JPH03255902A - Interference optical system - Google Patents
Interference optical systemInfo
- Publication number
- JPH03255902A JPH03255902A JP2053596A JP5359690A JPH03255902A JP H03255902 A JPH03255902 A JP H03255902A JP 2053596 A JP2053596 A JP 2053596A JP 5359690 A JP5359690 A JP 5359690A JP H03255902 A JPH03255902 A JP H03255902A
- Authority
- JP
- Japan
- Prior art keywords
- optical path
- interference
- measurement
- glass
- optical system
- 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
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
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
- G03F7/70691—Handling of masks or workpieces
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Instruments For Measurement Of Length By Optical Means (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
【発明の詳細な説明】
〔産業上の利用分野〕
本発明は干渉計測において、大気のゆらぎの影響を低減
した干渉光学系に関する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an interference optical system that reduces the influence of atmospheric fluctuations in interferometric measurement.
光の干渉現象を応用した計測は、高精度非接触測定が可
能なことから多くの分野の精密計測に利用されている。Measurements that apply optical interference phenomena are used for precision measurements in many fields because they enable high-precision, non-contact measurements.
しかし、実際に高精度測定な実現するためには、光学系
の振動、熱変形、大気のゆらぎ等による穐々の誤差要因
を低減しなければならない、これらの誤差要因のうち、
大気のゆらぎの影響Ｋ１１１Ｉｌシて＊ Ｏｐｌｕｓ
ＦｉＮ１９１ （１９８７）第９９負から第１０５頁お
よびＯｐｌｕｓ Ｅ ８１９６（１９８７）第１０７頁
から第１１３頁に詳しく論じられており、その対策の一
つとして参照光路および測定光路を風よけカバーで覆う
方法がある。However, in order to actually achieve high-precision measurement, it is necessary to reduce the error factors caused by optical system vibration, thermal deformation, atmospheric fluctuations, etc. Among these error factors,
Effects of atmospheric fluctuationsK111Il*Oplus
This is discussed in detail in FiN191 (1987), pages 99 to 105, and Oplus E 8196 (1987), pages 107 to 113, and one of the countermeasures is to cover the reference optical path and measurement optical path with a windshield cover. There is a way.
しかし、上記従来技術にカバー内空気の経時的な温度安
定化の点、および、大気の圧力変動や湿度変動により屈
折率が変化する点について考慮されておらず、参照光と
測定光の光路長が長時間の周期で変動し、測定誤差を生
じるという問題があった。However, the above conventional technology does not take into consideration the temperature stabilization of the air inside the cover over time and the fact that the refractive index changes due to atmospheric pressure fluctuations and humidity fluctuations, and the optical path length of the reference light and measurement light There was a problem in that the value fluctuated over a long period of time, causing measurement errors.
本発明の目的は干渉計測において参照光路と測定光路に
温度の異なる空気の塊、即ち、大気のゆらぎが、直接あ
九らないようにし、更に大気の圧力変動や湿度変動によ
って光路媒質の屈折率が変動しない干渉光学系を提供す
ることにある。The purpose of the present invention is to prevent air masses with different temperatures, that is, fluctuations in the atmosphere, from directly aggravating the reference optical path and measurement optical path in interferometric measurements, and to prevent fluctuations in the refractive index of the optical path medium due to atmospheric pressure fluctuations and humidity fluctuations. The object of the present invention is to provide an interference optical system that does not fluctuate.
上記目的を達成するために、本発明は干渉光学系の参照
光路と１ＩＩｌ］定光路中に使用波長に対して透明な固
体物質を挿入したものである。In order to achieve the above object, the present invention inserts a solid material transparent to the wavelength used in the reference optical path and fixed optical path of an interference optical system.
さらに１光路媒質の温度変化による測定誤差をより小さ
くする九めに参照光路と測定光路に挿入する透明な固体
物質として、温度変化に対する光路長の変化がほとんど
ないアサーマルガラス（Ａｔｈｅｒｍａｌｇｌａｓｇ
）を用いたものである。Furthermore, to further reduce measurement errors caused by temperature changes in the optical path medium, athermal glass is used as a transparent solid material inserted into the reference optical path and measurement optical path.The optical path length hardly changes with temperature changes.
) is used.
干渉光学系の参照光路と測定光路中に使用波長に対して
透明な固体物質を挿入し、参照光と測定光を固体物質の
内部を透過させることにより、光路に直接温度の異なる
空気の塊があ九るのを防止し、空気のゆらぎが測定精度
に及ぼす影響を除去できる。また、参照光と測定光が透
過する媒質が固体物質であるため、圧力変動や湿度変動
の影響を受けず、固体物質の温度が一定であれば光路長
が変化せず測定誤差は生じない。By inserting a solid material that is transparent to the wavelength used in the reference and measurement optical paths of the interference optical system and transmitting the reference and measurement lights through the solid material, air masses with different temperatures can be directly placed in the optical path. This prevents the user from tampering and eliminates the influence of air fluctuations on measurement accuracy. Furthermore, since the medium through which the reference light and measurement light are transmitted is a solid material, it is not affected by pressure fluctuations or humidity fluctuations, and if the temperature of the solid material is constant, the optical path length does not change and measurement errors do not occur.
また、固体物質の温度を一定に保持できない場合は、参
照光路と測定光路に挿入する透明な固体物質として、温
度変化に対する光路長の変化がほとんどないアサーマル
ガラス（ＡｔｈｅｒｌＩＩａｌ ｇｌａｓｓ ）を用い
ることにより、測定誤差の発生を最小限におさえること
ができる。In addition, if the temperature of the solid material cannot be kept constant, athermal glass (Atherl IIal glass), whose optical path length hardly changes with temperature changes, can be used as the transparent solid material inserted into the reference optical path and the measurement optical path. The occurrence of errors can be minimized.
以下、本発明の一実施例を第１図により説明する。第１
図に露光！１１において、ウェノ１のチップ毎の高さと
傾きを干渉計を用いて計測する装置である。レーザ源１
％ハーフミラ−２、反射ミラー６、キューブビームスプ
リッタ７、参照ミラー５、レンズ８、リニアセ／す９、
ガラス／（−１ａ、１１から成り、露光時、ウェハ１６
のチップ毎の高さと傾きを検出する。５は参照ビーム、
４は測定ビームを示し、１３は縮小レンズ、１４はチル
トステージ、１５ｉＸＹＺステージである。この構成に
おいてレーザ光の分割と合成は以下のように行なう、す
なわちレーザ源１を出射した平行ビームはハーフミラ−
２により参照光３と測定光４の２不のビームに分割する
。参照光５は反射ミラー６で反射した後、キューブノ・
−７ミラー７、ガラスパー１０を透過し、参ｆｔ＠ミラ
ー５に垂直に入射する。一方、測定ビーム４は、キュー
ブハーフミラ−７、ガラスパー１０を透過した後、ウェ
ノ・１６０表面で反射し、参照ミラー５に垂直に入射す
る。An embodiment of the present invention will be described below with reference to FIG. 1st
Exposure to the figure! 11 is a device that measures the height and inclination of each chip of the wafer 1 using an interferometer. Laser source 1
%Half mirror 2, reflective mirror 6, cube beam splitter 7, reference mirror 5, lens 8, linear center 9,
Glass/(-1a, 11, during exposure, wafer 16
Detects the height and tilt of each chip. 5 is a reference beam,
4 indicates a measurement beam, 13 a reduction lens, 14 a tilt stage, and 15iXYZ stage. In this configuration, the laser beam is divided and combined as follows. In other words, the parallel beam emitted from the laser source 1 is split into a half mirror.
2 into two beams, a reference beam 3 and a measuring beam 4. After the reference beam 5 is reflected by the reflection mirror 6, it is reflected by the cube no.
-7 It passes through the mirror 7 and the glass par 10, and enters the reference ft@mirror 5 at right angles. On the other hand, the measurement beam 4 passes through the cube half mirror 7 and the glass par 10, is reflected by the surface of the Weno 160, and enters the reference mirror 5 at right angles.
参照ミラー５で反射した参照ビーム３と測定ビーム４に
、再び、元の光路な逆戻りし、キューブハーフばラー７
で反射後、レンズ８、ガラスパー１１を透過し、＋７
ニアセンサ９上で重なり合い、干渉縞を発生する。ここ
で参照ビーム３ｋにウニ／Ｓ１６の高さと傾き情報が含
まれている。従って、リニアセンナ９上の干渉縞のピッ
チと位相変化を検出することによって、ウェハ１６の傾
きと高さを知ることが可能となる。即ち、ウェノ・１６
が上、下に移動した場合は、干渉縞の位相が変化し、ウ
ェハ１６が傾いた時は干渉縞のピッチが変化する。The reference beam 3 and measurement beam 4 reflected by the reference mirror 5 return to their original optical paths again and pass through the cube half baller 7.
After reflection, it passes through lens 8 and glass par 11, +7
They overlap on the near sensor 9 and generate interference fringes. Here, the reference beam 3k includes height and inclination information of the sea urchin/S16. Therefore, by detecting the pitch and phase change of the interference fringes on the linear sensor 9, it is possible to know the inclination and height of the wafer 16. That is, Weno 16
When the wafer 16 moves upward or downward, the phase of the interference fringes changes, and when the wafer 16 is tilted, the pitch of the interference fringes changes.
本実施例のような干渉計測では、干渉光路で空気のゆら
ぎ、即ち、温度、圧力、湿度のむらが生じると空気の屈
折率が変化し、干渉縞のピッチ、および、位相に影響を
及ぼし計測誤差となる。従来、これらを防止する方法と
して干渉光路をカバーで覆うという方法があった。しか
し、カバーで覆った場合、干渉ビームの入出射端を開放
とし定場合には、圧力やａｆｆ化に対応できず、ま九、
カバーの両肩をガラス等でふさいだ場合に内部の空気の
熱交換が十分できず、経時的な温度安定化が図れないと
いう問題があった。第１図におけるガラスパー１０およ
び１１は、従来技術の問題を琳決するためく干渉光路中
く挿入したものである。In interferometric measurement as in this example, when air fluctuations, that is, unevenness in temperature, pressure, and humidity occur in the interference optical path, the refractive index of the air changes, which affects the pitch and phase of the interference fringes and causes measurement errors. becomes. Conventionally, a method for preventing these problems has been to cover the interference optical path with a cover. However, if it is covered with a cover and the input and output ends of the interference beam are open, it will not be able to cope with pressure and AF.
When both shoulders of the cover are covered with glass or the like, there is a problem in that sufficient heat exchange between the air inside the cover is not possible and temperature stabilization over time cannot be achieved. Glass lenses 10 and 11 in FIG. 1 are inserted into the interference optical path to solve the problems of the prior art.
ガラスパー１０．１１の挿入により空気の温度や圧力、
湿度変化が、直接、干渉光路に作用せず、空気のゆらぎ
の影響を除去できる。ガラスパー１０゜１１の材質とし
ては、温度変化の少ない環境で使用する場合は一般的な
光学ガラス、例えば、ＢＫ７等で十分効果があるが、温
度変化が比較的大きい環境で使用する場合は、温ｆｆ化
に対する光路長の変化がほとんどないアサーマルガラス
（Ａｔｈｓｒ−ｍａｌ ｇｌａｓｓ ）、例えば、ＨＯ
ＹＡ社のＡＴＣＩ 、Ａ’！’Ｆ２ 。The temperature and pressure of the air can be adjusted by inserting Glass Par 10.11.
Changes in humidity do not directly affect the interference optical path, and the influence of air fluctuations can be removed. Regarding the material for Glass Par 10°11, when used in an environment with little temperature change, general optical glass such as BK7 is effective, but when used in an environment with relatively large temperature changes, Athermal glass (Athsr-mal glass), which shows almost no change in optical path length due to
YA's ATCI, A'! 'F2.
Ａ’！’ＦＡ等を使用すればよい。A’! 'FA etc. can be used.
第２図は、本発明の他の実施例を示し丸もので干渉を利
用したレーザ測長装置を示す。レーザ測長の原理μ、レ
ーザ源１を出射し之平行ビームをキューブビームスプリ
ッタ２により参照光５と測定光４に分割し、参照光３は
固定の参照ミラー５で、測定光４は移動ステージ６に取
付けた反射ミ２−７で反射させた後、元の干渉光路を逆
戻りさせ光電変換素子９でステージ６の移動に伴う干渉
強度の変化を検出する６本実施例の場合も干渉光路に空
気のゆらぎが作用すると計測誤差が生じるが、ガラスパ
ー１０．１１の挿入により計測誤差が低減できる。FIG. 2 shows another embodiment of the present invention, and shows a round laser length measuring device using interference. Principle of laser length measurement μ, a parallel beam is emitted from a laser source 1 and is split into a reference beam 5 and a measurement beam 4 by a cube beam splitter 2.The reference beam 3 is a fixed reference mirror 5, and the measurement beam 4 is a moving stage. 6. After being reflected by the reflector 2-7 attached to stage 6, the original interference optical path is reversed and the photoelectric conversion element 9 detects the change in interference intensity as the stage 6 moves. Measurement errors occur when air fluctuations act, but measurement errors can be reduced by inserting glass pars 10 and 11.
第３図は本発明をホログラフィ−装置に適用した実施例
である。ホログラフィ−装置は物体７の形状を参照光３
と測定光４の合成によって生じる干渉縞として乾板６に
記録し、参照光３を乾板６に照射することによって物体
７の立体像を外戚する装置である。レーザ源１を出射し
九平行ビームは、キューブビームスプリッタ２により参
照光５と測定光４に分割する。参照光３は参照ミラー５
で反射した後、レンズ１４を介して乾板６を照射する。FIG. 3 shows an embodiment in which the present invention is applied to a holography device. The holography device uses a reference beam 3 to determine the shape of an object 7.
This device records on a dry plate 6 as interference fringes generated by the combination of the reference beam 3 and the measurement light 4, and generates a three-dimensional image of the object 7 by irradiating the dry plate 6 with the reference light 3. Nine parallel beams emitted from a laser source 1 are split into a reference beam 5 and a measurement beam 4 by a cube beam splitter 2. Reference light 3 is reference mirror 5
After being reflected by the lens 14, the dry plate 6 is irradiated with the light.
一方、測定光４は反射ミラー８で反射した後、レンズ１
５を介して物体７を照射し、物体７からの反射光が乾板
６上で参照光５と重ね合わされ干渉縞が生じる０本実施
例の場合も、干渉を利用しているため干渉光路に空気の
ゆらぎが作用すると物体像に歪が生じ、正確な記録が不
可能となる。これを防止するため、干渉光路にガラスパ
ー１０．１１．１２を挿入した。ガラスパー１０．１１
．１２を挿入した。ガラスパー１０．１１．１２の挿入
により空気の温度や圧力、湿度変化が、直接、干渉光路
に作用するのを防止し、歪のない物体像の記録、外戚が
可能となる。On the other hand, the measurement light 4 is reflected by the reflection mirror 8 and then reflected by the lens 1.
5, the reflected light from the object 7 is superimposed on the reference beam 5 on the dry plate 6, producing interference fringes.In the case of this embodiment as well, since interference is used, there is no air in the interference optical path. When this fluctuation occurs, the object image becomes distorted, making accurate recording impossible. To prevent this, glass pars 10, 11, and 12 were inserted into the interference optical path. glass par 10.11
．． 12 was inserted. By inserting the glass pars 10, 11, and 12, changes in air temperature, pressure, and humidity can be prevented from directly acting on the interference optical path, making it possible to record and visualize an object image without distortion.
本発明は、干渉光路中に使用波長く対して透明な固体物
質を挿入したので、空気の温度や圧力。In the present invention, a solid material that is transparent to the wavelength used is inserted into the interference optical path, so that the temperature and pressure of the air can be controlled.
湿度変化が直接、干渉光路に作用せず、高精度な干渉計
測が可能となった。また温度変化が比較的大きい環境で
の干渉計測では、温度変化に対して光路長変化がほとん
どないアサーマルガラスを干渉光路中に挿入したので、
温度的に悪い環境でも高精度な干渉計−１が可能となっ
た。Humidity changes do not directly affect the interference optical path, making highly accurate interference measurements possible. In addition, for interferometric measurements in environments where temperature changes are relatively large, we inserted athermal glass in the interference optical path, which shows almost no change in optical path length due to temperature changes.
Highly accurate interferometer-1 is now possible even in adverse temperature environments.
第１図は本発明の一実ＷＡガで露光製置においてウェハ
のチップ毎の高さと傾きを干渉を用いて計測する装置の
説明図、第２図はレーザ測長装ｆｆ１Ｋ本発明を適用し
た例の説明図、第５図はホログラフィｆ７ｆｃ＃に本発
ａＡを適用した例の説明図である。
１・・・レーザ源
５・・・参照光
４・・・測定光
９．１０．１１・・・ガラスパー
第 １１１￥１Fig. 1 is an explanatory diagram of a device for measuring the height and inclination of each chip of a wafer using interference in an exposure process using the WA model of the present invention, and Fig. 2 is an explanatory diagram of a device for measuring the height and inclination of each chip of a wafer using interference, and Fig. 2 shows a laser length measurement device ff1K to which the present invention is applied. FIG. 5 is an explanatory diagram of an example in which the aA of the present invention is applied to holography f7fc#. 1...Laser source 5...Reference light 4...Measurement light 9.10.11...Glass par No. 111 ¥1
Claims (1)
長に対して透明な固体物質を挿入したことを特徴とする
干渉光学系。 ２、透明な固体物質として温度変化に対する光路長の変
化がほとんどないアサーマルガラス （Ａｔｈｅｒｍａｌｇｌａｓｓ）を用いた請求項１に記
載の干渉光学系。[Claims] 1. An interference optical system characterized by inserting a solid substance transparent to the wavelength used in the reference optical path and measurement optical path of an interferometric measurement device. 2. The interference optical system according to claim 1, wherein the transparent solid material is athermal glass whose optical path length hardly changes due to temperature changes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2053596A JP2810194B2 (en) | 1990-03-07 | 1990-03-07 | Interference optical system and exposure apparatus having the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2053596A JP2810194B2 (en) | 1990-03-07 | 1990-03-07 | Interference optical system and exposure apparatus having the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03255902A true JPH03255902A (en) | 1991-11-14 |
| JP2810194B2 JP2810194B2 (en) | 1998-10-15 |
Family
ID=12947263
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2053596A Expired - Fee Related JP2810194B2 (en) | 1990-03-07 | 1990-03-07 | Interference optical system and exposure apparatus having the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2810194B2 (en) |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57173704A (en) * | 1981-04-20 | 1982-10-26 | Nippon Telegr & Teleph Corp <Ntt> | Highly stable interferometer |
| JPS6281505A (en) * | 1985-10-07 | 1987-04-15 | Omron Tateisi Electronics Co | Wave-guiding type optical displacement sensor |
-
1990
- 1990-03-07 JP JP2053596A patent/JP2810194B2/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS57173704A (en) * | 1981-04-20 | 1982-10-26 | Nippon Telegr & Teleph Corp <Ntt> | Highly stable interferometer |
| JPS6281505A (en) * | 1985-10-07 | 1987-04-15 | Omron Tateisi Electronics Co | Wave-guiding type optical displacement sensor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2810194B2 (en) | 1998-10-15 |
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