JPH0713565B2 - Mask alignment method - Google Patents
Mask alignment methodInfo
- Publication number
- JPH0713565B2 JPH0713565B2 JP61222599A JP22259986A JPH0713565B2 JP H0713565 B2 JPH0713565 B2 JP H0713565B2 JP 61222599 A JP61222599 A JP 61222599A JP 22259986 A JP22259986 A JP 22259986A JP H0713565 B2 JPH0713565 B2 JP H0713565B2
- Authority
- JP
- Japan
- Prior art keywords
- single crystal
- wafer
- mask
- substrate
- mask 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 - Lifetime
Links
- 238000000034 method Methods 0.000 title claims description 18
- 239000013078 crystal Substances 0.000 claims description 32
- 239000000758 substrate Substances 0.000 claims description 28
- 230000001678 irradiating effect Effects 0.000 claims 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- 238000001015 X-ray lithography Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
- 238000013519 translation Methods 0.000 description 1
- 238000002424 x-ray crystallography Methods 0.000 description 1
Landscapes
- Length-Measuring Devices Using Wave Or Particle Radiation (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
- Container, Conveyance, Adherence, Positioning, Of Wafer (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
Description
【発明の詳細な説明】 （イ） 産業上の利用分野 本発明は超LSI等の製造工程で利用されるリソグラフイ
ー技術に関し、特に、マスク位置合わせ方法に関するも
のである。DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a lithographic technique used in a manufacturing process of VLSI and the like, and more particularly to a mask alignment method.
（ロ） 従来の技術 半導体製造分野において1/4μｍ程度のスケールで微細
加工を行なう際の問題点はマスクの位置合せである。従
来は、1986年（昭和61年）春季第33回応用物理学関係連
合講演会講演予稿集P326所載の「Ｘ線リソグラフイー用
高精度位置合わせ法」と題する論文に記載されている如
く、マスクに付けた適当なマーク、ゾーンプレートや回
折格子にレーザー光を当ててその干渉光を観測してマス
クの位置合わせを行なうようにしている。(B) Conventional Technology In the field of semiconductor manufacturing, a problem when performing microfabrication on a scale of about 1/4 μm is mask alignment. Previously, as described in the paper entitled "High-precision registration method for X-ray lithography" published in Proceedings of the 33rd Joint Lecture Meeting on Applied Physics in Spring 1986 (1986), P326, Laser light is applied to appropriate marks, zone plates and diffraction gratings attached to the mask, and the interference light is observed to align the mask.
（ハ） 発明が解決しようとする問題点 この従来方法では0.01μｍ程度の高精度の位置合わせは
容易ではない。ところがサブミクロンの微細加工を行な
うには数種類のパターンを重ねて転写する必要があり、
マスクの位置合わせ精度として0.01μｍ程度の高いもの
が要求される。位置の自由度としてマスク面内の回転即
ち方位と、更に面に並行な２方向の並進の計３つの自由
度があり、３つ共正確に制御する必要があるＸ線リソグ
ラフイーを実用化するために、現在よりも精度の高い位
置合わせ方法の出現が待たれている。(C) Problems to be Solved by the Invention With this conventional method, highly accurate alignment of about 0.01 μm is not easy. However, in order to perform submicron fine processing, it is necessary to transfer several types of patterns in an overlapping manner,
The mask alignment accuracy is required to be as high as 0.01 μm. As a degree of freedom of position, there are a total of three degrees of freedom, that is, rotation or azimuth in the mask plane and translation in two directions parallel to the plane. Practical use of X-ray lithography that requires precise control of all three Therefore, the emergence of a more accurate alignment method than the present is awaited.
（ニ） 問題点を解決するための手段 本発明はマスクの基板として良質の単結晶が使えること
に着目し、上述の問題点のうち方位と並進の自由度を分
離して考え、Ｘ線のブラツグ反射現象を用いてマスクの
方位のみを正確に決める方法を提供するもので、本発明
は、単色平面波Ｘ線を単結晶マスク基板と該単結晶マス
ク基板上のパターンが転写されるウエハーに照射するプ
ロセスと、前記単結晶マスク基板と前記ウエハーとから
それぞれブラツグ反射した両Ｘ線の干渉によるモアレ像
を観測するプロセスを有するマスク位置合わせ方法であ
る。(D) Means for Solving the Problems Focusing on the fact that a high-quality single crystal can be used as a mask substrate in the present invention, the orientation and translational degrees of freedom among the above problems are considered separately, and The present invention provides a method for accurately determining only the orientation of a mask by using the Bragg reflection phenomenon. The present invention irradiates a single crystal plane wave X-ray on a single crystal mask substrate and a wafer onto which a pattern on the single crystal mask substrate is transferred. And a process for observing a moire image due to the interference of both X-rays reflected by the Bragg reflection from the single crystal mask substrate and the wafer.
（ホ） 作用 単結晶マスク基板とウエハーに単色平面波Ｘ線を照射
し、単結晶マスク基板によりブラツグ反射したＸ線と、
ウエハーによりブラツク反射したＸ線とが干渉してでき
るモアレ像を観測する。モアレ縞の方向は格子面（間隔
ｄ）に直角方向であり、縞間隔（Ｓ）は両結晶の方位角
のずれ（α）に反比例し、Ｓ＝d/αの関係がある（仁田
勇監修「Ｘ線結晶学」（丸善）上巻第641頁（9.2）式参
照）従って、方位が完全に一致した場合、縞間隔は無限
大になり縞模様は消滅する。Ｘ線強度が充分な時にはテ
レビカメラ等を用いてモアレ像を直視すれば結晶の方位
を正確にかつリアルタイムで検出できる。縞模様から角
度αも定量的に決定できる。(E) Action The single crystal mask substrate and the wafer are irradiated with monochromatic plane wave X-rays, and the X-rays are reflected by the single crystal mask substrate by Bragg reflection
Observe the moire image formed by the interference with the X-rays reflected by the wafer. The direction of the moire fringes is perpendicular to the lattice plane (spacing d), and the fringe spacing (S) is inversely proportional to the azimuthal deviation (α) of both crystals, and has a relationship of S = d / α (edited by Isa Nita) Therefore, when X-ray crystallography (Maruzen), Vol. 1, Vol. 641, p. 9.2, formula 9.2) is satisfied, the fringe spacing becomes infinite and the fringes disappear. When the X-ray intensity is sufficient, the crystal orientation can be detected accurately and in real time by directly looking at the moire image using a television camera or the like. The angle α can also be quantitatively determined from the striped pattern.
（ヘ） 実施例 第１図は本発明方法を実施する装置の概略構成を示す。
同図において、（１）は単色平面波Ｘ線（２）を発生す
るＸ線源、（３）はマスクパターンを支持するシリコン
単結晶（格子定数5.4301Å）からなる単結晶マスク基
板、（４）はマスクパターンが転写されるシリコン半結
晶からなるウエハー、（５）は単結晶マスク基板（３）
からブラツグ反射したＸ線（６）とウエハー（４）から
ブラツグ反射したＸ線（７）とを同時に受けるＸ線検出
器（テレビカメラ、写真乾板またはフイルム等の撮影機
器）、（８）単結晶マスク基板（３）とウエハー（４）
の相対方位を調整するため単結晶マスク基板（３）の位
置制御を行なう調整手段、（９）はＸ線検出器（５）出
力を調整手段（８）に付与し上記両Ｘ線のモアレ縞の縞
間陥（ｓ）を最大にするように該調整手段（８）を制御
する制御手段である。(F) Example FIG. 1 shows a schematic configuration of an apparatus for carrying out the method of the present invention.
In the figure, (1) is an X-ray source for generating monochromatic plane wave X-rays (2), (3) is a single crystal mask substrate made of silicon single crystal (lattice constant 5.4301Å) supporting a mask pattern, (4) Is a wafer made of silicon semi-crystal to which the mask pattern is transferred, (5) is a single crystal mask substrate (3)
X-ray detector (TV camera, photographic dry plate, film, or other imaging device) that simultaneously receives X-rays (6) black-reflected from the wafer and X-rays (7) black-reflected from the wafer (4), (8) single crystal Mask substrate (3) and wafer (4)
Adjusting means for controlling the position of the single-crystal mask substrate (3) for adjusting the relative orientation of the X-ray detector (5) and the output of the X-ray detector (5) to the adjusting means (8). The control means controls the adjusting means (8) so as to maximize the inter-strip gap (s).
このような装置を構成して、単結晶マスク基板（３）と
ウエハー（４）とにＸ線源（１）からの単色平面波Ｘ線
（２）を照射する。単結晶マスク基板（３）に上記Ｘ線
（２）を照射すると該基板からブラツグ反射したＸ線
（６）が出力され、又ウエハー（４）に上記Ｘ線（２）
を照射すると該ウエハーからブラツグ反射したＸ線
（７）が出力される。これら両Ｘ線（６）（７）が空間
的に重なる領域（10）では両Ｘ線は干渉を起こす。基板
（３）とウエハー（４）の方位が僅かに異なる場合には
回転モアレ像がＸ線検出器（５）にて検出される。この
モアレ像の間隔（ｓ）は結晶の方位のずれによって敏感
に変化する。この縞模様の間隔（ｓ）が最大になるよう
に調整手段（８）を調整することにより正確な方位調節
が可能である。The single crystal mask substrate (3) and the wafer (4) are irradiated with monochromatic plane wave X-rays (2) from the X-ray source (1) by configuring such an apparatus. When the single crystal mask substrate (3) is irradiated with the X-ray (2), the X-ray (6) reflected by the Bragg is output from the substrate, and the wafer (4) is irradiated with the X-ray (2).
Is irradiated, X-rays (7) reflected by the Bragg are output from the wafer. In the region (10) where these X-rays (6) and (7) spatially overlap, both X-rays cause interference. When the orientations of the substrate (3) and the wafer (4) are slightly different, the rotational moire image is detected by the X-ray detector (5). The interval (s) of the moire image is sensitively changed by the deviation of the crystal orientation. Accurate azimuth adjustment is possible by adjusting the adjusting means (8) so that the interval (s) of the striped pattern becomes maximum.
次に本発明の具体的実施例を数値を挙げて説明する。Ｘ
線源（１）として例えばモリブデンターゲツトを用いた
回転対陰極型Ｘ線管からのMo−Ｋα線（波長λ＝0.7093
Å）をモノクロメーターで単色平面波としたものを用い
る。単結晶マスク基板（３）として100シリコンウエハ
ーを用いる場合を例にとる。基板面に垂直に110格子面
があるのでその面の220反射を使用する。Mo−Ｋα線の
場合、ブラツグ角はθＢ＝10.65度である。波長は２枚
のシリコンを透過するものであればよくMo−Ｋα線に限
らない。0.5〜１Å程度であれば充分である。220反射の
面間隔はｄ＝1.92Åであるから２枚の結晶の方位のずれ
がα＝0.1秒（4.85×10-7ラジアン）の場合には、間隔
（ｓ）が約0.4mmの平行な干渉縞が現れる。Next, specific examples of the present invention will be described with numerical values. X
Mo-Kα rays (wavelength λ = 0.7093) from a rotating anticathode X-ray tube using, for example, a molybdenum target as the radiation source (1).
Å) is a monochromatic plane wave with a monochromator. The case where a 100 silicon wafer is used as the single crystal mask substrate (3) is taken as an example. Since there are 110 lattice planes perpendicular to the substrate plane, we use 220 reflections on that plane. In the case of Mo-Kα rays, the Bragg angle is θ B = 10.65 degrees. The wavelength is not limited to Mo-Kα rays as long as it can pass through two silicon sheets. About 0.5 to 1Å is sufficient. Since the surface spacing of 220 reflections is d = 1.92Å, if the misorientation of the two crystals is α = 0.1 seconds (4.85 × 10 -7 radian), the spacing (s) is approximately 0.4 mm, and Interference fringes appear.
２枚の理想的に完全な基板結晶を全面照射した場合、第
２図に示す様な縞模様が現れる。ここで、中央の縞模様
が現われていない領域（11）が単結晶マスク基板（３）
上のパターン形成部に対応している。実際の基板にはマ
スクパターンを設けたために導入される格子歪みや、も
ともと結晶中に何がしかの歪みが存在するため干渉縞は
乱れる場合が多い。When two ideally perfect substrate crystals are irradiated over the entire surface, a striped pattern as shown in FIG. 2 appears. Here, the region (11) where the central striped pattern does not appear is the single crystal mask substrate (3).
It corresponds to the upper pattern forming part. In many cases, the interference fringes are disturbed because the lattice distortion introduced by the provision of the mask pattern on the actual substrate and some distortion originally existing in the crystal.
しかし、２枚の基板結晶（マスク基板とウエハー）の方
位が完全に一致する場合に最も広くなり方位がどこで一
致するかは容易に判定できる。However, when the orientations of the two substrate crystals (mask substrate and wafer) completely coincide with each other, it becomes widest, and it can be easily determined where the orientations coincide.
（ト） 発明の効果 本発明は以上の説明から明らかな如く、マスク基板とし
て単結晶を使用し結晶格子面から反射するＸ線の干渉に
よるモアレ像を観察するのでマスク基板の方位を極めて
正確に検出し位置合わせに利用できる。現在のアライナ
ーやステツパーに利用すれば0.01μｍ以下の微細加工用
アライナーの方位調節の問題が解決する。この方法で方
位が正確に決まれば、並進の位置合わせに使用するマー
クは１個で足り、従来のアライナーの様に複数個（例え
ば４隅に）使用してそれらからの信号を処理するという
ような煩わしさから解放される。(G) Effect of the Invention As is apparent from the above description, the present invention uses a single crystal as a mask substrate and observes a moire image due to interference of X-rays reflected from the crystal lattice plane, so that the orientation of the mask substrate can be extremely accurately determined. It can be used for detection and alignment. If it is used for current aligners and steppers, the problem of orientation adjustment of fine processing aligners of 0.01 μm or less can be solved. If the azimuth is accurately determined by this method, only one mark is required for translational alignment, and a plurality of marks (for example, four corners) are used like a conventional aligner to process signals from them. Free from the hassle.
第１図は本発明方法を実施する装置の概略構成図、第２
図は２枚のシリコン単結晶を透過したＸ線の干渉によっ
てできる回転モアレ像の模式図である。 （１）……Ｘ線源、（３）……単結晶マスク基板、
（４）……ウエハー、（６）（７）……回折Ｘ線、（1
0）……モアレが現れる領域、（５）……Ｘ線検出器、
（８）……調整手段FIG. 1 is a schematic configuration diagram of an apparatus for carrying out the method of the present invention, and FIG.
The figure is a schematic diagram of a rotational moire image formed by interference of X-rays transmitted through two silicon single crystals. (1) …… X-ray source, (3) …… Single crystal mask substrate,
(4) …… Wafer, (6) (7) …… Diffraction X-ray, (1
0) ... Area where moire appears, (5) ... X-ray detector,
(8) …… Adjustment means
フロントページの続き (51)Int.Cl.6 識別記号 庁内整理番号 ＦＩ 技術表示箇所 Ｈ０１Ｌ 21/68 Ｆ Continuation of front page (51) Int.Cl. 6 Identification code Office reference number FI Technical display area H01L 21/68 F
Claims (2)
結晶マスク基板上のパターンが転写されるウエハーに照
射するプロセスと、前記単結晶マスク基板と前記ウエハ
ーとからそれぞれブラツグ反射した両Ｘ線の干渉による
モアレ像を観測するプロセスを有するマスク位置合わせ
方法。1. A process of irradiating a monochromatic plane wave X-ray onto a single crystal mask substrate and a wafer onto which a pattern on the single crystal mask substrate is transferred, and both Xs which are Bragg-reflected from the single crystal mask substrate and the wafer, respectively. A mask alignment method having a process of observing a moiré image due to line interference.
置合わせ方法において、前記観測プロセスによる観測結
果を、前記単結晶プロセス基板と前記ウエハーの相対方
位を制御する手段に付与するプロセスを備えることを特
徴とするマスク位置合わせ方法。2. The mask alignment method according to claim 1, further comprising a step of applying the observation result of the observation process to a means for controlling the relative orientation of the single crystal process substrate and the wafer. A method for aligning a mask, comprising:
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61222599A JPH0713565B2 (en) | 1986-09-19 | 1986-09-19 | Mask alignment method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61222599A JPH0713565B2 (en) | 1986-09-19 | 1986-09-19 | Mask alignment method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6378016A JPS6378016A (en) | 1988-04-08 |
| JPH0713565B2 true JPH0713565B2 (en) | 1995-02-15 |
Family
ID=16784997
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61222599A Expired - Lifetime JPH0713565B2 (en) | 1986-09-19 | 1986-09-19 | Mask alignment method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0713565B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5168513A (en) * | 1991-10-11 | 1992-12-01 | International Business Machines Corporation | X-ray metrology and alignment detection system |
| FR2755298B1 (en) * | 1996-10-30 | 1999-02-26 | Commissariat Energie Atomique | METHOD AND DEVICE FOR PRECISE POSITIONING OF MONOCRYSTALLINE OBJECTS IN RELATION TO OTHERS ACCORDING TO THEIR CRYSTALLOGRAPHIC PLANS |
| GB2356786B (en) | 1999-11-29 | 2003-09-03 | Marconi Electronic Syst Ltd | Method and apparatus for aligning a crystalline substrate |
| GB2371731B (en) | 2001-01-23 | 2004-07-14 | Marconi Caswell Ltd | Method of alignment |
| US7344307B2 (en) * | 2004-11-12 | 2008-03-18 | General Electric Company | System and method for integration of a calibration target into a C-arm |
-
1986
- 1986-09-19 JP JP61222599A patent/JPH0713565B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6378016A (en) | 1988-04-08 |
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