Claims
- 1. A method of cleaning a photomask, comprising:a first step of cleaning the surface of a photomask to be used as a master in a photolithography step in a process for the production of a semiconductor device with a hot mixture of sulfuric acid and hydrogen peroxide to decompose organic objects present thereon and to remove metallic impurities; a second step of removing residual sulfuric acid from the surface of said photomask with anodic water, wherein said anodic water is heated to a temperature of not lower than 30° C.; a third step of removing foreign objects attached to the surface of said photomask; and a fourth step of drying said photomask.
- 2. The method of cleaning a photomask according to claim 1, wherein at least one of said first to third steps involves ultrasonic treatment as well.
- 3. The method of cleaning a photomask according to claim 1, wherein said photomask to be cleaned is a quartz substrate on which light shielding film is formed.
- 4. The method of cleaning a photomask according to claim 1, wherein said photomask to be cleaned is half tone mask of a quartz substrate on which semi transparent pattern as a phase shifter is formed.
- 5. The method of cleaning a photomask according to claim 1, wherein said photomask to be cleaned is half tone mask of a quartz substrate on which semi transparent pattern as a phase shifter and light shielding film of metal and metal compound are formed.
- 6. The method of cleaning a photomask according to claim 1, wherein said photomask to be cleaned is a quartz substrate on which light shielding film of metal and metal compound are formed.
- 7. The method of cleaning a photomask according to claim 1, wherein said photomask to be cleaned is a photomask formed by laser trimming.
- 8. The method of cleaning a photomask according to claim 4, wherein said phase shifter comprise a MoSiON film.
- 9. The method of cleaning a photomask according to claim 6, wherein said light shielding film comprise a CrON film.
- 10. A method of cleaning a photomask, comprising:a first step of cleaning a surface of a photomask to be used as a master in a photolithography step in a process for the production of a semiconductor device with a hot mixture of sulfuric acid and hydrogen peroxide to decompose organic objects present thereon and to remove metallic impurities; a second step of removing residual sulfuric acid from the surface of said photomask with anodic water, wherein said anodic water is heated to a temperature of not lower than 30° C.; a third step of removing foreign objects attached to the surface of said photomask with cathodic water; and a fourth step of drying said photomask.
- 11. The method of cleaning a photomask according to claim 10, wherein said cathodic water to be used in said third step contains ammonia.
Priority Claims (1)
Number |
Date |
Country |
Kind |
9-331797 |
Dec 1997 |
JP |
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Parent Case Info
This application is a Divisional of application Ser. No. 09/122,763 filed Jul. 27, 1998, now U.S. Pat. No. 6,076,376.
US Referenced Citations (9)
Foreign Referenced Citations (2)
Number |
Date |
Country |
359195653 |
Nov 1984 |
JP |
411167195 |
May 1999 |
JP |
Non-Patent Literature Citations (1)
Entry |
Nagamura et al. “High Performance photomask cleaning process using electrolyzed water”. Proc. SPIE—Int. Soc. Opt. Eng Photomask & X-Ray Mask Technology V) 395-404, Apr. 1998. |