JP2909317B2 - Photo mask - Google Patents
Photo maskInfo
- Publication number
- JP2909317B2 JP2909317B2 JP22135192A JP22135192A JP2909317B2 JP 2909317 B2 JP2909317 B2 JP 2909317B2 JP 22135192 A JP22135192 A JP 22135192A JP 22135192 A JP22135192 A JP 22135192A JP 2909317 B2 JP2909317 B2 JP 2909317B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- resist
- pattern
- photomask
- etching
- 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
Landscapes
- Preparing Plates And Mask In Photomechanical Process (AREA)
- Weting (AREA)
Description
【０００１】[0001]
【産業上の利用分野】この発明は、一般にフォトマスク
に関するものであり、より特定的には、レジストパター
ン寸法に忠実に加工された精度の高いフォトマスクに関
する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a photomask, and more particularly, to a high-precision photomask faithfully processed to a resist pattern dimension.
【０００２】[0002]
【従来の技術】フォトマスク上の拡大パターンをウェハ
上に縮小して繰返し結像させ、所望のＬＳＩパターンを
形成するフォトリソグラフィ技術は、従来より、よく知
られている。2. Description of the Related Art A photolithography technique for forming a desired LSI pattern by reducing an enlarged pattern on a photomask on a wafer and repeatedly forming an image thereon has been well known.
【０００３】図３は、従来のフォトマスクの基板を作成
する原理を断面図で示したものである。FIG. 3 is a sectional view showing the principle of producing a conventional photomask substrate.
【０００４】図３（ａ）を参照して、合成石英基板１の
表面上に、遮光パターンとなる、たとえばクロムからな
る金属膜６を、蒸着等により形成する。金属膜６の上
に、たとえば有機高分子材料からなる電子線レジスト３
を、スピンコーティング等の方法を用いて、成膜する。Referring to FIG. 3A, a metal film 6 made of, for example, chromium, serving as a light-shielding pattern, is formed on the surface of synthetic quartz substrate 1 by vapor deposition or the like. An electron beam resist 3 made of, for example, an organic polymer material is formed on the metal film 6.
Is formed using a method such as spin coating.
【０００５】図３（ｂ）を参照して、電子線レジスト３
を、電子線露光機を用いて選択的に露光する。その後、
電子線レジスト３を現像することにより、レジストパタ
ーン４を形成する。Referring to FIG. 3B, electron beam resist 3
Is selectively exposed using an electron beam exposure machine. afterwards,
A resist pattern 4 is formed by developing the electron beam resist 3.
【０００６】図３（ｃ）を参照して、レジストパターン
４をマスクとして、金属膜６を、たとえば塩素等のガス
を用いたドライエッチングで加工し、所望のマスクパタ
ーン７を形成する。Referring to FIG. 3C, using the resist pattern 4 as a mask, the metal film 6 is processed by dry etching using a gas such as chlorine to form a desired mask pattern 7.
【０００７】図３（ｃ）および（ｄ）を参照して、酸素
プラズマ等でレジストパターン４を除去し、それによっ
てフォトマスク１０を作成する。なお、上記従来例で
は、金属膜にクロムを用いた場合を例示したが、ＭｏＳ
ｉ等の他の金属が用いられることもある。Referring to FIGS. 3C and 3D, the resist pattern 4 is removed by oxygen plasma or the like, thereby forming a photomask 10. In the above conventional example, the case where chromium is used for the metal film is illustrated.
Other metals such as i may be used.
【０００８】また、金属膜の加工に塩素ガスを用いるド
ライエッチング法を例示したが、硝酸セリウムアンモニ
ウム水溶液等のエッチング液でエッチングを行なう、ウ
ェットエッチング法を用いることもある。Although the dry etching method using chlorine gas for processing the metal film has been exemplified, a wet etching method in which etching is performed using an etching solution such as an aqueous cerium ammonium nitrate solution may be used.
【０００９】[0009]
【発明が解決しようとする課題】従来のフォトマスクの
作成原理は以上のとおりであるが、実際にこの原理に基
づいてフォトマスクを製造すると、図４に示すような問
題点があった。The principle of manufacturing a conventional photomask is as described above. However, when a photomask is actually manufactured based on this principle, there is a problem as shown in FIG.
【００１０】すなわち、図４を参照して、レジスト４を
マスクに金属膜６を、ウェットエッチングやガス圧が
０．１Ｔｏｒｒ以上のドライエッチングを行なうと、等
方的にエッチングが進み、レジスト４の下部の金属膜６
をエッチングされてしまい、レジストの寸法が忠実に反
映されず、遮光パターンの寸法変動が生じるという問題
点があった。この寸法変動は、金属膜７の両端でそれぞ
れ膜厚分起こるため、片側で約０．１μｍ寸法変動が生
じるとすれば、両側あわせて、約０．２μｍとなり、無
視できない値となる。That is, referring to FIG. 4, when the metal film 6 is subjected to wet etching or dry etching at a gas pressure of 0.1 Torr or more using the resist 4 as a mask, the etching proceeds isotropically, Lower metal film 6
Is etched, the dimensions of the resist are not faithfully reflected, and the dimensions of the light-shielding pattern vary. Since this dimensional variation occurs by the film thickness at both ends of the metal film 7, if a dimensional variation of about 0.1 μm occurs on one side, it will be about 0.2 μm on both sides, which is a value that cannot be ignored.
【００１１】この発明は、上記のような問題点を解決す
るためになされたもので、初期のレジストパターン寸法
に忠実に加工された精度の高いフォトマスクを得ること
を目的とする。SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to obtain a highly accurate photomask which is faithfully processed to the initial resist pattern dimensions.
【００１２】[0012]
【課題を解決するための手段】この発明に係るフォトマ
スクは、透明基板と、上記透明基板の上に設けられた、
金属シリサイドを含む材料からなる遮光パターンと、を
備える。上記遮光パターン中における酸素含有率は、該
遮光パターンの下層部から上層部に向けて連続的に増大
している。 A photomask according to the present invention comprises: a transparent substrate; and a photomask provided on the transparent substrate.
A light-shielding pattern made of a material containing metal silicide. The oxygen content in the light-shielding pattern is
Continuously increases from the lower part to the upper part of the shading pattern
doing.
【００１３】[0013]
【作用】上述の構造を有する遮光パターンは、基板の上
に設けられた、酸素含有率がその下層部から上層部に向
けて連続的に増大している遮光金属膜をエッチングする
ことによって得られる。このような遮光金属膜において
は、エッチングが横方向に進むよりも、深さ方向に速く
進むため、結果として異方的なエッチングが可能とな
り、初期のレジスト寸法が忠実に反映された遮光パター
ンとなる。The light-shielding pattern having the above-mentioned structure is provided on the substrate.
The oxygen content ratio is increased from the lower layer to the upper layer.
The continuously increasing light-shielding metal film
Obtained by: In such a light-shielding metal film,
Is faster in the depth direction than in the etching direction
As a result, anisotropic etching becomes possible as a result.
As a result, a light-shielding pattern faithfully reflects the initial resist dimensions.
【００１４】[0014]
【実施例】以下、この発明の一実施例を図について説明
する。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.
【００１５】図１は、この発明の一実施例に係るフォト
マスクの製造方法の順序の各工程における基板の断面図
である。FIG. 1 is a cross-sectional view of a substrate in each step of a method of manufacturing a photomask according to an embodiment of the present invention.
【００１６】図１（ａ）を参照して、合成石英基板１の
主表面上に、後に遮光パターンとなる、たとえばＭｏＳ
ｉからなる遮光膜２を、スパッタ法等により、約０．１
μｍ蒸着法により形成する。このとき、蒸着中に、雰囲
気中の酸素（Ｏ2 ）圧力を、連続的に増加させ、膜の下
層部に対して、上層部の方が含有酸素濃度が高くなるよ
うに成膜する。Referring to FIG. 1A, on the main surface of synthetic quartz substrate 1, for example, MoS
The light-shielding film 2 made of i.
It is formed by a μm evaporation method. At this time, during the vapor deposition, the oxygen (O 2 ) pressure in the atmosphere is continuously increased, and the film is formed such that the oxygen concentration in the upper layer is higher than that in the lower layer of the film.
【００１７】遮光膜２の上に、たとえば、ポリメチルメ
タクリレートからなる電子線レジスト材を、たとえば溶
剤に溶かして、回転している基板１上に約５ｍｌ滴下
し、乾燥させる。これによって、約０．５μｍの膜厚の
レジスト膜３を成膜する。On the light-shielding film 2, an electron beam resist material made of, for example, polymethyl methacrylate is dissolved in a solvent, for example, and about 5 ml is dropped on the rotating substrate 1 and dried. Thus, a resist film 3 having a thickness of about 0.5 μm is formed.
【００１８】図１（ｂ）を参照して、レジスト膜３に向
けて、電子線露光機等で、たとえば２０ｋＶの加速電圧
で、約１００μＣ／ｃｍ2 の電子線を照射することによ
り、レジスト分子を選択的に分解する。その後、溶剤等
で現像することにより、レジストパターン４を形成す
る。Referring to FIG. 1B, an electron beam of about 100 μC / cm 2 is applied to resist film 3 by an electron beam exposure machine or the like at an acceleration voltage of 20 kV, for example. Is selectively decomposed. Thereafter, the resist pattern 4 is formed by developing with a solvent or the like.
【００１９】図１（ｃ）を参照して、レジストパターン
４をマスクにして、たとえば四フッ化炭素（ＣＦ4 ）等
のプラズマを用いて、ＭｏＳｉからなる遮光膜２をドラ
イエッチングし、ＭｏＳｉ金属パターン５を形成する。Referring to FIG. 1C, using the resist pattern 4 as a mask, the light-shielding film 2 made of MoSi is dry-etched using a plasma of, for example, carbon tetrafluoride (CF 4 ). The pattern 5 is formed.
【００２０】図１（ｄ）を参照して、酸素プラズマ等で
レジストパターン４を除去することにより、フォトマス
クを作成する。Referring to FIG. 1D, a photomask is formed by removing the resist pattern 4 using oxygen plasma or the like.
【００２１】この方法によれば、初期のレジスト寸法が
忠実に反映された遮光パターンが得られる。このことに
ついて、図２を用いてさらに詳細に説明する。According to this method, a light-shielding pattern in which the initial resist dimensions are faithfully reflected can be obtained. This will be described in more detail with reference to FIG.
【００２２】図２は、図１（ｃ）に示す工程を、拡大し
て示した断面図である。四フッ化炭素（ＣＦ4 ）等のプ
ラズマを用いたドライエッチングでは、一般的に、等方
的なエッチングが進む。しかし、遮光膜２は、上層部ほ
ど酸素含有率が高くなるように成膜されており、上層部
ほどエッチング速度は遅い。逆に、下層部ほどエッチン
グ速度が速くなっている。このため、エッチングは、横
方向に進むよりも速く、下方向（深さ方向に）に進むた
め、結果として、異方的なエッチングとなり、ひいて
は、レジスト形状に忠実なエッチングが行なわれる。そ
の結果、レジスト４の寸法とＭｏＳｉパターン５の寸法
変動量を小さくすることができる。FIG. 2 is an enlarged cross-sectional view of the step shown in FIG. In dry etching using plasma such as carbon tetrafluoride (CF 4 ), isotropic etching generally proceeds. However, the light-shielding film 2 is formed such that the oxygen content is higher in the upper layer portion, and the etching rate is lower in the upper layer portion. Conversely, the lower the layer, the higher the etching rate. For this reason, the etching proceeds in a downward direction (in the depth direction) faster than in the lateral direction. As a result, anisotropic etching is performed, and etching that is faithful to the resist shape is performed. As a result, the dimension variation of the resist 4 and the dimension variation of the MoSi pattern 5 can be reduced.
【００２３】なお、遮光膜２の膜厚は、このフォトマス
クを用いる際の露光光に対して透過率が１／１０００以
下となればよく、上記の値に限定されない。The thickness of the light-shielding film 2 is not limited to the above value, as long as the transmittance for exposure light when using this photomask is 1/1000 or less.
【００２４】また、上記実施例では、電子線レジスト３
にポリメチルメタクリレートを用いた場合を例示した
が、この発明はこれに限られるものでなく、他の電子線
レジストを用いることも可能であり、また、電子線レジ
ストの代わりにフォトレジストを用いて、感光させ、パ
ターニングすることも可能である。In the above embodiment, the electron beam resist 3
Although the case of using polymethyl methacrylate is exemplified, the present invention is not limited to this, it is also possible to use other electron beam resist, also, using a photoresist instead of the electron beam resist It is also possible to expose and pattern.
【００２５】さらに、上記実施例２では遮光膜２にＭｏ
Ｓｉを用いた場合を例示したが、透過率を減少できる材
料なら、いずれのものも使用できる。In the second embodiment, the light shielding film 2 is made of Mo.
Although the case where Si is used has been exemplified, any material can be used as long as the material can reduce the transmittance.
【００２６】また、上記実施例では、エッチング速度を
変化させる方法として、酸素含有率を変化させる場合を
例示したが、この発明はこれに限られるものでなく、た
とえば、スパッタ時の放電ガスたとえばアルゴンの圧力
を変えて、スパッタ膜の組成を変化させても、実施例と
同様の効果を実現する。Further, in the above-described embodiment, the case where the oxygen content is changed is exemplified as a method of changing the etching rate. However, the present invention is not limited to this. Even if the composition of the sputtered film is changed by changing the pressure, the same effect as that of the embodiment can be realized.
【００２７】[0027]
【発明の効果】以上説明したとおり、この発明に係るフ
ォトマスクによれば、遮光パターンが、基板の上に設け
られた、酸素含有率がその下層部から上層部に向けて連
続的に増大している遮光金属膜をエッチングすることに
よって得られている。このような遮光金属膜において
は、エッチングが横方向に進むよりも、深さ方向に速く
進むため、結果として異方的なエッチングとなり、初期
のレジスト寸法が忠実に反映された遮光パターンとな
る。その結果、レジストパターン寸法に忠実に加工され
た精度の高いフォトマスクが得られる。As described above, according to the present invention, full according to the present invention
According to the photomask, the light shielding pattern is provided on the substrate.
, The oxygen content is linked from the lower layer to the upper layer.
Etching a continuously increasing light-shielding metal film
Therefore, it is obtained. In such a light-shielding metal film,
Is faster in the depth direction than in the etching direction
As a result, anisotropic etching results, resulting in a light-shielding pattern in which the initial resist dimensions are faithfully reflected. As a result, it is possible to obtain a highly accurate photomask that has been faithfully processed to the resist pattern dimensions.
【図１】この発明の一実施例に係るフォトマスクの製造
方法の順序の各工程における基板の断面図である。FIG. 1 is a cross-sectional view of a substrate in each step of an order of a method of manufacturing a photomask according to one embodiment of the present invention.
【図２】初期レジスト寸法が忠実に反映された遮光パタ
ーンが得られる原理を示す断面図である。FIG. 2 is a cross-sectional view illustrating a principle of obtaining a light-shielding pattern in which an initial resist dimension is faithfully reflected.
【図３】従来のフォトマスクの製造方法の順序の各工程
における基板の断面図である。FIG. 3 is a cross-sectional view of a substrate in each step of a conventional photomask manufacturing method.
【図４】従来のフォトマスクの製造方法の問題点を示す
図である。FIG. 4 is a view showing a problem of a conventional photomask manufacturing method.
１ 透明基板 ５ 遮光パターン 1 transparent substrate 5 shading pattern
Claims (1)
材料からなる遮光パターンと、を備え、 前記遮光パターン中における酸素含有率は、該遮光パタ
ーンの下層部から上層部に向けて連続的に増大してい
る、フォトマスク。And 1. A transparent substrate, provided on the transparent substrate, comprising: a light-shielding pattern made of a material containing a metal silicide, the oxygen content in the shielding pattern in the light-shielding pattern
Continually increasing from the lower layer to the upper layer
That, the photo mask.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22135192A JP2909317B2 (en) | 1992-08-20 | 1992-08-20 | Photo mask |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP22135192A JP2909317B2 (en) | 1992-08-20 | 1992-08-20 | Photo mask |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH0669185A JPH0669185A (en) | 1994-03-11 |
| JP2909317B2 true JP2909317B2 (en) | 1999-06-23 |
Family
ID=16765443
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP22135192A Expired - Lifetime JP2909317B2 (en) | 1992-08-20 | 1992-08-20 | Photo mask |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2909317B2 (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007029826A1 (en) * | 2005-09-09 | 2007-03-15 | Hoya Corporation | Photomask blank and production method thereof, and photomask production method, and semiconductor device production method |
| JP6150299B2 (en) | 2014-03-30 | 2017-06-21 | Hoya株式会社 | Mask blank, transfer mask manufacturing method, and semiconductor device manufacturing method |
| JP6292581B2 (en) * | 2014-03-30 | 2018-03-14 | Hoya株式会社 | Mask blank, transfer mask manufacturing method, and semiconductor device manufacturing method |
| JP2020034666A (en) | 2018-08-29 | 2020-03-05 | Hoya株式会社 | Reflective mask blank, reflective mask and method of manufacturing the same, and method of manufacturing semiconductor device |
-
1992
- 1992-08-20 JP JP22135192A patent/JP2909317B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0669185A (en) | 1994-03-11 |
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