TWI592978B - Method for processing substrate in a plasma processing chamber - Google Patents
Method for processing substrate in a plasma processing chamber Download PDFInfo
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- H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
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- H01J37/32174—Circuits specially adapted for controlling the RF discharge
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Description
本申請案係與於2012年2月22日提出申請之名為「多頻率射頻脈衝用之頻率增強阻抗相關功率控制」、代理人案號P2301P/LMRX-P222P1、申請序號61/602,040之共同轉讓的專利申請案相關，以及與於2012年2月22日提出申請之名為「用以同步電漿處理系統中之射頻脈衝的方法及設備」、代理人案號P2296P/LMRX-P221P1、申請序號61/602,401之共同轉讓的專利申請案相關，其係全數併入於此作為參考。 This application is a joint transfer of the frequency-enhanced impedance-related power control for multi-frequency RF pulses, and the agent's case number P2301P/LMRX-P222P1, application number 61/602,040, which was filed on February 22, 2012. Related to the patent application, and the method and equipment for synchronizing the radio frequency pulse in the plasma processing system, filed on February 22, 2012, the agent's case number P2296P/LMRX-P221P1, application serial number The commonly-assigned patent application of 61/602, 401 is incorporated herein by reference in its entirety.
本發明關於用以控制電漿處理系統中之電漿的方法及設備。 The present invention relates to methods and apparatus for controlling plasma in a plasma processing system.
電漿處理長久以來已被用於處理基板(例如，晶圓或平板或其他基板)以製造電子元件(例如，積體電路或平板顯示器)。在電漿處理中，基板係置於電漿處理腔室中，該電漿處理腔室使用一或更多電極以激發來源氣體(其可為蝕刻來源氣體或沉積來源氣體)以形成用以處理基板之電漿。電極可由射頻信號所激發，射頻信號係由例如射頻產生器所輸送。 Plasma processing has long been used to process substrates (eg, wafers or plates or other substrates) to fabricate electronic components (eg, integrated circuits or flat panel displays). In the plasma processing, the substrate is placed in a plasma processing chamber that uses one or more electrodes to excite source gases (which may be etch source gases or deposition source gases) to form for processing Plasma of the substrate. The electrodes can be excited by a radio frequency signal that is delivered by, for example, a radio frequency generator.
在一些電漿處理系統中，數個射頻信號，其一部份可具有相同的或不同的射頻頻率，可提供至承載基板之電極(以下亦稱為下部電極或夾盤)，以當上部電極接地時產生電漿。例如，在電容耦合式電漿處理系統中，當頂部電極接地時，一或更多射頻信號可提供至底部電極。 In some plasma processing systems, a plurality of RF signals, a portion of which may have the same or different RF frequencies, may be provided to an electrode carrying a substrate (hereinafter also referred to as a lower electrode or a chuck) to serve as an upper electrode Produces plasma when grounded. For example, in a capacitively coupled plasma processing system, one or more RF signals can be provided to the bottom electrode when the top electrode is grounded.
在一些應用中，可脈衝地產生該複數射頻信號。對於任何既 定之射頻信號，射頻脈衝牽涉到在一脈衝頻率下打開和關閉射頻信號(或是在高功率位準與低功率位準之間交替，因為脈衝並不總是需要關閉電源)，該脈衝頻率可能不同於(且通常慢於)該射頻頻率。一般來說，在過去執行射頻脈衝是為了改善特定的處理結果(例如改善均勻性或減少與蝕刻有關的損害)。 In some applications, the complex RF signal can be pulsed. For any The RF signal, the RF pulse involves turning the RF signal on and off at a pulse frequency (either alternate between high power level and low power level, because the pulse does not always need to be turned off), the pulse frequency may Unlike (and usually slower than) the RF frequency. In general, RF pulses have been performed in the past to improve specific processing results (eg, to improve uniformity or reduce damage associated with etching).
各種射頻信號之脈衝可為不同步或同步。例如同步脈衝之情形，若兩個信號RF1和RF2係同步，則對於信號RF2之每一主動脈衝，皆有信號RF1之主動脈衝。該兩個射頻信號之脈衝可為同相，或是一射頻脈衝之前緣可落後於另一射頻脈衝之前緣，或是一個射頻脈衝之後緣可落後於另一射頻脈衝之後緣，或是該等射頻脈衝可為不同相。 The pulses of various RF signals can be out of sync or synchronized. For example, in the case of a sync pulse, if the two signals RF1 and RF2 are synchronized, for each active pulse of the signal RF2, there is an active pulse of the signal RF1. The pulses of the two RF signals may be in phase, or the leading edge of one RF pulse may lag behind the leading edge of another RF pulse, or the trailing edge of one RF pulse may lag behind the trailing edge of another RF pulse, or the RF The pulses can be different phases.
各種射頻信號之脈衝若未受妥善控制，則會有射頻功率不穩定性導致電漿擾動的風險，此發生在該等射頻信號之一或更多者由低至高(或反向)之轉變期間。這是因為在此由射頻信號之一或更多者的轉變期間，處理腔室中的電漿狀態改變所致。此改變可由匹配網路及/或其他射頻產生器所偵測，匹配網路及/或其他射頻產生器可能試圖補償所偵測到之電漿狀態的改變。此補償之反應性本質意味著，在偵測電漿狀態改變及成功的補償之間之一段期間，存在著導致電漿不穩定性的射頻功率擾動。 If the pulses of various RF signals are not properly controlled, there is a risk that the RF power instability will cause the plasma to be disturbed, which occurs during the transition from low to high (or reverse) of one or more of the RF signals. . This is due to a change in the state of the plasma in the processing chamber during the transition from one or more of the RF signals. This change may be detected by the matching network and/or other RF generators, and the matching network and/or other RF generators may attempt to compensate for changes in the detected plasma state. The reactive nature of this compensation means that there is a radio frequency power disturbance that causes plasma instability during a period between the detection of plasma state changes and successful compensation.
圖1呈現此射頻功率擾動之範例，此射頻功率擾動可導致在此等脈衝射頻信號之其中一者的轉變期間之電漿不穩定性。在圖1之範例中，2MHz之射頻信號在100Hz脈衝，並具有介於2,500W和0W之間之50%的工作週期。為便於說明，假設60MHz之射頻信號係在無脈衝之情況下於連續波(CW)模式下操作。隨著2MHz之射頻信號從低狀態102轉變至高狀態104，腔室內的電漿狀態係回應變化之供電而改變。當偵測到此電漿狀態之變化時，60MHz之射頻信號係顯示為補償(亦經由在60MHz之電源供應器中或在匹配網路中的補償電路)所偵測到的電漿狀態改變。 Figure 1 presents an example of such a radio frequency power disturbance that can result in plasma instability during transitions of one of the pulsed radio frequency signals. In the example of Figure 1, the 2 MHz RF signal is pulsed at 100 Hz and has a 50% duty cycle between 2,500 W and 0 W. For ease of explanation, it is assumed that the 60 MHz RF signal operates in continuous wave (CW) mode without pulses. As the 2 MHz RF signal transitions from the low state 102 to the high state 104, the plasma state within the chamber changes in response to the varying power supply. When this change in plasma state is detected, the 60 MHz RF signal is shown as a change in the plasma state detected by compensation (also via a compensation circuit in a 60 MHz power supply or in a matching network).
然而，這是一種反應性的回應，並取決於首先偵測由該2MHz之脈衝射頻信號(其如前所述地在為100Hz之脈衝頻率脈衝)由低至高的轉變所致之電漿狀態變化。延遲和隨後的回應導致由參考號碼106所示出之射頻功率位準擾動，射頻功率位準擾動顯示在2MHz的射頻信號由 低至高之轉變後，60MHz之射頻信號的功率位準暫時下降。另一個由於60MHz射頻信號之延遲回應所造成之60MHz之射頻信號的射頻功率位準擾動的情形，係顯示於參考號碼108中，此發生於2MHz之射頻信號由高(110)至低(112)之轉移後。其他射頻功率擾動係由例如參考數字114和116顯示於圖1中。如圖1中可看出，這些射頻功率擾動可在正方向或負方向，並可具有不同的強度。此等擾動導致不穩定及/或控制不佳的電漿事件，進而影響處理結果及/或元件良率。 However, this is a reactive response and depends on first detecting the change in plasma state caused by the low to high transition of the 2 MHz pulsed RF signal (which is pulsed at 100 Hz as previously described). . The delay and subsequent response result in a radio frequency power level disturbance as indicated by reference numeral 106, and the RF power level disturbance is displayed in the 2 MHz RF signal. After the low-to-high transition, the power level of the 60 MHz RF signal temporarily drops. Another case of RF power level disturbance of a 60 MHz RF signal caused by a delayed response of a 60 MHz RF signal is shown in reference number 108, which occurs from a high (110) to a low (110) RF signal at 2 MHz. After the transfer. Other RF power disturbances are shown in Figure 1 by, for example, reference numerals 114 and 116. As can be seen in Figure 1, these RF power disturbances can be in the positive or negative direction and can have different intensities. Such disturbances result in unstable and/or poorly controlled plasma events, which in turn affect processing results and/or component yield.
此外，現今的電漿處理在高密度、高性能元件之製造上，對於處理結果施加嚴格的要求。利用傳統的恆定波形射頻信號或利用傳統的射頻脈衝方法，一些製程容許度(process window)係無法到達或相當狹窄。 In addition, today's plasma processing imposes stringent requirements on the processing results in the manufacture of high density, high performance components. With conventional constant waveform RF signals or with conventional RF pulse methods, some process windows are unreachable or fairly narrow.
操縱和進一步控制各種射頻信號之脈衝，以改善電漿穩定性及/或提供額外的處理控制旋鈕，係為本發明之實施例的諸多目標之一。 Manipulating and further controlling the pulses of various radio frequency signals to improve plasma stability and/or provide additional processing control knobs is one of many goals of embodiments of the present invention.
在一實施例中，本發明關於一種用以處理在具有至少一電極之電漿處理腔室中之基板的方法。該電漿處理腔室具有複數射頻電源供應器，該等射頻電源供應源係耦接以提供複數射頻信號至該電極。本方法包含以第一脈衝頻率將基礎射頻脈衝信號脈衝地產生於高功率位準與低功率位準之間，該基礎射頻脈衝信號代表該複數射頻信號之第一射頻信號，該第一射頻信號具有在該複數射頻信號之脈衝頻率之間最低的脈衝頻率，該第一脈衝頻率係不同於於該基礎射頻脈衝信號之射頻頻率。 In one embodiment, the invention is directed to a method for processing a substrate in a plasma processing chamber having at least one electrode. The plasma processing chamber has a plurality of RF power supplies coupled to provide a plurality of RF signals to the electrodes. The method includes pulsing a base radio frequency pulse signal between a high power level and a low power level at a first pulse frequency, the base radio frequency pulse signal representing a first radio frequency signal of the complex radio frequency signal, the first radio frequency signal Having a lowest pulse frequency between the pulse frequencies of the complex RF signals, the first pulse frequency being different from the RF frequency of the base RF pulse signal.
本方法亦包含發送控制信號至少至該複數射頻電源供應器之一子集，其中該控制信號係以主動方式產生，使在處理該基板的同時，不需要感測由於該基礎脈衝信號之該脈衝所導致之一或更多腔室參數的改變。 The method also includes transmitting a control signal to at least a subset of the plurality of RF power supplies, wherein the control signal is generated in an active manner such that while the substrate is being processed, there is no need to sense the pulse due to the base pulse signal A change in one or more chamber parameters is caused.
本方法包含回應該控制信號，將複數射頻電源供應器之每一子集脈衝地產生於第一預定之射頻電源供應器特有的功率位準以及第二預定之射頻電源供應器特有的功率位準之間，該第二預定之射頻電源供應器特有的功率位準係不同於該第一預定之射頻電源供應器特有的功率位準。 The method includes a control signal that pulses each subset of the plurality of RF power supplies to generate a power level specific to the first predetermined RF power supply and a power level specific to the second predetermined RF power supply The power level specific to the second predetermined RF power supply is different from the power level specific to the first predetermined RF power supply.
本發明之這些及其它特徵將於以下的本發明之詳細說明並結合下列圖式予以詳細描述。 These and other features of the present invention will be described in detail in the following detailed description of the invention.
102‧‧‧低狀態 102‧‧‧Low state
104‧‧‧高狀態 104‧‧‧High state
106‧‧‧射頻功率位準擾動 106‧‧‧RF power level disturbance
108‧‧‧射頻功率位準擾動 108‧‧‧RF power level disturbance
110‧‧‧高狀態 110‧‧‧High state
112‧‧‧低狀態 112‧‧‧Low state
114‧‧‧其他的射頻功率擾動 114‧‧‧Other RF power disturbances
116‧‧‧其他的射頻功率擾動 116‧‧‧Other RF power disturbances
202‧‧‧電漿處理系統 202‧‧‧Plastic Processing System
204‧‧‧電漿處理腔室 204‧‧‧The plasma processing chamber
206‧‧‧上部電極 206‧‧‧Upper electrode
208‧‧‧下部電極 208‧‧‧lower electrode
220‧‧‧射頻電源供應器 220‧‧‧RF power supply
222‧‧‧射頻電源供應器 222‧‧‧RF power supply
224‧‧‧射頻電源供應器 224‧‧‧RF power supply
230‧‧‧匹配網路 230‧‧‧match network
231‧‧‧導管 231‧‧‧ catheter
232‧‧‧導管 232‧‧‧ catheter
234‧‧‧導管 234‧‧‧ catheter
250‧‧‧控制電路 250‧‧‧Control circuit
302‧‧‧2MHz之射頻信號 302‧‧2MHz RF signal
304‧‧‧60MHz之射頻信號 RF signal of 304‧‧60MHz
320‧‧‧功率擾動 320‧‧‧Power disturbance
322‧‧‧功率擾動 322‧‧‧Power disturbance
324‧‧‧功率擾動 324‧‧‧Power disturbance
328‧‧‧功率擾動 328‧‧‧Power disturbance
402‧‧‧2MHz之射頻信號 402‧‧2MHz RF signal
404‧‧‧60MHz之射頻信號 404‧‧60MHz RF signal
502‧‧‧射頻信號 502‧‧‧RF signal
504‧‧‧射頻信號 504‧‧‧RF signal
602‧‧‧射頻信號 602‧‧‧RF signal
604‧‧‧射頻信號 604‧‧‧RF signal
606‧‧‧射頻信號 606‧‧‧RF signal
700‧‧‧點 700‧‧ points
702‧‧‧射頻功率線 702‧‧‧RF power line
704‧‧‧點 704‧‧ points
706‧‧‧點 706‧‧ points
708‧‧‧點 708‧‧ points
710‧‧‧點 710‧‧ points
712‧‧‧點 712‧‧ points
714‧‧‧點 714‧‧ points
730‧‧‧線 730‧‧‧ line
802‧‧‧步驟 802‧‧ steps
804‧‧‧步驟 804‧‧‧ steps
806‧‧‧步驟 806‧‧‧Steps
902‧‧‧步驟 902‧‧ steps
904‧‧‧步驟 904‧‧‧Steps
906‧‧‧步驟 906‧‧‧Steps
本發明係藉由例示而非限制之方式顯示於隨附圖式中之圖形，且其中相似的參考數字表示相似的元件，且其中：圖1顯示此射頻功率擾動之範例，此射頻功率擾動可導致在該等脈衝射頻信號之其中一者的轉變期間的電漿不穩定性。 The present invention is shown by way of example, and not limitation, FIG. Causes plasma instability during transitions of one of the pulsed RF signals.
圖2顯示根據本發明之一實施例之簡化的電容耦合式電漿處理系統，該系統具有電漿處理腔室並用以進行各種射頻信號脈衝狀態之功率位準的控制。 2 shows a simplified capacitively coupled plasma processing system having a plasma processing chamber for controlling the power level of various RF signal pulse states in accordance with an embodiment of the present invention.
圖3為一曲線圖，顯示對於兩個射頻信號之所輸出功率與時間的關係，以說明主動同步各種射頻信號之間之脈衝的影響。 Figure 3 is a graph showing the output power versus time for two RF signals to illustrate the effect of actively synchronizing the pulses between various RF signals.
圖4顯示根據本發明之一實施例中，該60MHz之射頻信號使其功率位準配合該2MHz之射頻信號的脈衝狀態的情形。 4 shows a situation in which the 60 MHz RF signal has its power level matched to the pulse state of the 2 MHz RF signal, in accordance with an embodiment of the present invention.
圖5顯示根據本發明之另一實施例中，該60MHz之射頻信號使其功率位準配合該2MHz之射頻信號的脈衝狀態的情形。 FIG. 5 shows a situation in which the 60 MHz RF signal has its power level matched to the pulse state of the 2 MHz RF signal in accordance with another embodiment of the present invention.
圖6顯示根據本發明之另一實施例中，27MHz之射頻信號以及60MHz之射頻信號使其功率位準配合該2MHz之射頻信號的脈衝狀態的情形。 6 shows a situation in which a 27 MHz RF signal and a 60 MHz RF signal have their power levels matched to the pulse state of the 2 MHz RF signal in accordance with another embodiment of the present invention.
圖7顯示一概念驗證曲線圖，顯示在某些條件下，非基礎射頻產生器無法在期望之功率設定點提供射頻功率。 Figure 7 shows a proof of concept curve showing that under certain conditions, the non-base RF generator is unable to provide RF power at the desired power set point.
圖8顯示根據本發明之一實施例中，一種用於得知當基礎射頻產生器產生脈衝時，對於非基礎射頻產生器之最佳調諧射頻頻率的方法。 8 shows a method for knowing the optimal tuning of a radio frequency for a non-base radio frequency generator when a base radio frequency generator generates a pulse, in accordance with an embodiment of the present invention.
圖9顯示根據本發明之一實施例中，一種用以當電漿腔室設置脈衝基礎射頻信號和至少一非基礎射頻信號時，將最佳射頻功率傳送至電漿腔室中之電漿負載的方法。 9 shows a plasma load for delivering optimal RF power to a plasma chamber when a plasma chamber is provided with a pulsed base RF signal and at least one non-base RF signal, in accordance with an embodiment of the present invention. Methods.
本發明現將參照如隨附圖式中呈現之其若干較佳實施方式加以詳述。在以下敘述中，提出許多具體細節以提供對本發明之深入了解。然而對熟悉本技藝者將顯而易見，本發明可在缺少這些具體細節的部份或所有者的情況下實施。在其它情況下，已為人所熟知之程序步驟以及/或是結構將不再詳述，以不非必要地使本發明失焦。 The invention will now be described in detail with reference to a number of preferred embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth. It will be apparent to those skilled in the art, however, that the invention may be practiced without the In other instances, well-known procedural steps and/or structures will not be described in detail to unnecessarily de-focus the present invention.
各種實施例係描述於下，包含方法和技術。吾人應謹記本發明亦可涵蓋包含電腦可讀取媒體之製品，該電腦可讀取媒體之製品儲存了實施本發明技術之實施例的電腦可讀取指令。電腦可讀取媒體可包含例如半導體、磁性、光磁、光學、或其他形式之用以儲存電腦可讀取碼的電腦可讀取媒體。再者，本發明亦可涵蓋用以實施本發明實施例的設備。此等設備可包含專用及/或可程式化之電路，以實施與本發明之實施例相關的任務。此設備之範例包含適當程式化之通用電腦，且可包含電腦/計算裝置及專用/可程式化之電路之組合，此組合係適用於和本發明之實施例的各種任務。 Various embodiments are described below, including methods and techniques. It should be borne in mind that the present invention also encompasses articles comprising computer readable media that store computer readable instructions embodying embodiments of the present technology. Computer readable media can include, for example, semiconductor, magnetic, magneto-optical, optical, or other forms of computer readable media for storing computer readable code. Furthermore, the invention may also encompass apparatus for practicing embodiments of the invention. Such devices may include dedicated and/or programmable circuitry to carry out tasks associated with embodiments of the present invention. Examples of such devices include suitably stylized general purpose computers, and may include a combination of computer/computing devices and special/programmable circuits that are suitable for various tasks with embodiments of the present invention.
本發明之實施例關於用以控制電漿處理的方法及設備，此係藉由主動設定一或更多更高頻率之射頻信號的射頻功率位準、以及主動控制脈衝將在處理期間之射頻功率擾動最小化而為之。更高頻率之射頻信號的功率位準係回應該基礎脈衝射頻信號的脈衝狀態決定並接著分開設定。換言之，更高頻率之射頻信號的功率位準係針對基礎脈衝射頻信號之高脈衝以及基礎脈衝射頻信號之低脈衝決定並接著分開設定。 Embodiments of the present invention relate to methods and apparatus for controlling plasma processing by actively setting RF power levels of one or more higher frequency RF signals, and actively controlling the RF power during processing The disturbance is minimized. The power level of the higher frequency RF signal is determined by the pulse state of the fundamental pulsed RF signal and then set separately. In other words, the power level of the higher frequency RF signal is determined for the high pulse of the base pulsed RF signal and the low pulse of the base pulsed RF signal and then separately set.
如本文所用之用語，基礎脈衝射頻信號表示脈衝地產生的最低頻率射頻信號。例如，若下部電極設置三個射頻信號(2MHz、27MHz、及60MHz)且該2MHz之射頻信號係脈衝地產生，則該2MHz之射頻信號代表基礎脈衝射頻信號，因為它是脈衝式產生之最低頻率射頻信號。作為另一個例子，若電漿處理腔室設置三個射頻信號至其下部電極(2MHz、27MHz、及60MHz)且該2MHz之射頻信號係以連續波形(即非脈衝模式)操作，且該27MHz之射頻信號和該60MHz之射頻信號係脈衝地產生，則該27MHz之射頻信號代表基礎脈衝射頻信號。 As used herein, the base pulsed radio frequency signal represents the lowest frequency radio frequency signal that is pulsed. For example, if the lower electrode is provided with three RF signals (2 MHz, 27 MHz, and 60 MHz) and the 2 MHz RF signal is pulsed, the 2 MHz RF signal represents the base pulse RF signal because it is the lowest frequency of the pulse generation. RF signal. As another example, if the plasma processing chamber is provided with three RF signals to its lower electrodes (2 MHz, 27 MHz, and 60 MHz) and the 2 MHz RF signal is operated in a continuous waveform (ie, non-pulse mode), and the 27 MHz The RF signal and the 60 MHz RF signal are pulsed, and the 27 MHz RF signal represents the base pulse RF signal.
為了使用語更清楚，基礎脈衝射頻信號可同於或不同於主要 射頻信號，主要射頻信號代表獨立的脈衝射頻信號。當數個射頻電源供應器脈衝時，此等射頻電源供應器之其中一者可被指定為主要射頻電源供應器並獨立地以脈衝式產生其主要射頻信號。主要射頻電源供應器可發出控制信號至其他射頻電源供應器以同步化脈衝。並未規定主要射頻信號需為最低頻率的射頻信號。因此，27MHz的脈衝射頻信號可作為2MHz之脈衝射頻信號的主信號，且反之亦然。然而，如該用語於本文中所用，基礎脈衝射頻信號係為脈衝式產生之最低頻率的射頻信號。此時吾人應注意，使用主要射頻電源供應器以同步化射頻電源供應器之間的脈衝僅為同步化脈衝的一個方法。例如，亦可採用外部電路以同步化所有射頻電源供應器之間的脈衝。 In order to make the term clearer, the basic pulsed RF signal can be the same or different from the main RF signal, the main RF signal represents an independent pulsed RF signal. When several RF power supplies are pulsed, one of these RF power supplies can be designated as the primary RF power supply and independently pulsed to generate its primary RF signal. The primary RF power supply can send control signals to other RF power supplies to synchronize the pulses. The main RF signal is not required to be the lowest frequency RF signal. Therefore, a 27 MHz pulsed RF signal can be used as the primary signal for a 2 MHz pulsed RF signal, and vice versa. However, as the term is used herein, the base pulsed radio frequency signal is the lowest frequency radio frequency signal that is pulsed. At this point, we should note that using the primary RF power supply to synchronize the pulses between the RF power supplies is only one way to synchronize the pulses. For example, an external circuit can also be employed to synchronize the pulses between all RF power supplies.
在一或更多實施例中，當基礎射頻信號係脈衝地產生時，其它脈衝射頻信號之每一者與該基礎脈衝射頻信號的脈衝狀態同步，在其第一預設功率位準以及其第二預設功率位準之間主動交替。第一預設功率位準代表為基礎射頻信號之高脈衝所建立之其它脈衝射頻信號的功率位準。第二預設功率位準代表為基礎射頻信號之低脈衝所建立之其它脈衝射頻信號的功率位準。 In one or more embodiments, when the base radio frequency signal is pulsed, each of the other pulsed radio frequency signals is synchronized with the pulse state of the base pulse radio frequency signal, at its first predetermined power level and its The two preset power levels alternate actively. The first predetermined power level represents the power level of other pulsed RF signals established by the high pulse of the base RF signal. The second predetermined power level represents the power level of other pulsed RF signals established by the low pulses of the base RF signal.
例如，假設電漿處理腔室設置三個射頻信號至其下部電極(2MHz、27MHz、及60MHz)，且2MHz和27MHz之射頻信號兩者皆以100Hz脈衝地產生。2MHz之基礎脈衝射頻信號將以100Hz，於2MHz的高功率位準和2MHz的低功率位準之間脈衝地產生。27MHz之射頻信號係回應來自主要射頻電源供應器或外部同步控制電路之控制信號，主動於第一預設的功率位準(此係回應該2MHz的高功率位準而產生)和第二預設功率(此係回應該2MHz低功率位準而產生)之間交替。 For example, assume that the plasma processing chamber is provided with three RF signals to its lower electrodes (2 MHz, 27 MHz, and 60 MHz), and both 2 MHz and 27 MHz RF signals are pulsed at 100 Hz. The 2 MHz base pulsed RF signal will be pulsed between 100 Hz, a high power level of 2 MHz and a low power level of 2 MHz. The 27MHz RF signal responds to the control signal from the main RF power supply or the external synchronous control circuit, and is active at the first preset power level (this is generated by the high power level of 2MHz) and the second preset. The power (which is generated by the 2MHz low power level) alternates.
非基礎脈衝射頻信號(例如在前例中之27MHz的射頻信號)之預設功率位準係確認及/或建立以達到某些期望之處理結果。另外，非基礎脈衝射頻信號的第一預設功率位準與第二預設功率位準之每一者係獨立地針對該基礎脈衝射頻信號之每個脈衝狀態所建立。因此，它們係針對在基礎射頻信號之高狀態(如在前面的例子中之2MHz之射頻信號)及基礎射頻信號之低狀態期間存在之電漿狀態獨立地確認及/或建立。一旦建 立此等針對非基礎射頻信號(例如，在配方形成期間)之預設功率位準，非基礎射頻信號會回應來自主要射頻電源供應器或來自外部同步控制電路之控制信號，主動在製造期間(例如，在基板處理期間)，當基礎脈衝射頻信號於其高狀態及其低狀態之間脈衝地產生時，於第一預設功率位準和第二預設功率位準(此係回應該2MHz低功率位準而產生)之間交替。另一種說明這一點的方式是，非基礎脈衝射頻信號之回應係不僅取決於基礎射頻信號係脈衝地產生，亦取決於該基礎射頻信號之狀態(高或低)。 The preset power level of the non-base pulsed RF signal (e.g., the 27 MHz RF signal in the previous example) is confirmed and/or established to achieve some desired processing results. Additionally, each of the first predetermined power level and the second predetermined power level of the non-base pulsed RF signal is independently established for each pulse state of the base pulsed RF signal. Therefore, they are independently confirmed and/or established for the plasma state that exists during the high state of the base RF signal (such as the 2 MHz RF signal in the previous example) and the low state of the underlying RF signal. Once built For these preset power levels for non-base RF signals (eg, during formulation formation), non-base RF signals will respond to control signals from the primary RF power supply or from external synchronous control circuits, actively during manufacturing ( For example, during substrate processing, when the base pulsed RF signal is pulsed between its high state and its low state, at the first predetermined power level and the second predetermined power level (this should be 2 MHz) Alternate between low power levels. Another way to illustrate this is that the response of the non-base pulsed RF signal depends not only on the pulse generation of the underlying RF signal, but also on the state (high or low) of the underlying RF signal.
在一或更多實施例中，主動回應係用以在脈衝期間使射頻功率的不穩定性最佳化。如該用語於本文中所用，主動或主動之反應係指射頻信號的補償及/或脈衝係主動地執行，而不是反應式地。如前所討論的，反應式回應發生於當匹配網路或當與射頻信號相關之射頻電源供應器偵測到由於其它射頻信號之其中一者的脈衝，而造成腔室中的電漿狀態(例如電漿阻抗)改變。在反應式回應模式中，發生此偵測後，匹配網路或射頻電源供應器回應以補償所偵測到的電漿狀態改變。為了詳細說明，在反應式回應模式中，匹配網路或射頻電源供應器只在作出偵測後進行回應。 In one or more embodiments, the active response is used to optimize RF power instability during the pulse. As used herein, active or active reaction refers to the compensation of the RF signal and/or the active implementation of the pulse train, rather than reactive. As discussed previously, the reactive response occurs when the matching network or when the RF power supply associated with the RF signal detects a pulse due to one of the other RF signals, causing a plasma state in the chamber ( For example, plasma impedance) changes. In the reactive response mode, after this detection occurs, the matching network or RF power supply responds to compensate for the detected plasma state change. For detailed explanation, in the reactive response mode, the matching network or RF power supply responds only after detection is made.
相反地，在主動式回應模式中，其它射頻信號之匹配網路或射頻電源供應器之回應係由控制信號主動發起，而無需等待偵測。例如，外部控制電路及/或處理器及/或電腦可主動發送控制信號以指示匹配網路或射頻電源供應器根據其對於其它射頻信號之一或更多者的脈衝行為/時序之了解進行回應。此控制信號和回應無需等待偵測到與脈衝相關之電漿狀態改變即可發生。作為另一個例子，脈衝射頻信號之其中一者用的射頻產生器可與其它射頻產生器溝通，以提供控制信號以啟動由其他射頻產生器之回應。在此情況下，發出控制信號的射頻產生器將作為主要射頻產生器，且其他射頻產生器作為從屬射頻產生器。主要射頻產生器主動發出控制信號至其從屬射頻產生器，而不是回應對於電漿狀態改變之偵測。 Conversely, in the active response mode, the response of the matching network or RF power supply of other RF signals is initiated by the control signal without waiting for detection. For example, an external control circuit and/or processor and/or computer can actively send control signals to indicate that the matching network or RF power supply responds based on its knowledge of the pulse behavior/timing of one or more of the other RF signals. . This control signal and response can occur without waiting for a change in the plasma state associated with the pulse. As another example, a radio frequency generator for one of the pulsed RF signals can communicate with other RF generators to provide a control signal to initiate a response by other RF generators. In this case, the RF generator that sends the control signal will act as the primary RF generator and the other RF generators will act as the slave RF generator. The primary RF generator actively sends a control signal to its slave RF generator instead of responding to the detection of changes in the plasma state.
藉由主動控制匹配網路之回應及/或其他射頻產生器之回應，由脈衝所導致之射頻功率不穩定性及/或電漿擾動在持續時間及/或強度上降低。以此方式，功率擾動降低且電漿穩定度提高。 By actively controlling the response of the matching network and/or the response of other RF generators, the RF power instability and/or plasma disturbance caused by the pulses is reduced in duration and/or strength. In this way, the power disturbance is reduced and the plasma stability is increased.
本發明實施例之特點及優點可參照以下之圖式及討論加以 深入理解。 The features and advantages of the embodiments of the present invention can be referred to the following figures and discussion. Deep understanding.
圖2顯示根據本發明之一實施例中，具有電漿處理腔室204之簡化的電容耦合式電漿處理系統202。儘管典型的電漿處理系統可具有數個腔室，但僅顯示一個腔室以供說明。還省略了其他熟悉本技藝者所周知的細節，例如機器人輸送臂、儲存匣、氣體供應器等等。 2 shows a simplified capacitively coupled plasma processing system 202 having a plasma processing chamber 204 in accordance with an embodiment of the present invention. Although a typical plasma processing system can have several chambers, only one chamber is shown for illustration. Other details known to those skilled in the art, such as robotic transport arms, storage cartridges, gas supplies, and the like, are also omitted.
在圖2之範例中，上部電極206係接地而代表基板支架或夾盤之下部電極208係配有3個射頻信號(2MHz、27MHz、及60MHz)，此等信號係經由匹配網路230，分別來自三個射頻電源供應器220、222、和224。雖然顯示出三個射頻信號和三個射頻電源供應器，但下部電極208可依期望配有少如一個或多如許多個射頻信號。另外，雖然為了說明選擇2MHz、27MHz、及60MHz的射頻頻率，但若期望，可使用不同的射頻頻率。如圖所示，電漿處理腔室204係用以進行介電質蝕刻。 In the example of FIG. 2, the upper electrode 206 is grounded to represent the substrate holder or the lower electrode 208 of the chuck is equipped with three radio frequency signals (2 MHz, 27 MHz, and 60 MHz), and the signals are respectively connected via the matching network 230. From three RF power supplies 220, 222, and 224. Although three radio frequency signals and three radio frequency power supplies are shown, the lower electrode 208 can be configured with as little as one or as many RF signals as desired. In addition, although RF frequencies of 2 MHz, 27 MHz, and 60 MHz are selected for illustration, different RF frequencies may be used if desired. As shown, the plasma processing chamber 204 is used to perform dielectric etching.
正如熟悉本領域者所了解，匹配網路230將射頻電源供應器220、222、和224之阻抗與電漿處理腔室中的電漿負載之阻抗相匹配，以使反射功率最小化，並將功率輸送最大化。在根據本發明之一實施例中，射頻電源供應器220、222、和224係相連，俾使若射頻電源供應器之其中一者作為射頻主脈衝，則該射頻電源供應器可主動發送控制信號至其它射頻信號，以主動引起其它射頻信號的脈衝。 As is known to those skilled in the art, matching network 230 matches the impedance of RF power supplies 220, 222, and 224 with the impedance of the plasma load in the plasma processing chamber to minimize reflected power and Maximize power delivery. In an embodiment in accordance with the present invention, the RF power supplies 220, 222, and 224 are connected such that if one of the RF power supplies is used as the RF main pulse, the RF power supply can actively transmit the control signal. To other RF signals to actively induce pulses of other RF signals.
例如，射頻電源供應器220(2MHz的射頻電源供應器)可作為主脈衝並經由導管231和232將數位或類比控制信號(其可為例如電子或學光信號)分別傳送至射頻電源供應器222及224，以指示射頻電源供應器222和224，以將其脈衝與主脈衝2MHz之射頻信號之脈衝同步化，(例如，在2MHz射頻脈衝週期之前緣、後緣、或任何預定的時間)，而無需等待偵測到電漿處理腔室204中之電漿狀態的改變。 For example, a radio frequency power supply 220 (2 MHz RF power supply) can be used as a main pulse and transmit digital or analog control signals (which can be, for example, electronic or optical signals) to the RF power supply 222 via conduits 231 and 232, respectively. And 224 to indicate the RF power supplies 222 and 224 to synchronize their pulses with the pulse of the main pulse 2 MHz RF signal (eg, at the leading edge, trailing edge, or any predetermined time of the 2 MHz RF pulse period), There is no need to wait for a change in the state of the plasma in the plasma processing chamber 204 to be detected.
作為另一個例子，射頻電源供應器222(27MHz的射頻電源供應器)可作為主脈衝並經由導管234和232將數位或類比控制信號(其可為例如電子或光學信號)分別傳送至射頻電源供應器220及224，以指示射頻電源供應器222和224，以將其脈衝與主脈衝27MHz之射頻信號之脈衝同步化，(例如，在27MHz射頻脈衝週期之前緣、後緣、或任何預定的 時間)，而無需等待偵測到電漿處理腔室204中之電漿狀態的改變。 As another example, a radio frequency power supply 222 (a 27 MHz RF power supply) can be used as a primary pulse and transmit digital or analog control signals (which can be, for example, electronic or optical signals) to the RF power supply via conduits 234 and 232, respectively. And 220 and 224 to indicate the RF power supplies 222 and 224 to synchronize their pulses with the pulse of the main pulse 27 MHz RF signal (eg, at the leading edge, trailing edge, or any predetermined of the 27 MHz RF pulse period) Time) without waiting for a change in the state of the plasma in the plasma processing chamber 204 to be detected.
可替代地，控制電路250可用以提供控制信號給射頻電源供應器220、222、和224三者，如圖所示。在此情況下，此等射頻電源供應器沒有任何一者需要作為主脈衝，且三者皆可從控制電路250接收控制信號，此等控制信號主動指示射頻電源供應器產生脈衝。藉由主動控制各種射頻信號之脈衝，可將射頻功率擾動最小化，此將顯示於下方之圖3。 Alternatively, control circuit 250 can be used to provide control signals to RF power supplies 220, 222, and 224, as shown. In this case, none of the RF power supplies need to be the primary pulse, and all three can receive control signals from the control circuit 250, and the control signals actively instruct the RF power supply to generate pulses. By actively controlling the pulses of various RF signals, RF power disturbances can be minimized, as shown in Figure 3 below.
圖3顯示兩個射頻信號之已輸出功率與時間變化的曲線圖：2MHz之射頻信號302和60MHz之射頻信號304。2MHz之射頻信號以100Hz脈衝地產生，並具有介於2,500W和0W之間之50%的工作週期。為求說明清楚，在圖3之範例中，60MHz之射頻信號304脈衝時，其針對2MHz之射頻信號之高脈衝期間的第一預設功率位準為900W，且其針對2MHz之射頻信號之低脈衝期間的第二預設功率位準亦為900W。在圖3之範例中，產生這些脈衝射頻信號之2MHz和60MHz的射頻電源供應器兩者，從共同的控制電路(例如圖2之控制電路250)接收控制信號，且因此同時主動地產生脈衝，而無需等待偵測電漿狀態之改變。可替代地，此等射頻電源供應器之其中一者(例如，2MHz之射頻電源供應器或27MHz之射頻電源供應器)可作為另一射頻電源供應器之主脈衝，並可主動發出控制信號，以指示另一射頻電源供應器實質上同時產生脈衝，而無需等待偵測電漿狀態之改變。 Figure 3 shows a plot of the output power versus time for two RF signals: a 2 MHz RF signal 302 and a 60 MHz RF signal 304. A 2 MHz RF signal is pulsed at 100 Hz and has a frequency between 2,500 W and 0 W. 50% of the work cycle. For the sake of clarity, in the example of FIG. 3, when the 60 MHz RF signal is pulsed at 304, the first predetermined power level during the high pulse period of the 2 MHz RF signal is 900 W, and its low frequency for the 2 MHz RF signal. The second preset power level during the pulse is also 900W. In the example of FIG. 3, both the 2 MHz and 60 MHz RF power supplies that generate the pulsed RF signals receive control signals from a common control circuit (eg, control circuit 250 of FIG. 2), and thus actively generate pulses simultaneously. There is no need to wait to detect changes in the plasma state. Alternatively, one of the RF power supplies (eg, a 2 MHz RF power supply or a 27 MHz RF power supply) can serve as the primary pulse of another RF power supply and can actively generate control signals. To instruct another RF power supply to generate pulses substantially simultaneously without waiting for a change in the state of the detected plasma.
如圖3中可看出，對於2MHz基礎脈衝射頻信號302之每個高至低或低至高的轉變，在60MHz之射頻信號304中之功率擾動係實質上維持較低(在圖3的情況下低於3%)。這些係由參考號碼320、322、324、和328所示。與圖2之情況相比，圖3之情況實質上具有較少射頻功率擾動，在圖2之情況中，60MHz的射頻電源供應器在反應模式下操作(即，回應電漿狀態改變之偵測而進行補償)。這是因為一旦決定非基礎脈衝射頻信號之功率位準設定點，非基礎脈衝射頻信號可在接收到控制信號時，在無延遲之情況下於其兩個功率設定點之間脈衝地產生，從而有助於更穩定的射頻功率輸送。 As can be seen in Figure 3, for each high to low or low to high transition of the 2 MHz base pulsed RF signal 302, the power disturbance in the 60 MHz RF signal 304 remains substantially low (in the case of Figure 3) Less than 3%). These are shown by reference numerals 320, 322, 324, and 328. Compared with the case of FIG. 2, the situation of FIG. 3 has substantially less RF power disturbance. In the case of FIG. 2, the 60 MHz RF power supply operates in the reactive mode (ie, responds to the detection of the plasma state change). And compensated). This is because once the power level set point of the non-base pulse RF signal is determined, the non-base pulse RF signal can be pulsed between its two power set points without delay when the control signal is received. Helps more stable RF power delivery.
在一或更多實施例中，非基礎脈衝射頻信號(即，較高的射 頻頻率脈衝信號)之第一功率位準和第二功率位準每一者可從一或更多可測量的電漿處理腔室參數(例如夾盤偏壓或例如返回的射頻電流)動態地確定。所謂「動態」，吾人應理解這種對於功率位準之確認，可以在例如配方形成或機器校正期間以演算法進行，或在處理期間以即時運算模式進行。非基礎脈衝射頻信號的第一功率位準(當基礎脈衝射頻信號係在其高狀態時，對應於非基礎脈衝射頻信號之功率位準)可自動從一或更多電漿處理腔室參數之感應器測量值加以運算地確認，並計算以用於基礎脈衝射頻信號的高狀態。同樣地，非基礎脈衝射頻信號的第二功率位準(當基礎脈衝射頻信號係在其低狀態時，對應於非基礎脈衝射頻信號之功率位準)可自動從一或更多電漿處理腔室參數之感應器測量值加以運算地確認，並計算以用於基礎脈衝射頻信號的低狀態。 In one or more embodiments, a non-base pulsed RF signal (ie, a higher shot) The first power level and the second power level of the frequency frequency pulse signal can each be dynamically from one or more measurable plasma processing chamber parameters (eg, chuck bias or, for example, returning RF current) determine. By "dynamic", we should understand that this confirmation of the power level can be performed algorithmically during, for example, recipe formation or machine correction, or in an immediate computing mode during processing. The first power level of the non-base pulsed RF signal (when the base pulsed RF signal is in its high state, corresponding to the power level of the non-base pulsed RF signal) can automatically be processed from one or more plasma processing chamber parameters The sensor measurements are mathematically confirmed and calculated for the high state of the base pulsed RF signal. Similarly, the second power level of the non-base pulsed RF signal (when the base pulsed RF signal is in its low state, corresponding to the power level of the non-base pulsed RF signal) can automatically be from one or more plasma processing chambers The sensor measurements of the chamber parameters are mathematically confirmed and calculated for the low state of the base pulsed RF signal.
在此情況下，根據在基礎射頻脈衝信號之高狀態和低狀態期間之一或更多電漿處理腔室參數的感應器測量值，使用例如程式化的電腦，動態地決定並設定非基礎脈衝射頻信號(即，較高頻率的脈衝射頻信號)之功率位準的能力以達到期望的處理參數，代表一項優勢，因為在基礎脈衝射頻信號的高狀態期間以及在基礎脈衝射頻信號的低狀態期間，較高頻率之脈衝射頻功率信號的功率位準現在是獨立之處理控制旋鈕。其後，非基礎脈衝射頻信號在接收到來自主要射頻電源供應器或來自外部控制器(例如，圖2之控制器電路250)之控制信號後，從第一預定功率位準轉變到第二預定功率位準(反之亦然)。 In this case, the non-base pulse is dynamically determined and set using, for example, a stylized computer based on sensor measurements of one or more of the plasma processing chamber parameters during the high and low states of the base RF pulse signal. The ability of the RF signal (i.e., the higher frequency pulsed RF signal) to achieve the desired processing parameters represents an advantage because of the high state of the fundamental pulsed RF signal and the low state of the fundamental pulsed RF signal. During this time, the power level of the higher frequency pulsed RF power signal is now a separate processing control knob. Thereafter, the non-base pulsed RF signal transitions from the first predetermined power level to the second predetermined after receiving a control signal from the primary RF power supply or from an external controller (eg, controller circuit 250 of FIG. 2). Power level (and vice versa).
需注意第一預定功率位準和第二預定功率位準係為每個射頻電源供應器特有的。換言之，27MHz的電源供應器可具有其自己的第一預定之射頻電源供應器特有的功率位準，以及第二預定之射頻電源供應器特有的功率位準，而60MHz的射頻電源供應器可具有其自己的第一預定之射頻電源供應器特有的功率位準，以及第二預定之射頻電源供應器特有的功率位準，此等功率位準不同於27MHz的射頻電源供應器之功率位準。 It is noted that the first predetermined power level and the second predetermined power level are unique to each RF power supply. In other words, the 27 MHz power supply can have its own first predetermined RF power supply-specific power level and the second predetermined RF power supply-specific power level, while the 60 MHz RF power supply can have The power level specific to its own first predetermined RF power supply, and the power level specific to the second predetermined RF power supply, which are different from the power level of the 27 MHz RF power supply.
在一或更多實施例中，基礎脈衝射頻信號的功率位準(即高脈衝功率位準及低脈衝功率位準)亦可動態地確定，例如使用程式化之電腦，根據一或更多電漿處理腔室參數(如夾盤偏壓)之感應器測量值，以 獲得期望之處理參數(如沉積率)。根據一或更多電漿處理腔室參數的感應器測量值，例如使用程式化的電腦，動態地決定基礎脈衝射頻信號之功率位準的能力以達到期望的處理參數，代表一項優勢，因為基礎脈衝射頻功率信號的功率位準現在是獨立之處理控制旋鈕。 In one or more embodiments, the power level of the base pulsed RF signal (ie, the high pulse power level and the low pulse power level) can also be dynamically determined, such as using a stylized computer, based on one or more The sensor measurement of the slurry processing chamber parameters (such as chuck bias) to Obtain the desired processing parameters (such as deposition rate). The ability to dynamically determine the power level of the fundamental pulsed RF signal to achieve the desired processing parameters based on one or more sensor measurements of the plasma processing chamber parameters, such as using a stylized computer, represents an advantage because The power level of the base pulsed RF power signal is now an independent processing control knob.
圖4顯示根據本發明之一實施例之情形，其中2MHz之射頻信號402以100Hz脈衝地產生，並具有介於2,500W和0W之間之50%的工作週期。60MHz之射頻信號404係以主動的方式同步，俾使針對2MHz之射頻信號之高狀態，60MHz之射頻信號的功率位準係在900W，且在2MHz之射頻信號之低狀態期間，60MHz之射頻信號的功率位準為450W。需注意60MHz之射頻信號之此兩個功率位準的每一者係根據基礎射頻脈衝信號(例如，2MHz之射頻信號)之特有狀態(高或低)各別確定並設定，以獲得期望之處理結果(如低聚合物沉積、晶圓偏壓降低等)。此外，圖4之兩個射頻信號的脈衝係主動地發生，即無需等待偵測到電漿狀態之改變，或偵測到一或更多腔室參數之改變，此等腔室參數之改變反映由於基礎射頻信號脈衝所致之電漿狀態改變。因此，射頻功率擾動與射頻電漿不穩定性可大幅降低。 4 shows a situation in which a 2 MHz RF signal 402 is pulsed at 100 Hz and has a 50% duty cycle between 2,500 W and 0 W, in accordance with an embodiment of the present invention. The 60MHz RF signal 404 is synchronized in an active manner, so that the high-level state of the RF signal for 2MHz, the power level of the 60MHz RF signal is 900W, and the RF signal of 60MHz during the low state of the 2MHz RF signal. The power level is 450W. It should be noted that each of the two power levels of the 60 MHz RF signal is individually determined and set according to the unique state (high or low) of the basic RF pulse signal (for example, a 2 MHz RF signal) to obtain the desired processing. Results (eg low polymer deposition, wafer bias reduction, etc.). In addition, the pulse of the two RF signals of Figure 4 takes place actively, that is, there is no need to wait for a change in the state of the plasma to be detected, or a change in one or more chamber parameters is detected, and the changes in the parameters of the chambers are reflected. The plasma state changes due to the pulse of the basic RF signal. Therefore, RF power disturbance and RF plasma instability can be greatly reduced.
圖5顯示根據本發明之另一實施例的情形，其中2MHz之射頻信號502以100Hz脈衝地產生，並具有介於2,500W和0W之間之50%的工作週期。60MHz之射頻信號504係以主動的方式同步，俾使針對2MHz之射頻信號之高狀態，60MHz之射頻信號的功率位準係在900W。在2MHz之射頻信號之低狀態期間，60MHz之射頻信號的功率位準係增加至1125W。圖4圖5顯示非基礎射頻信號(即，較高頻率之脈衝射頻信號)的功率位準，在基礎脈衝射頻信號由高狀態轉變至低狀態後，可能會更高或更低。再次注意60MHz之射頻信號之此兩個功率位準的每一者係根據基礎射頻脈衝信號(例如，2MHz之射頻信號)之特有狀態(高或低)確定並設定，並確定和設定以獲得期望之處理結果(如低聚合物沉積、晶圓偏壓降低等)。此外，圖4之兩個射頻信號的脈衝係主動地發生，即無需等待偵測電漿狀態之改變。因此，射頻功率擾動與射頻電漿不穩定性可大幅降低。 Figure 5 shows a situation in which a 2 MHz RF signal 502 is pulsed at 100 Hz and has a 50% duty cycle between 2,500 W and 0 W, in accordance with another embodiment of the present invention. The 60 MHz RF signal 504 is synchronized in an active manner so that the power level of the 60 MHz RF signal is 900 W for the high state of the 2 MHz RF signal. During the low state of the 2 MHz RF signal, the power level of the 60 MHz RF signal is increased to 1125W. Figure 4 Figure 5 shows the power level of a non-base RF signal (i.e., a higher frequency pulsed RF signal) that may be higher or lower after the base pulse RF signal transitions from a high state to a low state. Note again that each of the two power levels of the 60 MHz RF signal is determined and set according to the unique state (high or low) of the underlying RF pulse signal (eg, 2 MHz RF signal), and is determined and set to achieve the desired Processing results (such as low polymer deposition, wafer bias reduction, etc.). In addition, the pulses of the two RF signals of Figure 4 occur actively, that is, there is no need to wait to detect changes in the plasma state. Therefore, RF power disturbance and RF plasma instability can be greatly reduced.
圖6顯示根據本發明之另一實施例的情形，其中2MHz之射頻信號602以100Hz脈衝地產生，並具有介於2,500W和0W之間之50%的工作週期。60MHz之射頻信號604係以主動的方式同步，俾使針對2MHz之射頻信號之高狀態，60MHz之射頻信號的功率位準係在500W。在2MHz之射頻信號的低狀態期間，60MHz之射頻信號之功率位準係增加至625W。27MHz之射頻信號606係以主動的方式同步，俾使針對2MHz之射頻信號之高狀態，27MHz之射頻信號的功率位準係在1000W。在2MHz之射頻信號的低狀態期間，27MHz之射頻信號的功率位準係降低到250W。需注意60MHz之射頻信號以及27MHz之射頻信號之此兩個功率位準的每一者係根據基礎射頻脈衝信號(例如，2MHz之射頻信號)之特有狀態(高或低)確定並設定，並確定和設定以獲得期望之處理結果(如低聚合物沉積、晶圓偏壓降低等)。 6 shows a situation in which a 2 MHz RF signal 602 is pulsed at 100 Hz and has a 50% duty cycle between 2,500 W and 0 W, in accordance with another embodiment of the present invention. The 60 MHz RF signal 604 is synchronized in an active manner so that the power level of the 60 MHz RF signal is at 500 W for the high state of the 2 MHz RF signal. During the low state of the 2 MHz RF signal, the power level of the 60 MHz RF signal is increased to 625W. The 27 MHz RF signal 606 is synchronized in an active manner so that the power level of the 27 MHz RF signal is 1000 W for the high state of the 2 MHz RF signal. During the low state of the 2 MHz RF signal, the power level of the 27 MHz RF signal is reduced to 250 W. It should be noted that each of the two power levels of the 60 MHz RF signal and the 27 MHz RF signal is determined and set according to the unique state (high or low) of the basic RF pulse signal (for example, a 2 MHz RF signal), and is determined. And settings to achieve desired processing results (eg, low polymer deposition, wafer bias reduction, etc.).
在圖6的情況下，射頻電源供應器(如2MHz的射頻電源供應器、27MHz的射頻電源供應器、或60MHz的射頻電源供應器)之其中一者可作為主脈衝，並發送控制信號到其它射頻電源供應器以主動地同步化脈衝。可替代地，外部控制電路可作為主脈衝，並可發送控制信號至三個射頻電源供應器以主動地同步化脈衝。 In the case of Figure 6, one of the RF power supplies (such as a 2MHz RF power supply, a 27MHz RF power supply, or a 60MHz RF power supply) can be used as the main pulse and send control signals to other The RF power supply actively synchronizes the pulses. Alternatively, an external control circuit can act as a main pulse and can send control signals to three RF power supplies to actively synchronize the pulses.
如前所述，各種射頻信號之射頻功率位準可在基礎脈衝射頻信號的高狀態期間以及基礎脈衝射頻信號的低狀態期間分別調諧，以獲得期望之處理結果。作為一個例子，離子能量被認為可以藉由增加2MHz之射頻信號的射頻功率位準而增加。雖然增加離子能量是有利的，但在某些情況下，亦可導致不必要的過量聚合物沉積。在2MHz射頻信號之最佳脈衝頻率以及最佳之高和低射頻功率位準下使其脈衝地產生，可使離子能量增加，而不會造成不必要的聚合物沉積。 As previously mentioned, the RF power levels of the various RF signals can be separately tuned during the high state of the base pulsed RF signal and during the low state of the base pulsed RF signal to achieve the desired processing result. As an example, ion energy is believed to increase by increasing the RF power level of the 2 MHz RF signal. While it is advantageous to increase the ion energy, in some cases it may also result in unnecessary excess polymer deposition. Pulsed generation at the optimum pulse frequency of the 2MHz RF signal and optimal high and low RF power levels allows the ion energy to be increased without causing unnecessary polymer deposition.
一旦基礎脈衝射頻信號之最佳射頻功率位準係確定及/或設定，非基礎脈衝射頻信號之射頻功率位準(即較高頻率的脈衝射頻信號)可針對基礎脈衝射頻信號的高狀態和基礎脈衝射頻信號的低狀態單獨確定並設定，以進一步調諧該處理(如調諧電漿密度，因為更高頻率射頻信號之功率位準往往更會影響電漿密度)。因此，這些不同的射頻脈衝信號之不 同的射頻功率位準可用以做為單獨的處理用之控制旋鈕。 Once the optimal RF power level of the fundamental pulsed RF signal is determined and/or set, the RF power level of the non-base pulsed RF signal (ie, the higher frequency pulsed RF signal) can be used for the high state and basis of the base pulsed RF signal. The low state of the pulsed RF signal is individually determined and set to further tune the process (eg, tuning the plasma density because the power level of the higher frequency RF signal tends to affect the plasma density). Therefore, these different RF pulse signals are not The same RF power level can be used as a separate control knob.
如前所述，由於各種脈衝射頻信號係主動地同步，因此射頻功率擾動係降至最低。即使射頻信號(例如60MHz之射頻信號)受配方指定在連續的波形(CW)模式下操作，在一實施例中，期望的作法可為將此射頻信號設定為主動地在基礎脈衝射頻信號(如2MHz之射頻信號)之兩個高狀態期間，以相同的功率位準(如900W)脈衝地產生，因為如圖3所示，在相同功率位準之此脈衝相較於反應式補償方法，可降低射頻功率擾動。 As mentioned earlier, the RF power disturbance is minimized since the various pulsed RF signals are actively synchronized. Even though a radio frequency signal (e.g., a 60 MHz radio frequency signal) is specified by the recipe to operate in a continuous waveform (CW) mode, in one embodiment, it may be desirable to set the radio frequency signal to be actively on the underlying pulsed radio frequency signal (e.g., During the two high states of the 2MHz RF signal, the same power level (such as 900W) is pulsed, because as shown in Figure 3, the pulse at the same power level is comparable to the reactive compensation method. Reduce RF power disturbances.
在一或更多實施例中，基礎脈衝射頻信號和非基礎射頻信號之射頻功率位準係設定俾使電漿在脈衝期間可持續。換句話說，電漿在基礎脈衝射頻信號的低狀態期間及/或非基礎脈衝射頻信號的低狀態期間並未熄滅。使電漿保持點燃使得由單獨的射頻功率位準(如前所述)之處理旋鈕施加之處理控制更有效率，且亦減少電漿的干擾，因為電漿點燃及/或點火(如果允許電漿熄滅，這將是必要的)不像連續的電漿為妥善控制的處理。因此，重複性和均勻性得以增強。 In one or more embodiments, the RF power levels of the base pulsed RF signal and the non-base RF signal are set such that the plasma is sustainable during the pulse. In other words, the plasma is not extinguished during the low state of the base pulsed RF signal and/or during the low state of the non-base pulsed RF signal. Keeping the plasma ignited so that the process control applied by the processing knob of a separate RF power level (as described above) is more efficient and also reduces plasma interference because the plasma ignites and/or ignites (if electricity is allowed) The slurry is extinguished, which will be necessary) unlike continuous plasma treatment for proper control. Therefore, the repeatability and uniformity are enhanced.
在一或更多實施例中，揭露雙模自動頻率調諧技術及其設備。在雙模自動頻率調諧方法中，當基礎射頻信號之脈衝從一個狀態到另一個狀態時，非基礎射頻信號之調諧頻率係主動轉變，以確保基礎射頻信號之每一狀態的高效且穩定的功率輸送。 In one or more embodiments, dual mode automatic frequency tuning techniques and apparatus are disclosed. In the dual-mode automatic frequency tuning method, when the pulse of the basic RF signal is from one state to another, the tuning frequency of the non-base RF signal is actively converted to ensure efficient and stable power of each state of the basic RF signal. delivery.
為詳細說明，現今的射頻電源供應器能夠調諧其輸送之射頻頻率，以提高功率輸送(例如藉由改變傳送到負載的射頻頻率)。作為一個範例，60MHz之射頻產生器或許可改變其調諧射頻頻率的例如，5至10%(即改變輸送至負載的射頻頻率60MHz+/-5%至10%)。 To elaborate, today's RF power supplies are capable of tuning the RF frequencies they deliver to improve power delivery (eg, by varying the RF frequency delivered to the load). As an example, a 60 MHz RF generator may be allowed to change its tuned RF frequency, for example, 5 to 10% (ie, change the RF frequency delivered to the load by 60 MHz +/- 5% to 10%).
然而，到目前為止，此頻率變化之執行係作為當射頻產生器之感應器偵測到輸送至負載之射頻功率量改變時，對射頻產生器之事後回應。此種偵測往往取決於，例如，反射功率對於正向功率(也被稱為伽瑪)之比例的測量值。當射頻產生器偵測到象徵功率輸送不足之狀態(例如根據一些預設的伽瑪門檻)時，射頻產生器將以頻率調諧方法改變其調諧之射頻頻率，以更有效地將功率輸送至負載。 However, to date, this frequency change has been performed as a post hoc response to the RF generator when the RF generator's sensor detects a change in the amount of RF power delivered to the load. Such detection often depends, for example, on the measurement of the ratio of reflected power to forward power (also known as gamma). When the RF generator detects a condition that indicates insufficient power delivery (eg, according to some preset gamma threshold), the RF generator will change its tuned RF frequency by frequency tuning to more efficiently deliver power to the load. .
然而，現今的頻率調諧方法之事後的本質，往往意味著當電漿阻抗或電漿負載發生變化時，回應出現延遲。在此延遲時間期間，在某些狀態下，例如當基礎射頻信號之脈衝從一個狀態到另一個狀態時，非基礎射頻產生器可能效率低落或可能無法以所需之功率設定點(由配方所指定)輸送功率，直到非基礎射頻產生器改變其調諧頻率而足以適應改變之電漿負載。 However, the afterthought of today's frequency tuning methods often means that when the plasma impedance or plasma load changes, the response is delayed. During this delay time, in certain states, such as when the pulse of the underlying RF signal is from one state to another, the non-base RF generator may be inefficient or may not be able to set the desired power point (by the recipe The power is delivered until the non-base RF generator changes its tuning frequency to accommodate the changing plasma load.
根據本發明之一或更多實施例，非基礎射頻信號之調諧頻率係針對基礎射頻信號的每個脈衝狀態(例如，高或低)預先確定。有鑑於此情況，例如，當2MHz之基礎射頻信號以約1kHz脈衝地產生，並具有50%的工作週期。例如，在學習階段中，可確定當2MHz之基礎射頻信號在其低脈衝狀態(即在脈衝至低點後)時，60MHz之射頻產生器的功率輸送在當60MHz射頻產生器實際使用61MHz的調諧頻率輸送其射頻功率時，十分有效率。此外，在另一實施例中，亦可以確定在學習階段中，當2MHz之射頻信號在其高脈衝狀態(即在脈衝至高點後),60MHz之射頻產生器在當60MHz射頻產生器實際使用59MHz的調諧頻率輸送其射頻功率時，十分有效率。 In accordance with one or more embodiments of the present invention, the tuning frequency of the non-base radio frequency signal is predetermined for each pulse state (e.g., high or low) of the base radio frequency signal. In view of this, for example, when a 2 MHz base radio frequency signal is pulsed at about 1 kHz, it has a 50% duty cycle. For example, during the learning phase, it can be determined that when the 2MHz base RF signal is in its low pulse state (ie, after the pulse reaches the low point), the 60MHz RF generator's power is delivered when the 60MHz RF generator actually uses 61MHz tuning. It is very efficient when transmitting its RF power at a frequency. In addition, in another embodiment, it can also be determined that in the learning phase, when the 2 MHz RF signal is in its high pulse state (ie, after the pulse reaches the high point), the 60 MHz RF generator actually uses 59 MHz when the 60 MHz RF generator is used. The tuned frequency is very efficient when delivering its RF power.
在一或更多實施例中，在產生期間，60MHz之射頻產生器(即本範例中之非基礎射頻產生器)會在當基礎射頻信號之脈衝從一個狀態至另一狀態之同時，主動地改變其調諧頻率。頻率的改變被視為主動，是因為由非基礎射頻產生器所致之調諧頻率之改變，並非根據由於基礎射頻信號的脈衝，由60MHz之射頻產生器發現之電漿狀態改變或阻抗改變的事後偵測所引起。 In one or more embodiments, a 60 MHz RF generator (ie, a non-base RF generator in this example) actively generates a pulse of the underlying RF signal from one state to another during generation. Change its tuning frequency. The change in frequency is considered active because the change in the tuning frequency caused by the non-base RF generator is not based on the post-mortem change or impedance change found by the 60 MHz RF generator due to the pulse of the underlying RF signal. Caused by detection.
相反地，由非基礎射頻產生器所致之調諧射頻頻率之改變係同步化，俾使此改變發生在最佳的時間，以確保當基礎射頻信號之脈衝從一狀態至另一狀態時之足夠及/或有效的功率輸送。例如，60MHz之射頻產生器可根據協調信號(其可由2MHz之射頻產生器或該等射頻產生器之任何一者發出，或由協調射頻產生器之獨立的控制電路所發出)主動改變其射頻調諧頻率，而不是等待由於基礎射頻信號的脈衝，由60MHz之射頻產生器發現之電漿狀態改變或阻抗改變的偵測。一般來說，非基礎射頻產 生器可在基礎射頻信號之脈衝從一個脈衝狀態到另一脈衝狀態之同時或之前改變其調諧頻率。 Conversely, the change in the tuned RF frequency caused by the non-base RF generator is synchronized so that this change occurs at the optimum time to ensure that the pulse of the underlying RF signal is sufficient from one state to another. And / or effective power delivery. For example, a 60 MHz RF generator can actively change its RF tuning based on a coordinated signal (which can be issued by either a 2 MHz RF generator or any of the RF generators, or by a separate control circuit that coordinates the RF generator). The frequency, rather than waiting for the detection of the plasma state change or impedance change found by the 60 MHz RF generator due to the pulse of the underlying RF signal. Generally speaking, non-basic RF products The generator can change its tuning frequency while or during the pulse of the underlying RF signal from one pulse state to another.
圖7為一概念驗證之曲線圖，顯示在某些條件下，非基礎射頻產生器無法在期望之功率設定點輸送射頻功率。這是例如在先前技術中之情況。在圖7之範例中，基礎2MHz之射頻產生器具有9kW之功率設定點(在圖7中未示出)，且60MHz之射頻產生器具有為750W的功率設定點。這是各自射頻產生器之理想功率位準。另外，在圖7之範例中，基礎2MHz之射頻信號從高狀態到低狀態變化了5秒鐘(從2.2秒至7.2秒)。 Figure 7 is a conceptual verification graph showing that under certain conditions, a non-base RF generator cannot deliver RF power at a desired power set point. This is the case, for example, in the prior art. In the example of Figure 7, the base 2 MHz RF generator has a 9 kW power set point (not shown in Figure 7) and the 60 MHz RF generator has a power set point of 750 W. This is the ideal power level for each RF generator. In addition, in the example of FIG. 7, the base 2 MHz RF signal changes from a high state to a low state for 5 seconds (from 2.2 seconds to 7.2 seconds).
在圖7中，左邊的垂直軸表示由60MHz之射頻產生器所輸送之功率量，而右邊的垂直軸表示60MHz之射頻產生器的調諧頻率。兩個垂直軸係相對於水平時間軸繪製。線702代表所輸送之射頻功率量。線730代表60MHz之射頻產生器的調諧頻率。 In Figure 7, the vertical axis on the left represents the amount of power delivered by the 60 MHz RF generator, while the vertical axis on the right represents the tuning frequency of the 60 MHz RF generator. Two vertical axis systems are drawn relative to the horizontal time axis. Line 702 represents the amount of radio frequency power delivered. Line 730 represents the tuning frequency of the 60 MHz RF generator.
在點700處，2MHz之射頻產生器係位於高脈衝狀態。在此點上，60MHz之射頻產生器以約為61MHz(線730在時間t=2秒處)之調諧射頻頻率有效率地輸送其功率。 At point 700, the 2 MHz RF generator is in a high pulse state. At this point, the 60 MHz RF generator efficiently delivers its power at a tuned RF frequency of approximately 61 MHz (line 730 at time t = 2 seconds).
在時間2.2秒處，2MHz之基礎射頻信號開始朝向低處，在7.2秒內達到低狀態。由射頻功率線702可看出，60MHz之射頻產生器感應到電漿負載中之改變，並試圖維持其750W之功率設定點。在某個時間點，始於約5秒(點704處)，60MHz之射頻產生器開始向下改變其調諧頻率，以回應於偵測到之在電漿負載中的變化(由朝向低狀態之2MHz之基礎信號造成)，以增加射頻功率傳輸效率。 At 2.2 seconds, the 2 MHz base RF signal begins to go low and reaches a low state within 7.2 seconds. As can be seen from the RF power line 702, the 60 MHz RF generator senses a change in the plasma load and attempts to maintain its 750 W power set point. At some point in time, starting at about 5 seconds (at point 704), the 60 MHz RF generator begins to change its tuning frequency down in response to the detected change in the plasma load (from the low state) 2MHz base signal is caused) to increase the efficiency of RF power transmission.
在時間為7.2秒處(水平時間軸上之參考數字706)，2MHz之基礎射頻信號係處於其低狀態。如圖7中可看出，由60MHz之射頻產生器所輸送之射頻功率量從點708處暫時下降到點710處之約220W。此由60MHz之射頻產生器輸送之射頻功率量係實質上低於60MHz之射頻產生器之750W的功率設定點。此為不理想的情況。 At a time of 7.2 seconds (reference number 706 on the horizontal time axis), the 2 MHz base radio frequency signal is in its low state. As can be seen in Figure 7, the amount of radio frequency power delivered by the 60 MHz RF generator temporarily drops from point 708 to about 220 W at point 710. The amount of RF power delivered by the 60 MHz RF generator is substantially less than the 750 W power set point of the 60 MHz RF generator. This is not ideal.
從點706到點712處，60MHz之射頻產生器搜尋調諧射頻頻率，此調諧射頻頻率能夠使60MHz的射頻功率在所要求之750W的功率設定點輸送，且2MHz之射頻信號係位於其低脈衝狀態。在點714處，60MHz 之射頻產生器落於約為59.75MHz之調諧射頻頻率。在此較低之調諧射頻頻率處，60MHz之產生器能夠在其750W之設定點輸送射頻功率。 From point 706 to point 712, the 60 MHz RF generator searches for a tuned RF frequency that enables 60 MHz RF power to be delivered at the required 750 W power set point, and the 2 MHz RF signal is at its low pulse state. . At point 714, 60 MHz The RF generator falls at a tuned RF frequency of approximately 59.75 MHz. At this lower tuned RF frequency, the 60 MHz generator is capable of delivering RF power at its 750 W set point.
圖7之概念驗證曲線圖顯示針對2MHz之基礎射頻信號的每個脈衝狀態，60MHz之射頻產生器皆有理想之諧射頻頻率。再者，若60MHz之產生器以事後之方式(即如圖7所示，偵測到由於2MHz之基礎射頻信號的脈衝所致之電漿負載的改變後)改變其調諧射頻頻率，則可能出現功率設定點和射頻頻率使得60MHz之射頻產生器無法達到其要求之功率設定點之情形。此係顯示於圖7中，介於點706和點712之間處。 The proof-of-concept plot of Figure 7 shows that for each pulse state of the 2 MHz base RF signal, the 60 MHz RF generator has an ideal harmonic RF frequency. Furthermore, if the 60 MHz generator changes its tuned RF frequency in an after-the-fact manner (ie, after detecting a change in the plasma load due to the pulse of the 2 MHz base RF signal), it may appear. The power set point and RF frequency make it impossible for a 60 MHz RF generator to reach its required power set point. This is shown in Figure 7, between point 706 and point 712.
圖8顯示根據本發明之一實施例之用以得知當基礎射頻產生器產生脈衝時，對於非基礎射頻產生器之最佳調諧射頻頻率的方法。在步驟802中，電漿腔室係由脈衝基礎射頻信號以及至少一非基礎射頻信號所供電。在步驟804中，(複數)非基礎射頻產生器係以自動調諧模式操作，以使非基礎射頻產生器分別針對基礎射頻信號之高狀態和低狀態尋求其最佳的射頻頻率(f1和f2)。在此自動調諧模式下，非基礎射頻產生器得以在基礎射頻信號的每一狀態期間，尋求其自己的調諧射頻頻率。對於基礎射頻信號之狀態的每一者之最佳射頻頻率(對於非基礎射頻信號)係作為預定之射頻頻率，且當基礎射頻信號脈衝地產生時，非基礎射頻產生器主動從一預定之射頻頻率切換至另一預定之射頻頻率。 8 shows a method for knowing the optimal tuning of a radio frequency for a non-base radio frequency generator when the base radio frequency generator generates a pulse, in accordance with an embodiment of the present invention. In step 802, the plasma chamber is powered by a pulsed base radio frequency signal and at least one non-base radio frequency signal. In step 804, the (plural) non-base radio frequency generator operates in an auto-tuning mode to cause the non-base radio frequency generator to seek its optimal radio frequency (f1 and f2) for the high and low states of the base radio frequency signal, respectively. . In this auto-tuning mode, the non-base RF generator is able to seek its own tuned RF frequency during each state of the underlying RF signal. The optimal RF frequency (for non-base RF signals) for each of the states of the base RF signal is the predetermined RF frequency, and when the base RF signal is pulsed, the non-base RF generator actively takes a predetermined RF The frequency is switched to another predetermined RF frequency.
如該用語於本文中所用，非基礎射頻產生器之最佳射頻頻率係指非基礎射頻產生器能以可接受或有效率的方式輸送其功率(根據一些預定之指標)及/或可滿足其功率輸送設定點之射頻頻率。如本文所討論，有至少兩個非基礎產生器用之最佳射頻頻率。此兩個最佳射頻頻率對應於基礎射頻信號之兩個切換的狀態。 As used herein, the preferred radio frequency of a non-base radio frequency generator means that the non-base radio frequency generator can deliver its power in an acceptable or efficient manner (according to some predetermined criteria) and/or can satisfy it. The RF frequency of the power delivery set point. As discussed herein, there are at least two optimal RF frequencies for non-base generators. These two optimal RF frequencies correspond to the state of the two switching of the underlying RF signals.
需注意，在產生期間所採用之第一預定的射頻頻率和第二預定的射頻頻率係為每個射頻電源供應器所特有。換言之，27MHz之電源供應器可具有其自己的第一預定之射頻電源供應器特有的射頻頻率，以及其自己的第二預定之射頻電源供應器特有的射頻頻率，而60MHz之射頻電源供應器可具有其自己的第一預定之射頻電源供應器特有的射頻頻率，以及其自己的第二預定之射頻電源供應器特有的射頻頻率，此等射頻頻率皆不 同於27MHz之射頻電源供應器之射頻頻率。 It is noted that the first predetermined RF frequency and the second predetermined RF frequency employed during generation are unique to each RF power supply. In other words, the 27MHz power supply can have its own unique RF power supply specific to the RF power supply, as well as its own second predetermined RF power supply-specific RF frequency, while the 60MHz RF power supply can It has its own RF frequency unique to the first predetermined RF power supply, and its own RF frequency unique to the second predetermined RF power supply. These RF frequencies are not Same as the RF frequency of the 27MHz RF power supply.
在一或更多實施例中，腔室之所有其他條件係較佳地配置，俾使其盡可能地密切模仿製造之條件。在另一實施例中，非基礎射頻產生器之頻率可手動更改，以確定(例如，藉由測量伽瑪)用於基礎射頻信號之高狀態和低狀態之各自的最佳頻率f1和f2。 In one or more embodiments, all other conditions of the chamber are preferably configured such that they closely mimic the conditions of manufacture as closely as possible. In another embodiment, the frequency of the non-base radio frequency generator can be manually modified to determine (eg, by measuring gamma) the respective optimal frequencies f1 and f2 for the high and low states of the base radio frequency signal.
在步驟806中，此等對於基礎射頻信號之高狀態和低狀態之最佳非基礎射頻產生器頻率被記錄及/或儲存，以供製造期間使用(即在學習階段中已得知最佳非基礎射頻產生器頻率後之基板的製造期間)。在製造期間，當基礎射頻信號脈衝地產生時，非基礎射頻產生器主動地在最佳射頻頻率f1和最佳射頻頻率f2之間切換，而不是等待偵測到電漿阻抗或伽馬之改變。 In step 806, the best non-base RF generator frequencies for the high and low states of the base radio frequency signal are recorded and/or stored for use during manufacturing (ie, the best non-learning is known during the learning phase). During the manufacture of the substrate after the base RF generator frequency). During manufacture, when the underlying RF signal is pulsed, the non-base RF generator actively switches between the optimal RF frequency f1 and the optimal RF frequency f2, rather than waiting for a change in the plasma impedance or gamma to be detected. .
圖9顯示根據本發明之一實施例中，用以當電漿腔室設置脈衝基礎射頻信號以及至少一非基礎射頻信號時，輸送最佳射頻功率至電漿腔室中的電漿負載的方法。在步驟902中，電漿腔室係由脈衝基礎射頻信號以及至少一非基礎射頻信號所供電。在步驟904中，(複數)非基礎射頻產生器係在非自動調諧模式下操作。在步驟906中，非基礎射頻信號的頻率切換係主動與基礎射頻產生器之脈衝同步。當基礎射頻信號在其高狀態和低狀態之間脈衝地產生時，此主動之同步使非基礎射頻產生器可在先前得知之最佳調諧頻率f1和先前得知之最佳調諧頻率f2之間切換其調諧頻率。非基礎射頻產生器之調諧頻率的切換在製造期間係被視為主動，此係因為該切換係回應一同步信號而執行，且與改變的電漿負載狀態之偵測無關(即，與腔室參數的改變之偵測無關，而腔室參數的改變反映出由於基礎射頻信號之脈衝所導致之改變的電漿負載狀態)。 9 shows a method for delivering optimal RF power to a plasma load in a plasma chamber when a plasma chamber is provided with a pulsed base RF signal and at least one non-base RF signal, in accordance with an embodiment of the present invention. . In step 902, the plasma chamber is powered by a pulsed base radio frequency signal and at least one non-base radio frequency signal. In step 904, the (complex) non-base RF generator operates in a non-auto-tuning mode. In step 906, the frequency switching of the non-base radio frequency signal is actively synchronized with the pulse of the base radio frequency generator. This active synchronization allows the non-base RF generator to switch between the previously known optimal tuning frequency f1 and the previously known optimal tuning frequency f2 when the base RF signal is pulsed between its high state and low state. Its tuning frequency. The switching of the tuning frequency of the non-base RF generator is considered active during manufacturing because the switching is performed in response to a synchronization signal and is independent of the detection of the changed plasma load state (ie, with the chamber) The detection of the change in parameters is independent, and the change in the chamber parameters reflects the changed plasma load state due to the pulse of the underlying RF signal).
同步信號可能由，基礎射頻產生器、數個射頻產生器之任何的射頻產生器、或由例如外部同步電路或電腦所發出。在一實施例中，當基礎射頻信號從一個狀態切換到另一個狀態的同時，非基礎射頻產生器主動地從先前得知的最佳射頻頻率f1切換至另一先前得知的最佳射頻頻率f2。 The synchronization signal may be generated by a base RF generator, any of the RF generators of the plurality of RF generators, or by, for example, an external synchronization circuit or a computer. In an embodiment, while the base radio frequency signal is switched from one state to another, the non-base radio frequency generator actively switches from the previously known optimal radio frequency f1 to another previously known optimal radio frequency. F2.
例如，若用於非基礎射頻產生器之先前得知的最佳射頻頻率 f1係被確認為對於基礎射頻信號之高狀態而言有效率，且用於非基礎射頻產生器之先前得知的最佳射頻頻率f2係被確認為對於基礎射頻信號之低狀態有效率，則當基礎射頻產生器脈衝至高狀態時，非基礎射頻產生器可回應於同步信號，切換至先前得知之最佳射頻頻率f1。另外，當基礎射頻產生器脈衝至低狀態時，非基礎射頻產生器可回應於同步信號，切換至先前得知之最佳射頻頻率f2。 For example, if the best known RF frequency for a non-base RF generator F1 is confirmed to be efficient for the high state of the base RF signal, and the previously known optimal RF frequency f2 for the non-base RF generator is confirmed to be efficient for the low state of the base RF signal, then When the base RF generator is pulsed to a high state, the non-base RF generator can switch to the previously known optimal RF frequency f1 in response to the synchronization signal. In addition, when the base RF generator is pulsed to a low state, the non-base RF generator can switch to the previously known optimal RF frequency f2 in response to the synchronization signal.
在另一實施例中，非基礎射頻產生器甚至可稍微在基礎射頻信號從一個狀態切換至另一個狀態之前，主動地從先前得知的最佳射頻頻率f1切換至另一個先前得知的最佳射頻頻率f2。 In another embodiment, the non-base radio frequency generator can actively switch from the previously known best radio frequency f1 to another previously known most even before the base radio frequency signal is switched from one state to another. Good RF frequency f2.
在另一實施例中，非基礎射頻產生器甚至可稍微在基礎射頻信號從一個狀態切換至另一個狀態之後，主動地從先前得知的最佳射頻頻率f1切換至另一個先前得知的最佳射頻頻率f2。 In another embodiment, the non-base radio frequency generator can actively switch from the previously known optimal radio frequency f1 to another previously known most even after the base radio frequency signal is switched from one state to another. Good RF frequency f2.
在一或更多實施例中，非基礎射頻產生器之主動的非基礎射頻信號頻率切換(例如，介於先前得知的射頻頻率f1和先前得知的射頻頻率f2之間)可與非基礎射頻產生器之主動功率位準設定結合，以在當基礎射頻信號脈衝地產生時，改善射頻功率傳輸的效率和穩定性。在一或更多實施例中，非基礎射頻信號之主動的頻率切換及/或非基礎射頻產生器的主動功率位準切換，可與基礎射頻信號之脈衝同步。若涉及數個非基礎射頻信號，當基礎射頻信號脈衝地產生時，此等非基礎射頻信號之頻率及/或功率位準可主動地切換，此係使用於單一非基礎射頻信號的情況中所討論之相似的配置。 In one or more embodiments, the active non-base radio frequency signal switching of the non-base radio frequency generator (eg, between the previously known radio frequency f1 and the previously known radio frequency f2) may be non-based. The active power level setting of the RF generator is combined to improve the efficiency and stability of the RF power transmission when the underlying RF signal is pulsed. In one or more embodiments, the active frequency switching of the non-base radio frequency signals and/or the active power level switching of the non-base radio frequency generators can be synchronized with the pulses of the base radio frequency signals. If a plurality of non-base radio frequency signals are involved, the frequency and/or power level of the non-base radio frequency signals can be actively switched when the basic radio frequency signals are pulsed, which is used in the case of a single non-base radio frequency signal. Discuss similar configurations.
從前述內容可理解，本發明之實施例在當基礎射頻信號在其高狀態和低狀態之間脈衝地產生時，改善射頻功率傳送的穩定性和效率。藉由主動地改變非基礎射頻產生器或數個非基礎射頻產生器(若涉及數個非基礎射頻產生器時)之射頻功率位準，當基礎射頻信號在其高狀態和低狀態之間脈衝地產生時，功率輸送之穩定度係可提升。藉由主動地在用於非基礎射頻產生器或數個非基礎射頻產生器(若涉及數個非基礎射頻產生器時)之先前得知的最佳射頻頻率之間切換，功率輸送之效率係得到改善，或可達成用於基礎射頻信號之每一脈衝狀態的功率輸送、以及用於基礎射 頻信號之高至低及低至高轉變時之持續時間的功率輸送。 As can be appreciated from the foregoing, embodiments of the present invention improve the stability and efficiency of radio frequency power transfer when the base radio frequency signal is pulsed between its high state and low state. By actively changing the RF power level of a non-base RF generator or a number of non-base RF generators (if several non-base RF generators are involved), when the base RF signal is pulsed between its high and low states When the ground is generated, the stability of power transmission can be improved. By actively switching between previously known optimal RF frequencies for non-base RF generators or several non-base RF generators (if several non-base RF generators are involved), the efficiency of power delivery is Improved, or power delivery for each pulse state of the base RF signal, and for base shots Power transmission of the high to low frequency of the frequency signal and the duration of the low to high transition.
藉由提供這些額外的控制旋鈕，可打開製程配方容許度以適應更嚴格的處理要求，從而提高處理和高密度/高性能元件之產率。 By providing these additional control knobs, process recipe tolerances can be opened to accommodate more stringent processing requirements, resulting in improved processing and high density/high performance component yields.
本發明雖已透過數個較佳實施例加以說明，但仍有許多落於本發明範疇內之替換、修改及各種置換均等物。亦應注意有許多實施本發明之方法及裝置的替代性方式。雖然在此提供各種範例，但關於本發明之此等範例應為說明性而非限制性。 The present invention has been described in terms of several preferred embodiments, and many alternatives, modifications, and various substitutions are possible within the scope of the invention. It should also be noted that there are many alternative ways of implementing the methods and apparatus of the present invention. The various examples of the invention are intended to be illustrative and not restrictive.
202‧‧‧電漿處理系統 202‧‧‧Plastic Processing System
204‧‧‧電漿處理腔室 204‧‧‧The plasma processing chamber
206‧‧‧上部電極 206‧‧‧Upper electrode
208‧‧‧下部電極 208‧‧‧lower electrode
220‧‧‧射頻電源供應器 220‧‧‧RF power supply
222‧‧‧射頻電源供應器 222‧‧‧RF power supply
224‧‧‧射頻電源供應器 224‧‧‧RF power supply
230‧‧‧匹配網路 230‧‧‧match network
231‧‧‧導管 231‧‧‧ catheter
232‧‧‧導管 232‧‧‧ catheter
234‧‧‧導管 234‧‧‧ catheter
250‧‧‧控制電路 250‧‧‧Control circuit
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