JPS63311322A - Polarizing device - Google Patents
Polarizing deviceInfo
- Publication number
- JPS63311322A JPS63311322A JP62148624A JP14862487A JPS63311322A JP S63311322 A JPS63311322 A JP S63311322A JP 62148624 A JP62148624 A JP 62148624A JP 14862487 A JP14862487 A JP 14862487A JP S63311322 A JPS63311322 A JP S63311322A
- Authority
- JP
- Japan
- Prior art keywords
- light
- polarized light
- polarization
- intensity
- component
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000010287 polarization Effects 0.000 claims abstract description 69
- 230000003287 optical effect Effects 0.000 claims abstract description 56
- 230000002194 synthesizing effect Effects 0.000 claims abstract 3
- 238000000926 separation method Methods 0.000 claims description 6
- 230000015572 biosynthetic process Effects 0.000 claims description 4
- 238000003786 synthesis reaction Methods 0.000 claims description 4
- 239000002131 composite material Substances 0.000 abstract description 6
- 239000000203 mixture Substances 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 21
- 238000001514 detection method Methods 0.000 description 14
- 239000010409 thin film Substances 0.000 description 8
- 239000010408 film Substances 0.000 description 5
- 230000004907 flux Effects 0.000 description 5
- 230000005484 gravity Effects 0.000 description 5
- 239000000758 substrate Substances 0.000 description 5
- 238000005259 measurement Methods 0.000 description 3
- 230000002093 peripheral effect Effects 0.000 description 3
- 238000002834 transmittance Methods 0.000 description 3
- 230000010363 phase shift Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000572 ellipsometry Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 229920002120 photoresistant polymer Polymers 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
- G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
- G03F9/7065—Production of alignment light, e.g. light source, control of coherence, polarization, pulse length, wavelength
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
- G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
- G03F9/7003—Alignment type or strategy, e.g. leveling, global alignment
- G03F9/7023—Aligning or positioning in direction perpendicular to substrate surface
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
- G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
- G03F9/7073—Alignment marks and their environment
- G03F9/7076—Mark details, e.g. phase grating mark, temporary mark
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Measurement Of Optical Distance (AREA)
Abstract
Description
【発明の詳細な説明】
〔発明の目的〕
（産業上の利用分野）
本発明は、所望の偏光状態の光束を得るための偏光装置
に関し、特に、光の反射に起因する偏光の強度比を任意
に抑制するのに好適な偏光装置に関する。Detailed Description of the Invention [Objective of the Invention] (Industrial Application Field) The present invention relates to a polarization device for obtaining a luminous flux with a desired polarization state, and in particular, to The present invention relates to a polarization device suitable for arbitrary suppression.
（従来の技術）
自然光のような非偏光光であっても物体表面にて反射す
ると、その反射光は、入射面に平行な偏光成分（Ｐ偏光
）と入射面に垂直な偏光成分（Ｓ偏光）の偏光の強度比
が変化することが知られて居り、その反射光中の偏光成
分の光強度比を抑制する手段として、透過する電磁波の
ある成分を選択的に吸収して非偏光光を直線偏光にする
偏光フィルターが一般によ（知られている。この偏光フ
ィルターは、そのフィルターの軸に平行な偏光方向の成
分はほぼ１００％透過し、偏光面に垂直な偏光成分は、
はぼ１００％吸収する。すなわち、この偏光フィルター
による透過光の、軸に平行な偏光成分とこれに垂直な偏
光成分との比は、はぼｔｏｏ：ｏである。(Prior art) When even non-polarized light such as natural light is reflected by an object surface, the reflected light consists of a polarized light component parallel to the plane of incidence (P polarized light) and a polarized light component perpendicular to the plane of incidence (S polarized light). ) is known to change, and as a means of suppressing the light intensity ratio of polarized light components in the reflected light, it is possible to selectively absorb a certain component of the electromagnetic wave that passes through it and convert it into non-polarized light. Polarizing filters that convert linearly polarized light are generally known. This polarizing filter transmits almost 100% of the polarized light component parallel to the axis of the filter, and transmits almost 100% of the polarized light component perpendicular to the polarization plane.
Absorbs 100%. That is, the ratio of the polarized light component parallel to the axis and the polarized light component perpendicular to the axis of the light transmitted through this polarizing filter is about too:o.
（発明が解決しようとする問題点）
しかしながら、上記の従来から用いられている偏光フィ
ルターにおいては、入射光のほぼ半分が吸収されてしま
うため、得られる光線の強度は、例えば自然光の場合入
射光の１／２またはそれ以下となる。従って、入射光中
に挿入された偏光フィルターの偏光面を入射面に対して
傾けて、偏光フィルターを透過した光を入射面に平行な
Ｘ方向（Ｐ偏光）と垂直なＸ方向（Ｓ偏光）のヘク］・
ル成分に分解し、その成分比を偏光フィルターを回転し
”Ｃ変化させても各成分は入射光の１／２以下になって
しまう。特に成分比が２１の場合には各成分は強度は入
射光の１／４以下になり、表面反射を利用して表面位置
や薄膜の性質等を測定する測定装置においては検出精度
が低下するという問題点があった。(Problem to be solved by the invention) However, in the conventionally used polarizing filter described above, almost half of the incident light is absorbed, so the intensity of the obtained light ray is 1/2 or less. Therefore, by tilting the polarization plane of a polarizing filter inserted into the incident light with respect to the plane of incidence, the light transmitted through the polarizing filter is divided into the X direction parallel to the plane of incidence (P polarization) and the X direction perpendicular to the plane of incidence (S polarization). Heku]・
Even if the component ratio is changed by rotating the polarizing filter, each component will be less than 1/2 of the incident light. Especially when the component ratio is 21, the intensity of each component will be The amount of light is less than 1/4 of the incident light, and there has been a problem in that detection accuracy is reduced in measuring devices that use surface reflection to measure surface positions, properties of thin films, and the like.
従って本発明は、上記従来の偏光フィルターのような偏
光装置の問題点を解決し、偏光方向が互いに垂直な２つ
の偏光成分の強度比を任意の値に容易に変化させること
ができ、その変化した２つの偏光成分を効率よく再び合
成して射出する偏光装置を提供することを目的とするも
のである。Therefore, the present invention solves the problems of polarizing devices such as the conventional polarizing filters described above, and can easily change the intensity ratio of two polarized light components whose polarization directions are perpendicular to each other to an arbitrary value. It is an object of the present invention to provide a polarizing device that efficiently combines and emits the two polarized light components.
（問題点を解決する為の手段）
上記の目的を達成するために、本発明においては、入射
光を偏光方向が互いに直角な２つの偏光成分に分離する
偏光分離光学手段と、この偏光分離光学手段を介して射
出される２つの偏光成分の強度比を任意に変え得る偏光
強度可変手段と、その偏光強度可変手段によって強度比
が変えられた２つの偏光成分を合成して一方向に射出す
る偏光合成光学手段とを設けることを、問題解決の手段
とするものである。 ゛
（作用）
種々の偏光状態を異にする入射光（Ｌ１）は、偏光分離
光学手段（１，２１）によって偏光方向が互いに直角な
Ｐ偏光成分とＳ偏光成分とに分離され、それぞれ異なる
方向に射出される。その際、光エネルギーの損失が殆ん
ど無く、分離されたＰ偏光成分の強度とＳ偏光成分の強
度との和は、入射光（Ｌ１）の光強度に等しい。この偏
光合成光学手段（１）によって分離されるＳ＠光成分と
Ｐ偏光成分とは、偏光強度可変手段（５，６，７，７Ａ
、７Ｂ、３１．４１）によってその強度比が任意に変え
られる。特に実施例に示すようにλ／４板（３１）やλ
／２板（４１）を回転調節して、Ｐ偏光成分とＳ偏光成
分との比を変える場合には、光エネルギーの損失が殆ん
ど無い。さらに、偏光強度可変手段（５，６，７，７Ａ
、７Ｂ、３１゜４１）にて強度比が任意に変えられたＰ
偏光成分とＳ偏光成分とは、偏光合成光学手段（２）に
て合成され一方向にのみ射出される。この合成の場合に
も殆んど光エネルギーのｔｌ失が無い。従って、入射光
に対する合成射出光のエネルギーｔｊｌ失を少なくして
、しかも合成射出光に含まれるＰ偏光成分とＳ偏光成分
との比を広い範囲で効率よく変えることができる。(Means for Solving the Problems) In order to achieve the above object, the present invention provides a polarization separation optical means for separating incident light into two polarization components whose polarization directions are perpendicular to each other, and a polarization separation optical means for separating incident light into two polarization components whose polarization directions are perpendicular to each other. A polarized light intensity variable means that can arbitrarily change the intensity ratio of two polarized light components emitted through the means, and a polarized light intensity variable means that synthesizes the two polarized light components whose intensity ratio has been changed by the polarized light intensity variable means and emits the synthesized light in one direction. The problem is solved by providing a polarization combining optical means.゛(Function) The incident light (L1) having various polarization states is separated by the polarization separation optical means (1, 21) into a P polarization component and an S polarization component whose polarization directions are perpendicular to each other. is injected into the At this time, there is almost no loss of optical energy, and the sum of the intensity of the separated P-polarized light component and the intensity of the S-polarized light component is equal to the light intensity of the incident light (L1). The S@ light component and the P polarized light component separated by the polarization combining optical means (1) are separated by the polarization intensity variable means (5, 6, 7, 7A).
, 7B, 31.41), the intensity ratio can be changed arbitrarily. In particular, as shown in the examples, the λ/4 plate (31) and the λ
When the ratio of the P-polarized light component to the S-polarized light component is changed by adjusting the rotation of the /2 plate (41), there is almost no loss of optical energy. Furthermore, polarization intensity variable means (5, 6, 7, 7A
, 7B, 31°41), the intensity ratio was arbitrarily changed.
The polarized light component and the S-polarized light component are combined by a polarization combining optical means (2) and emitted in only one direction. In this synthesis, there is almost no tl loss of optical energy. Therefore, the loss of energy tjl of the combined emitted light with respect to the incident light can be reduced, and the ratio of the P-polarized light component and the S-polarized light component included in the combined emitted light can be efficiently changed over a wide range.
（実施例）
次に、本発明の実施例を添付のし１面に基づいて説明す
る。(Example) Next, an example of the present invention will be described based on the attached first page.
第１図は、本発明の第１実施例を示す光学系構成図で、
第１偏光プリズム１および第２偏光プリズム２は、それ
ぞれの接合面１ａ、２ａに誘電体多層膜を有し、第１偏
光プリズムｌに入射する光源ｌＯからの非偏光（ランダ
ム偏光）または円偏光の光束Ｌ１は、接合面１ａで、そ
の接合面に垂直な入射面に平行なＰ偏光成分と入射面に
垂直で且つＰ偏光成分と等しい強度のＳ偏光成分とに分
離され、Ｐ偏光成分は接合面１ａを透過して第２偏光プ
リズム２へ向う、また、他方のＳ偏光成分は、接合面１
ａにて反射され、更に２個のミラー３．４を介して第２
偏光プリズム２に向う。第２偏光プリズム２に向った一
方のＰ偏光は接合面２ａを透過し、他方のＳ偏光は接合
面２ａにて反射し、Ｐ偏光とＳ偏光とは合成され°Ｃ１
合成射出光Ｌ２として第２偏光プリズム２から射出され
る。FIG. 1 is an optical system configuration diagram showing a first embodiment of the present invention.
The first polarizing prism 1 and the second polarizing prism 2 have dielectric multilayer films on their respective joint surfaces 1a and 2a, and unpolarized light (randomly polarized light) or circularly polarized light from a light source 10 that enters the first polarizing prism 1 The luminous flux L1 is separated at the cemented surface 1a into a P-polarized light component parallel to the plane of incidence perpendicular to the cemented surface and an S-polarized light component that is perpendicular to the plane of incidence and has the same intensity as the P-polarized light component, and the P-polarized light component is The other S-polarized light component passes through the cemented surface 1a and goes to the second polarizing prism 2.
a, and further passes through two mirrors 3.4 to the second
Head toward polarizing prism 2. One P-polarized light directed toward the second polarizing prism 2 is transmitted through the cemented surface 2a, and the other S-polarized light is reflected at the cemented surface 2a, and the P-polarized light and the S-polarized light are combined at °C1
The combined emitted light L2 is emitted from the second polarizing prism 2.
また、第１偏光プリズム１と第２偏光プリズム２との間
のＰ偏光とＳ偏光がそれぞれ通過する光路上には、透過
率を任意に変えることができる濃度フィルター５．６が
それぞれ設けられ、双方の濃度フィルター５及び６は、
共にｉ３過率をほぼ１００％から０％まで任意に変える
ことができる。In addition, density filters 5.6 whose transmittances can be arbitrarily changed are provided on the optical paths between the first polarizing prism 1 and the second polarizing prism 2 through which the P-polarized light and the S-polarized light pass, respectively. Both density filters 5 and 6 are
In both cases, the i3 pass rate can be changed arbitrarily from approximately 100% to 0%.
また、入射光り、は第１偏光プリズムｌによって、エネ
ルギの損失な（強度の互いに等しいＰ偏光とＳ偏光に２
分され、また２分されたＰ偏光とＳ偏光とは、エネルギ
の損失無く、第２偏光プリズム２によって合成される。In addition, the incident light is divided into P-polarized light and S-polarized light with equal intensities by the first polarizing prism l, which causes energy loss.
The P-polarized light and the S-polarized light that have been separated into two are combined by the second polarizing prism 2 without loss of energy.
従って双方の濃度フィルター５及び６が透過率１００％
の状態にセットされている場合には、第２偏光プリズム
２から射出される合成射出光Ｌ２の光強度は、入射光Ｌ
１のそれとほぼ等しいものとなる。この場合、入射光Ｌ
１の強度を１００とすると合成射出光り、に含まれるＰ
偏光とＳ偏光とはそれぞれ５０であり、このＩ）偏光と
Ｓ偏光の光強度を、濃度フィルター５および６によって
、それぞれ５０〜Ｏの間で自由に変えることができ、Ｐ
偏光とＳ偏光の強度比を任意に変えて合成射出光Ｌ８と
することができる。 。Therefore, both density filters 5 and 6 have a transmittance of 100%.
When the state is set, the light intensity of the combined emitted light L2 emitted from the second polarizing prism 2 is equal to
It is almost the same as that of 1. In this case, the incident light L
If the intensity of 1 is set to 100, the P contained in the composite emitted light is
Polarized light and S-polarized light are each 50, and the light intensities of I) polarized light and S-polarized light can be freely changed between 50 and 0 using density filters 5 and 6, respectively, and P
The intensity ratio of the polarized light and the S-polarized light can be arbitrarily changed to form the composite emitted light L8. .
第２図は、Ｐ偏光成分の光路長とＳ偏光成分の光路長と
を等しくした本発明の第２実施例を示す光学系構成図で
ある。第１図の実施例と同じ機能を有する部分には第１
図と同じ符号を付し、その構成についての詳しい説明は
省略する。FIG. 2 is an optical system configuration diagram showing a second embodiment of the present invention in which the optical path length of the P-polarized light component and the optical path length of the S-polarized light component are made equal. The parts having the same functions as the embodiment shown in FIG.
The same reference numerals as those in the figure are used, and detailed explanation of the structure will be omitted.
第２図において、非偏光（ランダム偏光）または円偏光
の入射光り、は、第１偏光プリズムｌによってＰ偏光と
Ｓ偏光とに分離され、Ｐ偏光の光束は、接合面１ａを透
過した後、第１濃度フィルター５を通過して適当な光強
度に変えられ、ミラー４にて反射され、第２偏光プリズ
ム２接合面２ａを透過する。また一方、第１偏光プリズ
ムｌの接合面１ａにて反射されたＳ偏光の光束は、ミラ
ー３にて反射された後、第２偏光プリズム２の接合面２
ａにて反射され、Ｐ偏光と合成されて第２偏光プリズム
２から合成射出光Ｌ２として射出される。この合成射出
光ｔ、ｇの■）偏光成分とＳ偏光成分との強度比は、濃
度フィルター５及び６によって任意に変えられる。この
場合、Ｐ偏光とＳ偏光とは互いに光路長が等しいが、第
１図の実施例と同様に互いに干渉することなく、単に両
者の光強度の和として合成される。In FIG. 2, unpolarized (randomly polarized) or circularly polarized incident light is separated into P-polarized light and S-polarized light by the first polarizing prism l, and the P-polarized light beam passes through the cemented surface 1a, and then The light passes through the first density filter 5, is changed to an appropriate light intensity, is reflected by the mirror 4, and is transmitted through the joint surface 2a of the second polarizing prism 2. On the other hand, the S-polarized light beam reflected by the cemented surface 1a of the first polarizing prism l is reflected by the mirror 3, and then is reflected by the cemented surface 1a of the second polarizing prism 2.
a, is combined with the P-polarized light, and is emitted from the second polarizing prism 2 as a combined emitted light L2. The intensity ratio between the polarized light component (2) and the S-polarized light component of the combined emitted light t and g can be arbitrarily changed by the density filters 5 and 6. In this case, the P-polarized light and the S-polarized light have the same optical path length, but as in the embodiment of FIG. 1, they do not interfere with each other and are simply combined as the sum of their light intensities.
第２図においては、合成射出光Ｌ２が入射光Ｌ１に対し
て直角方向に射出する例を示したが、第３図はＰ偏光と
Ｓ偏光の光路長が互いに等しく且つ入射光り、と同じ方
向に合成射出光り、が射出される本発明の第３実施例の
光学系構成図である。In Fig. 2, an example is shown in which the combined emitted light L2 is emitted in a direction perpendicular to the incident light L1, but in Fig. 3, the optical path lengths of the P-polarized light and the S-polarized light are equal to each other and in the same direction as the incident light. FIG. 4 is a configuration diagram of an optical system according to a third embodiment of the present invention in which a composite emitted light is emitted.
第１図及び第２図と同じ機能を有する部分には第１図、
第２図と同じ符号を付し、その構成についての詳しい説
明は省略する。Parts having the same functions as those in Figures 1 and 2 are shown in Figure 1,
The same reference numerals as in FIG. 2 are given, and detailed explanation of the structure will be omitted.
第３図において、互いに光路長が等しいＰ偏光とＳ偏光
のそれぞれの光路上には濃度フィルター５．６およびλ
／２板７が設けられ、このλ／２板７によってＰ偏光成
分とＳ偏光成分とは、それぞれ偏光方向が９０°回転さ
れる。これにより、第１偏光プリズムｌの接合面１ａを
透過したＰ偏光成分の光束は、第２偏光プリズム２の接
合面２ａにて反射され、また、第１偏光プリズム！の接
合面１ａにて反射したＳ偏光成分の光束は第２偏光プリ
ズム２の接合面２ａを透過し、合成射出光Ｌ２は、入射
光り、と同方向に射出される。この場合にもＰ偏光とＳ
偏光の光路長は等しいが、合成射出光り、に含まれるＰ
偏光成分とＳ偏光成分とは互いに干渉することなく、合
成射出光Ｌ２の強度は、射出光り怠を構成するＩ）偏光
成分とＳ偏光成分との光強度の和となる。In FIG. 3, a concentration filter 5.6 and a λ
A /2 plate 7 is provided, and the polarization directions of the P-polarized light component and the S-polarized light component are each rotated by 90 degrees by the λ/2 plate 7. As a result, the light flux of the P-polarized light component transmitted through the cemented surface 1a of the first polarizing prism l is reflected by the cemented surface 2a of the second polarizing prism 2, and the light beam of the first polarizing prism ! The light flux of the S-polarized component reflected at the cemented surface 1a of the second polarizing prism 2 passes through the cemented surface 2a of the second polarizing prism 2, and the combined emitted light L2 is emitted in the same direction as the incident light. In this case as well, P polarized light and S
Although the optical path length of the polarized light is equal, the P included in the composite emitted light is
The polarized light component and the S-polarized light component do not interfere with each other, and the intensity of the combined emitted light L2 is the sum of the light intensities of the I) polarized light component and the S-polarized light component that constitute the emitted light beam.
第１図乃至第３図の実施例では、Ｐ偏光成分とＳ偏光成
分との強度比を変えるために濃度フィルター５．６を用
いたが、その濃度フィルター５．６の代りに、第４図に
示すような偏光フィルター８を用いてもよい。第４図に
おいて、偏光フィルター８の軸方向ｑを入射光の偏光方
向ｐに対して傾けること゛により、その偏光フィルター
８を透過する透過光の強度を自由に変えることができる
。In the embodiments shown in FIGS. 1 to 3, the density filter 5.6 was used to change the intensity ratio of the P-polarized light component and the S-polarized light component. A polarizing filter 8 as shown in FIG. 1 may also be used. In FIG. 4, by tilting the axial direction q of the polarizing filter 8 with respect to the polarization direction p of the incident light, the intensity of the transmitted light passing through the polarizing filter 8 can be freely changed.
その傾向をθとすると、透過光の強度１１は、１１ （
Ｘ： Ｃｏｓ” １）
となる、従って、Ｐ偏光とＳ偏光のそれぞれの光路上に
設けられる偏光フィルター７を回転して、傾角θを任意
に調整することにより、合成射出光Ｌ２を構成する。Ｐ
偏光成分とＳ偏光成分との強度比を連続的に変化される
ことが可能となる。なお、第２偏光プリズム２において
も、光強度の減少が生じるため、合成射出光Ｌ８におけ
る各偏光の強度Ｉｇは、ｌ 、 ｏｅ （０３’ θと
なる。If the tendency is θ, the intensity 11 of the transmitted light is 11 (
X: Cos'' 1) Therefore, by rotating the polarizing filters 7 provided on the respective optical paths of the P-polarized light and the S-polarized light and arbitrarily adjusting the inclination θ, the combined emitted light L2 is constructed. P
It becomes possible to continuously change the intensity ratio between the polarized light component and the S-polarized light component. Note that since the light intensity decreases in the second polarizing prism 2 as well, the intensity Ig of each polarized light in the combined emitted light L8 becomes l, oe (03' θ).
第５図は、合成射出光りよの中心部と周辺部とで偏光方
向が異なるように構成された本発明の第４実施例を示す
光学系構成図である。第２図の実施例と同様に、Ｐ偏光
とＳ偏光とは光路長が等しくなるように構成され、濃度
フィルター５．６の代りに、Ｐ偏光光路上には、第６図
に示すように中心部７ａが遮光された回転可能な偏光フ
ィルター７Ａが設けられ、Ｓ偏光光路上には第７図に示
すように周辺部７ｂが遮光された回転可能な偏光フィル
ター７Ｂが設けられている。また、双方の偏光フィルタ
ー７Ａ、７Ｂは、第２偏光プリズム２までの光路長が等
しくなる位置に配置されている。FIG. 5 is a diagram illustrating the configuration of an optical system according to a fourth embodiment of the present invention, in which the polarization direction is different between the central part and the peripheral part of the composite emission light beam. Similar to the embodiment shown in FIG. 2, the P-polarized light and the S-polarized light are constructed so that their optical path lengths are equal, and instead of the density filter 5.6, there is a filter on the P-polarized light path as shown in FIG. A rotatable polarizing filter 7A whose central portion 7a is shielded from light is provided, and a rotatable polarizing filter 7B whose peripheral portion 7b is shielded from light is provided on the S-polarized light path as shown in FIG. Moreover, both polarizing filters 7A and 7B are arranged at positions where the optical path lengths to the second polarizing prism 2 are equal.
これにより、第２偏光プリズム２から射出される合成射
出光Ｌ２は、第８図に示すように中央部分がＳ偏光成分
、周辺部分はＰ偏光成分となり、このＰ偏光とＳ偏光と
は、偏光フィルター７Ａ、７Ｂを適当な角度に回転させ
ることにより、その光強度を変えることができる。従っ
て、合成射出光Ｌ２の周辺部光盪と中央部光量との比を
任意に変えることが可能となる。As a result, the combined emitted light L2 emitted from the second polarizing prism 2 has an S-polarized light component in the central part and a P-polarized light component in the peripheral part, as shown in FIG. By rotating the filters 7A and 7B at appropriate angles, the light intensity can be changed. Therefore, it is possible to arbitrarily change the ratio of the amount of light at the periphery and the amount at the center of the combined emitted light L2.
第９図は、直線偏光を発する光源を用いた場合の本発明
の第５実施例を示す光学系構成図である。FIG. 9 is a configuration diagram of an optical system showing a fifth embodiment of the present invention in which a light source that emits linearly polarized light is used.
第１図と同じ機能を有する部分には第１図と同一の符号
を付し、その構成についての詳しい説明は省略する。Components having the same functions as those in FIG. 1 are designated by the same reference numerals as in FIG. 1, and detailed explanations of their configurations will be omitted.
第９図において、直線偏光を発する光源２０と第１偏光
プリズム１との間の光路上にはλ／４板２板上１けられ
、これにより直線偏光は円偏光となって第１偏光プリズ
ムｌに入射する。この円偏光の入射光束は、第１図の実
施例と同様に、第１偏光プリズムｌによって強度の互い
に等しいＰ偏光とＳ偏光に分離され、さらに濃度フィル
ター５．６にてＰ偏光とＳ偏光との強度が任意の値に調
整された後、第２偏光プリズム２にて合成される。In FIG. 9, two λ/4 plates are placed on the optical path between the light source 20 that emits linearly polarized light and the first polarizing prism 1, so that the linearly polarized light becomes circularly polarized light and is passed through the first polarizing prism. incident on l. Similar to the embodiment shown in FIG. 1, this circularly polarized incident light beam is separated into P-polarized light and S-polarized light with equal intensities by a first polarizing prism l, and then filtered through a density filter 5.6 into P-polarized light and S-polarized light. After the intensity is adjusted to an arbitrary value, they are combined in the second polarizing prism 2.
この合成された合成射出光Ｌ３は第２偏光プリズム２か
ら、入射光Ｌ＋ と同方向に射出される。なお、この場
合、第１偏光プリズム１とλ／４板２板上１もって偏光
分離光学手段が構成される。This combined output light L3 is emitted from the second polarizing prism 2 in the same direction as the incident light L+. In this case, the first polarizing prism 1, two λ/4 plates 1 constitute a polarization separation optical means.
また、第９図の実施例において、λ／４板２板上１をＰ
偏光とＳ偏光の偏光方向に対して４５゜に固定してもよ
い、このようにすると、直線偏光の偏光方向が変わって
も、射出されるＰ偏光成分とＳ偏光成分の強度比が以下
に示すように不変である。いま、第９Ａ図において、λ
／４板２板上１射する直線偏光をａ、λ／４板２板上１
過した後の楕円偏光をｂ、第１偏光プリズム１から射出
される偏光をＰおよびＳとすると、λ／４板２板上１が
１）、Ｓ方向に対して４５°＋ＩＪＩいているため、λ
／４板２板上１射出される光は、楕円軸がＰ、Ｓ方向に
対して４５″をなす楕円偏光すとなる。In addition, in the embodiment shown in FIG. 9, P
It may be fixed at 45 degrees with respect to the polarization directions of polarized light and S-polarized light. In this way, even if the polarization direction of linearly polarized light changes, the intensity ratio of the emitted P-polarized light component and S-polarized light component will be as follows. It is unchanged as shown. Now, in Figure 9A, λ
/4 plate 2 The linearly polarized light incident on plate 2 is a, λ/4 plate 2 plate 1
Let b be the elliptically polarized light after passing through the polarizing prism 1, and P and S be the polarized light emitted from the first polarizing prism 1.Since the λ/4 plate 2 and the top 1 are angled by 45° + IJI with respect to the S direction, λ
The light emitted from the two /4 plates is elliptically polarized light whose ellipse axes make an angle of 45'' with respect to the P and S directions.
従って、第１偏光プリズムｌによって分がされたＰＳＳ
偏光のそれぞれの強度は等しくなる。それ故、濃度フィ
ルター５．６によって、Ｐ、Ｓ偏光の強度比を調整すれ
ば、第２偏光プリズム２から射出される光束Ｌ２のＰ偏
光とＳ偏光の強度比は、入射光束Ｌ１の直線偏光の偏光
方向が変っても不変となる。Therefore, the PSS separated by the first polarizing prism l
The intensity of each polarized light will be equal. Therefore, if the intensity ratio of P and S polarized light is adjusted by the density filter 5.6, the intensity ratio of P polarized light and S polarized light of the light beam L2 emitted from the second polarizing prism 2 will be equal to the linearly polarized light of the incident light beam L1. remains unchanged even if the polarization direction of is changed.
第１０図は、Ｐ偏光とＳ偏光との強度比をλ／４板を用
いて変える本発明の第６実施例を示す光学系構成図であ
る。この場合、光源には円偏光を発するものが用いられ
る。なお、第１図の実施例と同じ機能を有する部分には
第１図と同一の符号を付し、その構成についての詳しい
説明は省略する。FIG. 10 is a configuration diagram of an optical system showing a sixth embodiment of the present invention in which the intensity ratio of P-polarized light and S-polarized light is changed using a λ/4 plate. In this case, a light source that emits circularly polarized light is used. Components having the same functions as those in the embodiment shown in FIG. 1 are designated by the same reference numerals as in FIG. 1, and detailed explanations of their configurations will be omitted.
第１０図におてい、円偏光を発する光源３０と第１偏光
プリズムｌとの間に入射光り、の光路上に入射光Ｌ１に
垂直な面内で回転調節可能なλ／４板３１が設けられる
。このλ／４板３１により円偏光は直線偏光に変えられ
、その直線偏光の偏光方向は、λ／４板３１を適当な回
転角だけ回転させることにより、第１偏光プリズムｌの
接合面に垂直な面に対して任意の角度だけ傾けることが
できる。これにより、その頭角を適当に変えて、第１偏
光プリズムｌによって分離されるＰ偏光成分とＳ偏光成
分とを任意の強度比に変えることができる。In FIG. 10, a λ/4 plate 31 that can be rotated and adjusted in a plane perpendicular to the incident light L1 is provided on the optical path of the incident light between the light source 30 that emits circularly polarized light and the first polarizing prism l. It will be done. This λ/4 plate 31 converts the circularly polarized light into linearly polarized light, and by rotating the λ/4 plate 31 by an appropriate rotation angle, the polarization direction of the linearly polarized light is perpendicular to the cemented surface of the first polarizing prism l. It can be tilted at any angle relative to the surface. Thereby, by appropriately changing the head angle, it is possible to change the intensity ratio of the P-polarized light component and the S-polarized light component separated by the first polarizing prism l to an arbitrary intensity ratio.
この第１０図に示す第６実施例においては、分離された
Ｐ偏光成分とＳ偏光成分との光路上に濃度フィルターの
ような光吸収部材が設けられていないので、その各偏光
成分をそれぞれ独立して変えることはできないが、原理
的に光エネルギーを損失する部分が無いから、第２偏光
プリズム２で合成されて射出される合成射出光り、の強
度は、常に入射光Ｌ１とほぼ等しい値となる。従って、
λ／４板３１を回転調整してＰ偏光成分とＳ偏光成分の
いずれか一方の成分の強度を零（ゼロ）にすれば、第２
偏光プリズム２から射出される合成射出光はＰ偏光成分
のみとなり且つその強度は入射光Ｌ１の強度にほぼ等し
い値とすることが可能である。その為、この第１０図に
示す偏光装置を偏光解析装置や屈折率測定装置に用いれ
ば、測定精度の向上が可能となる。In the sixth embodiment shown in FIG. 10, since no light absorbing member such as a concentration filter is provided on the optical path of the separated P-polarized light component and S-polarized light component, each of the polarized light components can be separated independently. Although it cannot be changed, in principle there is no part that loses optical energy, so the intensity of the combined emitted light that is combined and emitted by the second polarizing prism 2 is always approximately the same value as the incident light L1. Become. Therefore,
By adjusting the rotation of the λ/4 plate 31 to make the intensity of either the P-polarized light component or the S-polarized light component zero, the second
The combined emitted light emitted from the polarizing prism 2 has only a P-polarized light component, and its intensity can be set to a value approximately equal to the intensity of the incident light L1. Therefore, if the polarization device shown in FIG. 10 is used in an ellipsometry device or a refractive index measurement device, it is possible to improve measurement accuracy.
第１１図は、光強度可変手段としてλ／２板を用いた本
発明の第７実施例の光学系構成図である。FIG. 11 is a configuration diagram of an optical system according to a seventh embodiment of the present invention using a λ/2 plate as a light intensity variable means.
この場合、光源には、直線偏光または楕円偏光のいずれ
かを発するものが用いられる。なお、第１図の実施例と
同じ機能を有する部分には第１図と同一の符号を付し、
その構成についての詳しい説明は省略する。In this case, the light source used is one that emits either linearly polarized light or elliptically polarized light. Note that parts having the same functions as those in the embodiment shown in FIG. 1 are given the same reference numerals as in FIG.
A detailed explanation of its configuration will be omitted.
直線偏光または楕円偏光を発する光源４０と第１偏光プ
リズムｌとの間の入射光り、の光路中には、第１偏光プ
リズムｌによって分離されるＰ偏光成分とＳ偏光成分と
の強度比を変えるためのλ／２板４１が設けられている
。このλ／２板４１を通過した光の互いに直角なＸ方向
成分とｙ方向成分とは、位相が１８０’ずれ且つλ／２
板４１を回転すると、その直線偏光と楕円偏光の偏光方
向をその回転に地じて変えることができる。従って、λ
／２板４１を入射光り、に垂直な面内で適当に回転調整
することにより、第１偏光プリズムｌによって分離され
るＰ偏光成分とＳ偏光成分との強度比を変ることができ
る。この場合、直線偏光ではある方向の強度を零（ゼロ
）にできるので、分離されるＰ、Ｓ偏光成分の強度比を
、第１θ図の第６実施例の場合と同様に（０：１００）
〜（５０：５０）〜（１００１）の間で自由に変ること
ができる。しかし、楕円偏光では、任意の方向の強度が
有限であって零（ゼロ）でないので、Ｐ偏光成分とＳ偏
光成分との比を等しく（５（１５０）にはできるが、そ
の比はある程度までの範囲しかできない。During the optical path of the incident light between the light source 40 that emits linearly polarized light or elliptically polarized light and the first polarizing prism l, the intensity ratio of the P polarized light component and the S polarized light component separated by the first polarized light component is changed. A λ/2 plate 41 is provided for this purpose. The X-direction component and the Y-direction component, which are perpendicular to each other, of the light that has passed through the λ/2 plate 41 have a phase shift of 180' and a λ/2
When the plate 41 is rotated, the polarization directions of the linearly polarized light and the elliptically polarized light can be changed according to the rotation. Therefore, λ
By appropriately rotating and adjusting the /2 plate 41 in a plane perpendicular to the incident light, the intensity ratio of the P-polarized light component and the S-polarized light component separated by the first polarizing prism 1 can be changed. In this case, since the intensity in a certain direction can be made zero for linearly polarized light, the intensity ratio of the P and S polarized components to be separated is set to (0:100) as in the case of the sixth embodiment in Fig. 1θ.
It can be freely changed between ~(50:50) and (1001). However, in elliptically polarized light, the intensity in any direction is finite and not zero, so the ratio of the P-polarized light component and the S-polarized light component can be made equal (5 (150)), but the ratio is limited to a certain extent. It can only be done within the range of.
第１２図は、光強度可変手段として、λ／２板と濃度フ
ィルターとを用いた本発明の第８実施例の光学系構成図
である。この場合、光源には第１１図の実施例と同様に
直線偏光または楕円偏光を発するものが用いられる。な
お、第１図の実施例と同じ機能を有する部分には第１図
と同一の符号を付し、その構成についての詳しい説明は
省略する。FIG. 12 is a diagram showing the configuration of an optical system according to an eighth embodiment of the present invention, which uses a λ/2 plate and a density filter as the light intensity variable means. In this case, a light source that emits linearly polarized light or elliptically polarized light is used as in the embodiment shown in FIG. Components having the same functions as those in the embodiment shown in FIG. 1 are designated by the same reference numerals as in FIG. 1, and detailed explanations of their configurations will be omitted.
第１２図において、直線偏光または楕円偏光を発する光
ａ１４０と第１偏光プリズムｌとの間の入射光り、の光
路上には回転調整可能なλ／２板４１が配置されている
。このλ／２板４１の軸を、第１偏光プリズムｌの接合
面１ａに垂直な入射面に対して適当に回転調整して、第
１偏光プリズムｌによって分離されるＰ偏光成分とＳ偏
光成分とが等しい値になるように調節される。この場合
Ｐ偏光成分とＳ偏光成分のそれぞれの強度の和は入射光
り、の強度に等しい、そのＰ偏光成分とＳ偏光成分とは
濃度フィルター５．６により、それぞれ任意の強度に変
られた後、第２偏光プリズム２にて合成され、Ｐ、Ｓ偏
光成分の強度比が任意に変えられた合成射出光Ｌ２とし
て第２偏光プリズム２から射出される。この実施例にお
いては、λ／２板４１と濃度フィルター５．６との両者
によってＰ偏光成分とＳ偏光成分との強度を変えられる
ので、入射光り、のエネルギーの損失を最小限にして、
楕円偏光であっても、Ｐ、Ｓ偏光成分の強度比を任意に
変えることができる。In FIG. 12, a rotationally adjustable λ/2 plate 41 is placed on the optical path of the light a 140 emitting linearly polarized light or elliptically polarized light and the incident light between the first polarizing prism l. The axis of this λ/2 plate 41 is appropriately rotated and adjusted with respect to the incident plane perpendicular to the joining surface 1a of the first polarizing prism l, and the P polarized light component and the S polarized light component are separated by the first polarizing prism l. are adjusted so that they are equal. In this case, the sum of the respective intensities of the P-polarized light component and the S-polarized light component is equal to the intensity of the incident light, and the P-polarized light component and the S-polarized light component are changed to arbitrary intensities by the density filter 5.6. , are synthesized by the second polarizing prism 2, and are emitted from the second polarizing prism 2 as combined emitted light L2 in which the intensity ratio of the P and S polarized components is arbitrarily changed. In this embodiment, since the intensity of the P-polarized light component and the S-polarized light component can be changed by both the λ/2 plate 41 and the density filter 5.6, the energy loss of the incident light is minimized.
Even for elliptically polarized light, the intensity ratio of P and S polarized light components can be changed arbitrarily.
なお、第１２図の実施例においては、光源に直線偏光ま
たは楕円偏光を発するものを用いたが、光源が円偏光や
ランダム偏光のものは勿論、いかなる偏光状態の光に対
しても差支え無い。In the embodiment shown in FIG. 12, a light source that emits linearly polarized light or elliptically polarized light is used, but the light source may emit circularly polarized light or randomly polarized light, or may emit light of any polarization state.
第１３図は、異なる偏光状態の２種（またはそれ以上）
の光源を用いる場合の本発明の第９実施例の光学系構成
図である。第１２図と同じ機能を有する部分には第１２
図と同一の符号を付し、その構成についての詳しい説明
は省略する。Figure 13 shows two types (or more) of different polarization states.
FIG. 9 is a configuration diagram of an optical system according to a ninth embodiment of the present invention when using a light source of FIG. Parts with the same functions as those in Figure 12 are
The same reference numerals as those in the figure are given, and detailed explanation of the structure will be omitted.
ランダム偏光または円偏光を発する第１光源１０と、直
線偏光または楕円偏光を発する第２光源４０からの光束
り、は切換えミラ゛−５１によって任意に切り換えられ
、λ／２板４１を通して第１偏光プリズム１に入射する
。切換えミラー５１が実線にて示す位置に有るときは、
第２光源４０からの光束は遮断され、第１光源ｌＯから
のランダム偏光または円偏光は、切換えミラー５１にて
反射され、λ／２板４１に入射する。この場合、λ／２
板４１の軸がどのように傾いていても、透過する光の偏
光状態は不変である。従って、そのλ／２板４１を通し
て第１偏光プリズムロこ入射する光は、第１図の実施例
と同様に強度の互いに等しいＰ偏光成分とＳ偏光成分と
に分離される。分離された、各偏光成分は濃度フィルタ
ー５．６によってそれぞれその強度が任意に変えられた
後、第２偏光プリズム２にて合成され、合成射出光り、
とじて射出される。The light beams from the first light source 10 that emits randomly polarized light or circularly polarized light and the second light source 40 that emits linearly polarized light or elliptically polarized light are arbitrarily switched by a switching mirror 51, and the first polarized light passes through the λ/2 plate 41. The light enters prism 1. When the switching mirror 51 is in the position indicated by the solid line,
The light flux from the second light source 40 is blocked, and the randomly polarized light or circularly polarized light from the first light source IO is reflected by the switching mirror 51 and enters the λ/2 plate 41. In this case, λ/2
No matter how the axis of the plate 41 is tilted, the polarization state of the transmitted light remains unchanged. Therefore, the light incident on the first polarizing prism through the λ/2 plate 41 is separated into a P-polarized light component and an S-polarized light component with equal intensities, similar to the embodiment shown in FIG. The intensity of each separated polarized light component is arbitrarily changed by a density filter 5.6, and then combined by a second polarizing prism 2, resulting in a combined emitted light,
Closed and ejected.
また、切換えミラー５１を鎖線の位置まで回動すると入
射光り、は、第２光源４０からの直線偏光または楕円偏
光に切換えられ、その切換えられた直線偏光または楕円
偏光の入射光り、は、λ／２板４１を通して、第１偏光
プリズムｌに入射する。λ／２板４１は、第１偏光プリ
ズムｌにて分離されるＰ偏光成分とＳ偏光成分との強度
が互いに等しくなるように、軸の傾きをあらかじめ回転
謂整されている。従って、第１偏光プリズムｌに入射し
た直線偏光または楕円偏光の光束は、等しい強度のＰ偏
光成分とＳ偏光成分とに分離される。Furthermore, when the switching mirror 51 is rotated to the position indicated by the chain line, the incident light is switched to linearly polarized light or elliptically polarized light from the second light source 40, and the incident light of the switched linearly polarized light or elliptically polarized light is λ/ The light passes through the second plate 41 and enters the first polarizing prism l. The inclination of the axis of the λ/2 plate 41 is rotated or adjusted in advance so that the intensities of the P-polarized light component and the S-polarized light component separated by the first polarizing prism l are equal to each other. Therefore, the linearly polarized or elliptically polarized light beam incident on the first polarizing prism l is separated into a P polarized light component and an S polarized light component of equal intensity.
そのＰ偏光成分とＳ偏光成分とは、濃度フィルター５．
６にてその強度比を任意の値に変えられ、第２プリズム
２にて合成されて、合成射出光Ｌ２として射出される。The P polarized light component and the S polarized light component are filtered by the density filter 5.
6, the intensity ratio is changed to an arbitrary value, and the light beams are combined in the second prism 2 and emitted as a combined emitted light L2.
この第１３図の第９実施例においては、λ／２板４１を
挿脱することなく、偏光状態の異なる種々の光束を切換
え使用できるので、使用範囲が拡大される。In the ninth embodiment shown in FIG. 13, various light beams having different polarization states can be switched and used without inserting or removing the λ/2 plate 41, so that the range of use is expanded.
第１４図は、本発明の偏光装置を組み込んだ斜入射型表
面位置検出装置の光学系の概略構成図である。この第１
４図においては、第１図に示す非偏光（ランダム偏光）
を発する光源ｌＯを用いた第１実施例の偏光装置を用い
たが、他の第２図乃至第１３図に示す実施例装置を組み
込んでもよいことは言うまでも無い。FIG. 14 is a schematic diagram of the optical system of an oblique incidence type surface position detection device incorporating the polarization device of the present invention. This first
In Figure 4, the non-polarized light (randomly polarized light) shown in Figure 1 is
Although the polarizing device of the first embodiment using the light source 10 that emits light is used, it goes without saying that other embodiment devices shown in FIGS. 2 to 13 may be incorporated.
第１４図において、光：ａｌｏからの入射光Ｌ１は、コ
リメータレンズ１１でほぼ平行な光束となって第１偏光
プリズム１に入射する。第１偏光プリズムｌによって分
離された強度の等しいＰ偏光成分とＳ偏光成分とは、そ
れぞれ濃度フィルター５．６を通して適当な光強度比に
変えられ、第２偏光プリズム２にて合成された後、合成
射出光り、とじて射出される。この合成射出光Ｌ７は、
フィールドレンズ１２及びこれに近接して設けられた送
光スリット１３のスリット開口１３Ａを通り、検出光り
、として投光側対物レンズ１４Ａを介して被検出物体（
例えば半導体ウェハ）１５上にブリユースクー角より大
きい入射角θ、をもって投射され、その被検出面１５Ａ
上にスリット間口１３Ａと共役なスリット光像が結像さ
れる。In FIG. 14, incident light L1 from alo is turned into a substantially parallel light beam by the collimator lens 11 and is incident on the first polarizing prism 1. The P-polarized light component and the S-polarized light component with equal intensities separated by the first polarizing prism 1 are changed into an appropriate light intensity ratio through a density filter 5.6, and then combined in the second polarizing prism 2. Synthetic emitted light is emitted. This combined emitted light L7 is
The detection light passes through the field lens 12 and the slit opening 13A of the light transmission slit 13 provided in close proximity to the field lens 12, and is transmitted to the object to be detected (
For example, a semiconductor wafer) 15 is projected onto the detection surface 15A with an incident angle θ larger than the Brieuxkoo angle.
A slit light image conjugate to the slit frontage 13A is formed above.
その被検出面１５Ａからの反射光り、は、受光側対物レ
ンズ１４Ｂを介して受光スリット１６上に集光され、そ
の受光スリット１６上にスリット構造が再結像される。The reflected light from the detection surface 15A is focused onto the light receiving slit 16 via the light receiving objective lens 14B, and the slit structure is re-imaged on the light receiving slit 16.
このスリット光像の再結像位置は、被検出物体１５の表
面１５Ａが第１４図中で上下に変位すると、受光スリッ
ト１６上では、その変位に応じて受光側対物レンズＩ
４１１の光軸に垂直な方向に変位する。この再結像され
たスリフト光像の基準位置からのズレ量を検出すること
により、被検出面１５Ａの上下方向の位置を検出するこ
とができる。その表面位置検出のために、例えば光電顕
微鏡の原理が用いられ、受光スリット１６は、矢印り方
向に往復移動して、スリット光像を受光スリット１６に
形成されたスリット間口１６Ａによって走査するように
構成される。スリット開口１６Ａを通過した光は、レン
ズ１７を介して受光器（光電変換素子）１Ｂによって受
光され、スリット光像の光！重心の位置が検出される。When the surface 15A of the object to be detected 15 is displaced up and down in FIG. 14, the re-imaging position of this slit light image is determined by
411 in a direction perpendicular to the optical axis. By detecting the amount of deviation of this re-formed thrift light image from the reference position, the vertical position of the detection surface 15A can be detected. To detect the surface position, for example, the principle of a photoelectron microscope is used, and the light receiving slit 16 is moved back and forth in the direction of the arrow, so that the slit light image is scanned by the slit frontage 16A formed in the light receiving slit 16. configured. The light passing through the slit opening 16A is received by the light receiver (photoelectric conversion element) 1B via the lens 17, and the light of the slit optical image! The position of the center of gravity is detected.
この光量重心の基準位置からのズレ量から被検出面１５
Ａの位置を検出できる。Based on the amount of deviation from the reference position of the light intensity center of gravity, the detection surface 15
The position of A can be detected.
一方、被検出物体１５の基板１５Ｂの表面には、例えば
フォトレジストのような光透過性を有する薄膜１５Ｃが
設けられている。このｆｉｌｌ膜１５Ｃに投射された検
出光り、は、その一部は第１５図に示すように１膜表面
１５Ａにて反射し、受光スリ・シト１６上にスリット光
像を結像し、他の一部は破線にて示すようにｆｌｉｌ１
表面１５Ａを透過する。On the other hand, on the surface of the substrate 15B of the object to be detected 15, a thin film 15C having light transmittance, such as photoresist, is provided. A part of the detection light projected onto the fill film 15C is reflected by the film surface 15A as shown in FIG. Some parts are flil1 as shown by broken lines.
Transmits through surface 15A.
その薄膜表面１５Ａを透過した光は、基板表面１５Ｄに
て反射し、薄膜表面１５Ａを再び透過した後、受光スリ
ット１６上にスリット光像を結像する。この基板表面１
５Ｄにて反射した反射光り。The light that has passed through the thin film surface 15A is reflected on the substrate surface 15D, and after passing through the thin film surface 15A again, forms a slit light image on the light receiving slit 16. This substrate surface 1
Reflected light reflected by 5D.
によるスリット光像は、薄膜１５Ｃの膜厚に応じて、ｆ
’Ｕ１９表面１５Ａでの反射光り、によるスリット光像
に対してわずかに横ずれして結像され、両者のスリット
光像は、一部が重畳された状態となる。この一部重畳さ
れる双方のスリット光像の合成光量の重心位置が受光ス
リット１６の走査によって検出される。The slit optical image by f
The slit light image is formed with a slight lateral deviation from the slit light image due to the reflected light from the U19 surface 15A, and both slit light images are partially superimposed. The position of the center of gravity of the combined light quantity of both partially superimposed slit light images is detected by scanning the light receiving slit 16.
また一方、双方のスリット光像が重畳した部分の反射光
Ｌ４とり、とは、ｆｌｌＩｌ１５ｃの薄厚が薄いため互
いに干渉し、明暗の干渉縞を生じる。その結果、光の干
渉による重畳部分の明暗の差により、スリット光像の合
成光量の重心位置が大きく変動することになり、レジス
ト１５Ｃの塗布ムラ、つまり膜厚のわずかな製造誤差で
も、表面位置検出に大きい誤差を生じさせることになる
。On the other hand, the reflected light L4 of the portion where both the slit light images are superimposed interfere with each other due to the small thickness of the flIl15c, producing bright and dark interference fringes. As a result, the center of gravity position of the combined light amount of the slit light image changes greatly due to the difference in brightness and darkness of the superimposed part due to light interference, and even a slight manufacturing error in the coating thickness of resist 15C, that is, the surface position This will cause a large error in detection.
ところで、検出光り、の薄膜表面１５Ａに対する入射角
θｌは、表部位置の検出精度を高めるためにブリュース
ター角より大きい角度に設定されている。しかし、薄膜
表面１５Ａを透過する光は、その表面１５Ａで屈折する
ため、基板表面１５０に対する入射角θ、はブリュース
ター角より小さい、入射角がブリエースター角に達する
と、入射面に平行なＰ偏光成分の反射率は零（ゼロ）と
なり、反射光は入射面に垂直なＳ偏光成分のみとなるこ
とが一般に知られている。このブリュースター角を超え
て入射角が大きくなると、第１５図中で矢印Ｐ、、Ｐｇ
で示すように、ｍ膜表面１５Ａからの反射光Ｌ４のＰ偏
光成分Ｐ、と基板表面１５Ｄからの反射光り、のＰ偏光
成分Ｐ！とは互いに位相が１８０’逆転する。しかし、
反射光Ｌａ。By the way, the incident angle θl of the detection light with respect to the thin film surface 15A is set to be larger than the Brewster angle in order to improve the detection accuracy of the surface position. However, since the light transmitted through the thin film surface 15A is refracted at the surface 15A, the incident angle θ with respect to the substrate surface 150 is smaller than the Brewster angle. It is generally known that the reflectance of the P-polarized light component is zero, and that the reflected light is only the S-polarized light component perpendicular to the plane of incidence. When the angle of incidence increases beyond this Brewster's angle, arrows P, , Pg in FIG.
As shown, the P-polarized light component P of the reflected light L4 from the m-film surface 15A and the P-polarized light component P! of the reflected light from the substrate surface 15D. The phases are 180' reversed from each other. but,
Reflected light La.
Ｌｓに含まれるＳ偏光成分Ｓｔ、Ｓｔとは位相が同じで
不変である。従ってＰ ＋、Ｐ ｚによる干渉縞とＳ＋
、Ｓｓによる干渉縞とは互いに位相が１８０１ずれるこ
とになり、また、Ｐ偏光成分による干渉縞の明暗の強度
変化は小さいが、Ｓ偏光成分による干渉縞は、Ｐ偏光成
分の干渉縞よりはるかに大きい変化を薄膜誤差に応じて
示すことになる。The S-polarized light components St and St included in Ls have the same phase and remain unchanged. Therefore, the interference fringes due to P +, P z and S +
, Ss interference fringes are out of phase with each other by 1801 degrees, and although the change in intensity of the brightness of the interference fringes due to the P polarization component is small, the interference fringes due to the S polarization component are much larger than the interference fringes due to the P polarization component. A large variation will be shown depending on the thin film error.
そこで、上記の干渉縞の明暗によって生じる表面位置検
出誤差を小さくするためには、Ｐ偏光成分とＳ偏光成分
による１８０″′位相がずれた干渉縞のそれぞれの明暗
の度合いを調節して、反射光ｌ、１とり、によるスリッ
ト光像の光量重心の位置の膜厚誤差による変動を補正す
るようにすればよい、その為、第１４図中の濃度フィル
ター５及び６を調節して合成射出光り、中に含まれるＰ
偏光成分とＳ偏光成分との強度比を適当に変えることに
より、薄膜１５Ｃの膜厚誤差に起因するスリット光像の
光量重心位置のずれを許容限度内に入れることができる
。Therefore, in order to reduce the surface position detection error caused by the brightness and darkness of the interference fringes mentioned above, it is necessary to adjust the degree of brightness and darkness of each of the interference fringes with a 180'' phase shift due to the P-polarized light component and the S-polarized light component. It is only necessary to correct the fluctuation due to the film thickness error in the position of the light intensity center of the slit light image due to the light beams 1 and 1. Therefore, by adjusting the density filters 5 and 6 in FIG. , P contained in
By appropriately changing the intensity ratio between the polarized light component and the S-polarized light component, it is possible to keep the shift in the center of gravity of the light amount of the slit light image due to the thickness error of the thin film 15C within the permissible limit.
〔発明の効果）
以上のように本発明によれば、偏光の分離と合成に光エ
ネルギーの損失が無い、偏光分離光学手段と偏光合成光
学手段を用い、分離されたＰ偏光成分とＳ−光成分とは
、偏光強度可変手段によって、その強度比を任、αに変
えられるように構成したから、射出光中に含まれるＰ偏
光成分とＳ偏光成分の強度を必要に応じた値に容易且つ
効率よく変化させることができるから、偏光を利用する
各種の検出器、測定機や実施例の如く表面反射光を検出
して、その表面の位置や状態等を検出する装置等に用い
れば、その検出精度や測定精度を向上させることができ
る。[Effects of the Invention] As described above, according to the present invention, the separated P-polarized light component and the S-light are separated by using the polarized light separating optical means and the polarized light combining optical means, which cause no loss of optical energy in separating and combining polarized light. The component is configured so that the intensity ratio can be changed to α by the polarization intensity variable means, so the intensity of the P-polarized component and the S-polarized component contained in the emitted light can be easily adjusted to a value as required. Since it can be efficiently changed, it can be used in various detectors and measuring instruments that use polarized light, as well as devices that detect surface reflected light and detect the position and state of the surface, etc. Detection accuracy and measurement accuracy can be improved.
第１図は、入射光が非偏光（ランダム偏光）または円偏
光の場合の本発明の第１状態を示す光学系構成図、第２
図及び第３図は分離された２つの偏光の光路長を等しく
構成した場合の本発明のそれぞれ別の実施例を示す光学
系構成図で、第２図は合成射出光の射出方向が入射光に
対して直角な本発明の第２実施例、第３図は合成射出光
の射出方向が入射光と同一方向となるように構成された
本発明の第３実施例を示し、第４図は、第１図、第２図
及び第３図中の濃度フィルターの代わりに挿入される偏
光フィルターの射視説明図、第５図は、第２図中の濃度
フィルターの代りに特殊偏光フィルターを用いた本発明
の第４実施例を示す光学系構成図、第６図は第５図中の
Ｐ偏光光路上に設けられる特殊偏光フィルターの平面図
、第７図は第５図中のＳ偏光光路上に設けられる特殊偏
光フィルターの平面図、第８図は第５図中の合成射出光
のＰ偏光成分とＳ偏光成分との分離状態を示す平面図、
第９図は入射光が直線偏光の場合の本発明の第５実施例
を示す光学系構成図、第９Ａ図は第９図中のλ／４板の
軸をＰ、Ｓ偏光方向に対して４５°傾けて固定した場合
の偏光状態説明図、第１Ｏ図は偏光強度可変手段として
λ／４板を用いた本発明の第６実施例を示す光学系構成
図、第１１図は偏光強度可変手段としてλ／２板を用い
た本発明の第７実施例を示す光学系構成図、第１２図は
λ／２板を偏光強度可変手段の一部に用いた本発明の第
８実施例を示す光学系構成図、第１３図は非偏光または
円偏光の入射光と直線偏光または楕円偏光の入射光とに
切換え可能に構成された本発明の第９実施例を示す光学
系構成図、第１４図は第１図の実施例装置を組み込んだ
斜入射型表面位置検出装置の概略構成図、第１５図は第
１４図に示す反射光のＰ偏光成分とＳ偏光成分との状態
を示す説明図である。
（主要部分の符号の説明）
２・・・第２偏光プリズム（偏光合成光学手段）３．４
・・・ミラー
ｌＯ・・・非偏光または円偏光光源
２０・・・直線偏光光源 □
３０・・・円偏光光源
４０・・・直線偏光または楕円偏光光源Ｌ１・・・入射
光
Ｌｘ・・・合成射出光FIG. 1 is an optical system configuration diagram showing the first state of the present invention when the incident light is unpolarized light (randomly polarized light) or circularly polarized light;
3 and 3 are optical system configuration diagrams showing different embodiments of the present invention in which the optical path lengths of the two separated polarized lights are configured to be equal. In FIG. 3 shows a third embodiment of the invention in which the exit direction of the combined emitted light is the same as the incident light, and FIG. , a perspective illustration of a polarizing filter inserted in place of the density filter in Figures 1, 2, and 3, and Figure 5 shows a case in which a special polarizing filter is used in place of the density filter in Figure 2. FIG. 6 is a plan view of a special polarizing filter provided on the P-polarized light path in FIG. 5, and FIG. 7 is a diagram showing the S-polarized light in FIG. 5. A plan view of a special polarizing filter installed on the road; FIG. 8 is a plan view showing the state of separation of the P-polarized light component and the S-polarized light component of the combined emitted light in FIG. 5;
Fig. 9 is an optical system configuration diagram showing the fifth embodiment of the present invention when the incident light is linearly polarized light, and Fig. 9A shows the axis of the λ/4 plate in Fig. 9 relative to the P and S polarization directions. An explanatory diagram of the polarization state when fixed at an angle of 45 degrees, Figure 1O is a configuration diagram of an optical system showing the sixth embodiment of the present invention using a λ/4 plate as a polarization intensity variable means, and Figure 11 is a polarization intensity variable diagram. An optical system configuration diagram showing a seventh embodiment of the present invention using a λ/2 plate as a means, and FIG. 12 shows an eighth embodiment of the present invention using a λ/2 plate as a part of the polarization intensity variable means. FIG. 13 is an optical system configuration diagram showing a ninth embodiment of the present invention, which is configured to be able to switch between non-polarized or circularly polarized incident light and linearly polarized or elliptically polarized incident light. FIG. 14 is a schematic configuration diagram of an oblique incidence type surface position detection device incorporating the embodiment device of FIG. 1, and FIG. 15 is an explanation showing the states of the P-polarized light component and the S-polarized light component of the reflected light shown in FIG. 14. It is a diagram. (Explanation of symbols of main parts) 2...Second polarizing prism (polarization combining optical means) 3.4
...Mirror lO...Non-polarized or circularly polarized light source 20...Linearly polarized light source □ 30...Circularly polarized light source 40...Linearly polarized or elliptically polarized light source L1...Incoming light Lx...Synthesis Emitted light
Claims (3)
に分離する偏光分離光学手段と、前記偏光分離光学手段
を介して分離される前記一対の偏光成分の強度比を任意
に変え得る偏光強度可変手段と、前記偏光強度可変手段
によって強度比の変えられた前記一対の偏光成分を合成
して一方向に射出する偏光合成光学手段とを有すること
を特徴とする偏光装置。(1) Polarized light separating optical means for separating incident light into a pair of polarized light components whose polarization directions are perpendicular to each other; and a polarized light capable of arbitrarily changing the intensity ratio of the pair of polarized light components separated through the polarized light separating optical means. A polarization device comprising: an intensity variable means; and a polarization synthesis optical means for synthesizing the pair of polarized light components whose intensity ratio has been changed by the polarization intensity variable means and emitting the synthesized light in one direction.
とは、偏光方向が入射面に平行な偏光成分を透過し且つ
入射面に垂直な偏光成分を反射する偏光プリズム（１、
２）を含み、前記光強度可変手段は、前記２つの偏光プ
リズム（１、２）の間の双方の偏光成分の光路上にそれ
ぞれ設けられた濃度フィルター（５、６）または偏光フ
ィルター（７、７Ａ、７Ｂ）または前記入射光（Ｌ＿１
）の通路上に設けられた回転調整可能な位相板（３１、
４１）にて構成されていることを特徴とする特許請求の
範囲第１項記載の偏光装置。(2) The polarization separation optical means and the polarization synthesis optical means are polarization prisms (1,
2), the light intensity variable means includes density filters (5, 6) or polarization filters (7, 7, 7A, 7B) or the incident light (L_1
) A rotationally adjustable phase plate (31,
41) A polarizing device according to claim 1, characterized in that the polarizing device is configured as described in claim 1.
成分を透過し且つ入射面に垂直な偏光成分を反射する接
合面（１ａ）を有する第１偏光プリズムと、前記入射光
（Ｌ＿１）の通路上に設けられ且つ直線偏光の前記入射
光（Ｌ＿１）を円偏光に変えるλ／４板（２１）とから
構成されている特許請求の範囲第１項記載の偏光装置。(3) The polarized light separating optical means includes a first polarizing prism having a cemented surface (1a) that transmits a polarized light component parallel to the incident plane and reflects a polarized light component perpendicular to the incident plane, and the incident light (L_1 2. The polarizing device according to claim 1, further comprising a λ/4 plate (21) provided on the path of the linearly polarized incident light (L_1) to circularly polarized light.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62148624A JP2546206B2 (en) | 1987-06-15 | 1987-06-15 | Surface position detector |
| US07/189,831 US4864123A (en) | 1987-05-08 | 1988-05-03 | Apparatus for detecting the level of an object surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62148624A JP2546206B2 (en) | 1987-06-15 | 1987-06-15 | Surface position detector |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS63311322A true JPS63311322A (en) | 1988-12-20 |
| JP2546206B2 JP2546206B2 (en) | 1996-10-23 |
Family
ID=15456949
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62148624A Expired - Lifetime JP2546206B2 (en) | 1987-05-08 | 1987-06-15 | Surface position detector |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2546206B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4969730A (en) * | 1988-10-13 | 1990-11-13 | U.S. Philips Corporation | Image projection arrangement |
| JP2007010354A (en) * | 2005-06-28 | 2007-01-18 | Opcell Co Ltd | Device for observing/measuring surface shape of object |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59124044A (en) * | 1982-12-28 | 1984-07-18 | Toshiba Corp | Optical device |
-
1987
- 1987-06-15 JP JP62148624A patent/JP2546206B2/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59124044A (en) * | 1982-12-28 | 1984-07-18 | Toshiba Corp | Optical device |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4969730A (en) * | 1988-10-13 | 1990-11-13 | U.S. Philips Corporation | Image projection arrangement |
| JP2007010354A (en) * | 2005-06-28 | 2007-01-18 | Opcell Co Ltd | Device for observing/measuring surface shape of object |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2546206B2 (en) | 1996-10-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |