JP2000081321A - Sample inspection equipment - Google Patents
Sample inspection equipmentInfo
- Publication number
- JP2000081321A JP2000081321A JP10251134A JP25113498A JP2000081321A JP 2000081321 A JP2000081321 A JP 2000081321A JP 10251134 A JP10251134 A JP 10251134A JP 25113498 A JP25113498 A JP 25113498A JP 2000081321 A JP2000081321 A JP 2000081321A
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- JP
- Japan
- Prior art keywords
- sample
- inspection
- inspection apparatus
- interference
- measurement
- 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
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- Length Measuring Devices By Optical Means (AREA)
- Image Processing (AREA)
- Image Analysis (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、検査試料の形状を
測定する試料検査装置に係り、殊に薄板状の検査試料の
面形状や厚さむら測定に好適な試料検査装置に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sample inspection apparatus for measuring the shape of an inspection sample, and more particularly to a sample inspection apparatus suitable for measuring the surface shape and thickness unevenness of a thin plate-shaped inspection sample.
【０００２】[0002]
【従来技術】半導体素子製造過程における半導体ウエハ
等の検査試料の面形状や厚さむらを測定するものとして
は、静電容量センサ等の変位センサを用いた装置が知ら
れている。しかし変位センサはポイント的な測定である
ため、試料全面の詳細な測定データを得る上では変位セ
ンサを試料全面で走査させる必要があり、測定に非常に
時間が掛かる。2. Description of the Related Art As a device for measuring the surface shape and thickness unevenness of an inspection sample such as a semiconductor wafer in a semiconductor element manufacturing process, an apparatus using a displacement sensor such as a capacitance sensor is known. However, since the displacement sensor is a point-based measurement, it is necessary to scan the entire surface of the sample to obtain detailed measurement data of the entire surface of the sample, and the measurement takes a very long time.
【０００３】測定に時間を掛けずに測定を行うものとし
ては、干渉計を用いた装置が知られている。従来、この
種による測定では、高精度に平面研磨された基準平面を
持つ吸着台に検査試料の裏面を密着させることにより試
料の裏面と基準平面とを一致させ、試料の表面に可干渉
光を投光し、表面と参照面から反射される反射光により
形成される干渉縞からその表面形状を得ていた。殊に斜
入射干渉計は、斜め方向から測定面へ可干渉光を入射さ
せるので、比較的凹凸の大きな面も測定可能であり、ま
た、可干渉光の測定面への入射角度を変えることにより
測定感度を変更することができるので有利である。An apparatus using an interferometer is known as one that performs measurement without taking much time. Conventionally, in this type of measurement, the back surface of the test sample is brought into close contact with the reference plane by bringing the back surface of the test sample into close contact with a suction table that has a reference plane polished with high precision, and coherent light is applied to the surface of the sample. Light is projected and the surface shape is obtained from interference fringes formed by reflected light reflected from the surface and the reference surface. In particular, the grazing incidence interferometer allows coherent light to be incident on the measurement surface from an oblique direction, so that it is possible to measure even a surface with relatively large irregularities. Advantageously, the measurement sensitivity can be changed.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上記の
干渉計を用いた装置において、吸着台に試料裏面を密着
させて試料を保持する構成ものは、吸着台と試料裏面と
の間に異物が混入すると、これにより表面形状測定の誤
差となったり、試料裏面に損傷を生じさせるという問題
があった。また、接触面が多いためダストの付着や接触
による汚れなどの化学的汚染の可能性が大きくなる。微
細なパターンを形成する半導体素子製造においては、こ
れらをできるだけ低減することが望まれている。However, in the apparatus using the above interferometer, the structure in which the back surface of the sample is brought into close contact with the suction table and the sample is held, foreign matter is mixed between the suction table and the back surface of the sample. Then, there is a problem that this causes an error in surface shape measurement and causes damage to the back surface of the sample. Further, since there are many contact surfaces, the possibility of chemical contamination such as adhesion of dust and dirt due to contact increases. In the manufacture of semiconductor devices for forming fine patterns, it is desired to reduce these as much as possible.
【０００５】本発明は上記問題点に鑑み、上記のような
検査試料へのダメージを抑え、試料の面形状や厚さむら
を高精度に、素早く測定検査することのできる試料検査
装置を提供することを技術課題とする。In view of the above problems, the present invention provides a sample inspection apparatus capable of suppressing damage to an inspection sample as described above and measuring and inspecting the surface shape and thickness unevenness of the sample with high precision and speed. This is a technical issue.
【０００６】[0006]
【課題を解決するための手段】上記課題を解決するため
に、本発明は以下のような構成を備えることを特徴とす
る。Means for Solving the Problems In order to solve the above problems, the present invention is characterized by having the following configuration.
【０００７】（１） 検査試料の形状を測定する試料検
査装置において、前記検査試料の測定表面及び測定裏面
を除く部分を保持する保持手段と、該保持手段に保持さ
れた検査試料の測定表面に可干渉光を投光して第１参照
面と測定表面との光干渉により干渉縞を形成し該干渉縞
を撮像素子により撮像する第１検査光学系と、前記保持
手段に保持された検査試料の測定裏面に可干渉光を投光
して第２参照面と測定裏面との光干渉により干渉縞を形
成し該干渉縞を撮像素子により撮像する第２検査光学系
と、前記第１及び第２検査光学系によりそれぞれ得られ
る干渉縞画像に基づいて前記検査試料の面形状情報を得
る解析手段と、を備えることを特徴とする。(1) In a sample inspection apparatus for measuring the shape of an inspection sample, a holding means for holding a portion of the inspection sample other than a measurement surface and a measurement back surface, and a measurement surface of the inspection sample held by the holding means. A first inspection optical system for projecting coherent light to form interference fringes by optical interference between the first reference surface and the measurement surface and imaging the interference fringes with an image sensor, and an inspection sample held by the holding unit A second inspection optical system for projecting coherent light onto the measurement back surface to form interference fringes by optical interference between the second reference surface and the measurement back surface and imaging the interference fringes with an image sensor; And analyzing means for obtaining surface shape information of the test sample based on the interference fringe images obtained by the two test optical systems.
【０００８】（２） （１）の試料検査装置において、
前記第１及び第２検査手段の撮像素子は、それぞれ得る
干渉縞画像を同期して撮像することを特徴とする。(2) In the sample inspection apparatus of (1),
The image pickup devices of the first and second inspection means synchronously image interference fringe images obtained respectively.
【０００９】（３） （１）の試料検査装置において、
前記保持手段は少なくとも３点で前記試料の端部を狭持
することを特徴とする。(3) In the sample inspection apparatus of (1),
The holding means may hold the end of the sample at at least three points.
【００１０】（４） （１）の試料検査装置は、さらに
前記第１参照面と第２参照面との相対的平行度を検出す
る平行度検出手段を備え、前記解析手段は検出された平
行度情報に基づいて検査試料の表裏面の相対的な面形状
情報を補正することを特徴とする。(4) The sample inspection apparatus of (1) further comprises a parallelism detecting means for detecting a relative parallelism between the first reference surface and the second reference surface, and the analyzing means comprises a detecting means for detecting the detected parallelism. It is characterized in that the relative surface shape information of the front and back surfaces of the test sample is corrected based on the degree information.
【００１１】（５） （１）又は（４）の解析手段は、
前記検査試料の表裏面の厚さむらを得ることを特徴とす
る。(5) The analyzing means of (1) or (4) is
It is characterized in that the thickness irregularity of the front and back surfaces of the test sample is obtained.
【００１２】（６） （１）の試料検査装置において、
さらに前記第１及び第２検査光学系に対して前記保持手
段に保持された検査試料を相対移動させる移動手段を備
え、第１及び第２検査光学系は該移動手段により相対移
動される前記検査試料の測定面の干渉縞画像を参照面の
大きさに応じて分割して得ることを特徴とする。(6) In the sample inspection apparatus of (1),
And a moving means for relatively moving the test sample held by the holding means with respect to the first and second inspection optical systems, wherein the first and second inspection optical systems are moved relatively by the moving means. The method is characterized in that an interference fringe image of the measurement surface of the sample is obtained by being divided according to the size of the reference surface.
【００１３】（７） （６）の試料検査装置は、さらに
分割して得られる干渉縞画像に基づく面形状情報を得る
と共に、該面形状情報を繋ぎ合わせて全体の面形状情報
を得る分割画像解析手段を備えることを特徴とする。(7) The sample inspection apparatus of (6) obtains surface shape information based on the interference fringe image obtained by further dividing, and combines the surface shape information to obtain the entire surface shape information. It is characterized by comprising analysis means.
【００１４】（８） （１）の試料検査装置において、
前記第１及び第２検査光学系は対を成すことを特徴とす
る。(8) In the sample inspection apparatus of (1),
The first and second inspection optical systems form a pair.
【００１５】（９） （１）の試料検査装置において、
前記第１及び第２検査光学系は共に斜入射干渉計として
構成したことを特徴とする。(9) In the sample inspection apparatus of (1),
The first and second inspection optical systems are both configured as oblique incidence interferometers.
【００１６】[0016]
【発明の実施の形態】以下、本発明の実施の形態を図面
に基づいて説明する。図１は本発明に係る試料検査装置
の光学系要部図であり、本形態の装置は斜入射干渉計を
使用して構成している。Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a main view of an optical system of a sample inspection apparatus according to the present invention. The apparatus of the present embodiment is configured using an oblique incidence interferometer.
【００１７】検査試料であるウェハＷの測定表面ＷF及
び測定裏面ＷBは、一対の表面検査光学系１と裏面検査
光学系２により検査される。ウェハＷは、後述するウエ
ハ保持ユニットによりその周端部を３つの保持チャック
で狭持され、表面検査光学系１と裏面検査装置２との間
に置かれる。The measurement surface W F and measuring the back surface W B of the wafer W as an inspection sample is tested by a pair of surface inspection optical system 1 and the back surface inspection optical system 2. The peripheral edge of the wafer W is sandwiched by three holding chucks by a wafer holding unit described later, and is placed between the front surface inspection optical system 1 and the back surface inspection device 2.
【００１８】表面検査光学系１は光源１０、エキスパン
ダレンズ１１、コリメータレンズ１２、プリズム１３、
スクリーン１４、フィールドレンズ１５、ＴＶカメラ１
６から構成されている。光源１０は可干渉光を出射する
レーザ光源であり、本実施形態ではＨｅ−Ｎｅレーザ光
源を使用している。光源１０から出射されたレーザ光
は、エキスパンダレンズ１１により必要な大きさの光束
に拡張された後、コリメータレンズ１２により平行光束
にされ、プリズム１３に入射する。プリズム１３の参照
面１３ａで反射した光束と、プリズム１３を透過して測
定表面ＷFで反射した光束とが干渉現象を起こし、これ
がスクリーン１４に投影される。スクリーン１４に投影
された干渉縞は、フィールドレンズ１５を介してＴＶカ
メラ１６に撮像される。The surface inspection optical system 1 includes a light source 10, an expander lens 11, a collimator lens 12, a prism 13,
Screen 14, field lens 15, TV camera 1
6. The light source 10 is a laser light source that emits coherent light, and in this embodiment, a He-Ne laser light source is used. The laser light emitted from the light source 10 is expanded into a light beam of a required size by an expander lens 11, converted into a parallel light beam by a collimator lens 12, and incident on a prism 13. A light beam reflected by the reference surface 13a of the prism 13, the light beam reflected by the measurement surface W F passes through the prism 13 cause interference phenomenon, which is projected on the screen 14. The interference fringes projected on the screen 14 are captured by the TV camera 16 via the field lens 15.
【００１９】裏面検査光学系２は表面検査光学系１と同
一要素の、光源２０、エキスパンダレンズ２１、コリメ
ータレンズ２２、プリズム２３、スクリーン２４、フィ
ールドレンズ２５、ＴＶカメラ２６から構成されてお
り、プリズム２３を透過して測定裏面ＷBで反射した光
束と、プリズム２３の参照面２３ａで反射した光束とが
干渉現象を起こし、これがスクリーン２４に投影され
る。スクリーン２４に投影された干渉縞は、フィールド
レンズ２５を介してＴＶカメラ２６に撮像される。光源
２０はウェハＷを挟んで光源１０に対向するように配置
されており、各々の光源からの光束が対向する側のＴＶ
カメラ１６、２６に入射し難いように配置されている。The back surface inspection optical system 2 comprises a light source 20, an expander lens 21, a collimator lens 22, a prism 23, a screen 24, a field lens 25, and a TV camera 26 having the same elements as the front surface inspection optical system 1. a light beam reflected by the measured rear surface W B passes through the prism 23, the light beam reflected by the reference surface 23a of the prism 23 cause interference phenomenon, which is projected on the screen 24. The interference fringes projected on the screen 24 are captured by the TV camera 26 via the field lens 25. The light source 20 is disposed so as to face the light source 10 with the wafer W interposed therebetween.
They are arranged so that they are hardly incident on the cameras 16 and 26.
【００２０】１７及び２７はピエゾ素子等からなるアク
チエータで、測定表面ＷFとプリズム１３の参照面１３
ａとの距離、測定裏面ＷBとプリズム２３の参照面１３
ａとの距離をそれぞれ変化させる。[0020] 17 and 27 in actuator comprising a piezoelectric element or the like, the reference surface 13 of the measuring surface W F and the prism 13
distance between a, reference surface 13 of the measurement back surface W B and the prism 23
The distances to a are changed.
【００２１】なお、コリメータレンズ１２とプリズム１
３との間、及びコリメータレンズ２２とプリズム２３と
の間には、共に図示なき入射角調整プリズムが配置され
ており、各プリズムへのレーザ光束の入射角度を変える
ことにより、測定感度を変化させることができるように
なっている。The collimator lens 12 and the prism 1
3, and between the collimator lens 22 and the prism 23, an incident angle adjusting prism (not shown) is disposed, and the measurement sensitivity is changed by changing the incident angle of the laser beam to each prism. You can do it.
【００２２】図２（ａ）はウェハＷを保持する保持ユニ
ット３０の概略構成を示す図であり、ウェハＷは保持リ
ング３１に設けられた３つの保持チャック３２によりそ
の周端面が保持され、測定表面ＷF及び測定裏面ＷBは非
接触となっている。図２（ｂ）に示すように、保持チャ
ック３２の先端部は、ウェハＷの端部のテーパ形状に合
う傾斜面を持つＶ字溝が設けられており、保持チャック
３２が進退移動することによりウェハＷの狭持、解放を
行なう。また、この保持チャック３２はウェハＷの幅と
ほぼ同で幅を持ち、ウェハＷを保持したままプリズム１
３の参照面１３ａとプリズム２３の参照面２３ａとの間
に配置できるようになっている。なお、保持ユニット３
０はウェハＷを狭持した状態で図示なき搬送装置により
移動される。FIG. 2A is a view showing a schematic structure of a holding unit 30 for holding a wafer W. The wafer W is held at its peripheral end face by three holding chucks 32 provided on a holding ring 31, and measurement is performed. surface W F and measuring the back surface W B are not in contact. As shown in FIG. 2B, a V-shaped groove having an inclined surface matching the tapered shape of the end of the wafer W is provided at the tip of the holding chuck 32, and the holding chuck 32 moves forward and backward. The wafer W is held and released. The holding chuck 32 has substantially the same width as the width of the wafer W, and holds the prism W while holding the wafer W.
3 and the reference surface 23a of the prism 23. The holding unit 3
0 is moved by a transfer device (not shown) while holding the wafer W.
【００２３】次に、以上のような構成を備える試料検査
装置について、その動作を図３の制御系要部図に基づい
て以下に説明する。Next, the operation of the sample inspection apparatus having the above-described configuration will be described with reference to FIG.
【００２４】保持ユニット３０により保持されたウェハ
Ｗを表面検査光学系１及び裏面検査光学系２の各プリズ
ム１３、２３の間に配置する。光源１０及び２０からの
レーザ光によりスクリーン１４及び２４にはそれぞれ干
渉縞が形成され、これがＴＶカメラ１６、２６により撮
像される。ＴＶカメラ１６、２６からの各映像信号は画
像処理部４２に取り込まれ、画像処理部４２内のメモリ
にデジタル変換された画像データが記憶される。このと
きのＴＶカメラ１６、２６による画像データは、タイミ
ングジェネレータ４１の信号により同期して同時に撮像
されたものが取り込まれる。The wafer W held by the holding unit 30 is arranged between the prisms 13 and 23 of the front surface inspection optical system 1 and the back surface inspection optical system 2. Interference fringes are formed on the screens 14 and 24 by the laser beams from the light sources 10 and 20, respectively, and these are captured by the TV cameras 16 and 26. Each video signal from the TV cameras 16 and 26 is taken into the image processing unit 42, and digitally converted image data is stored in a memory in the image processing unit 42. At this time, the image data taken by the TV cameras 16 and 26 are taken in synchronization with the signal of the timing generator 41 and taken simultaneously.
【００２５】１枚目の各画像データが得らると、制御部
４０はアクチュエータ１７、２７を駆動して、干渉縞の
位相を所定の縞感度分だけ変化すべく、それぞれプリズ
ム１３、２３（参照面１３ａ、２３ａ）を移動する。そ
の後、ＴＶカメラ１６、２６により撮像される画像デー
タは、前述と同様にタイミングジェネレータ４１の信号
により同期して画像処理部４２に取り込まれる。When the first image data is obtained, the control unit 40 drives the actuators 17 and 27 to change the phase of the interference fringes by the predetermined fringe sensitivity by the prisms 13 and 23 (respectively). The reference planes 13a and 23a) are moved. Thereafter, the image data captured by the TV cameras 16 and 26 is taken into the image processing unit 42 in synchronization with the signal of the timing generator 41 in the same manner as described above.
【００２６】こうして位相を変化させた画像データの取
り込みを所定の枚数分行う。ウエハＷの両測定面におけ
る所定数の画像データが得られると、画像処理部４２は
各測定面の画像データに対して、それぞれウエハ面の解
析領域を決定して位相シフト法による所定の解析処理を
施すことにより各面毎の面形状データを得る（例えば、
本出願人による特開平１０−２２１０３３号公報に記載
されているように、８枚の画像データから解析する方法
を使用することができる）。そして、ウェハＷの測定表
面ＷF及び測定裏面ＷBの各面形状データを対応させるこ
とにより、厚さむらデータが算出される。得られた解析
結果は、モニタ４５に表示される。このようなウエハの
面形状の解析において、参照面１３ａと参照面２３ａと
の間が平行でなく、傾斜成分が発生している場合は次の
ようにしてその傾斜成分による誤差を取り除くことがで
きる。The image data whose phase has been changed in this way is taken in by a predetermined number. When a predetermined number of image data on both measurement surfaces of the wafer W are obtained, the image processing unit 42 determines an analysis region on the wafer surface for each of the image data on each measurement surface and performs a predetermined analysis process by the phase shift method. To obtain surface shape data for each surface (for example,
As described in JP-A-10-221033 by the present applicant, a method of analyzing from eight pieces of image data can be used). Then, by associating the measurement surface W F and each face shape data of the measurement back surface W B of the wafer W, the thickness unevenness data is calculated. The obtained analysis result is displayed on the monitor 45. In such an analysis of the wafer surface shape, if the reference plane 13a and the reference plane 23a are not parallel and a tilt component is generated, an error due to the tilt component can be removed as follows. .
【００２７】図４は、参照面１３ａに対して参照面２３
ａが傾斜していた場合の干渉縞画像の例を示す図であ
り、ウエハ領域外にはプリズム１３の参照面１３ａで反
射した光束と対向するプリズム２３の参照面２３ａで反
射した光束とによる干渉縞も形成されている。画像処理
部４２はこのようにウエハ領域外に形成される参照面間
の干渉縞を利用して、参照面１３ａと参照面２３ａとの
相対的平行度（傾斜）の情報を得る。すなわち、ウエハ
領域外に測定感度分の干渉縞が得られるので、ウエハ面
の形状解析と同様に解析領域を決定して、位相シフト法
による解析処理を行うことによりその傾斜成分を検出す
る。この傾斜情報に基づいて前述のように算出される厚
さむらデータを補正することにより、精度の良い測定結
果を得ることができる。FIG. 4 shows the reference surface 23a with respect to the reference surface 13a.
FIG. 9 is a diagram illustrating an example of an interference fringe image when a is inclined, in which interference is caused by a light beam reflected by a reference surface 13a of a prism 13 and a light beam reflected by a reference surface 23a of a prism 23 facing the outside of the wafer region. Stripes are also formed. The image processing unit 42 obtains information on the relative parallelism (inclination) between the reference surface 13a and the reference surface 23a using the interference fringes between the reference surfaces formed outside the wafer region in this manner. That is, since interference fringes corresponding to the measurement sensitivity are obtained outside the wafer area, the analysis area is determined in the same manner as in the shape analysis of the wafer surface, and the inclination component is detected by performing the analysis processing by the phase shift method. By correcting the uneven thickness data calculated as described above based on the tilt information, a highly accurate measurement result can be obtained.
【００２８】なお、プリズムの参照面１３ａ、２３ａ間
の平行度を検出する方法としては、専用の検出光学系を
設けて構成することもできる。図５はその例を示す図で
ある。平行度検出光学系５０は参照面１３ａ、２３ａ間
の異なる３点を測定できる位置に３組配置されており
（図では１組の図示を略している）、測定光束を出射す
る半導体レーザ光源５１、ビームスプリッタ５２、受光
素子５３から構成されている。その検出光軸は、プリズ
ム１３に入射した測定光束が参照面１３ａに対して略垂
直に透過するように配置されている。As a method for detecting the degree of parallelism between the reference surfaces 13a and 23a of the prism, it is possible to provide a dedicated detection optical system. FIG. 5 is a diagram showing the example. The parallelism detection optical system 50 is arranged in three sets at positions where three different points between the reference surfaces 13a and 23a can be measured (one set is omitted in the figure), and a semiconductor laser light source 51 that emits a measurement light beam. , A beam splitter 52, and a light receiving element 53. The detection optical axis is arranged such that the measurement light beam incident on the prism 13 is transmitted substantially perpendicularly to the reference surface 13a.
【００２９】プリズム１３に入射した測定光束は参照面
１３ａで反射されるとともに、透過した光束がプリズム
２３の参照面２３ａで反射される。この２つの反射光は
共に略同じ光路となって受光素子５３により検出され
る。２つの反射光の位相差成分は干渉を起し、受光素子
５３により検出される光強度は２つの反射光の光路差に
応じて変化する。したがって、各受光素子５３からの出
力信号の変化から測定点間の距離の変化量を検出するこ
とができ、これに基づいて参照面１３ａ、２３ａ間の平
行度を知ることができる。The measurement light beam incident on the prism 13 is reflected by the reference surface 13a, and the transmitted light beam is reflected by the reference surface 23a of the prism 23. The two reflected lights have substantially the same optical path and are detected by the light receiving element 53. The phase difference component between the two reflected lights causes interference, and the light intensity detected by the light receiving element 53 changes according to the optical path difference between the two reflected lights. Therefore, the amount of change in the distance between the measurement points can be detected from the change in the output signal from each light receiving element 53, and based on this, the parallelism between the reference surfaces 13a and 23a can be known.
【００３０】以上の実施形態においては、測定面に対し
て斜め方向から可干渉光を入射させる斜入射干渉計を例
にとって説明したが、測定面に対して垂直方向から可干
渉光を入射させる垂直入射型の干渉計で構成してもよ
い。In the above embodiment, the oblique incidence interferometer in which the coherent light is incident on the measurement surface from an oblique direction has been described as an example. It may be constituted by an incident type interferometer.
【００３１】また、プリズム参照面の相対的平行度を検
出する方法としては、上記した変容の他、マイクロメー
タや変位センサ等により参照面位置を測定する構成とす
ることも可能である。As a method of detecting the relative parallelism of the prism reference surface, in addition to the above-described transformation, a configuration in which the position of the reference surface is measured by a micrometer, a displacement sensor, or the like can be used.
【００３２】さらに、プリズムサイズ以上の大口径の試
料を測定する場合には、試料表面及び裏面のそれぞれの
測定領域を複数に分割して撮影し、各撮影像毎に両面の
形状を算出した後、これらを繋ぎ合わせることにより全
面の領域を形状結果を得ることも可能である。例えば、
図６に示すように、ＭＡ1（斜線部）の領域を１回目の
測定領域として面形状を算出した後、ＭＡ2の領域が撮
影できるように検査光学系に対して試料を相対移動させ
る（平行移動又は回転移動で行う）。ＭＡ2領域の面形
状が測定できたら、同様にＭＡ3、ＭＡ4の順に各々面形
状を測定する。各ＭＡ1〜ＭＡ4の重複部分ＰAとして、
面形状の凹凸情報が一致する部分を重ね合わせて繋ぎ合
わせることにより、試料全面の面形状情報が得られる。
各領域の繋ぎ合わせ方法は、凹凸情報の一致だけではな
く、例えば、予め与えておいた特異点を重ね合わせた
り、試料外形を一致させるようにして繋ぎ合わせてもよ
い。このように、１つの試料を複数に分割して測定する
ことにより、試料の大型化にも比較的容易に対応するこ
とができる。Further, when measuring a sample having a large diameter equal to or larger than the prism size, each of the measurement areas on the front surface and the back surface of the sample is divided into a plurality of pieces and photographed. By connecting these, it is also possible to obtain a shape result over the entire area. For example,
As shown in FIG. 6, after calculating the surface shape using the area of MA 1 (shaded area) as the first measurement area, the sample is moved relative to the inspection optical system so that the area of MA 2 can be imaged ( Performed by parallel or rotational movement). Once it measured surface shape of the MA 2 region, similarly to measure each surface shape in the order of MA 3, MA 4. As overlapping portion P A of the MA 1 to MA 4,
By superimposing and joining the portions where the surface shape unevenness information coincides, the surface shape information of the entire surface of the sample is obtained.
The joining method of the respective regions is not limited to the matching of the concavo-convex information. For example, the joining may be performed such that the singular points given in advance are overlapped or the outer shape of the sample is matched. As described above, by dividing one sample into a plurality of pieces and measuring, it is possible to relatively easily cope with an increase in the size of the sample.
【００３３】[0033]
【発明の効果】以上説明したように、本発明によれば、
検査試料の測定表面及び測定裏面を非接触の状態で同時
に測定できるので、検査試料へのダメージを抑え、試料
の面形状や厚さむらを高精度に測定できる。また、干渉
計を利用した測定であるので、大きな面を持つ検査試料
の測定も高速に行うことができる。As described above, according to the present invention,
Since the measurement surface and the measurement back surface of the test sample can be measured simultaneously in a non-contact state, damage to the test sample can be suppressed, and the surface shape and thickness unevenness of the sample can be measured with high accuracy. In addition, since the measurement is performed using an interferometer, measurement of a test sample having a large surface can be performed at high speed.
【図１】本発明に係る試料検査装置の光学系要部図であ
る。FIG. 1 is a main view of an optical system of a sample inspection apparatus according to the present invention.
【図２】ウェハＷを保持する保持ユニットの概略構成図
である。FIG. 2 is a schematic configuration diagram of a holding unit that holds a wafer W.
【図３】本発明に係る試料検査装置の制御系要部図であ
る。FIG. 3 is a main view of a control system of the sample inspection apparatus according to the present invention.
【図４】参照面１３ａに対して参照面２３ａが傾斜して
いた場合の干渉縞画像の例を示す図である。FIG. 4 is a diagram illustrating an example of an interference fringe image when the reference surface 23a is inclined with respect to the reference surface 13a.
【図５】プリズムの参照面間の平行度を検出する検出光
学系の説明図である。FIG. 5 is an explanatory diagram of a detection optical system that detects parallelism between reference surfaces of a prism.
【図６】分割して測定する場合の測定領域を示した模式
図である。FIG. 6 is a schematic diagram showing a measurement area when measuring by dividing.
【符号の説明】 １ 表面検査光学系 ２ 裏面検査光学系 １０、２０ 光源 １２、２２ コリメータレンズ １３、２３ プリズム １３ａ、２３ａ 参照面 １６、２６ ＴＶカメラ ３２ 保持チャック ４０ 制御部 ４１ タイミングジェネレータ ４２ 画像処理部[Description of Signs] 1 Surface inspection optical system 2 Back surface inspection optical system 10, 20 Light source 12, 22 Collimator lens 13, 23 Prism 13a, 23a Reference surface 16, 26 TV camera 32 Holding chuck 40 Control unit 41 Timing generator 42 Image processing Department
Claims (9)
において、前記検査試料の測定表面及び測定裏面を除く
部分を保持する保持手段と、該保持手段に保持された検
査試料の測定表面に可干渉光を投光して第１参照面と測
定表面との光干渉により干渉縞を形成し該干渉縞を撮像
素子により撮像する第１検査光学系と、前記保持手段に
保持された検査試料の測定裏面に可干渉光を投光して第
２参照面と測定裏面との光干渉により干渉縞を形成し該
干渉縞を撮像素子により撮像する第２検査光学系と、前
記第１及び第２検査光学系によりそれぞれ得られる干渉
縞画像に基づいて前記検査試料の面形状情報を得る解析
手段と、を備えることを特徴とする試料検査装置。1. A sample inspection apparatus for measuring the shape of an inspection sample, comprising: holding means for holding a portion of the inspection sample other than a measurement surface and a measurement back surface; A first inspection optical system for projecting interference light to form interference fringes by optical interference between the first reference surface and the measurement surface and imaging the interference fringes by an imaging element; A second inspection optical system for projecting coherent light on the measurement back surface to form interference fringes by optical interference between the second reference surface and the measurement back surface and imaging the interference fringes with an imaging device; and the first and second inspection optical systems. A sample inspection apparatus comprising: an analysis unit configured to obtain surface shape information of the inspection sample based on interference fringe images respectively obtained by the inspection optical system.
第１及び第２検査手段の撮像素子は、それぞれ得る干渉
縞画像を同期して撮像することを特徴とする試料検査装
置。2. The sample inspection apparatus according to claim 1, wherein the imaging elements of the first and second inspection means synchronously image interference fringe images obtained respectively.
保持手段は少なくとも３点で前記試料の端部を狭持する
ことを特徴とする試料検査装置。3. The sample inspection apparatus according to claim 1, wherein said holding means clamps an end of said sample at at least three points.
第１参照面と第２参照面との相対的平行度を検出する平
行度検出手段を備え、前記解析手段は検出された平行度
情報に基づいて検査試料の表裏面の相対的な面形状情報
を補正することを特徴とする試料検査装置。4. The sample inspection apparatus according to claim 1, further comprising parallelism detecting means for detecting a relative parallelism between the first reference surface and the second reference surface, and wherein the analyzing means detects the detected parallelism. A sample inspection apparatus, wherein relative surface shape information of front and back surfaces of an inspection sample is corrected based on information.
試料の表裏面の厚さむらを得ることを特徴とする試料検
査装置。5. The sample inspection apparatus according to claim 1, wherein the analysis means obtains uneven thickness of the front and back surfaces of the inspection sample.
に前記第１及び第２検査光学系に対して前記保持手段に
保持された検査試料を相対移動させる移動手段を備え、
第１及び第２検査光学系は該移動手段により相対移動さ
れる前記検査試料の測定面の干渉縞画像を参照面の大き
さに応じて分割して得ることを特徴とする試料検査装
置。6. The sample inspection apparatus according to claim 1, further comprising a moving unit that relatively moves the inspection sample held by the holding unit with respect to the first and second inspection optical systems.
A sample inspection apparatus, wherein the first and second inspection optical systems obtain an interference fringe image of a measurement surface of the inspection sample, which is relatively moved by the moving unit, according to a size of a reference surface.
して得られる干渉縞画像に基づく面形状情報を得ると共
に、該面形状情報を繋ぎ合わせて全体の面形状情報を得
る分割画像解析手段を備えることを特徴とする試料検査
装置。7. The sample inspection apparatus according to claim 6, further comprising obtaining surface shape information based on an interference fringe image obtained by further dividing, and connecting the surface shape information to obtain the entire surface shape information. A sample inspection apparatus comprising:
第１及び第２検査光学系は対を成すことを特徴とする試
料検査装置。8. The sample inspection apparatus according to claim 1, wherein the first and second inspection optical systems form a pair.
第１及び第２検査光学系は共に斜入射干渉計として構成
したことを特徴とする試料検査装置。9. The sample inspection apparatus according to claim 1, wherein said first and second inspection optical systems are both configured as oblique incidence interferometers.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25113498A JP4011205B2 (en) | 1998-09-04 | 1998-09-04 | Sample inspection equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP25113498A JP4011205B2 (en) | 1998-09-04 | 1998-09-04 | Sample inspection equipment |
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| Publication Number | Publication Date |
|---|---|
| JP2000081321A true JP2000081321A (en) | 2000-03-21 |
| JP2000081321A5 JP2000081321A5 (en) | 2005-10-27 |
| JP4011205B2 JP4011205B2 (en) | 2007-11-21 |
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ID=17218188
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003522939A (en) * | 2000-01-25 | 2003-07-29 | ザイゴ コーポレーション | Optical system for measuring the shape and geometric dimensions of precision industrial parts |
| JP2012518185A (en) * | 2009-02-18 | 2012-08-09 | ケーエルエー−テンカー コーポレイション | Method and apparatus for measuring substrate shape or thickness information |
| CN108489422A (en) * | 2018-03-12 | 2018-09-04 | 四川大学 | A kind of method of frequency conversion phase shift least-squares iteration superposition face shape separation |
-
1998
- 1998-09-04 JP JP25113498A patent/JP4011205B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2003522939A (en) * | 2000-01-25 | 2003-07-29 | ザイゴ コーポレーション | Optical system for measuring the shape and geometric dimensions of precision industrial parts |
| JP2012518185A (en) * | 2009-02-18 | 2012-08-09 | ケーエルエー−テンカー コーポレイション | Method and apparatus for measuring substrate shape or thickness information |
| CN108489422A (en) * | 2018-03-12 | 2018-09-04 | 四川大学 | A kind of method of frequency conversion phase shift least-squares iteration superposition face shape separation |
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