JPH0820208B2 - Position measurement method - Google Patents
Position measurement methodInfo
- Publication number
- JPH0820208B2 JPH0820208B2 JP60059529A JP5952985A JPH0820208B2 JP H0820208 B2 JPH0820208 B2 JP H0820208B2 JP 60059529 A JP60059529 A JP 60059529A JP 5952985 A JP5952985 A JP 5952985A JP H0820208 B2 JPH0820208 B2 JP H0820208B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- sample
- measuring method
- incident light
- incident
- 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.)
- Expired - Lifetime
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/026—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness by measuring distance between sensor and object
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Length Measuring Devices By Optical Means (AREA)
- Measurement Of Optical Distance (AREA)
Description
【発明の詳細な説明】 〔発明の技術分野〕 本発明は、被測定物の位置を光学的に測定する位置測
定方法に係わり、特に被測定物面の高さを測定するのに
適した位置測定方法に関する。TECHNICAL FIELD OF THE INVENTION The present invention relates to a position measuring method for optically measuring the position of an object to be measured, and particularly to a position suitable for measuring the height of the surface of the object to be measured. Regarding measurement method.
LSI製造装置、例えば電子ビーム露光装置において、
半導体ウエハやマスク基板等の試料にパターンを描画形
成する場合、試料の反りその他の要因により試料表面の
高さ（光学系に対する距離）が変動すると、描画パター
ンに誤差が生じる。そこで従来、試料の高さ方向の変動
量を測定し、該変動量に応じてその補正を行う方法を採
用している。In an LSI manufacturing apparatus, for example, an electron beam exposure apparatus,
When a pattern is formed by drawing on a sample such as a semiconductor wafer or a mask substrate, if the height of the sample surface (distance to the optical system) changes due to warpage of the sample or other factors, an error occurs in the drawing pattern. Therefore, conventionally, a method has been adopted in which the variation in the height direction of the sample is measured and the variation is corrected according to the variation.
被測定物としての試料表面の高さ測定装置としては、
第６図に示す如く光学的手法を利用したものがある（特
開昭56-2632号公報）。この装置では、レーザ光源Ｌか
ら放射された光レンズL1によりスポツト状に集束して試
料面上に照射し、その反射光をレンズL2によつてラテラ
ル光効果を用いた半導***置検出器Ｄ上に結像させる。
そして、この検出器Ｄの検出出力を演算処理することに
よつて、試料表面の高さ位置を測定している。As a device for measuring the height of the sample surface as the object to be measured,
There is one using an optical method as shown in FIG. 6 (JP-A-56-2632). In this device, a semiconductor lens position detector D using a lateral light effect is focused by a light lens L 1 emitted from a laser light source L in a spot shape and irradiated on a sample surface, and the reflected light is reflected by a lens L 2 . Focus on top.
Then, the height position of the sample surface is measured by arithmetically processing the detection output of the detector D.
しかしながら、この種の測定装置にあつては次のよう
な問題があつた。即ち、試料面上に照射された光束内
で、第７図に示す如く試料70の表面に反射率の高い部分
71と反射率の低い部分72とがあると、反射率の差異によ
る光束内光量分布にアンバランスが生じ測定誤差を生じ
る。例えば、最近多くの所で使用されている光量の重心
位置を測定するPSD（半導***置検出素子）を検出器に
使用した場合、第８図（ａ）に示す如き光量分布の差に
よつて、同図（ｂ）に示す如く重心位置が変動してしま
い、測定誤差を生じる。また、例えば光電顕微鏡等で良
く知られている振動スリツト法による位置検出手段によ
つても同様なことが言え、光束内光量分布の変化によつ
て測定誤差を生じることになる。However, this type of measuring device has the following problems. That is, in the light flux irradiated on the sample surface, as shown in FIG.
If there is a portion 71 and a portion 72 having a low reflectance, an imbalance occurs in the light quantity distribution within the light flux due to the difference in reflectance, causing a measurement error. For example, when a PSD (semiconductor position detecting element) that measures the barycentric position of the light quantity used in many places these days is used for the detector, the difference in the light quantity distribution as shown in FIG. The position of the center of gravity fluctuates as shown in FIG. The same can be said with the position detecting means by the vibration slit method, which is well known in, for example, a photoelectric microscope, and a measurement error occurs due to a change in the light quantity distribution in the light flux.
このような誤差を低減させる方法の１つとしてスリツ
ト状の入射光を被測定面上のパターン（多くの場合直交
している）に対して傾けて照射する特開昭56-42205号公
報に述べられている方法がある。この方法によると直交
パターンに対して45°傾けることが最大の効果が得られ
る。As one of the methods for reducing such an error, Japanese Patent Laid-Open No. 56-42205 discloses that a slit-like incident light is irradiated while being inclined with respect to a pattern (in most cases orthogonal) on a surface to be measured. There is a method. According to this method, the maximum effect can be obtained by tilting at 45 ° with respect to the orthogonal pattern.
しかしながら、半導体ICパターンでは直交パターンの
他に任意の傾きをもつたパターンを作る場合も多く、上
記方法では十分に測定誤差を低減することができなかつ
た。However, in the semiconductor IC pattern, a pattern having an arbitrary inclination is often formed in addition to the orthogonal pattern, and the above method cannot sufficiently reduce the measurement error.
本発明は上記事情を考慮してなされたもので、その目
的とするところは、被測定面の反射率の差によつて生じ
る測定誤差を低減することができ、測定精度の向上をは
かり得る位置測定方法を提供することにある。The present invention has been made in consideration of the above circumstances, and an object of the present invention is to reduce a measurement error caused by a difference in reflectance of a surface to be measured, and to improve measurement accuracy. It is to provide a measuring method.
本発明の骨子は、反射光の光束内光量分布の変化によ
る測定誤差を低減するために、入射光を振動させてその
誤差を平均化することにある。The essence of the present invention is to oscillate the incident light and average the error in order to reduce a measurement error due to a change in the light amount distribution in the light flux of the reflected light.
即ち本発明は、被測定物の表面に対し斜め方向から集
束光をパターンに傾けて照射し、被測定物の表面で反射
された反射光を光検出器で検出して前記表面の位置を測
定する位置測定方法において、前記被測定物の表面に入
射する入射光を振動し、該振動によつて或いは被測定物
表面上のパターン若しくは反射率の差によつて変動する
前記光検出器の検出信号を平均化処理するようにしたも
のである。That is, the present invention measures the position of the surface of the object to be measured by irradiating the surface with a focused light obliquely in a pattern and detecting the reflected light reflected by the surface of the object to be measured with a photodetector. In the position measuring method, the incident light incident on the surface of the object to be measured is vibrated, and the detection of the photodetector is changed by the vibration or by the pattern on the surface of the object to be measured or the difference in reflectance. The signal is averaged.
また、本発明は上記構成に加え、前記被測定物表面か
らの反射光を振動して、入射光の振動に起因する検出器
上での反射光の位置変動をなくすようにしたものであ
る。In addition to the above configuration, the present invention vibrates the reflected light from the surface of the object to be measured so as to eliminate the positional fluctuation of the reflected light on the detector due to the vibration of the incident light.
本発明によれば、被測定物表面に入射するパターンに
傾けて照射された入射光を振動させ、被測定物表面上で
の多数の測定点を平均化しているので、従来方法に比し
て被測定物表面の反射率の差異等に起因する測定誤差を
大幅に低減することができる。さらに、従来方法に比し
て入射光を振動させる構成、例えば振動ミラーを付加す
るのみで容易に実現できる等の利点がある。また、被測
定物表面からの反射光をも振動させることにより、入射
光の振動によるダイナミツクレンジの縮小を防ぐことが
できる。According to the present invention, the incident light irradiated while being inclined to the pattern incident on the DUT surface is vibrated, and a large number of measurement points on the DUT surface are averaged. It is possible to significantly reduce the measurement error caused by the difference in the reflectance of the surface of the object to be measured. Further, compared to the conventional method, there is an advantage that it can be easily realized by a configuration in which incident light is vibrated, for example, only by adding a vibrating mirror. Further, by vibrating the reflected light from the surface of the object to be measured, it is possible to prevent the dynamic range from being reduced due to the vibration of the incident light.
以下、本発明の詳細を図面を参照しながら説明する。 Hereinafter, details of the present invention will be described with reference to the drawings.
第１図は本発明の一実施例に於いて用いる試料面高さ
測定装置を示す概略構成図である。なお、この実施例で
は電子ビーム露光装置の試料室に配置され、試料室内の
試料面の高さを測定するものとした。図中10は電子ビー
ム露光装置の試料室を形成する真空容器であり、この容
器10の上壁には電子ビーム光学鏡筒（以下EOSと略記す
る）20が取付けられている。EOS20は電子銃，各種レン
ズ及び各種偏向系等からなるもので、このEOS20からの
電子ビームは容器10内に配置された被測定物としての試
料30上に照射されるものとなつている。FIG. 1 is a schematic configuration diagram showing a sample surface height measuring device used in one embodiment of the present invention. In this embodiment, the height of the sample surface in the sample chamber is arranged in the sample chamber of the electron beam exposure apparatus. In the figure, 10 is a vacuum container forming a sample chamber of the electron beam exposure apparatus, and an electron beam optical lens barrel (hereinafter abbreviated as EOS) 20 is attached to the upper wall of the container 10. The EOS 20 is composed of an electron gun, various lenses, various deflection systems, etc., and the electron beam from the EOS 20 is to be irradiated onto a sample 30 as an object to be measured arranged in the container 10.
EOS20の左右には、本実施例に係わる試料面高さ測定
装置を構成する照射系40及び受光系50がそれぞれ設けら
れている。照射系40は、レーザ光源41,スリツト42,反射
ミラー43,44,集束レンズ45,反射ミラー（振動ミラー）4
6,振動器47及び駆動回路48等から構成されている。レー
ザ光源41から放射された光はスリツト42を通過し、反射
ミラー43,44で反射され、集束レンズ45により集束され
て振動ミラー46に照射される。そして、振動ミラー46で
反射された集束光49が前記試料30の表面に照射されるも
のとなつている。ここで、上記集束光49が試料30に対す
る入射光となる。An irradiation system 40 and a light receiving system 50, which constitute the sample surface height measuring apparatus according to the present embodiment, are provided on the left and right of the EOS 20, respectively. The irradiation system 40 includes a laser light source 41, a slit 42, reflection mirrors 43 and 44, a focusing lens 45, and a reflection mirror (vibration mirror) 4
It is composed of a vibrator 47, a drive circuit 48, and the like. The light emitted from the laser light source 41 passes through the slit 42, is reflected by the reflection mirrors 43 and 44, is focused by the focusing lens 45, and is applied to the vibrating mirror 46. Then, the focused light 49 reflected by the vibrating mirror 46 is applied to the surface of the sample 30. Here, the focused light 49 becomes incident light on the sample 30.
試料面上の入射スリツト像99は第９図に示すように、
例えば試料面の直交パターン100（すなわち反射率の変
化をもたらすパターン）に対して45°の傾きをもつて照
射される。この場合45°以外の角度でも良い。The incident slit image 99 on the sample surface is as shown in FIG.
For example, irradiation is performed with an inclination of 45 ° with respect to an orthogonal pattern 100 (that is, a pattern that causes a change in reflectance) on the sample surface. In this case, an angle other than 45 ° may be used.
振動ミラー46は圧電素子からなる振動器47に取付けら
れており、振動器47は駆動回路48により振動されるもの
となつている。ここで、振動ミラー46の振動数は試料面
高さ変動測定周波数より十分高い周波数である。また、
振動振幅は後述するPSO等の光検出器の受光面の長さ或
いは誤差を低減させる割合い等に応じて定めればよい。The vibrating mirror 46 is attached to a vibrator 47 composed of a piezoelectric element, and the vibrator 47 is vibrated by a drive circuit 48. Here, the frequency of the vibrating mirror 46 is a frequency sufficiently higher than the measurement frequency of the height variation of the sample surface. Also,
The vibration amplitude may be determined according to the length of the light receiving surface of a photodetector such as PSO described later or the rate of reducing the error.
一方、受光系50は、反射ミラー51,集束レンズ52,光検
出器として公知のラテラル光効果を用いた半導***置検
出器（PSD）53,加算器54,減算器55,除算器56,平均化処
理回路57及び位置測定回路58等から構成されている。前
記試料30の表面への入射光49の照射による反射光59は、
反射ミラー51で反射され集束レンズ52を介してPSD53の
受光面に結像される。PSD53は半導体基板上に抵抗性薄
膜を形成すると共に、該薄膜の両端に出力端子を設け、
半導体基板を接地したもので、光スポツトの抵抗性薄膜
照射位置の変位により一対の出力端子からアンバランス
な信号が出力される。PSD53の検出信号は、加算器54,減
算器55及び除算器56等からなる信号処理回路により信号
処理されて平均化処理回路57に入力される。平均化処理
回路57は上記入力した信号を例えばローパスフイルタを
通して平均化するものであり、この平均化された信号
（位置信号）は位置測定回路58に供給される。位置測定
回路58は、上記入力した位置信号に応じて前記試料30の
表面高さ位置を演算するものとなつている。On the other hand, the light receiving system 50 includes a reflection mirror 51, a focusing lens 52, a semiconductor position detector (PSD) 53 using a lateral light effect known as a photodetector, an adder 54, a subtractor 55, a divider 56, and an averaging device. It is composed of a processing circuit 57, a position measuring circuit 58, and the like. Reflected light 59 by irradiation of incident light 49 on the surface of the sample 30,
The light is reflected by the reflection mirror 51 and focused on the light receiving surface of the PSD 53 via the focusing lens 52. PSD53 forms a resistive thin film on a semiconductor substrate and provides output terminals at both ends of the thin film,
A semiconductor substrate is grounded, and an unbalanced signal is output from a pair of output terminals due to the displacement of the resistive thin film irradiation position of the optical spot. The detection signal of the PSD 53 is subjected to signal processing by a signal processing circuit including an adder 54, a subtractor 55, a divider 56, etc., and input to the averaging processing circuit 57. The averaging processing circuit 57 is for averaging the input signals through, for example, a low-pass filter, and the averaged signal (position signal) is supplied to the position measuring circuit 58. The position measuring circuit 58 calculates the surface height position of the sample 30 according to the input position signal.
このような構成であれば、スリツト状の入射光をパタ
ーンに対して傾けて照射する効果と入射光を振動させる
効果とが総合され、非常に誤差の少ない位置検出装置を
提供できる。すなわち、第10図に示すようにスリツト状
の入射光101をパターン102に対して傾けて照射する効果
は、例えば照射光でのスリツト幅をW,スリツト長さをｌ
としてl/W＝10の場合について測定誤差を計算すると第1
1図のθ＝０°にたいして、第12図のθ＝45°と低減す
る。さらにPSD53及び信号処理回路54,〜,56で得られる
検出出力は第２図の曲線１に示す如く前記振動ミラー46
の振動数及び振幅に相当するsin波となる。このとき、
途中で反射率に差のある所を光束が通つた場合、図中破
線で示したような誤差信号が生じる。しかし、その信号
を、例えば一番簡単な方法としてフイルターを通して平
均化することによつて、線２として示されるように誤差
信号は振動振幅全体に亙つて平均化されることになり、
入射光を振動させない時に比べて大幅に誤差が低減する
ことになる。即ち、入射光49の入射角を振動させ試料面
上で多数の測定点を平均化させることにより、従来の方
式によるものより測定誤差が大幅に低減されることにな
る。With such a configuration, the effect of inclining the slit-like incident light with respect to the pattern and the effect of oscillating the incident light are combined, and a position detecting device with very few errors can be provided. That is, as shown in FIG. 10, the effect of irradiating the slit-shaped incident light 101 with an inclination with respect to the pattern 102 is, for example, that the slit width of the irradiation light is W and the slit length is l.
When the measurement error is calculated for l / W = 10 as
Compared to θ = 0 ° in FIG. 1, it is reduced to θ = 45 ° in FIG. Further, the detection output obtained by the PSD 53 and the signal processing circuits 54 to 56 is the vibrating mirror 46 as shown by the curve 1 in FIG.
It becomes a sin wave corresponding to the frequency and amplitude of. At this time,
When a light beam passes through a portion where there is a difference in reflectance on the way, an error signal as shown by the broken line in the figure occurs. However, by averaging the signal through a filter, for example in the simplest way, the error signal will be averaged over the entire vibration amplitude, as shown by line 2.
The error will be significantly reduced compared to when the incident light is not vibrated. That is, by vibrating the incident angle of the incident light 49 and averaging a large number of measurement points on the sample surface, the measurement error can be significantly reduced as compared with the conventional method.
このように本実施例によれば、パターンにたいして傾
けた入射光49を振動させることにより試料面の反射率の
差異等に起因する測定誤差を大幅に低減することができ
る。このため、試料面の高さ測定を高精度に行うことが
できる。また、従来装置に比して、ミラー46を振動する
機構を設けるのみの簡易な構造で実現できる等の利点が
ある。As described above, according to the present embodiment, by vibrating the incident light 49 tilted with respect to the pattern, it is possible to significantly reduce the measurement error due to the difference in reflectance of the sample surface. Therefore, the height of the sample surface can be measured with high accuracy. Further, compared to the conventional device, there is an advantage that it can be realized with a simple structure in which only a mechanism for vibrating the mirror 46 is provided.
第３図は本発明の他の実施例で用いる装置の概略構成
図である。なお、第１図と同一部分には同一符号を付し
て、その詳しい説明は省略する。この実施例が先に説明
した実施例と異なる点は、照射系側のミラー46のみなら
ず、受光系側のミラー51も振動するようにしたことにあ
る。即ち、ミラー51は振動器61に取付けられており、こ
の振動器61は前記駆動回路48により駆動されるものとな
つている。ここで、ミラー51の振動は、前記ミラー46の
振動とは正確に逆位相である。また、光学倍率をキヤン
セルするようにその振動振幅は、入射光49の振動による
PSD53上での光束の振動が生じないように調整されてい
る。つまり、入射光49の振動が生じても、受光側の反射
光59のPSD53上での位置は変動しないものとなつてい
る。FIG. 3 is a schematic configuration diagram of an apparatus used in another embodiment of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. The difference of this embodiment from the above-described embodiment is that not only the mirror 46 on the irradiation system side but also the mirror 51 on the light receiving system side vibrates. That is, the mirror 51 is attached to the vibrator 61, and the vibrator 61 is driven by the drive circuit 48. Here, the vibration of the mirror 51 is exactly opposite in phase to the vibration of the mirror 46. In addition, its vibration amplitude depends on the vibration of the incident light 49 so as to cancel the optical magnification.
It is adjusted so that the vibration of the light flux on PSD53 does not occur. That is, even if the incident light 49 vibrates, the position of the reflected light 59 on the light receiving side on the PSD 53 does not change.
このような構成であれば、入射光49の振動によるもの
は反射光59の補正によつてキヤンセルされ、実際の試料
面の高さ方向による光束の移動は入射光49の振動成分と
異なるため、PSD53上には光束の移動として現われてく
ることになる。即ち、反射光59を振動させない場合第４
図（ａ）に示す如く検出出力に入射光49の振動成分が現
われるが、反射光59を振動させた場合同図（ｂ）に示す
如く入射光49の振動成分は現われないことになる。従つ
て、PSD53上での光束の移動は、実際の試料面の高さ変
動によるもののみとなり、検出器の測定ダイナミツクレ
ンジが拡大することになる。また、その分だけ、小さな
検出器を用いることが可能となり、検出器の分解能が上
がることになる。With such a configuration, the vibration of the incident light 49 is canceled by the correction of the reflected light 59, and the actual movement of the light beam in the height direction of the sample surface is different from the vibration component of the incident light 49. It will appear as a movement of the light flux on PSD53. That is, when the reflected light 59 is not vibrated, the fourth
A vibration component of the incident light 49 appears in the detection output as shown in FIG. 7A, but when the reflected light 59 is vibrated, the vibration component of the incident light 49 does not appear as shown in FIG. Therefore, the movement of the light flux on the PSD 53 is only due to the actual height variation of the sample surface, and the measurement dynamic range of the detector is expanded. In addition, a small detector can be used correspondingly, and the resolution of the detector is increased.
ここで、前記第１図に示す装置では、入射光49の振動
により検出器（PSD）側で光束が第５図に示す如く変動
してしまう。なお、第５図中53aはPSD53の受光面、59a
は反射光59の結像光束を示している。これらは検出器か
ら後の信号処理回路によつてフイルター等を通して平均
化し、正確な位置座標として算出しているが、検出器側
の光束は試料面高さ方向の変位感度を稼ぐためには、光
学倍率によつて拡大する必要がある。この場合、入射光
49を微小に振動させても検出器の測定範囲内全体に光束
が振動してしまう。大型の検出器を用いるとこの点はカ
バーできるが、この場合測定分解能が低下する虞れがあ
るので、むやみに大きな検出器を用いることはできな
い。このような理由から、測定のダイナミツクレンジを
大きくすることは難しくなるのである。Here, in the device shown in FIG. 1, the luminous flux fluctuates on the detector (PSD) side as shown in FIG. 5 due to the vibration of the incident light 49. In FIG. 5, reference numeral 53a denotes a light receiving surface of the PSD 53, and 59a
Indicates the image forming light flux of the reflected light 59. These are averaged through a filter or the like by a signal processing circuit after the detector, and are calculated as accurate position coordinates.However, in order to gain displacement sensitivity in the height direction of the sample surface, the light flux on the detector side is: It is necessary to enlarge by the optical magnification. In this case, the incident light
Even if 49 is vibrated slightly, the luminous flux vibrates over the entire measuring range of the detector. If a large-sized detector is used, this point can be covered, but in this case, the measurement resolution may be deteriorated, so that a large detector cannot be used unnecessarily. For this reason, it is difficult to increase the dynamic range of measurement.
これに対し本実施例では、反射光59を上記入射光49の
振動と同期して逆位相に振動することにより、入射光49
を振動しても、検出器の測定範囲内で光束が移動するこ
とはないのである。従つて本実施例によれば、先の実施
例と同様な効果は勿論のこと、測定のダイナミツクレン
ジを拡大することができ、その効果は絶大である。On the other hand, in the present embodiment, the reflected light 59 vibrates in the opposite phase in synchronization with the vibration of the incident light 49, so that the incident light 49
Even if oscillates, the light beam does not move within the measuring range of the detector. Therefore, according to this embodiment, not only the same effects as those of the previous embodiment but also the dynamic range of measurement can be expanded, and the effect is great.
なお、本発明は上述した各実施例に限定されるもので
はない。例えば、前記試料面上に入射する入射光はスリ
ツト状の集束光に限るものではなく、円形スポツト状で
あつてもよい。また、試料表面に入射する入射光を振動
させる手段として、入射角を機械的に振動する以外に、
例えば音響的手段を用いた方法、また電圧を印加するこ
とにより光の偏向面の透過率と屈折率が異なるようなも
のを用いてもよい。機械的な駆動方法としても圧電素子
を用いたり、電磁的なものを使用してもよい。また、入
射角を振動させる代りに、入射光位置を平行移動するこ
とによつて振動させることも可能である。さらに、平均
化処理回路は、前記除算器の前段若しくは加減算器の前
後に設置してもよい。Note that the present invention is not limited to the above-described embodiments. For example, the incident light incident on the sample surface is not limited to the slit-shaped focused light, and may be a circular spot-shaped light. Further, as means for vibrating the incident light incident on the sample surface, in addition to mechanically vibrating the incident angle,
For example, a method using acoustic means or a method in which the transmittance and the refractive index of the light deflection surface are different by applying a voltage may be used. As a mechanical driving method, a piezoelectric element may be used or an electromagnetic driving method may be used. Further, instead of vibrating the incident angle, it is also possible to vibrate by moving the incident light position in parallel. Further, the averaging processing circuit may be installed before the divider or before and after the adder / subtractor.
また、実施例では試料面の高さ測定について説明した
が、本発明は位置測定に広く利用することが可能であ
る。また、信号処理については一番簡単な方法としてロ
ーパスフイルターを通して平均化する方法を述べたが、
他の方法であつてもよいのは勿論である。さらに、振動
振幅は大きい程平均化効果が大きく誤差を低減できる
が、装置の仕様に応じて適宜定めればよい。また、振動
波形は正弦波に限るものではなく、三角波，鋸歯状波等
に適宜変更可能である。さらに、光源は連続点灯でも、
変調されていてもよい。また、前記位置測定回路は必ず
しも必要はなく、例えば前記平均化処理回路の出力を直
接高さ制御機構に送ることもできる。その他、本発明の
要旨を逸脱しない範囲で、種々変形して実施することが
できる。Further, although the height of the sample surface is measured in the embodiment, the present invention can be widely used for position measurement. Regarding the signal processing, I mentioned the method of averaging through a low-pass filter as the simplest method.
Of course, other methods may be used. Further, the larger the vibration amplitude is, the larger the averaging effect is and the more the error can be reduced. Further, the vibration waveform is not limited to the sine wave, but may be appropriately changed to a triangular wave, a sawtooth wave, or the like. Furthermore, even if the light source is continuously lit,
It may be modulated. Further, the position measuring circuit is not always necessary, and for example, the output of the averaging processing circuit can be directly sent to the height control mechanism. In addition, various modifications can be made without departing from the scope of the present invention.
第１図は本発明の一実施例で用いる試料面高さ測定装置
を示す概略構成図、第２図は上記実施例の作用を説明す
るための信号波形図、第３図は本発明の他の実施例で用
いる装置を示す概略構成図、第４図は上記他の実施例の
作用を説明するための信号波形図、第５図は入射光を振
動した場合の問題点を説明するための模式図、第６図乃
至第８図はそれぞれ従来方法の問題点を説明するための
図、第９図及び第10図はパターンに対し入射光が傾斜し
た場合の説明図、第11図及び第12図は各々本発明の効果
を示す特性図である。 10……真空容器、20……電子光学鏡筒、30……試料、40
……照射系、41……レーザ光源、45,52……集束レン
ズ、46,51……反射ミラー（振動ミラー）、47,61……振
動器、48……駆動回路、53……検出器（PSD）、54,55,5
6……信号処理回路、57……平均化処理回路、58……位
置測定回路、100,102……試料面パターン、99,101……
試料面上の入射スリツト像。FIG. 1 is a schematic configuration diagram showing a sample surface height measuring device used in one embodiment of the present invention, FIG. 2 is a signal waveform diagram for explaining the operation of the above embodiment, and FIG. 4 is a schematic configuration diagram showing an apparatus used in this embodiment, FIG. 4 is a signal waveform diagram for explaining the operation of the other embodiment, and FIG. 5 is a diagram for explaining a problem when the incident light is vibrated. Schematic diagrams, FIGS. 6 to 8 are diagrams for explaining the problems of the conventional method, FIGS. 9 and 10 are explanatory diagrams when incident light is inclined with respect to the pattern, FIG. 11 and FIG. FIG. 12 is a characteristic diagram showing the effect of the present invention. 10 ... Vacuum container, 20 ... Electron optical lens barrel, 30 ... Sample, 40
...... Irradiation system, 41 ...... Laser light source, 45,52 …… Focusing lens, 46,51 …… Reflecting mirror (vibrating mirror), 47,61 …… Vibrator, 48 …… Driving circuit, 53 …… Detector (PSD), 54,55,5
6 …… Signal processing circuit, 57 …… Averaging processing circuit, 58 …… Position measuring circuit, 100,102 …… Sample surface pattern, 99,101 ……
Incident slit image on the sample surface.
Claims (10)
を有する平板状の試料表面に対し、斜め方向から前記入
射光束を照射すると共に、前記試料の表面状態を平均化
して表面位置を検出するために前記試料の表面に入射す
る入射光の照射位置を試料面高さ変動周波数と分離した
周波数で変動せしめ、前記光の照射により前記試料表面
で反射された一光を検出し、前記試料表面の所定方向に
対する位置に応じた信号を得るとともに、この信号に対
して、前記入射光の変動に起因して生じる変動成分及び
前記試料の表面の反射率の差異に起因して生じる測定誤
差成分を一括して取除くために平均化処理して前記所定
方向に対応した前記試料表面の位置信号を得ることを特
徴とする位置測定方法。1. A flat-plate-shaped sample surface having regions having different reflectances in the incident light beam is irradiated with the incident light beam from an oblique direction, and the surface state of the sample is averaged to detect the surface position. In order to change the irradiation position of the incident light incident on the surface of the sample at a frequency separated from the sample surface height fluctuation frequency, to detect one light reflected on the sample surface by the irradiation of the light, the sample surface A signal corresponding to the position in the predetermined direction is obtained, and a variation component caused by the variation of the incident light and a measurement error component caused by the difference in the reflectance of the surface of the sample with respect to the signal are obtained. A position measuring method characterized by obtaining a position signal of the sample surface corresponding to the predetermined direction by performing an averaging process in order to remove them collectively.
導***置検出素子を用いたことを特徴とする特許請求の
範囲第１項記載の位置測定方法。2. The position measuring method according to claim 1, wherein a semiconductor position detecting element using a lateral light effect is used for the light detection.
に、駆動源として圧電素子を用い、この圧電素子により
前記照射された光を反射して前記試料表面に照射するた
めのミラーの位置を変動させることを特徴とする特許請
求の範囲第１項記載の位置測定方法。3. A piezoelectric element is used as a drive source for varying the irradiation position of the incident light, and the position of a mirror for reflecting the irradiated light by the piezoelectric element and irradiating the sample surface is set. The position measuring method according to claim 1, wherein the position measuring method is varied.
ーパスフィルタを用いたことを特徴とする特許請求の範
囲第１項記載の位置測定方法。4. The position measuring method according to claim 1, wherein a low-pass filter is used for averaging the detection signals.
射光束を前記平板状の試料のパターンに対して傾けて照
射するとともに、前記試料の表面状態を平均化して表面
位置を検出するために前記試料の表面に入射する入射光
の照射位置を変動せしめ、また、この変動された前記光
の照射により前記試料表面で反射された反射光に対し、
前記入射光の変動に起因して生じる変動成分を取除くた
めに前記変動と逆位相となるように前記反射光を変動さ
せ、この変動により変動される前記反射光を検出し、前
記試料表面の所定方向に対する位置に応じた信号を得
て、この信号に対して、前記試料の表面の反射率の差異
に起因して生じる測定誤差成分を平均化処理して前記所
定方向に対応した前記試料表面の位置信号を得ることを
特徴とする位置測定方法。5. In order to detect the surface position by irradiating the surface of the flat plate sample with an incident light beam obliquely with respect to the pattern of the flat plate sample and averaging the surface state of the sample. To change the irradiation position of the incident light incident on the surface of the sample, also, with respect to the reflected light reflected on the sample surface by the irradiation of the changed light,
In order to remove the fluctuation component caused by the fluctuation of the incident light, the reflected light is fluctuated so as to be in the opposite phase to the fluctuation, and the reflected light fluctuated by this fluctuation is detected, The signal corresponding to the position in the predetermined direction is obtained, and the measurement error component caused by the difference in the reflectance of the surface of the sample is averaged with respect to this signal, and the sample surface corresponding to the predetermined direction is obtained. A position measuring method characterized by obtaining the position signal of
導***置検出素子を用いたことを特徴とする特許請求の
範囲第５項記載の位置測定方法。6. The position measuring method according to claim 5, wherein a semiconductor position detecting element using a lateral light effect is used for the light detection.
して圧電素子を用い、この圧電素子により前記照射され
た光を反射して前記試料表面に照射するミラーの位置を
変動させることを特徴とする特許請求の範囲第５項記載
の位置測定方法。7. A piezoelectric element is used as a drive source to change the incident light, and the position of a mirror that reflects the irradiated light by the piezoelectric element and irradiates the sample surface is changed. The position measuring method according to claim 5.
して圧電素子を用い、この圧電素子により前記試料表面
からの反射光を反射させるミラーの位置を変動させるこ
とを特徴とする特許請求の範囲第５項記載の位置測定方
法。8. A piezoelectric element is used as a drive source to change the reflected light, and the position of a mirror that reflects the reflected light from the sample surface is changed by the piezoelectric element. The position measuring method according to the fifth item.
ルタを用いたことを特徴とする特許請求の範囲第５項記
載の位置測定方法。9. The position measuring method according to claim 5, wherein a low-pass filter is used for the averaging process.
は、前記入射光の変動により前記光を検出する際には受
光される反射光の位置が変動しないように調整されてい
ることを特徴とする特許請求の範囲第５項記載の位置測
定方法。10. The vibration amplitude when varying the reflected light is adjusted so that the position of the reflected light received when detecting the light due to the variation of the incident light does not vary. The position measuring method according to claim 5.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60059529A JPH0820208B2 (en) | 1985-03-26 | 1985-03-26 | Position measurement method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60059529A JPH0820208B2 (en) | 1985-03-26 | 1985-03-26 | Position measurement method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61218902A JPS61218902A (en) | 1986-09-29 |
| JPH0820208B2 true JPH0820208B2 (en) | 1996-03-04 |
Family
ID=13115891
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP60059529A Expired - Lifetime JPH0820208B2 (en) | 1985-03-26 | 1985-03-26 | Position measurement method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0820208B2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0447210A (en) * | 1990-06-13 | 1992-02-17 | Matsushita Electric Ind Co Ltd | Height measuring apparatus by laser spot light |
| US5721089A (en) * | 1990-11-16 | 1998-02-24 | Canon Kabushiki Kaisha | Photosensitive material, color filter and liquid crystal device having the color filter |
| EP3929529A4 (en) * | 2019-02-21 | 2022-10-12 | Nikon Corporation | Surface position detecting device, exposure apparatus, substrate processing system and device manufacturing method |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56120905A (en) * | 1980-02-29 | 1981-09-22 | Anritsu Corp | Measuring device for true roundness |
| JPS56137102A (en) * | 1980-03-28 | 1981-10-26 | Sumitomo Metal Ind Ltd | Range finder |
| JPS56137103A (en) * | 1980-03-28 | 1981-10-26 | Sumitomo Metal Ind Ltd | Range finder |
| JPS59120909A (en) * | 1982-12-28 | 1984-07-12 | Fujitsu Ltd | Method for measuring thickness of resist coated film |
-
1985
- 1985-03-26 JP JP60059529A patent/JPH0820208B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61218902A (en) | 1986-09-29 |
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