The pedestal is a part of the main pulse that precedes the primary part of the main pulse in time but is still part of the main pulse. The CE data shown in Figure 6C is used for plasma generation events initiated by irradiating the final target with a 1 µm pre-pulse with a duration of 1 ns to 100 ns.

圖6C中所展示之資料包括表示針對分別為0毫焦耳(mJ)、0.5 mJ、1 mJ、1.5 mJ及2 mJ之基座能量作為初始目標形狀比率之函數的CE (%)的標繪圖681、682、683、684、695。一起檢閱標繪圖681至685揭露出作為初始目標形狀比率之函數的CE針對所有基座能量具有相似的量變曲線。此指示CE受初始目標形狀影響，而無基座能量無關。標繪圖681至685指示對於經測試條件，不論基座能量如何，約為1之比率皆產生最佳CE。The data shown in Figure 6C includes plots 681 representing CE (%) for pedestal energies of 0 millijoules (mJ), 0.5 mJ, 1 mJ, 1.5 mJ, and 2 mJ as a function of the initial target shape ratio. , 682, 683, 684, 695. Reviewing the plots 681 to 685 together reveals that CE as a function of the initial target shape ratio has similar quantitative curves for all pedestal energies. This indicates that the CE is affected by the initial target shape, regardless of the energy without the base. Plots 681 to 685 indicate that for the tested conditions, a ratio of approximately 1 produces the best CE regardless of the base energy.

圖6D展示作為針對六個不同初始目標形狀之初始目標大小(µm)之函數的經量測CE (%)。在圖6D中，六個不同初始目標形狀為六個不同初始目標形狀比率，且CE (%)被標繪為初始目標在目標行進之方向(例如圖1之X方向)上之大小的函數。Figure 6D shows the measured CE (%) as a function of the initial target size (µm) for six different initial target shapes. In FIG. 6D, the six different initial target shapes are six different initial target shape ratios, and CE (%) is plotted as a function of the size of the initial target in the direction in which the target travels (for example, the X direction in FIG. 1).

CE係用於藉由運用具有12 ps持續時間之1.064 µm預脈衝輻照最終目標而起始的電漿產生事件。圖6D包括表示針對自分別具有0.6、0.8、1.0、1.2、1.4及1.6之初始目標形狀比率之初始目標所產生的最終目標之CE的標繪圖691、692、693、694、695、696。具有為1.0之目標形狀比率的初始目標為大體上球形之目標且因此為未失真目標，或初始形狀並未由諸如程序300之程序控制的目標。如圖6D中所展示，CE取決於初始目標形狀。特定言之，對於相對較大目標(例如大於約650 µm)，未失真初始目標並不產生最高CD。因此，藉由以程序300判定初始目標形狀，可達成效能改良。CE is used for plasma generation events initiated by irradiating the final target with a 1.064 µm pre-pulse with a duration of 12 ps. FIG. 6D includes plots 691, 692, 693, 694, 695, 696 representing the CE of the final target generated from the initial target having initial target shape ratios of 0.6, 0.8, 1.0, 1.2, 1.4, and 1.6, respectively. An initial target with a target shape ratio of 1.0 is a substantially spherical target and therefore an undistorted target, or a target whose initial shape is not controlled by a program such as program 300. As shown in Figure 6D, CE depends on the initial target shape. In particular, for relatively large targets (for example, greater than about 650 µm), the undistorted initial target does not produce the highest CD. Therefore, by using the program 300 to determine the initial target shape, performance improvement can be achieved.

圖7A為包括源收集器模組SO之微影系統700的方塊圖。微影系統700為微影系統101之實例。微影系統700亦包括：經組態以調節輻射光束B之照明系統IL。輻射光束B可為自源收集器模組SO發射之EUV光束。微影系統700亦包括經建構以支撐圖案化器件MA之支撐結構MT。支撐結構MT可為例如光罩台，且圖案化器件MA可為例如光罩或倍縮光罩。當輻射光束B與圖案化器件MA相互作用時，與圖案化器件MA相關聯之空間圖案被賦予至輻射光束B上。支撐結構MT耦接至經組態以定位圖案化器件MA之第一***PM。另外，系統700包括其經建構以固持基板W之基板台WT，該基板W可例如為抗蝕劑塗佈晶圓。基板台WT連接至經組態以定位基板W之第二***PW。系統700亦包括經組態以將經圖案化輻射光束E (亦被稱作曝光光E或曝光光束E)投影至基板W之目標部分C上之投影系統PS。目標部分C可為基板W之任何部分。在圖7A之實例中，基板W包括複數個晶粒D，且目標部分C包括晶粒D中之多於一者。FIG. 7A is a block diagram of the lithography system 700 including the source collector module SO. The lithography system 700 is an example of the lithography system 101. The lithography system 700 also includes an illumination system IL configured to adjust the radiation beam B. The radiation beam B may be an EUV beam emitted from the source collector module SO. The lithography system 700 also includes a support structure MT constructed to support the patterned device MA. The support structure MT can be, for example, a photomask stage, and the patterned device MA can be, for example, a photomask or a reduction photomask. When the radiation beam B interacts with the patterned device MA, the spatial pattern associated with the patterned device MA is imparted to the radiation beam B. The support structure MT is coupled to a first positioner PM configured to position the patterned device MA. In addition, the system 700 includes a substrate table WT configured to hold a substrate W, which may be, for example, a resist-coated wafer. The substrate table WT is connected to a second positioner PW configured to position the substrate W. The system 700 also includes a projection system PS configured to project a patterned radiation beam E (also referred to as exposure light E or exposure beam E) onto a target portion C of the substrate W. The target portion C can be any portion of the substrate W. In the example of FIG. 7A, the substrate W includes a plurality of dies D, and the target portion C includes more than one of the dies D.

照明系統IL包括用於引導、塑形及/或控制輻射光束B及曝光光E的光學組件。該等光學組件可包括折射、反射、磁性、電磁、靜電或任何其他類型之光學組件。The illumination system IL includes optical components for guiding, shaping and/or controlling the radiation beam B and the exposure light E. The optical components may include refractive, reflective, magnetic, electromagnetic, electrostatic or any other types of optical components.

支撐結構MT以取決於圖案化器件MA之定向、微影系統700之設計及/或其他條件(諸如(例如)圖案化器件MA是否被固持於真空環境中)之方式來固持圖案化器件MA。支撐結構MT可使用機械、真空、靜電及/或其他夾持技術以固持圖案化器件MA。支撐結構MT可為(例如)框架或台，其可固定或可移動。支撐結構MT可確保圖案化器件MA (例如)相對於投影系統PS處於所要位置。The support structure MT holds the patterned device MA in a manner that depends on the orientation of the patterned device MA, the design of the lithography system 700, and/or other conditions (such as, for example, whether the patterned device MA is held in a vacuum environment). The support structure MT may use mechanical, vacuum, electrostatic and/or other clamping techniques to hold the patterned device MA. The support structure MT may be, for example, a frame or a table, which may be fixed or movable. The support structure MT can ensure that the patterned device MA (for example) is in a desired position relative to the projection system PS.

圖案化器件MA為可用以將圖案賦予至輻射光束B上之任何器件。圖案化器件MA可為透射的或反射的。圖案化器件之實例包括光罩、可程式化鏡面陣列，及可程式化LCD面板。在圖案化器件MA為光罩之實施中，圖案化器件MA可為例如二元光罩、交變相移光罩，或衰減式相移或混合光罩類型。在圖案化器件MA為可程式化鏡面陣列之實施中，圖案化器件MA包括鏡面之矩陣配置，該等鏡面中之每一者可個別地傾斜使得該等鏡面中之每一者能夠在不同方向上反射輻射光束B，該方向並不取決於輻射光束B由該矩陣中之其他鏡面反射之方向。被賦予至入射光上之圖案係藉由矩陣中之各個鏡面之位置予以判定。該圖案可對應於基板W之目標部分C中所產生之器件中的特定功能層。舉例而言，該圖案可對應於一起形成積體電路之電子特徵。The patterned device MA is any device that can be used to impart a pattern to the radiation beam B. The patterned device MA may be transmissive or reflective. Examples of patterned devices include photomasks, programmable mirror arrays, and programmable LCD panels. In an implementation where the patterned device MA is a photomask, the patterned device MA may be, for example, a binary photomask, an alternating phase shift photomask, or an attenuated phase shift or hybrid photomask type. In the implementation of the patterned device MA as a programmable mirror array, the patterned device MA includes a matrix configuration of mirrors, each of the mirrors can be individually tilted so that each of the mirrors can be in a different direction The radiation beam B is reflected upward, and the direction does not depend on the direction in which the radiation beam B is reflected by other mirrors in the matrix. The pattern imparted to the incident light is determined by the position of each mirror in the matrix. The pattern may correspond to a specific functional layer in the device produced in the target portion C of the substrate W. For example, the pattern may correspond to electronic features that together form an integrated circuit.

投影系統PS包括將曝光光E引導至目標部分C之光學組件。投影系統PS之光學組件可為折射的、反射的、磁性的、電磁的、靜電的，及/或適於正使用之曝光輻射或適於諸如真空之使用之其他因素的其他類型之光學組件。此外，可需要將真空用於EUV輻射，此係因為氣體可能吸收EUV輻射。因此可憑藉真空壁及真空泵提供真空環境。The projection system PS includes an optical component that guides the exposure light E to the target portion C. The optical components of the projection system PS may be refractive, reflective, magnetic, electromagnetic, electrostatic, and/or other types of optical components suitable for the exposure radiation being used or other factors such as the use of vacuum. In addition, it may be necessary to use vacuum for EUV radiation because the gas may absorb EUV radiation. Therefore, a vacuum environment can be provided by means of a vacuum wall and a vacuum pump.

在圖7A及圖7B之實例中，系統700為包括反射光學組件及反射圖案化器件MA之反射類型。微影系統700可屬於具有兩個(雙載物台)或多於兩個基板台(及/或兩個或多於兩個圖案化器件台)之類型。在此等多載物台機器中，可並行地使用額外台，或可在一或多個台上進行預備步驟，同時將一或多個其他台用於曝光。In the example of FIGS. 7A and 7B, the system 700 is a reflective type including a reflective optical component and a reflective patterning device MA. The lithography system 700 may be of a type having two (dual stage) or more than two substrate stages (and/or two or more patterned device stages). In such multi-stage machines, additional tables can be used in parallel, or preparatory steps can be performed on one or more tables while one or more other tables are used for exposure.

照明系統IL自源收集器模組SO接收極紫外輻射光束B。EUV光源100 (圖1)、200A (圖2A)及200B (圖2B)及800 (圖8)為源收集器模組SO之實例。The illumination system IL receives the extreme ultraviolet radiation beam B from the source collector module SO. The EUV light source 100 (Figure 1), 200A (Figure 2A), 200B (Figure 2B) and 800 (Figure 8) are examples of the source collector module SO.

照明系統IL可包括用於調整輻射光束之角強度分佈之調整器。通常，可調整照明器之光瞳平面中之強度分佈的至少外部徑向範圍及/或內部徑向範圍(通常分別被稱作σ外部及σ內部)。另外，照明系統IL可包括各種其他組件，諸如琢面化場鏡面器件及琢面化光瞳鏡面器件。照明系統IL可用以調節輻射光束B，以在其橫截面中具有所要均一性及強度分佈。The illumination system IL may include an adjuster for adjusting the angular intensity distribution of the radiation beam. Generally, at least the outer radial extent and/or the inner radial extent (usually referred to as σ outer and σ inner, respectively) of the intensity distribution in the pupil plane of the illuminator can be adjusted. In addition, the illumination system IL may include various other components, such as a faceted field mirror device and a faceted pupil mirror device. The illumination system IL can be used to adjust the radiation beam B to have the desired uniformity and intensity distribution in its cross section.

輻射光束B與圖案化器件MA相互作用使得圖案被賦予至輻射光束B上。輻射光束B自圖案化器件MA反射，其具有被賦予為曝光光E之圖案。曝光光E穿過投影系統PS，投影系統PS將該光束聚焦至基板W之目標部分C上。憑藉第二***PW及第二位置感測器PS2，可準確地移動基板台WT，例如以便將不同目標部分C定位於輻射光束B之路徑中。相似地，第一***PM及另一位置感測器PS1可用以相對於輻射光束B之路徑來準確地定位圖案化器件(例如光罩) MA。定位感測器PS1及PS2可為例如干涉器件、線性編碼器及/或電容式感測器。可使用圖案化器件對準標記M1、M2及基板對準標記P1、P2來對準圖案化器件MA及基板W。The radiation beam B interacts with the patterning device MA so that the pattern is imparted to the radiation beam B. The radiation beam B is reflected from the patterned device MA, which has a pattern imparted to the exposure light E. The exposure light E passes through the projection system PS, and the projection system PS focuses the beam onto the target portion C of the substrate W. With the second positioner PW and the second position sensor PS2, the substrate table WT can be accurately moved, for example, to position different target parts C in the path of the radiation beam B. Similarly, the first positioner PM and the other position sensor PS1 can be used to accurately position the patterned device (such as a mask) MA relative to the path of the radiation beam B. The positioning sensors PS1 and PS2 can be interferometric devices, linear encoders and/or capacitive sensors, for example. The patterned device alignment marks M1, M2 and the substrate alignment marks P1, P2 can be used to align the patterned device MA and the substrate W.

微影系統700可在以下模式中之至少一者中使用：(1)步進模式、(2)掃描模式或(3)第三或其他模式。在步進模式中，在將被賦予至輻射光束B之整個圖案一次性投影至目標部分C上時，使支撐結構MT及基板台WT保持基本上靜止(亦即，單次靜態曝光)。接著，使基板台WT在X及/或Y方向上移位使得可曝光不同目標部分C。在掃描模式中，在將被賦予至輻射光束B之圖案投影至目標部分C上時，同步地掃描支撐結構MT及基板台WT (亦即單次動態曝光)。可藉由投影系統PS之放大率(縮小率)及影像反轉特性來判定基板台WT相對於支撐結構MT之速度及方向。在第三或其他模式中，在將被賦予至輻射光束之圖案投影至目標部分C上時，使支撐結構MT保持基本上靜止，從而固持可程式化圖案化器件，且移動或掃描基板台WT。在此模式中，通常使用脈衝式輻射源，且在基板台WT之每一移動之後或在掃描期間之順次輻射脈衝之間根據需要而更新可程式化圖案化器件。此操作模式可易於應用於利用可程式化圖案化器件(諸如上文所提及之類型的可程式化鏡面陣列)之無光罩微影。亦可使用此等三個使用模式之組合及/或變化或完全不同的使用模式。The lithography system 700 can be used in at least one of the following modes: (1) step mode, (2) scan mode, or (3) third or other mode. In the stepping mode, when the entire pattern imparted to the radiation beam B is projected onto the target portion C at one time, the support structure MT and the substrate table WT are kept substantially stationary (ie, a single static exposure). Next, the substrate table WT is shifted in the X and/or Y direction so that different target portions C can be exposed. In the scanning mode, when the pattern imparted to the radiation beam B is projected onto the target portion C, the support structure MT and the substrate table WT are simultaneously scanned (that is, a single dynamic exposure). The speed and direction of the substrate table WT relative to the support structure MT can be determined by the magnification (reduction ratio) and image reversal characteristics of the projection system PS. In the third or other mode, when the pattern imparted to the radiation beam is projected onto the target portion C, the support structure MT is kept substantially stationary, thereby holding the programmable patterned device, and moving or scanning the substrate table WT . In this mode, a pulsed radiation source is usually used, and the programmable patterned device is updated as needed after each movement of the substrate table WT or between successive radiation pulses during scanning. This mode of operation can be easily applied to maskless lithography using programmable patterned devices (such as the type of programmable mirror array mentioned above). Combinations and/or variations of these three usage modes or completely different usage modes can also be used.

圖7B更詳細地展示包括源收集器模組SO、照明系統IL及投影系統PS之微影系統700的實施。源收集器模組SO包括真空環境。系統IL及PS中之每一者亦包括真空環境。EUV輻射發射電漿形成於源收集器模組SO內。源收集器模組SO使自電漿發射之EUV輻射聚焦至中間焦點IF，使得輻射光束B (760)被提供至照明系統IL。FIG. 7B shows in more detail the implementation of the lithography system 700 including the source collector module SO, the illumination system IL, and the projection system PS. The source collector module SO includes a vacuum environment. Each of the systems IL and PS also includes a vacuum environment. EUV radiation emission plasma is formed in the source collector module SO. The source collector module SO focuses the EUV radiation emitted from the plasma to the intermediate focus IF, so that the radiation beam B (760) is provided to the illumination system IL.

輻射光束B橫穿照明系統IL，照明系統IL在圖7B之實例中包括琢面化場鏡面器件22及琢面化光瞳鏡面器件24。此等器件形成所謂的「蠅眼」照明器，其經配置以提供在圖案化器件MA處輻射光束21之所要角度分佈且維持圖案化器件MA處之輻射強度之均一性。在圖案化器件MA處光束B之反射後，形成曝光光E (經圖案化光束B)，且曝光光E (26)係由投影系統PS經由反射元件28、30而成像至基板W上。另外，曝光光E與對曝光光E塑形之隙縫相互作用，使得曝光光E在垂直於傳播方向之平面中具有矩形橫截面。為了曝光基板W上之目標部分C，源收集器模組SO產生輻射脈衝以形成輻射光束B，同時基板台WT及圖案化器件台MT執行同步移動以經由矩形曝光光E掃描圖案化器件MA上之圖案。The radiation beam B traverses the illumination system IL. The illumination system IL includes a faceted field mirror device 22 and a faceted pupil mirror device 24 in the example of FIG. 7B. These devices form so-called "fly-eye" illuminators that are configured to provide the desired angular distribution of the radiation beam 21 at the patterned device MA and maintain the uniformity of the radiation intensity at the patterned device MA. After the reflection of the light beam B at the patterned device MA, an exposure light E (patterned light beam B) is formed, and the exposure light E (26) is imaged onto the substrate W by the projection system PS via the reflective elements 28 and 30. In addition, the exposure light E interacts with the slits that shape the exposure light E, so that the exposure light E has a rectangular cross section in a plane perpendicular to the propagation direction. In order to expose the target portion C on the substrate W, the source collector module SO generates a radiation pulse to form a radiation beam B, while the substrate table WT and the patterned device table MT perform synchronous movement to scan the patterned device MA through the rectangular exposure light E The pattern.

每一系統IL及PS配置於其自有真空或近真空環境內，該環境係由圍封結構界定。比所展示元件更多之元件通常可存在於照明系統IL及投影系統PS中。另外，可存在比所展示鏡面更多的鏡面。舉例而言，除了圖7B所展示之反射元件以外，在照明系統IL及/或投影系統PS中亦可存在一至六個額外反射元件。Each system IL and PS is configured in its own vacuum or near-vacuum environment, which is defined by the enclosure structure. More elements than shown can generally be present in the illumination system IL and the projection system PS. In addition, there may be more mirrors than shown. For example, in addition to the reflective elements shown in FIG. 7B, there may also be one to six additional reflective elements in the illumination system IL and/or the projection system PS.

用於源收集器模組及微影系統700整體上之操作的眾多額外組件存在於典型裝置中，但在此處未予以說明。此等組件包括用於縮減或減輕經圍封真空內之污染效應之配置，例如，以防止燃料材料之沈積物損害或削弱收集器3及其他光學件之效能。存在但未予以詳細地描述之其他特徵為在控制微影系統700之各種組件及子系統時涉及之所有感測器、控制器及致動器。Many additional components for the overall operation of the source collector module and the lithography system 700 are present in a typical device, but are not described here. These components include arrangements for reducing or mitigating the effects of pollution in the enclosed vacuum, for example, to prevent deposits of fuel materials from damaging or impairing the performance of the collector 3 and other optical components. Other features that exist but are not described in detail are all the sensors, controllers, and actuators involved in controlling the various components and subsystems of the lithography system 700.

參看圖8，展示LPP EUV光源800之實施。光源800可用作微影系統700中之源收集器模組SO。此外，圖1及圖2之光學源108_2可為驅動雷射815之部分。Referring to Figure 8, the implementation of LPP EUV light source 800 is shown. The light source 800 can be used as the source collector module SO in the lithography system 700. In addition, the optical source 108_2 in FIG. 1 and FIG. 2 may be a part of driving the laser 815.

藉由運用經放大光束810輻照電漿形成區805處之目標混合物814而形成LPP EUV光源800，該經放大光束810沿著朝向目標混合物814之光束路徑行進。串流121中之目標之目標材料可為或包括目標混合物814。電漿形成區805係在真空腔室830之內部807內。當經放大光束810撞擊目標混合物814時，該目標混合物814內之目標材料轉換成具有在EUV範圍內之發射譜線之元素的電漿狀態。所產生電漿具有取決於目標混合物814內之目標材料之成份的某些特性。此等特性可包括由電漿產生之EUV光之波長，以及自電漿釋放之碎屑之類型及量。The LPP EUV light source 800 is formed by irradiating the target mixture 814 at the plasma formation region 805 with an amplified light beam 810 that travels along a beam path toward the target mixture 814. The target material of the target in the stream 121 may be or include the target mixture 814. The plasma formation region 805 is located in the interior 807 of the vacuum chamber 830. When the amplified light beam 810 hits the target mixture 814, the target material in the target mixture 814 is converted into a plasma state of elements with emission lines in the EUV range. The generated plasma has certain characteristics that depend on the composition of the target material in the target mixture 814. These characteristics may include the wavelength of EUV light generated by the plasma, and the type and amount of debris released from the plasma.

光源800包括驅動雷射系統815，驅動雷射系統815歸因於雷射系統815之一或若干增益介質內之粒子數反轉而產生經放大光束810。光源800包括雷射系統815與電漿形成區805之間的光束遞送系統，該光束遞送系統包括光束傳送系統820及聚焦總成822。光束傳送系統820自雷射系統815接收經放大光束810，且視需要轉向及修改經放大光束810且將經放大光束810輸出至聚焦總成822。聚焦總成822接收經放大光束810且將光束810聚焦至電漿形成區805。The light source 800 includes a driving laser system 815, and the driving laser system 815 generates an amplified light beam 810 due to the population inversion in one of the laser systems 815 or several gain media. The light source 800 includes a beam delivery system between the laser system 815 and the plasma forming area 805, and the beam delivery system includes a beam delivery system 820 and a focusing assembly 822. The beam delivery system 820 receives the amplified light beam 810 from the laser system 815, and turns and modifies the amplified light beam 810 as necessary and outputs the amplified light beam 810 to the focusing assembly 822. The focusing assembly 822 receives the amplified light beam 810 and focuses the light beam 810 to the plasma formation area 805.

在一些實施中，雷射系統815可包括用於提供一或多個主脈衝且在一些狀況下提供一或多個預脈衝之一或多個光學放大器、雷射及/或燈。每一光學放大器包括能夠以高增益光學地放大所要波長之增益介質、激發源及內部光學件。光學放大器可具有或可不具有形成雷射空腔之雷射鏡面或其他回饋器件。因此，雷射系統815即使在不存在雷射空腔的情況下歸因於雷射放大器之增益介質中之粒子數反轉亦會產生經放大光束810。此外，雷射系統815可在存在雷射空腔以將足夠回饋提供至雷射系統815的情況下產生作為相干雷射光束之經放大光束810。術語「經放大光束」涵蓋如下各者中之一或多者：來自雷射系統815之僅僅經放大但未必為相干雷射振盪的光，及來自雷射系統815之經放大且亦為相干雷射振盪的光。In some implementations, the laser system 815 may include one or more optical amplifiers, lasers, and/or lamps for providing one or more main pulses and, in some cases, one or more pre-pulses. Each optical amplifier includes a gain medium capable of optically amplifying a desired wavelength with high gain, an excitation source, and internal optics. The optical amplifier may or may not have a laser mirror or other feedback devices forming a laser cavity. Therefore, the laser system 815 will generate an amplified light beam 810 due to the population inversion in the gain medium of the laser amplifier even in the absence of a laser cavity. In addition, the laser system 815 can generate the amplified beam 810 as a coherent laser beam in the presence of a laser cavity to provide sufficient feedback to the laser system 815. The term "amplified light beam" covers one or more of the following: light from laser system 815 that is only amplified but not necessarily coherent laser oscillation, and from laser system 815 that is amplified and also coherent laser Shoot oscillating light.

雷射系統815中之光學放大器可包括填充氣體(包括CO₂ )作為增益介質，且可以大於或等於800倍之增益放大在約9100 nm與約11000 nm之間的波長下，且尤其在約10600 nm下的光。供用於雷射系統815中之合適放大器及雷射可包括脈衝式雷射器件，例如脈衝式氣體放電CO₂ 雷射器件，該脈衝式氣體放電CO₂ 雷射器件例如運用以相對較高功率(例如10 kW或高於10 kW)及高脈衝重複率(例如40 kHz或大於40 kHz)操作的DC或RF激發產生處於約9300 nm或約10600 nm之輻射。脈衝重複率可為例如50 kHz。雷射系統815中之光學放大器亦可包括可在較高功率下操作雷射系統815時使用的冷卻系統，諸如水。The optical amplifier in the laser system 815 may include a filling gas (including CO ₂ ) as a gain medium, and may have a gain greater than or equal to 800 times for amplification at a wavelength between about 9100 nm and about 11000 nm, and especially at about 10600. Light under nm. Suitable for use in laser amplifiers and laser system 815 may include a pulse of laser devices, for example, pulsed CO ₂ laser gas discharge device, the pulsed gas discharge CO ₂ laser device, for example, the use of a relatively high power ( For example, 10 kW or higher) and high pulse repetition rate (for example, 40 kHz or greater than 40 kHz) operation of DC or RF excitation produces radiation at about 9300 nm or about 10600 nm. The pulse repetition rate can be, for example, 50 kHz. The optical amplifier in the laser system 815 may also include a cooling system, such as water, which can be used when the laser system 815 is operated at a higher power.

光源800包括收集器鏡面835，該收集器鏡面具有孔隙840以允許經放大光束810穿過且到達電漿形成區805。收集器鏡面835可為例如在電漿形成區805處具有主焦點且在中間部位845處具有次級焦點(亦被稱為中間焦點)的橢球形鏡面，其中可自光源800輸出EUV光且可將該EUV光輸入至例如積體電路微影工具(圖中未繪示)。光源800亦可包括開端式中空圓錐形護罩850 (例如氣體錐體)，該圓錐形護罩自收集器鏡面835朝向電漿形成區805漸狹以縮減進入聚焦總成822及/或光束傳送系統820的電漿產生之碎屑之量，同時允許經放大光束810到達電漿形成區805。出於此目的，可將氣流提供於護罩中，該氣流經引導朝向電漿形成區805。The light source 800 includes a collector mirror 835 having an aperture 840 to allow the amplified light beam 810 to pass through and reach the plasma formation region 805. The collector mirror 835 can be, for example, an ellipsoidal mirror with a primary focus at the plasma formation area 805 and a secondary focus (also called an intermediate focus) at the middle part 845, wherein EUV light can be output from the light source 800 and can be The EUV light is input to, for example, an integrated circuit lithography tool (not shown in the figure). The light source 800 may also include an open-ended hollow cone-shaped shield 850 (such as a gas cone), which tapers from the collector mirror 835 toward the plasma formation area 805 to reduce access to the focusing assembly 822 and/or beam delivery The amount of debris generated by the plasma of the system 820, while allowing the amplified light beam 810 to reach the plasma forming area 805. For this purpose, an air flow may be provided in the shield, and the air flow may be directed toward the plasma formation area 805.

光源800亦可包括主控控制器855，該主控控制器連接至小滴位置偵測回饋系統856、雷射控制系統857及光束控制系統858。光源800可包括一或多個目標或小滴成像器860，該一或多個目標或小滴成像器提供指示小滴例如相對於電漿形成區805之位置之輸出且將此輸出提供至小滴位置偵測回饋系統856，該小滴位置偵測回饋系統可例如計算小滴位置及軌跡，自該小滴位置及軌跡可基於逐小滴地或平均地計算出小滴位置誤差。小滴位置偵測回饋系統856因此將小滴位置誤差作為輸入提供至主控控制器855。主控控制器855因此可將例如雷射位置、方向及時序校正信號提供至可用以例如控制雷射時序電路之雷射控制系統857及/或提供至光束控制系統858，以控制經放大光束位置及光束傳送系統820之塑形從而改變腔室830內之光束焦斑之部位及/或焦度。The light source 800 may also include a main control controller 855, which is connected to the droplet position detection feedback system 856, the laser control system 857, and the beam control system 858. The light source 800 may include one or more targets or droplet imagers 860 that provide an output indicating the position of the droplet, for example, relative to the plasma forming region 805 and provide this output to the small The drop position detection and feedback system 856 can, for example, calculate the droplet position and trajectory, from which the droplet position and trajectory can be calculated on a drop-by-drop basis or on an average basis. The droplet position detection feedback system 856 therefore provides the droplet position error as an input to the main control controller 855. The main control controller 855 can therefore provide, for example, laser position, direction, and timing correction signals to the laser control system 857 that can be used, for example, to control the laser timing circuit and/or to the beam control system 858 to control the position of the amplified beam And the shaping of the beam delivery system 820 so as to change the position and/or power of the focal spot of the beam in the chamber 830.

供應系統825包括目標材料遞送控制系統826，該目標材料遞送控制系統可操作以回應於來自例如主控控制器855之信號而修改由目標材料供應裝置827釋放之小滴之釋放點，以校正到達所要電漿形成區805的小滴之誤差。The supply system 825 includes a target material delivery control system 826 that is operable to modify the release point of the droplet released by the target material supply device 827 in response to a signal from, for example, the main control controller 855 to correct the arrival The error of the droplet in the desired plasma formation area 805.

另外，光源800可包括光源偵測器865及870，該等光源偵測器量測一或多個EUV光參數，包括但不限於脈衝能量、依據波長而變化的能量分佈、特定波長帶內之能量、特定波長帶之外之能量，及EUV強度之角度分佈及/或平均功率。光源偵測器865產生回饋信號以供主控控制器855使用。回饋信號可(例如)指示為了有效及高效EUV光產生而在適當地點及時間恰當地截取小滴的雷射脈衝之參數(諸如，時序及焦點)之誤差。In addition, the light source 800 may include light source detectors 865 and 870. The light source detectors measure one or more EUV light parameters, including but not limited to pulse energy, energy distribution that varies according to wavelength, and energy within a specific wavelength band. Energy, energy outside a specific wavelength band, and the angular distribution of EUV intensity and/or average power. The light source detector 865 generates a feedback signal for the main control controller 855 to use. The feedback signal may, for example, indicate errors in parameters (such as timing and focus) of laser pulses that appropriately intercept droplets at the appropriate place and time for effective and efficient EUV light generation.

光源800亦可包括導引雷射875，該導引雷射可用以對準光源800之各個區段或輔助將經放大光束810轉向至電漿形成區705。結合導引雷射875，光源800包括度量衡系統824，該度量衡系統被置放於聚焦總成822內以對來自導引雷射875之光之一部分及經放大光束810進行取樣。在其他實施中，度量衡系統824被置放於光束傳送系統820內。度量衡系統824可包括對光之子集進行取樣或重新引導之光學元件，此光學元件係由可耐受導引雷射光束及經放大光束810之功率的任何材料製成。光束分析系統係由度量衡系統824及主控控制器855形成，此係由於主控控制器855分析自導引雷射875取樣之光且使用此資訊以經由光束控制系統858調整聚焦總成822內之組件。The light source 800 may also include a guide laser 875, which can be used to align each section of the light source 800 or to assist in steering the amplified light beam 810 to the plasma formation region 705. In combination with the guide laser 875, the light source 800 includes a metrology system 824 that is placed in the focusing assembly 822 to sample a portion of the light from the guide laser 875 and the amplified beam 810. In other implementations, the metrology system 824 is placed in the beam delivery system 820. The metrology system 824 may include an optical element that samples or redirects a subset of light. The optical element is made of any material that can withstand the power of the guided laser beam and the amplified beam 810. The beam analysis system is formed by the metrology system 824 and the main control controller 855. This is because the main control controller 855 analyzes the light sampled by the self-guided laser 875 and uses this information to adjust the focus assembly 822 via the beam control system 858的components.

因此，概言之，光源800產生經放大光束810，該經放大光束沿著光束路徑經引導以輻照電漿形成區805處之目標混合物814，以將混合物814內之目標材料轉換成發射在EUV範圍內之光之電漿。經放大光束810在基於雷射系統815之設計及屬性而判定之特定波長(其亦被稱作驅動雷射波長)下操作。另外，當目標材料將足夠回饋提供回至雷射系統815中以產生相干雷射光時或在驅動雷射系統815包括合適光學回饋以形成雷射空腔的情況下，經放大光束810可為雷射光束。Therefore, in summary, the light source 800 generates an amplified light beam 810 that is guided along the beam path to irradiate the target mixture 814 at the plasma forming region 805 to convert the target material in the mixture 814 into emission Plasma of light within EUV range. The amplified light beam 810 operates at a specific wavelength determined based on the design and properties of the laser system 815 (which is also referred to as the driving laser wavelength). In addition, when the target material provides sufficient feedback to the laser system 815 to generate coherent laser light or in the case that the driving laser system 815 includes appropriate optical feedback to form a laser cavity, the amplified beam 810 can be a laser beam. Shoot the beam.

其他實施方案係在申請專利範圍之範疇內。Other implementation schemes are within the scope of the patent application.

在以下編號條項中闡明本發明之其他態樣。 1. 一種極紫外(EUV)光源，其包含：一真空容器；一目標材料供應系統，其經組態以將目標供應至該真空容器之一內部，該等目標包含至少一第一目標，其中該第一目標在該真空容器中之一初始目標區處具有一初始形狀；一第一光學源，其經組態以將一第一光束提供至該真空容器中之一第一目標區，該第一光束經組態以修改該初始目標之該初始形狀以形成一經修改目標；及一第二光學源，其經組態以將一第二光束提供至該真空容器中之一第二目標區，該第二目標區經組態以接收該經修改目標，該第二光束經組態以與該經修改目標相互作用且將該經修改目標中之目標材料中的至少一些轉換成發射EUV光之一電漿，其中該第一目標之該初始形狀受控制以藉此控制根據該第二光束與該經修改目標之間的該相互作用而產生的電漿之一量。 2. 如條項1之EUV光源，其中該目標材料包含一熔融金屬，且該供應系統包含：一儲集器，其經組態以固持該目標材料；一噴嘴，其經組態以流體地耦接至該儲集器且將該等目標發射至該真空容器之該內部中；及一致動器，其機械地連接至該噴嘴。 3. 如條項2之EUV光源，其中該初始目標區處之該第一目標之該初始形狀係藉由致使該致動器以多於一個頻率使該噴嘴振動來控制。 4. 如條項2之EUV光源，其中該第一目標與一第二目標之間的一間距係藉由調整施加至該儲集器中之該目標材料之一壓力來控制，且該第二目標在該第一目標之前由該目標供應系統供應。 5. 如條項4之EUV光源，其中該第一目標之該初始形狀係基於該第一目標與一第二目標之間的該受控間距。 6. 如條項1之EUV光源，其進一步包含經組態以將一第三光束提供至一第三目標區之一第三光學源，且其中該第三目標區經組態以接收該第一目標，且該初始目標區處之該第一目標之該初始形狀係藉由使該第一目標與該第三光束相互作用而控制。 7. 如條項6之EUV光源，其中該第三目標區比該第一目標區及該第二目標區更接近該目標材料供應系統。 8. 如條項1之EUV光源，其中該初始目標區處之該第一目標之該初始形狀包含熔融金屬之一扁圓球，該扁圓球具有沿著一第一方向之一第一範圍及沿著垂直於該第一方向之一第二方向之一第二範圍，且該第一範圍對該第二範圍之比率係介於0.6與0.8之間。 9. 如條項1之EUV光源，其中該初始目標區處之該第一目標之該初始形狀包含熔融金屬之一扁圓球，該扁圓球具有沿著一第一方向之一第一範圍及沿著垂直於該第一方向之一第二方向之一第二範圍，且該第一範圍對該第二範圍之比率係介於0.75與0.9之間。 10. 如條項1之EUV光源，其中該初始目標區處之該第一目標之該初始形狀包含熔融金屬之一扁圓球，該扁圓球具有沿著一第一方向之一第一範圍及沿著垂直於該第一方向之一第二方向之一第二範圍，且該第一範圍對該第二範圍之比率約為0.8。 11. 如條項1之EUV光源，其中該經修改目標具有藉由該初始目標區處之該第一目標之該初始形狀判定之一形態，該形態描述在三維中該目標之一形狀及/或一目標材料密度。 12. 如條項11之EUV光源，其中該經修改目標包含在該三維中之一者中的一側向範圍，該側向範圍取決於該第一目標區與該第二目標區之間的一距離。 13. 如條項1之EUV光源，其中該第一目標材料小滴之該初始形狀受控制以藉此控制根據該第二光束與該經修改目標之間的該相互作用而產生之電漿之一量包含：該第一目標材料之該初始形狀受控制以藉此控制該EUV光源之一轉換效率(CE)，該CE為供應至該經修改目標之能量對作為EUV光自該電漿發射之能量的一比率。 14. 如條項1之EUV光源，其中該初始目標區係介於該目標材料供應系統與該第一目標區之間。 15. 一種控制一極紫外(EUV)光源中之轉換效率(CE)之方法，該方法包含：藉由控制該EUV光源之一組件來判定一初始目標之一初始形狀；致使一預脈衝光束與該初始目標相互作用以形成一經修改目標；及致使一主光學脈衝與該經修改目標相互作用以產生發射EUV光之一電漿，其中該經修改目標與該主光學脈衝之間的該相互作用係與一轉換效率(CE)相關聯，該CE為供應至該經修改目標之能量對作為EUV光自該電漿發射之能量的一比率，且該CE係基於該初始目標之該經判定初始形狀而控制。 16. 如條項15之方法，其中該EUV光源之該組件包含作為一目標材料供應系統之一部分的一儲集器，且判定該初始目標之該初始形狀包含在由該目標供應系統產生該初始目標之前控制該儲集器中之熔融目標材料上的一壓力量。 17. 如條項16之方法，其中控制該儲集器中之該熔融目標材料上的該壓力量會控制該初始目標與另一目標之間的一間距，且該初始目標之該初始形狀係基於該間距。 18. 如條項15之方法，其中該EUV光源之該組件包含耦接至一目標材料供應系統之一毛細管之一致動器，且判定該初始目標之該初始形狀包含控制該致動器使得該致動器以多於一個頻率使該管振動。 19. 如條項18之方法，其中控制該致動器使得該致動器以多於一個頻率使該管振動會自一目標材料射流產生一聚結目標串流，且該方法進一步包含調整該多於一個頻率中之一者使得該等聚結目標中之兩者合併成一合併目標，且該初始目標係該合併目標。 20. 如條項15之方法，其中該EUV光源之組件包含經組態以供應該初始目標及至少一第二目標之一目標材料供應系統，且判定該初始目標之該初始形狀包含控制該目標材料供應系統使得調整該初始目標與該第二目標之間的一間距，該第二目標在該初始目標之前由該目標供應系統供應。 21. 如條項15之方法，其中該EUV光源之該組件包含經組態以提供一初始光束之一初始光源，且判定該初始目標之該初始形狀包含控制該初始光源使得該初始光束與該初始目標相互作用，且其中該初始目標之該初始形狀藉由使該初始目標與該初始光束相互作用而至少部分地判定。Other aspects of the present invention are explained in the following numbered items. 1. An extreme ultraviolet (EUV) light source, which includes: A vacuum container; A target material supply system configured to supply targets into one of the vacuum containers, the targets including at least one first target, wherein the first target has an initial target area in the vacuum container Initial shape A first optical source configured to provide a first light beam to a first target area in the vacuum vessel, the first light beam being configured to modify the initial shape of the initial target to form a modified target ;and A second optical source configured to provide a second light beam to a second target area in the vacuum vessel, the second target area being configured to receive the modified target, the second light beam being grouped State to interact with the modified target and convert at least some of the target materials in the modified target into a plasma that emits EUV light, wherein The initial shape of the first target is controlled to thereby control an amount of plasma generated according to the interaction between the second light beam and the modified target. 2. Such as the EUV light source of item 1, where the target material includes a molten metal, and the supply system includes: A reservoir configured to hold the target material; A nozzle configured to be fluidly coupled to the reservoir and launch the targets into the interior of the vacuum vessel; and An actuator, which is mechanically connected to the nozzle. 3. The EUV light source of Clause 2, wherein the initial shape of the first target at the initial target area is controlled by causing the actuator to vibrate the nozzle at more than one frequency. 4. Such as the EUV light source of Clause 2, wherein a distance between the first target and a second target is controlled by adjusting a pressure applied to the target material in the reservoir, and the second The target is supplied by the target supply system before the first target. 5. Such as the EUV light source of Clause 4, wherein the initial shape of the first target is based on the controlled distance between the first target and a second target. 6. As the EUV light source of Clause 1, it further includes a third optical source configured to provide a third light beam to a third target area, and wherein the third target area is configured to receive the third optical source A target, and the initial shape of the first target at the initial target area is controlled by making the first target interact with the third beam. 7. The EUV light source as in Clause 6, wherein the third target area is closer to the target material supply system than the first target area and the second target area. 8. The EUV light source of Clause 1, wherein the initial shape of the first target at the initial target area includes an oblate sphere of molten metal, and the oblate sphere has a first range along a first direction And a second range along a second direction perpendicular to the first direction, and the ratio of the first range to the second range is between 0.6 and 0.8. 9. Such as the EUV light source of Clause 1, wherein the initial shape of the first target at the initial target area includes an oblate sphere of molten metal, and the oblate sphere has a first range along a first direction And a second range along a second direction perpendicular to the first direction, and the ratio of the first range to the second range is between 0.75 and 0.9. 10. The EUV light source of Clause 1, wherein the initial shape of the first target at the initial target area includes an oblate sphere of molten metal, and the oblate sphere has a first range along a first direction And a second range along a second direction perpendicular to the first direction, and the ratio of the first range to the second range is about 0.8. 11. The EUV light source of Clause 1, wherein the modified target has a form determined by the initial shape of the first target at the initial target area, and the form describes a shape of the target in three dimensions and/ Or a target material density. 12. The EUV light source of Clause 11, wherein the modified target includes a lateral range in one of the three dimensions, and the lateral range depends on the distance between the first target area and the second target area A distance. 13. The EUV light source of Clause 1, wherein the initial shape of the first target material droplet is controlled to thereby control the plasma generated by the interaction between the second light beam and the modified target A quantity includes: the initial shape of the first target material is controlled to thereby control a conversion efficiency (CE) of the EUV light source, the CE being the energy pair supplied to the modified target as EUV light emitted from the plasma A ratio of its energy. 14. The EUV light source of item 1, wherein the initial target area is between the target material supply system and the first target area. 15. A method for controlling the conversion efficiency (CE) of an extreme ultraviolet (EUV) light source, the method includes: Determining an initial shape of an initial target by controlling a component of the EUV light source; Causing a pre-pulse beam to interact with the initial target to form a modified target; and Causing a main optical pulse to interact with the modified target to produce a plasma that emits EUV light, wherein the interaction between the modified target and the main optical pulse is associated with a conversion efficiency (CE), the CE is a ratio of the energy supplied to the modified target to the energy emitted from the plasma as EUV light, and the CE is controlled based on the determined initial shape of the initial target. 16. The method of clause 15, wherein the component of the EUV light source includes a reservoir as part of a target material supply system, and Determining the initial shape of the initial target includes controlling an amount of pressure on the molten target material in the reservoir before the initial target is generated by the target supply system. 17. The method of clause 16, wherein controlling the amount of pressure on the molten target material in the reservoir controls a distance between the initial target and another target, and the initial shape of the initial target is Based on the distance. 18. The method of clause 15, wherein the component of the EUV light source includes an actuator coupled to a capillary tube of a target material supply system, and Determining the initial shape of the initial target includes controlling the actuator so that the actuator vibrates the tube at more than one frequency. 19. The method of clause 18, wherein controlling the actuator so that the actuator vibrates the tube at more than one frequency will generate a coalescing target stream from a target material jet, and the method further comprises adjusting the One of more than one frequency causes two of the coalescing targets to merge into a merged target, and the initial target is the merged target. 20. The method of clause 15, wherein the components of the EUV light source include a target material supply system configured to supply one of the initial target and at least one second target, and Determining the initial shape of the initial target includes controlling the target material supply system to adjust a distance between the initial target and the second target, and the second target is supplied by the target supply system before the initial target. 21. The method of clause 15, wherein the component of the EUV light source includes an initial light source configured to provide an initial light beam, and Determining the initial shape of the initial target includes controlling the initial light source so that the initial beam interacts with the initial target, and wherein the initial shape of the initial target is determined at least in part by making the initial target interact with the initial beam .

1:列 2:列 3:列 21:輻射光束 22:琢面化場鏡面器件 24:琢面化光瞳鏡面器件 26:曝光光E 28:反射元件 30:反射元件 100:極紫外(EUV)光源 101:極紫外(EUV)微影系統 104_1:光脈衝/主脈衝 104_2:光脈衝 105_1:光束遞送系統 105_2:光束遞送系統 106_1:第一光束 106_2:第二光束 107_1:光學路徑 107_2:光束路徑/光學路徑 108:光學系統或光產生模組 108_1:光學源 108_2:光學源 109:真空腔室 110:目標供應系統 111:目標混合物 112_1:光學系統 112_2:光學系統 113:光學元件 114:毛細管 115:側壁 116:反射表面 117:目標形成結構 118:儲集器 119:孔口 121:目標串流 121m:經修改目標 121p:初始目標 124_1:目標區 124_2:目標區 125:連續射流 129:命令信號 130:感測器系統 132:調變器/致動器 135:感測器 150:控制系統 152:資料鏈路 154:電子處理器模組 156:電子儲存器 157:信號 158:I/O介面 170:壓力系統 193:極紫外(EUV)光 195:基板 196:電漿 197:光 198:極紫外(EUV)曝光光束 199:輸出裝置/微影裝置 200:極紫外(EUV)光源 201:極紫外(EUV)微影系統 204_3:第三光脈衝 205_3:光束遞送系統 206_3:光束 208_3:光學源 221i:目標 224_3:目標區 300:程序 310:步驟 320:步驟 330:步驟 400:極紫外(EUV)光源 404_2:脈衝 421_a:目標 421_b:目標 421p:初始目標 423:距離 496:電漿 500:極紫外(EUV)光源 681:標繪圖 682:標繪圖 683:標繪圖 684:標繪圖 685:標繪圖 691:標繪圖 692:標繪圖 693:標繪圖 694:標繪圖 695:標繪圖 696:標繪圖 700:微影系統 760:輻射光束B 800:雷射產生電漿(LPP)極紫外(EUV)光源 805:電漿形成區 807:內部 810:經放大光束 814:目標混合物 815:驅動雷射/驅動雷射系統 820:光束傳送系統 822:聚焦總成 825:供應系統 826:目標材料遞送控制系統 827:目標材料供應裝置 830:真空腔室 835:收集器鏡面 840:孔隙 845:中間部位 850:開端式中空圓錐形護罩 855:主控控制器 856:小滴位置偵測回饋系統 857:雷射控制系統 858:光束控制系統 860:目標或小滴成像器 865:光源偵測器 870:光源偵測器 875:導引雷射 A:行 B:行/輻射光束 C:行/目標部分 D:行 E:行 F:行 G:行 IF:中間焦點 IL:照明系統 M1:圖案化器件對準標記 M2:圖案化器件對準標記 MA:圖案化器件 MT:支撐結構 P1:基板對準標記 P2:基板對準標記 PM:第一*** PS:投影系統 PS1:位置感測器/定位感測器 PS2:第二位置感測器/定位感測器 PW:第二*** p:壓力 SO:源收集器模組 W:基板 WT:基板台1: column 2: column 3: column 21: Radiation beam 22: Faceted field mirror device 24: Faceted pupil mirror device 26: Exposure light E 28: reflective element 30: reflective element 100: extreme ultraviolet (EUV) light source 101: extreme ultraviolet (EUV) lithography system 104_1: light pulse/main pulse 104_2: light pulse 105_1: beam delivery system 105_2: beam delivery system 106_1: First beam 106_2: second beam 107_1: optical path 107_2: beam path/optical path 108: Optical system or light generating module 108_1: optical source 108_2: Optical source 109: Vacuum chamber 110: Target Supply System 111: Target Mix 112_1: optical system 112_2: optical system 113: Optical components 114: Capillary 115: side wall 116: reflective surface 117: Goal formation structure 118: Reservoir 119: Orifice 121: Target Stream 121m: modified target 121p: initial goal 124_1: target area 124_2: target area 125: continuous jet 129: Command signal 130: sensor system 132: Modulator/actuator 135: Sensor 150: control system 152: Data Link 154: Electronic processor module 156: Electronic Storage 157: Signal 158: I/O interface 170: Pressure System 193: extreme ultraviolet (EUV) light 195: Substrate 196: Plasma 197: Light 198: extreme ultraviolet (EUV) exposure beam 199: output device/lithography device 200: extreme ultraviolet (EUV) light source 201: Extreme Ultraviolet (EUV) Lithography System 204_3: third light pulse 205_3: beam delivery system 206_3: beam 208_3: Optical source 221i: target 224_3: target area 300: program 310: Step 320: step 330: Step 400: extreme ultraviolet (EUV) light source 404_2: Pulse 421_a: target 421_b: target 421p: initial goal 423: distance 496: Plasma 500: extreme ultraviolet (EUV) light source 681: Plotting 682: Plotting 683: Plotting 684: Plotting 685: Plotting 691: Plotting 692: Plotting 693: Plotting 694: Plotting 695: Plotting 696: Plotting 700: Lithography System 760: Radiation beam B 800: Laser-generated plasma (LPP) extreme ultraviolet (EUV) light source 805: Plasma Formation Area 807: internal 810: Amplified beam 814: Target Mix 815: Drive laser / drive laser system 820: beam delivery system 822: Focus assembly 825: Supply System 826: Target Material Delivery Control System 827: Target Material Supply Device 830: vacuum chamber 835: collector mirror 840: Pore 845: middle part 850: Open-ended hollow conical shield 855: Master Controller 856: Droplet position detection feedback system 857: Laser Control System 858: Beam Control System 860: Target or droplet imager 865: Light Source Detector 870: Light Source Detector 875: Guided Laser A: OK B: line/radiation beam C: line/target part D: OK E: OK F: OK G: OK IF: Intermediate focus IL: lighting system M1: Patterned device alignment mark M2: Patterned device alignment mark MA: Patterned device MT: Supporting structure P1: substrate alignment mark P2: substrate alignment mark PM: the first locator PS: Projection system PS1: Position Sensor/Position Sensor PS2: second position sensor/positioning sensor PW: second locator p: pressure SO: Source Collector Module W: substrate WT: substrate table

圖1為極紫外(EUV)光源之方塊圖。Figure 1 is a block diagram of an extreme ultraviolet (EUV) light source.

圖2為另一極紫外(EUV)光源之方塊圖。Figure 2 is a block diagram of another extreme ultraviolet (EUV) light source.

圖3為用以控制EUV光源中之轉換效率(CE)之實例程序的流程圖。Fig. 3 is a flowchart of an example program for controlling the conversion efficiency (CE) in the EUV light source.

圖4為另一極紫外(EUV)光源之方塊圖。Figure 4 is a block diagram of another extreme ultraviolet (EUV) light source.

圖5為另一極紫外(EUV)光源之方塊圖。Figure 5 is a block diagram of another extreme ultraviolet (EUV) light source.

圖6A至圖6D為實驗資料之實例。Figures 6A to 6D are examples of experimental data.

圖7A及圖7B為微影系統之方塊圖。Figures 7A and 7B are block diagrams of the lithography system.

圖8為另一極紫外(EUV)光源之方塊圖。Figure 8 is a block diagram of another extreme ultraviolet (EUV) light source.

100:極紫外(EUV)光源 100: extreme ultraviolet (EUV) light source

101:極紫外(EUV)微影系統 101: extreme ultraviolet (EUV) lithography system

104_1:光脈衝/主脈衝 104_1: light pulse/main pulse

104_2:光脈衝 104_2: light pulse

105_1:光束遞送系統 105_1: beam delivery system

105_2:光束遞送系統 105_2: beam delivery system

106_1:第一光束 106_1: First beam

106_2:第二光束 106_2: second beam

107_1:光學路徑 107_1: optical path

107_2:光束路徑/光學路徑 107_2: beam path/optical path

108:光學系統或光產生模組 108: Optical system or light generating module

108_1:光學源 108_1: optical source

108_2:光學源 108_2: Optical source

109:真空腔室 109: Vacuum chamber

110:目標供應系統 110: Target Supply System

111:目標混合物 111: Target Mix

112_1:光學系統 112_1: optical system

112_2:光學系統 112_2: optical system

113:光學元件 113: Optical components

114:毛細管 114: Capillary

115:側壁 115: side wall

116:反射表面 116: reflective surface

117:目標形成結構 117: Goal formation structure

118:儲集器 118: Reservoir

119:孔口 119: Orifice

121:目標串流 121: Target Stream

121m:經修改目標 121m: modified target

121p:初始目標 121p: initial goal

124_1:目標區 124_1: target area

124_2:目標區 124_2: target area

125:連續射流 125: continuous jet

129:命令信號 129: Command signal

130:感測器系統 130: sensor system

132:調變器/致動器 132: Modulator/actuator

135:感測器 135: Sensor

150:控制系統 150: control system

152:資料鏈路 152: Data Link

154:電子處理器模組 154: Electronic processor module

156:電子儲存器 156: Electronic Storage

157:信號 157: Signal

158:I/O介面 158: I/O interface

170:壓力系統 170: Pressure System

193:極紫外(EUV)光 193: extreme ultraviolet (EUV) light

195:基板 195: Substrate

196:電漿 196: Plasma

197:光 197: Light

198:極紫外(EUV)曝光光束 198: extreme ultraviolet (EUV) exposure beam

199:輸出裝置/微影裝置 199: output device/lithography device

p:壓力 p: pressure

Claims

一種極紫外(EUV)光源，其包含：一真空容器；一目標材料供應系統，其經組態以將目標供應至該真空容器之一內部，該等目標包含至少一第一目標，其中該第一目標在該真空容器中之一初始目標區處具有一初始形狀；一第一光學源，其經組態以將一第一光束提供至該真空容器中之一第一目標區，該第一光束經組態以修改該初始目標之該初始形狀以形成一經修改目標；及一第二光學源，其經組態以將一第二光束提供至該真空容器中之一第二目標區，該第二目標區經組態以接收該經修改目標，該第二光束經組態以與該經修改目標相互作用且將該經修改目標中之目標材料中的至少一些轉換成發射EUV光之一電漿，其中該第一目標之該初始形狀受控制以藉此控制根據該第二光束與該經修改目標之間的該相互作用而產生的電漿之一量。An extreme ultraviolet (EUV) light source, which includes: A vacuum container; A target material supply system configured to supply targets into one of the vacuum containers, the targets including at least one first target, wherein the first target has an initial target area in the vacuum container Initial shape A first optical source configured to provide a first light beam to a first target area in the vacuum vessel, the first light beam being configured to modify the initial shape of the initial target to form a modified target ;and A second optical source configured to provide a second light beam to a second target area in the vacuum vessel, the second target area being configured to receive the modified target, the second light beam being grouped State to interact with the modified target and convert at least some of the target materials in the modified target into a plasma that emits EUV light, wherein The initial shape of the first target is controlled to thereby control an amount of plasma generated according to the interaction between the second light beam and the modified target.

如請求項1之EUV光源，其中該目標材料包含一熔融金屬，且該供應系統包含：一儲集器，其經組態以固持該目標材料；一噴嘴，其經組態以流體地耦接至該儲集器且將該等目標發射至該真空容器之該內部中；及一致動器，其機械地連接至該噴嘴。Such as the EUV light source of claim 1, wherein the target material includes a molten metal, and the supply system includes: A reservoir configured to hold the target material; A nozzle configured to be fluidly coupled to the reservoir and launch the targets into the interior of the vacuum vessel; and An actuator, which is mechanically connected to the nozzle.

如請求項2之EUV光源，其中該初始目標區處之該第一目標之該初始形狀係藉由致使該致動器以多於一個頻率使該噴嘴振動來控制。Such as the EUV light source of claim 2, wherein the initial shape of the first target at the initial target area is controlled by causing the actuator to vibrate the nozzle at more than one frequency.

如請求項2之EUV光源，其中該第一目標與一第二目標之間的一間距係藉由調整施加至該儲集器中之該目標材料之一壓力來控制，且該第二目標在該第一目標之前由該目標供應系統供應。Such as the EUV light source of claim 2, wherein a distance between the first target and a second target is controlled by adjusting a pressure applied to the target material in the reservoir, and the second target is at The first target was previously supplied by the target supply system.

如請求項4之EUV光源，其中該第一目標之該初始形狀係基於該第一目標與一第二目標之間的該受控間距。Such as the EUV light source of claim 4, wherein the initial shape of the first target is based on the controlled distance between the first target and a second target.

如請求項1之EUV光源，其進一步包含經組態以將一第三光束提供至一第三目標區之一第三光學源，且其中該第三目標區經組態以接收該第一目標，且該初始目標區處之該第一目標之該初始形狀係藉由使該第一目標與該第三光束相互作用而控制。Such as the EUV light source of claim 1, which further includes a third optical source configured to provide a third light beam to a third target area, and wherein the third target area is configured to receive the first target , And the initial shape of the first target at the initial target area is controlled by making the first target interact with the third light beam.

如請求項6之EUV光源，其中該第三目標區比該第一目標區及該第二目標區更接近該目標材料供應系統。Such as the EUV light source of claim 6, wherein the third target area is closer to the target material supply system than the first target area and the second target area.

如請求項1之EUV光源，其中該初始目標區處之該第一目標之該初始形狀包含熔融金屬之一扁圓球，該扁圓球具有沿著一第一方向之一第一範圍及沿著垂直於該第一方向之一第二方向之一第二範圍，且該第一範圍對該第二範圍之比率係介於0.6與0.8之間。Such as the EUV light source of claim 1, wherein the initial shape of the first target at the initial target area includes an oblate sphere of molten metal, the oblate sphere having a first range along a first direction and an edge A second range is perpendicular to a second direction of the first direction, and the ratio of the first range to the second range is between 0.6 and 0.8.

如請求項1之EUV光源，其中該初始目標區處之該第一目標之該初始形狀包含熔融金屬之一扁圓球，該扁圓球具有沿著一第一方向之一第一範圍及沿著垂直於該第一方向之一第二方向之一第二範圍，且該第一範圍對該第二範圍之比率係介於0.75與0.9之間。Such as the EUV light source of claim 1, wherein the initial shape of the first target at the initial target area includes an oblate sphere of molten metal, the oblate sphere having a first range along a first direction and an edge A second range is perpendicular to a second direction of the first direction, and the ratio of the first range to the second range is between 0.75 and 0.9.

如請求項1之EUV光源，其中該初始目標區處之該第一目標之該初始形狀包含熔融金屬之一扁圓球，該扁圓球具有沿著一第一方向之一第一範圍及沿著垂直於該第一方向之一第二方向之一第二範圍，且該第一範圍對該第二範圍之比率約為0.8。Such as the EUV light source of claim 1, wherein the initial shape of the first target at the initial target area includes an oblate sphere of molten metal, the oblate sphere having a first range along a first direction and an edge A second range is perpendicular to the first direction and a second direction, and the ratio of the first range to the second range is about 0.8.

如請求項1之EUV光源，其中該經修改目標具有藉由該初始目標區處之該第一目標之該初始形狀判定之一形態，該形態描述在三維中該目標之一形狀及/或一目標材料密度。Such as the EUV light source of claim 1, wherein the modified target has a form determined by the initial shape of the first target at the initial target area, and the form describes a shape and/or a shape of the target in three dimensions Target material density.

如請求項11之EUV光源，其中該經修改目標包含在該三維中之一者中的一側向範圍，該側向範圍取決於該第一目標區與該第二目標區之間的一距離。Such as the EUV light source of claim 11, wherein the modified target includes a lateral range in one of the three dimensions, and the lateral range depends on a distance between the first target area and the second target area .

如請求項1之EUV光源，其中該第一目標材料小滴之該初始形狀受控制以藉此控制根據該第二光束與該經修改目標之間的該相互作用而產生之電漿之一量包含：該第一目標材料之該初始形狀受控制以藉此控制該EUV光源之一轉換效率(CE)，該CE為供應至該經修改目標之能量對作為EUV光自該電漿發射之能量的一比率。The EUV light source of claim 1, wherein the initial shape of the first target material droplet is controlled to thereby control an amount of plasma generated according to the interaction between the second light beam and the modified target Containing: the initial shape of the first target material is controlled to thereby control a conversion efficiency (CE) of the EUV light source, the CE being the energy pair supplied to the modified target as EUV light emitted from the plasma A ratio of.

如請求項1之EUV光源，其中該初始目標區係介於該目標材料供應系統與該第一目標區之間。Such as the EUV light source of claim 1, wherein the initial target zone is between the target material supply system and the first target zone.

一種控制一極紫外(EUV)光源中之轉換效率(CE)之方法，該方法包含：藉由控制該EUV光源之一組件來判定一初始目標之一初始形狀；致使一預脈衝光束與該初始目標相互作用以形成一經修改目標；及致使一主光學脈衝與該經修改目標相互作用以產生發射EUV光之一電漿，其中該經修改目標與該主光學脈衝之間的該相互作用係與一轉換效率(CE)相關聯，該CE為供應至該經修改目標之能量對作為EUV光自該電漿發射之能量的一比率，且該CE係基於該初始目標之該經判定初始形狀而控制。A method for controlling the conversion efficiency (CE) of an extreme ultraviolet (EUV) light source, the method includes: Determining an initial shape of an initial target by controlling a component of the EUV light source; Causing a pre-pulse beam to interact with the initial target to form a modified target; and Causing a main optical pulse to interact with the modified target to produce a plasma that emits EUV light, wherein the interaction between the modified target and the main optical pulse is associated with a conversion efficiency (CE), the CE is a ratio of the energy supplied to the modified target to the energy emitted from the plasma as EUV light, and the CE is controlled based on the determined initial shape of the initial target.

如請求項15之方法，其中該EUV光源之該組件包含作為一目標材料供應系統之一部分的一儲集器，且判定該初始目標之該初始形狀包含在由該目標供應系統產生該初始目標之前控制該儲集器中之熔融目標材料上的一壓力量。The method of claim 15, wherein the component of the EUV light source includes a reservoir as part of a target material supply system, and Determining the initial shape of the initial target includes controlling an amount of pressure on the molten target material in the reservoir before the initial target is generated by the target supply system.

如請求項16之方法，其中控制該儲集器中之該熔融目標材料上的該壓力量會控制該初始目標與另一目標之間的一間距，且該初始目標之該初始形狀係基於該間距。The method of claim 16, wherein controlling the amount of pressure on the molten target material in the reservoir controls a distance between the initial target and another target, and the initial shape of the initial target is based on the spacing.

如請求項15之方法，其中該EUV光源之該組件包含耦接至一目標材料供應系統之一毛細管之一致動器，且判定該初始目標之該初始形狀包含控制該致動器使得該致動器以多於一個頻率使該管振動。The method of claim 15, wherein the component of the EUV light source includes an actuator coupled to a capillary tube of a target material supply system, and Determining the initial shape of the initial target includes controlling the actuator so that the actuator vibrates the tube at more than one frequency.

如請求項18之方法，其中控制該致動器使得該致動器以多於一個頻率使該管振動會自一目標材料射流產生一聚結目標串流，且該方法進一步包含調整該多於一個頻率中之一者使得該等聚結目標中之兩者合併成一合併目標，且該初始目標係該合併目標。The method of claim 18, wherein controlling the actuator so that the actuator vibrates the tube at more than one frequency will generate a coalesced target stream from a target material jet, and the method further comprises adjusting the more than One of a frequency causes two of the coalescing targets to be merged into a merged target, and the initial target is the merged target.

如請求項15之方法，其中該EUV光源之組件包含經組態以供應該初始目標及至少一第二目標之一目標材料供應系統，且判定該初始目標之該初始形狀包含控制該目標材料供應系統使得調整該初始目標與該第二目標之間的一間距，該第二目標在該初始目標之前由該目標供應系統供應。The method of claim 15, wherein the component of the EUV light source includes a target material supply system configured to supply the initial target and at least one second target, and Determining the initial shape of the initial target includes controlling the target material supply system to adjust a distance between the initial target and the second target, and the second target is supplied by the target supply system before the initial target.

如請求項15之方法，其中該EUV光源之該組件包含經組態以提供一初始光束之一初始光源，且判定該初始目標之該初始形狀包含控制該初始光源使得該初始光束與該初始目標相互作用，且其中該初始目標之該初始形狀藉由使該初始目標與該初始光束相互作用而至少部分地判定。The method of claim 15, wherein the component of the EUV light source includes an initial light source configured to provide an initial light beam, and Determining the initial shape of the initial target includes controlling the initial light source so that the initial beam interacts with the initial target, and wherein the initial shape of the initial target is determined at least in part by making the initial target interact with the initial beam .