JP2920990B2 - Reference grating plate for measuring magnification or image size in the depth direction and lateral direction of scanning electron microscope, tunnel scanning microscope, etc. - Google Patents
Reference grating plate for measuring magnification or image size in the depth direction and lateral direction of scanning electron microscope, tunnel scanning microscope, etc.Info
- Publication number
- JP2920990B2 JP2920990B2 JP2023435A JP2343590A JP2920990B2 JP 2920990 B2 JP2920990 B2 JP 2920990B2 JP 2023435 A JP2023435 A JP 2023435A JP 2343590 A JP2343590 A JP 2343590A JP 2920990 B2 JP2920990 B2 JP 2920990B2
- Authority
- JP
- Japan
- Prior art keywords
- lattice
- microscope
- grating
- convex portion
- substrate
- 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 - Fee Related
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C23/00—Other surface treatment of glass not in the form of fibres or filaments
- C03C23/0005—Other surface treatment of glass not in the form of fibres or filaments by irradiation
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C15/00—Surface treatment of glass, not in the form of fibres or filaments, by etching
-
- C—CHEMISTRY; METALLURGY
- C03—GLASS; MINERAL OR SLAG WOOL
- C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
- C03C23/00—Other surface treatment of glass not in the form of fibres or filaments
- C03C23/0005—Other surface treatment of glass not in the form of fibres or filaments by irradiation
- C03C23/006—Other surface treatment of glass not in the form of fibres or filaments by irradiation by plasma or corona discharge
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Life Sciences & Earth Sciences (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Toxicology (AREA)
- Physics & Mathematics (AREA)
- Plasma & Fusion (AREA)
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Description
【発明の詳細な説明】 （産業上の利用分野） 本発明は走査型電子顕微鏡や走査型トンネル顕微鏡の
倍率の検定とか、それらによる像における長さの単位の
決定或は水平方向と深さ方向の寸法の同時正確な測定を
行う場合の較正等に用いる基準格子板のような精密格子
板に関する。DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to the verification of the magnification of a scanning electron microscope or a scanning tunneling microscope, the determination of the unit of length in an image, or the horizontal and depth directions. The present invention relates to a precision grating plate such as a reference grating plate used for calibration or the like when simultaneous and accurate measurement of the dimensions is performed.
（従来の技術） 走査型電子顕微鏡（SEM）とか走査型トンネル顕微鏡
（STEM）或は触針式表面粗さ計においては、同一の物を
測定しても、その時の測定条件，測定方法等により測定
値がばらつき、長時間使っていると真の値からずれて来
る。このため基準原器を決めて随時或は測定毎に倍率と
か像における寸法単位等の検定較正を行う必要がある。
従来上述した検定較正に用いる基準原器としてガラス基
板上に蒸着した金属を化学的にエッチングして段差を付
けたものとか回折格子等を用いていた。(Prior art) In a scanning electron microscope (SEM), a scanning tunneling microscope (STEM) or a stylus type surface roughness meter, even if the same object is measured, it depends on the measurement conditions and measurement method at that time. The measured values fluctuate and deviate from the true values when used for a long time. For this reason, it is necessary to determine the reference prototype and to perform calibration for the magnification or the dimensional unit in the image at any time or every measurement.
Conventionally, as a reference prototype used for the above-described calibration, a metal deposited on a glass substrate is chemically etched to provide a step, or a diffraction grating is used.
（発明が解決しようとする課題） 基準原器として回折格子は精度が高いものであるが、
それでも格子溝を機械切りしたものではどうしても格子
ピッチの周期的誤差が避けられない。(Problems to be Solved by the Invention) Although a diffraction grating has high accuracy as a reference prototype,
Nevertheless, in the case where the grating grooves are mechanically cut, periodic errors in the grating pitch cannot be avoided.
またSEMとかSTEMとかで像のｘ方向とｙ方向の倍率の
差或は像の歪を測定する場合、従来の平行溝格子では一
方向の長さしか測れないため、測定の場合、較正原器を
90°回転させて２回に分けて測定する必要がある。この
問題は格子を直交格子にすれば解決できるが、機械切り
の格子では格子交点の形が崩れて良好な格子が得難い。Also, when measuring the difference between the magnification of the image in the x and y directions or the distortion of the image using a SEM or STEM, the conventional parallel groove grating can measure only the length in one direction. To
It is necessary to rotate 90 ° and measure in two parts. This problem can be solved by making the grid an orthogonal grid, but it is difficult to obtain a good grid in a machine-cut grid because the shape of the grid intersections is broken.
ホログラフィック露光法を用いた回折格子では機械的
な精度から来る格子ピッチ誤差がなく、平行格子でも直
交格子でも形崩れすることなく作ることができ、また実
際上格子ピッチの誤差は零とみなせるが、溝断面形状が
正弦波状であるため、格子線のどこを測定点とするかを
明確に決めることが困難で、実際の測定操作において誤
差が入って来る。また格子溝に水平面がないため、深さ
方向の測定基準とするのが困難である。ホログラフィッ
ク露光法とイオンビームエッチングにより格子パターン
を形成したブレーズ回折格子は格子溝の断面が鋸歯状で
あるから、水平方向の測定基準としては上述したような
問題はないが、格子溝に水平面がないため、深さ方向の
測定基準とはなし難いものである。A diffraction grating using the holographic exposure method has no grating pitch error due to mechanical accuracy, and it can be made without loss of shape in both parallel and orthogonal gratings.In fact, the grating pitch error can be considered to be zero. Since the groove has a sinusoidal cross-sectional shape, it is difficult to clearly determine which of the grid lines is to be the measurement point, and an error occurs in the actual measurement operation. In addition, since there is no horizontal plane in the lattice groove, it is difficult to use the lattice groove as a reference in the depth direction. The blazed diffraction grating in which the grating pattern is formed by holographic exposure and ion beam etching has a sawtooth-shaped cross section of the grating groove. Therefore, there is no problem as described above as a measurement standard in the horizontal direction. Therefore, it is difficult to set a measurement standard in the depth direction.
本発明はSEMとかSTEMの倍率検定、像歪の測定、それ
らによる寸法測定における較正用の基準原器として使い
易く水平方向にも深さ方向にも超精密な基準となる格子
板を提供しようとするものである。The present invention seeks to provide a grid plate which is easy to use as a reference standard for calibration in SEM or STEM magnification verification, image distortion measurement, and dimensional measurement based on them, and serves as an ultra-precise reference in both the horizontal direction and the depth direction. Is what you do.
（課題を解決するための手段） 同形同高の方形の段状凸部が一定間隔で格子状に配列
され、これら各凸部の上面と基底部の面が共に格子面に
平行な平面であるような微細格子の精密格子板を提供す
る。(Means for Solving the Problems) Square step-shaped protrusions having the same shape and the same height are arranged in a grid pattern at regular intervals, and both the upper surface and the base surface of each of these protrusions are planes parallel to the grid surface. To provide a fine grid plate with a fine grid.
（作用） 上述したような精密格子板は下記のような方法で作る
ことができる。互いにコヒーレントな二つの平行光束を
一つの基板面に二つの方向から照射すると平行等間隔の
干渉パターンが形成される。この干渉パターンの格子間
隔は使用する光の波長と二光束の基板面への入射角によ
って決まり、機械的な誤差なく、完全に等間隔となる。
従ってホログラフィック露光法により得られる格子は機
械切り格子のような格子のピッチ誤差が全くない。(Operation) The precision grating plate as described above can be manufactured by the following method. When two mutually coherent parallel light fluxes are irradiated on one substrate surface from two directions, an interference pattern at parallel equal intervals is formed. The lattice spacing of the interference pattern is determined by the wavelength of the light to be used and the incident angle of the two light beams on the substrate surface, and is completely equal without any mechanical error.
Therefore, the grating obtained by the holographic exposure method has no grating pitch error such as a mechanically cut grating.
また、ホログラフィック露光の際、平行縞の干渉パタ
ーンを基板を90°回転させて二回露光を行うことにより
直交格子パターンも容易に作成することができる。Also, at the time of holographic exposure, an orthogonal lattice pattern can be easily formed by rotating the substrate by 90 ° and exposing it twice for the parallel fringe interference pattern.
本発明はホログラフィック露光法により形成されたレ
ジストパターンをマスクとして基板のエッチングを行っ
ているのでピッチ誤差のない格子が得られると共に、反
応性イオンビームエッチングにより格子溝を作るので、
化学エッチングと異なり、マスクパターンから露出して
いる部分のみ選択的にエッチングされ、かつエッチング
がイオンビームの照射方向にのみ進行し、エッチング深
さが10Å単位で制御できるから、所定深さの断面凹字状
つまり水平な凸部上面および溝底を有し、両岸が明確に
角立った格子溝が得られる。従って従来の断面正弦波状
のホログラフィック回折格子を基準原器に用いる場合の
問題点がなくなり、水平方向と深さ方向の同時測定用基
準原器として最適な格子が得られるのである。In the present invention, since the substrate is etched using the resist pattern formed by the holographic exposure method as a mask, a grating without a pitch error is obtained, and a grating groove is formed by reactive ion beam etching.
Unlike chemical etching, only the portion exposed from the mask pattern is selectively etched, and the etching proceeds only in the direction of irradiation of the ion beam, and the etching depth can be controlled in units of 10 mm. A lattice groove having a character-shaped, that is, a horizontal convex upper surface and a groove bottom, and having sharply sharp edges on both sides is obtained. Therefore, there is no problem when a conventional holographic diffraction grating having a sinusoidal cross section is used as a reference prototype, and an optimal grating can be obtained as a reference prototype for simultaneous measurement in the horizontal and depth directions.
（実施例） 第１図は本発明による格子の一実施例拡大図である。
この実施例は平行溝格子板についての実施例である。本
発明による格子の特徴は図に示されるように溝堤上面お
よび溝底面が共に平面で溝岸形状が明確に角立っている
点にある。(Embodiment) FIG. 1 is an enlarged view of an embodiment of the grating according to the present invention.
This embodiment relates to a parallel groove lattice plate. The feature of the lattice according to the present invention is that, as shown in the figure, the upper surface and the lower surface of the dike are both flat and the groove bank shape is clearly sharp.
第２図は格子パターンを焼付けるホログラフィック光
学系を示す。10はレーザでHe-Cdレーザを用い、波長は4
416Åである。このレーザから得られる光束は半透明鏡1
1で２分割され、夫々の光束は鏡12を経て、スペイシャ
ルフィルター13により球面波光束に変換された後、軸外
し放物面鏡14により断面が拡大された平行光束に再変換
され、平面鏡15で折返されて基板16上に二つの方向から
入射せしめられ、基板面に干渉パターンを形成する。干
渉パターンのピッチｄは各光束の基板面への入射面をθ
とすると、 2dsinθ＝λ であたえられる。FIG. 2 shows a holographic optical system for printing a grating pattern. 10 is a laser using a He-Cd laser, the wavelength is 4
416. The light beam obtained from this laser is
After being split into two by 1, each light beam passes through a mirror 12, is converted into a spherical wave light beam by a spatial filter 13, and then reconverted into a parallel light beam whose cross section is enlarged by an off-axis parabolic mirror 14, and is converted into a plane mirror. The light is turned back at 15 and is incident on the substrate 16 from two directions to form an interference pattern on the substrate surface. The pitch d of the interference pattern is determined by setting the incident surface of each light beam on the substrate surface to θ.
Then, 2dsinθ = λ is given.
第３図は溝加工の工程を示す。 FIG. 3 shows a groove processing step.
基板16としてガラス板１を用い、干渉パターンを焼付
けるフォトレジスト２としてノボラック系フォトレジス
トをスピンコートにより2500Åの厚さにコートした（第
３図Ａ）。干渉パターン焼付後現像により、第３図Ｂに
示すように半波正弦波状にフォトレジスト層２を残す。
フォトレジストの感光濃度は正弦波状であるが、露光量
或は現像時間を適当にすると、フォトレジスト除去部分
の幅が次第に拡大され、露光時間或は現像時間をかえる
ことによってフォトレジストによるマスク部分と非マス
ク部分の幅の比率を変えることができる。この図の例で
はこの幅の比を1:1とした。第３図Ｂのフォトレジスタ
パターンをマスクとして、反応ガスにCHF3を用い反応性
イオンビームエッチング（RIBE）でエッチングを行い第
３図Ｃに示すようにガラス基板の露出部をエッチングし
て溝３を形成する。このときエッチングはガラス基板の
露出部のみ選択的にイオン照射方向にのみ進行する。溝
の深さは時間による制御される。この実施例では溝深さ
を1000Åとした。イオンビームエッチングによる溝形成
後、レジストパターンをバレルタイププラズマエッチン
グ装置によりＯ2プラズマで灰化除去し、最後に洗滌を
行って第３図Ｄの格子を得る。この方法により格子溝数
百〜数千本/mmの高密度格子が得られる。A glass plate 1 was used as the substrate 16, and a novolak-based photoresist was coated by spin coating to a thickness of 2500 ° as a photoresist 2 for printing an interference pattern (FIG. 3A). After the interference pattern is printed, the photoresist layer 2 is left in a half-wave sine wave shape as shown in FIG. 3B by development.
Although the photosensitive density of the photoresist is sinusoidal, if the exposure amount or the development time is appropriate, the width of the photoresist removal portion is gradually increased, and by changing the exposure time or the development time, the photoresist mask portion and the photoresist portion are changed. The ratio of the width of the non-mask portion can be changed. In the example of this figure, the ratio of the width is 1: 1. Using the photoresist pattern of FIG. 3B as a mask, etching is performed by reactive ion beam etching (RIBE) using CHF 3 as a reaction gas, and the exposed portion of the glass substrate is etched as shown in FIG. To form At this time, the etching selectively proceeds only in the exposed portion of the glass substrate only in the ion irradiation direction. The depth of the groove is controlled by time. In this embodiment, the groove depth was set to 1000 °. After the grooves are formed by ion beam etching, the resist pattern is ashed and removed by O 2 plasma using a barrel type plasma etching apparatus, and finally washed to obtain the lattice shown in FIG. 3D. By this method, a high-density lattice of several hundreds to several thousand lines / mm can be obtained.
第４図は本発明の他の実施例を示す。この実施例は直
交格子で直交する二組の格子溝G1,G2に囲まれた方形の
凸部Ｐの上面は平面であり、この凸部の基底面である両
溝G1,G2の底が共通の一平面となっていて、凸部Ｐの上
面と基底面との間には一定の段差が形成されている。FIG. 4 shows another embodiment of the present invention. In this embodiment, the upper surface of a rectangular convex portion P surrounded by two sets of lattice grooves G1 and G2 orthogonal to each other with an orthogonal lattice is a flat surface, and the bottom surfaces of both grooves G1 and G2, which are the base surfaces of the convex portions, are common. And a certain level difference is formed between the upper surface and the base surface of the projection P.
この格子は前記実施例と全く同様の方法で製作され
る。格子パターンの露光には第２図の装置を用い、一方
向の平行縞干渉パターンの露光を行った後、基板16を90
°回転させて再度同じ干渉パターンを露光する。このよ
うにして直交格子パターンを焼付けた後、現像すること
により、第５図に示すように方形の島状にフォトレジス
トＲが残ったマスクが基板１上に形成される。このよう
にして方形島状のパターンの二次元配列よりなるマスク
を形成した後、前述実施例と同じ反応性イオンビームエ
ッチングにより島状部分以外の部分をエッチングして直
交格子溝の基底面を形成し、フォトレジストの島の部分
を凸部Ｐとして残し、直交格子を得る。This grating is manufactured in exactly the same way as in the previous embodiment. The apparatus shown in FIG. 2 is used for exposure of the lattice pattern.
Rotate by ° to expose the same interference pattern again. After baking the orthogonal lattice pattern in this manner, by developing, a mask in which the photoresist R is left in a rectangular island shape is formed on the substrate 1 as shown in FIG. After forming a mask consisting of a two-dimensional array of square island patterns in this manner, the base portions of the orthogonal lattice grooves are formed by etching the portions other than the island portions by the same reactive ion beam etching as in the previous embodiment. Then, an orthogonal lattice is obtained by leaving the island portions of the photoresist as the projections P.
（発明の効果） 本発明によれば、格子パターンがホログラフィック露
光法によって形成された干渉パターンを密着転写したも
のであるから、機械的原因による格子ピッチの誤差がな
く、溝断面が凹字状に形成されて凸部上面も溝底も共に
平面であり、溝深さが10Å程度の精度で蝕刻され、溝岸
が切立った形に形成されるので、きわめて高密度でかつ
水平方向および垂直方向の測定に対して同時に基準とな
し得る格子板が得られる。(Effects of the Invention) According to the present invention, since the grating pattern is obtained by closely transferring the interference pattern formed by the holographic exposure method, there is no error in the grating pitch due to mechanical causes, and the groove cross section is concave. Both the upper surface of the projection and the bottom of the groove are flat, the groove depth is etched with an accuracy of about 10 mm, and the groove shore is formed sharp, so it is extremely dense and horizontal and vertical A grid plate is obtained which can simultaneously serve as a reference for the direction measurement.
第１図は本発明により得られる格子板の一実施例の拡大
斜視図、第２図は本発明の一実施例で用いられるホログ
ラフィック光学系の平面図、第３図は上記実施例の格子
製造課程を示す図、第４図は本発明の他の実施例格子の
格子面の斜視図、第５図はこの実施例における基板上に
形成されたレジストパターンの斜視図である。 １……ガラス基板、２……フォトレジスト、３……溝、
10……レーザー、13……スペシャルフィルタ、14……放
物面鏡、16……基板。FIG. 1 is an enlarged perspective view of one embodiment of a grating plate obtained by the present invention, FIG. 2 is a plan view of a holographic optical system used in one embodiment of the present invention, and FIG. FIG. 4 is a perspective view of a grating surface of a grating according to another embodiment of the present invention, and FIG. 5 is a perspective view of a resist pattern formed on a substrate in this embodiment. 1 ... Glass substrate, 2 ... Photoresist, 3 ... Groove,
10 ... laser, 13 ... special filter, 14 ... parabolic mirror, 16 ... substrate.
Claims (1)
ンを基板上のレジスト層に焼付け、レジスト層を現像
後、上記干渉パターンに応じて形成される格子状レジス
トパターンをマスクとして基板を反応性イオンビームエ
ッチングによって凸部上面と基底面が夫々平面であるよ
うにエッチングして形成された格子板であって、同じ寸
法，同じ高さの凸部が基底面から段状に立上がってお
り、一定間隔で格子状に配置され、各凸部の上面と凸部
周囲の基底面とが共に、格子板面に平行な平面で、格子
ピッチが1mmの数百乃至数千分の一であり、凸部高さが1
0オングストローム程度の精度を持っている、走査型電
子顕微鏡，トンネル走査型顕微鏡等の深さ方向および横
方向の倍率或は像の寸法等の測定用基準格子板。An interference pattern is baked on a resist layer on a substrate by a holographic exposure method, and after developing the resist layer, the substrate is subjected to reactive ion beam etching using a lattice resist pattern formed in accordance with the interference pattern as a mask. Is a lattice plate formed by etching such that the upper surface of the convex portion and the base surface are respectively flat, and the convex portions having the same dimensions and the same height stand up from the base surface in a stepped manner, and are arranged at regular intervals. Arranged in a lattice shape, both the upper surface of each convex portion and the basal surface around the convex portion are planes parallel to the lattice plate surface, and the lattice pitch is hundreds to several thousandths of 1 mm, and the convex portion height is Saga 1
A reference grating plate having a precision of about 0 angstroms, such as a scanning electron microscope or a tunnel scanning microscope, for measuring the magnification in the depth direction and the lateral direction or the size of an image.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP10120789 | 1989-04-19 | ||
| JP1-101207 | 1989-04-19 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0367101A JPH0367101A (en) | 1991-03-22 |
| JP2920990B2 true JP2920990B2 (en) | 1999-07-19 |
Family
ID=14294478
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2023435A Expired - Fee Related JP2920990B2 (en) | 1989-04-19 | 1990-01-31 | Reference grating plate for measuring magnification or image size in the depth direction and lateral direction of scanning electron microscope, tunnel scanning microscope, etc. |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2920990B2 (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4801518B2 (en) * | 2006-07-07 | 2011-10-26 | 株式会社日立ハイテクノロジーズ | Charged particle beam microscopic method and charged particle beam apparatus |
| JP4968721B2 (en) * | 2006-09-21 | 2012-07-04 | Ｈｏｙａ株式会社 | Flatness measuring device calibration reference plate |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS63150984A (en) * | 1986-12-15 | 1988-06-23 | Sharp Corp | Forming method for diffraction grating |
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1990
- 1990-01-31 JP JP2023435A patent/JP2920990B2/en not_active Expired - Fee Related
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| JPH0367101A (en) | 1991-03-22 |
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