PHOTOMASK BLANK, PHOTOMASK, AND METHODS OF MANUFACTURING THE SAME

• US 20100075236A1
• Filed: 09/18/2009
• Published: 03/25/2010
• Est. Priority Date: 09/19/2008
• Status: Active Grant

• Current Assignee: Hoya Corporation
• Original Assignee: Hoya Corporation
• Inventors: Mitsui, Hideaki, Hashimoto, Masahiro
• Granted Patent: US 8,048,594 B2
• Time in Patent Office: Days
• US Class Current: 430/5
• CPC Class Codes: G03F 1/32 Attenuating PSM [att-PSM], e.g. halftone PSM or PSM having semi-transparent phase shift portion,; Preparation thereof
• CPC Class Codes: G03F 1/34 Phase-edge PSM, e.g. chromeless PSM; Preparation thereof
• CPC Class Codes: G03F 1/80 Etching

Abstract

A photomask blank is for fabricating a phase shift mask having a light-transmissive substrate provided with a phase shift part adapted to give a predetermined phase difference to transmitted exposure light. The phase shift part is a dug-down part formed by digging down the light-transmissive substrate from a surface thereof to a digging depth adapted to produce the predetermined phase difference with respect to exposure light transmitted through the light-transmissive substrate at a portion where the phase shift part is not provided. The photomask blank includes a light-shielding part formed in a peripheral area around a transfer pattern area of the surface of the light-transmissive substrate and adapted to shield exposure light and further includes an etching mask film formed in the transfer pattern area of the surface of the light-transmissive substrate and made of a material being substantially dry-etchable with a chlorine-based gas, but not substantially dry-etchable with a fluorine-based gas, the etching mask film serving as an etching mask at least until the digging depth is reached when forming the dug-down part.

Claims

1. A photomask blank for fabricating a phase shift mask having a light-transmissive substrate provided with a phase shift part adapted to give a predetermined phase difference to transmitted exposure tight,

wherein said phase shift part is a dug-down part formed by digging down said light-transmissive substrate from a surface thereof to a digging depth adapted to produce the predetermined phase difference with respect to exposure light transmitted through said light-transmissive substrate at a portion where said phase shift part is not provided,

said photomask blank comprising:

a tight-shielding part formed in a peripheral area around a transfer pattern area of the surface of said light-transmissive substrate and adapted to shield exposure light; and

an etching mask film formed in the transfer pattern area of the surface of said light-transmissive substrate and made of a material being substantially dry-etchable with a chlorine-based gas, but not substantially dry-etchable with a fluorine-based gas, said etching mask film serving as an etching mask at least until said digging depth is reached when forming said dug-down part.

3. The photomask blank according to claim 1 or 2, wherein said light-shielding part is made of a material mainly containing one of chromium, chromium nitride, chromium oxide, chromium oxynitride, and chromium oxycarbonitride.

4. The photomask blank according to claim 1 or 2, wherein said light-shielding part is made of a material mainly containing tantalum.

5. The photomask blank according to claim 1 or 2, wherein said light-shielding part has a thickness of 50 nm to 100 nm.

6. The photomask blank according to claim 1 or 2, wherein said etching mask film is made of a material mainly containing one of chromium, chromium nitride, chromium oxide, chromium oxynitride, and chromium oxycarbonitride.

7. The photomask blank according to claim 1 or 2, wherein said etching mask film has a thickness of 5 nm to 40 nm.

8. The photomask blank according to claim 1 or 2, wherein said etching mask film is also formed on an upper surface of said light-shielding part in said peripheral area.

11. A photomask fabricated using the photomask blank according to claim 1 or 2.

2. A photomask blank for fabricating a phase shift mask having a light-transmissive substrate provided with a phase shift part adapted to give a predetermined phase difference to transmitted exposure light,

wherein said phase shift part is a phase shift film formed on an upper surface of said light-transmissive substrate and adapted to give a predetermined phase change amount to said transmitted exposure light,

said photomask blank comprising:

a light-shielding part formed in a peripheral area around a transfer pattern area of a surface of said phase shift film and adapted to shield exposure light; and

an etching mask film formed in the transfer pattern area of the surface of said phase shift film and made of a material being substantially dry-etchable with a chlorine-based gas, but not substantially dry-etchable with a fluorine-based gas, said etching mask film serving as an etching mask at least until a transfer pattern is formed in said phase shift film by dry etching with a fluorine-based gas.

9. The photomask blank according to claim 2, wherein said phase shift film is made of a material mainly containing one of molybdenum silicide, molybdenum silicide nitride, molybdenum silicide oxide, and molybdenum silicide oxynitride.

10. The photomask blank according to claim 2, wherein said phase shift film comprises:

a phase adjusting layer made of a material mainly containing one of silicon oxide and silicon oxynitride; and

a transmittance adjusting layer made of a material mainly containing one of tantalum and a tantalum-hafnium alloy.

12. A method of manufacturing a phase shift mask having a light-transmissive substrate provided with a phase shift part adapted to give a predetermined phase difference to transmitted exposure light, said method comprising:

forming a light-shielding film on an upper surface of said light-transmissive substrate, said light-shielding film adapted to shield exposure light;

dry-etching said light-shielding film using a resist film pattern as a mask, thereby forming a light-shielding part in a peripheral area around a transfer pattern area;

forming an etching mask film on the upper surface of said light-transmissive substrate after said step of dry-etching;

dry-etching said etching mask film using a resist film pattern as a mask, thereby forming an etching mask film pattern; and

dry-etching said light-transmissive substrate using said etching mask film pattern as a mask, thereby forming said phase shift part by digging down said light-transmissive substrate from the upper surface thereof to a digging depth adapted to produce said predetermined phase difference.

13. A method of manufacturing a phase shift mask having a light-transmissive substrate provided with a phase shift part adapted to give a predetermined phase difference to transmitted exposure light, said method comprising:

forming a phase shift film on an upper surface of said light-transmissive substrate, said phase shift film adapted to give a predetermined phase change amount to transmitted exposure light;

forming a light-shielding film on an upper surface of said phase shift film, said light-shielding film adapted to shield exposure light;

dry-etching said light-shielding film using a resist film pattern as a mask, thereby forming a light-shielding part in a peripheral area around a transfer pattern area;

forming an etching mask film on the upper surface of said phase shift film after said step of dry-etching;

dry-etching said etching mask film using a resist film pattern as a mask, thereby forming an etching mask film pattern; and

dry-etching said phase shift film using said etching mask film pattern as a mask, thereby forming said phase shift part.