Photomask, method for producing the same, and method for forming pattern using the photomask

• US 20030203290A1
• Filed: 04/29/2003
• Published: 10/30/2003
• Est. Priority Date: 04/30/2002
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Misaka, Akio
• Granted Patent: US 7,001,694 B2
• Time in Patent Office: Days
• US Class Current: 430/5
• CPC Class Codes: G03F 1/29 Rim PSM or outrigger PSM; Preparation thereof
• CPC Class Codes: G03F 1/32 Attenuating PSM [att-PSM], e.g. halftone PSM or PSM having semi-transparent phase shift portion,; Preparation thereof

Abstract

A photomask includes a semi-light-shielding portion having a light-shielding property, a light-transmitting portion surrounded by the semi-light-shielding portion and a peripheral portion positioned in a periphery of the light-transmitting portion on a transparent substrate. The semi-light-shielding portion and the light-transmitting portion transmit the exposure light in the same phase each other, whereas the peripheral portion transmits the exposure light in a phase opposite to that of the light-transmitting portion. A phase shift film that transmits the exposure light in a phase opposite to that of the peripheral portion is formed on the transparent substrate in the semi-light-shielding portion formation region.

Claims

1. A photomask comprising on a transparent substrate:

a semi-light-shielding portion having a light-shielding property with respect to exposure light;

a light-transmitting portion surrounded by the semi-light-shielding portion and having a light-transmitting property with respect to exposure light; and

a peripheral portion surrounded by the semi-light-shielding portion and positioned in a periphery of the light-transmitting portion,

wherein the semi-light-shielding portion and the light-transmitting portion transmit the exposure light in a same phase,

the peripheral portion transmits the exposure light in a phase opposite to that of the semi-light-shielding portion and the light-transmitting portion, and

a phase shift film that has a transmittance that allows the exposure light to be transmitted partially and transmits the exposure light in a phase opposite to that of the peripheral portion is formed on the transparent substrate in a formation region for the semi-light-shielding portion.

2. The photomask according to claim 1,

wherein the transparent substrate in a formation region for the light-transmitting portion is dug down so as to have a thickness that transmits the exposure light in a phase opposite to that of the peripheral portion.

3. The photomask according to claim 1,

wherein a surface of the transparent substrate in a formation region for the peripheral portion is exposed.

4. The photomask according to claim 1,

wherein the phase shift film is a metal-containing oxide film.

5. The photomask according to claim 1,

wherein the phase shift film comprises:

a transmittance adjusting film having a transmittance lower than that of the transparent substrate with respect to the exposure light, and

a phase adjusting film that is formed on the transmittance adjusting film and transmits the exposure light in a phase opposite to that of the peripheral portion.

6. The photomask according to claim 5,

wherein the transmittance adjusting film is a thin film made of a metal or a metal alloy.

7. The photomask according to claim 6,

wherein the transmittance adjusting film has a thickness of 30 nm or less.

8. The photomask according to claim 5,

wherein the phase adjusting film is an oxide film.

9. The photomask according to claim 5,

wherein the peripheral portion is disposed apart from the light-transmitting portion by a predetermined distance, and

only the transmittance adjusting film of the phase shift film is formed between the peripheral portion and the light-transmitting portion.

10. The photomask according to claim 1,

wherein the peripheral portion is disposed so as to be in contact with the light-transmitting portion.

11. The photomask according to claim 1,

wherein the peripheral portion is disposed apart from the light-transmitting portion by a predetermined distance.

12. The photomask according to claim 1,

wherein the phase shift film comprises:

a transmittance adjusting film having a transmittance lower than that of the transparent substrate with respect to the exposure light,

a phase adjusting film that is formed on the transmittance adjusting film and transmits the exposure light in a phase opposite to that of the peripheral portion and

the transmittance adjusting film is also formed on the transparent substrate in a formation region for the peripheral portion.

13. The photomask according to claim 12,

wherein the transmittance adjusting film is made of a metal or a metal alloy and transmits the exposure light in a same phase as that of peripheral portion.

14. The photomask according to claim 13,

wherein the transmittance adjusting film has a thickness of 30 nm or less.

15. The photomask according to claim 12,

wherein the phase adjusting film is an oxide film.

16. The photomask according to claim 12,

wherein the peripheral portion is disposed so as to be in contact with the light-transmitting portion.

17. The photomask according to claim 12,

wherein the peripheral portion is disposed apart from the light-transmitting portion by a predetermined distance.

18. The photomask according to claim 1,

wherein the phase shift film comprises:

a phase adjusting film that transmits the exposure light in a phase opposite to that of the peripheral portion, and

a transmittance adjusting film that is formed on the phase adjusting film and has a transmittance lower than that of the transparent substrate with respect to the exposure light,

the phase adjusting film is also formed on the transparent substrate in a formation region for the light-transmitting portion, and

a surface of the transparent substrate in a formation region for the peripheral portion is exposed.

19. The photomask according to claim 18,

wherein the transmittance adjusting film is a thin film that is made of a metal or a metal alloy and transmits the exposure light in a same phase as that of peripheral portion.

20. The photomask according to claim 19,

wherein the transmittance adjusting film has a thickness of 30 nm or less.

21. The photomask according to claim 18,

wherein the phase adjusting film is an oxide film.

22. The photomask according to claim 18,

wherein the peripheral portion is disposed so as to be in contact with the light-transmitting portion.

23. The photomask according to claim 18,

wherein the peripheral portion is disposed apart from the light-transmitting portion by a predetermined distance.

24. The photomask according to claim 1,

wherein a transmittance with respect to the exposure light of the phase shift film is 6% or more and 15% or less.

25. A method for forming a pattern that uses the photomask according to claim 1, comprising the steps of:

forming a resist film on a substrate;

irradiating the resist film with the exposure light via the photomask, and

developing the resist film irradiated with the exposure light so as to pattern the resist film.

26. The method for forming a pattern according to claim 25,

off-axis illumination is used in the step of irradiating the resist film with the exposure light.

27. A method for producing a photomask comprising:

a semi-light-shielding portion having a light-shielding property with respect to exposure light;

a light-transmitting portion surrounded by the semi-light-shielding portion and having a light-transmitting property with respect to exposure light; and

a peripheral portion surrounded by the semi-light-shielding portion and positioned in a periphery of the light-transmitting portion on a transparent substrate,

the method comprising;

a first step of forming a phase shift film that has a transmittance that allows the exposure light to be transmitted partially and transmits the exposure light in a phase opposite to that of the peripheral portion on the transparent substrate in the semi-light-shielding portion formation region, and

a second step of digging down the transparent substrate in the light-transmitting portion formation region so as to have a thickness that transmits the exposure light in a phase opposite to that of the peripheral portion after the first step.

28. The method for producing a photomask according to claim 27,

wherein the first step includes the step of removing the phase shift film in the light-transmitting portion formation region and the peripheral portion formation region after the phase shift film is formed on an entire surface of the transparent substrate.

29. The method for producing a photomask according to claim 27,

wherein the first step includes the step of removing the phase shift film in the peripheral portion formation region after the phase shift film is formed on an entire surface of the transparent substrate, and

the second step includes the step of removing the phase shift film in the light-transmitting portion formation region before digging down the transparent substrate in the light-transmitting portion formation region.

30. The method for producing a photomask according to claim 27,

wherein the phase shift film comprises:

a transmittance adjusting film having a transmittance lower than that of the transparent substrate with respect to the exposure light, and

a phase adjusting film that is formed on the transmittance adjusting film and transmits the exposure light in a phase opposite to that of the peripheral portion.

31. The method for producing a photomask according to claim 27,

wherein the first step includes the step of forming a transmittance adjusting film having a transmittance lower than that of the transparent substrate with respect to the exposure light and a phase adjusting film that transmits the exposure light in a phase opposite to that of the peripheral portion sequentially on an entire surface of the transparent substrate, and then removing the phase adjusting film in the light-transmitting portion formation region and the peripheral portion formation region, so that the phase shift film including the transmittance adjusting film and the phase adjusting film is formed on the transparent substrate in the semi-light-shielding portion formation region, and

the second step includes the step of removing the transmittance adjusting film in the light-transmitting portion formation region before digging down the transparent substrate in the light-transmitting portion formation region.

32. The method for producing a photomask according to claim 27,

wherein the first step includes the step of forming a transmittance adjusting film having a transmittance lower than that of the transparent substrate with respect to the exposure light and a phase adjusting film that transmits the exposure light in a phase opposite to that of the peripheral portion sequentially on an entire surface of the transparent substrate, and then removing the phase adjusting film in the peripheral portion formation region, so that the phase shift film including the transmittance adjusting film and the phase adjusting film is formed on the transparent substrate in the semi-light-shielding portion formation region, and

the second step includes the step of sequentially removing the phase adjusting film and the transmittance adjusting film in the light-transmitting portion formation region before digging down the transparent substrate in the light-transmitting portion formation region.

33. The method for producing a photomask according to claim 27,

wherein a transmittance with respect to the exposure light of the phase shift film is 6% or more and 15% or less.

34. A method for producing a photomask comprising:

a semi-light-shielding portion having a light-shielding property with respect to exposure light;

a light-transmitting portion surrounded by the semi-light-shielding portion and having a light-transmitting property with respect to exposure light; and

a peripheral portion surrounded by the semi-light-shielding portion and positioned in a periphery of the light-transmitting portion on a transparent substrate,

the method comprising;

a first step of forming a phase adjusting film that transmits the exposure light in a phase opposite to that of the peripheral portion and a transmittance adjusting film having a transmittance lower than that of the transparent substrate with respect to the exposure light sequentially on an entire surface of the transparent substrate,

a second step of removing the phase adjusting film and the transmittance adjusting film in the peripheral portion formation region, and

a third step of removing the transmittance adjusting film in the light-transmitting portion formation region after the second step,

wherein the phase adjusting film and the transmittance adjusting film formed on the transparent substrate in the semi-light-shielding portion formation region constitute the phase shift film that has a transmittance that allows the exposure light to be transmitted partially and transmits the exposure light in a phase opposite to that of the peripheral portion.

35. The method for producing a photomask according to claim 34,

wherein a transmittance with respect to the exposure light of the phase shift film is 6% or more and 15% or less.