Claims
- 1. A photomask incorporated in an exposure apparatus which has a light source for illuminating said photomask and a lens system for converging a light passed through said photomask onto a resist film provided on a workpiece, said photomask comprising:
- a transparent substrate;
- a light shielding pattern formed at one major surface side of said transparent substrate; and
- a high reflection film formed at one major surface side of said transparent substrate for multiple-reflecting part of light passing between adjacent regions of said light shielding pattern,
- the following conditions being satisfied; ##EQU7## D.ltorsim.DOF where d.sub.2 and n.sub.2 represent, respectively, a thickness and a refractive index of said high reflection film, n.sub.4 represents a refractive index of said resist film, m represents a magnification of said lens system, DOF represents a depth of focus of said lens system with respect to transmitted light through said high refection film, and D represents a distance between respective focal points of said lens system with respect to said directly transmitted light through said high reflection film and primary reflected light by said high reflection film.
- 2. A photomask in accordance with claim 1, wherein said high reflection film is formed on one major surface of said transparent substrate, and said light shielding pattern is formed on said high reflection film.
- 3. A photomask in accordance with claim 2, wherein an antireflection film is further formed on said light shielding pattern.
- 4. A photomask in accordance with claim 3, wherein said antireflection film is formed of chromium oxide.
- 5. A photomask in accordance with claim 2, wherein an antireflection film is further formed between said light shielding pattern and said high reflection film, said antireflection film having the same form as said light shielding pattern.
- 6. A photomask in accordance with claim 5, wherein said antireflection film is formed of chromium oxide.
- 7. A photomask in accordance with claim 1, wherein said light shielding pattern in formed on one major surface of said transparent substrate, and said high reflection film is formed on one major surface of said transparent substrate to cover said light shielding pattern.
- 8. A photomask in accordance with any of claim 1, 2 or 7, wherein said transparent substrate is formed of quartz, and said high reflection film is formed of lead glass.
- 9. A photomask in accordance with any of claims 1, 2 or 7, wherein an antireflection film is further formed on the other major surface of said transparent substrate.
- 10. A photomask in accordance with claim 9, wherein said antireflection film is formed of MgF.sub.2.
- 11. A photomask incorporated in an exposure apparatus which has a light source for illuminating said photomask and a lens system for converging a light passed through said photomask onto a resist film provided on a workpiece, said photomask comprising:
- a transparent substrate;
- a light shielding pattern formed at one major surface side of said transparent substrate; and
- a high reflection film formed entirely over one major surface side of said transparent substrate, for multiple-reflecting part of light passing between adjacent regions of said light shielding pattern,
- the following conditions being satisfied; ##EQU8##
- D.ltorsim.DOF
- where d.sub.2 and n.sub.2 represent, respectively, a thickness and a refractive index of said high refection film, n.sub.4 represents a refractive index of said resist film, m represents a magnification of said lens system, DOF represents a depth of focus of said lens system with respect to transmitted light through said high reflection film, and D represents a distance between respective focal points of said lens system with respect to said directly transmitted light through said high reflection film and primary reflected light by said high reflection film.
- 12. The photomask in accordance with claim 11, wherein said high reflection film is formed on one major surface of said transparent substrate, and said light shielding pattern is formed on said high reflection film.
- 13. The photomask in accordance with claim 12, wherein an antireflection film is further formed on said light shielding pattern.
- 14. The photomask in accordance with claim 13, wherein said antireflection film is formed of chromium oxide.
- 15. The photomask in accordance with claim 12, wherein an antireflection film is further formed between said light shielding pattern and said high reflection film in correspondence to said light shielding pattern.
- 16. The photomask in accordance with claim 15, wherein said antireflection film is formed on chromium oxide.
- 17. The photomask in accordance with claim 11, wherein said light shielding pattern is formed on one major surface of said transparent substrate, and said high reflection film is formed on one major surface of said transparent substrate to cover said light shielding pattern.
- 18. The photomask in accordance with any of claims 11, 12 or 17, wherein said transparent substrate is formed of quartz, and said high reflection film is fomred of lead glass.
- 19. The photomask in accordance with any one of claims 11, 12 or 17, wherein an antireflection film is further formed on the other major surface of said transparent substrate.
- 20. The photomask in accordance with claim 19, wherein said antireflection film is formed of MgF.sub.2.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2-197474 |
Jul 1990 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 07/611,912, filed on Nov. 13, 1990, now abandoned.
US Referenced Citations (4)
Foreign Referenced Citations (5)
Number |
Date |
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0121441 |
Sep 1980 |
JPX |
0110939 |
Sep 1981 |
JPX |
0167025 |
Oct 1982 |
JPX |
62-67514 |
Mar 1987 |
JPX |
0214859 |
Aug 1989 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
611912 |
Nov 1990 |
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