Claims
- 1. A method of fabricating halftone phase shift photomask blank having a halftone phase shift layer on a substrate deemed to have 100% transmittance, the transmittance of said halftone phase shift layer being variable within the range of 1% to 50%, inclusive, said method comprising:
- forming a material for said phase shift layer such that its transmittance with respect to exposure light has a specific value
- forming said phase shift photomask blank using the formed material; and
- changing the transmittance of the material for the halftone phase shift layer to a desired transmittance value.
- 2. The method of claim 1, wherein said changing step includes exposing said halftone phase shift material to a temperature of at least 150.degree. C. and less than 450.degree. C.
- 3. The method of claim 1, wherein said changing step includes exposing said halftone phase shift material to an oxidizing atmosphere.
- 4. The method of claim 1, wherein said changing step includes exposing said halftone phase shift material to a reducing atmosphere.
- 5. The method of claim 1, wherein in said forming step, said halftone phase shift material is composed mainly of a chromium compound.
- 6. A method of fabricating the halftone phase shift photomask having a halftone phase shift portion on a substrate deemed to have 100% transmittance, the transmittance of said halftone phase shift portion being variable within the range 1%-50%, inclusive, said method comprising:
- forming a material for said phase shift portion;
- forming a photomask blank including said formed material;
- forming a photomask from said photomask blank; and
- changing the transmittance of the material for the halftone phase shift portion to a desired transmittance, wherein said changing step can be performed before, after, or concurrent with said step for forming a photo mask from the photomask blank.
- 7. The method of claim 6, wherein said changing step includes exposing said halftone phase shift material to a temperature of at least 150.degree. C. and less than 450.degree. C.
- 8. The method of claim 6, wherein said changing step includes exposing said halftone phase shift material to an oxidizing atmosphere.
- 9. The method of claim 6, wherein said changing step includes exposing said halftone phase shift material to a reducing atmosphere.
- 10. The method of claim 6, wherein in said forming step, said halftone phase shift material is composed mainly of a chromium compound.
Priority Claims (1)
Number |
Date |
Country |
Kind |
5-188586 |
Jul 1993 |
JPX |
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Parent Case Info
This is a divisional of application No. 08/282,465, filed Aug. 1, 1994, U.S. Pat. No. 5,614,335.
US Referenced Citations (3)
Divisions (1)
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Number |
Date |
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Parent |
282465 |
Aug 1994 |
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