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

• US 20030203291A1
• Filed: 04/29/2003
• Published: 10/30/2003
• Est. Priority Date: 04/30/2002
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Misaka, Akio
• Granted Patent: US 7,045,255 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 has a semi-light-shielding portion having a light-shielding property and a light-transmitting portion surrounded by the semi-light-shielding portion, and a peripheral portion positioned in the periphery of the light-transmitting portion. The semi-light-shielding portion and the light-transmitting portion transmit exposure light in the same phase, whereas the peripheral portion transmits exposure light in a phase opposite to that of the light-transmitting portion.

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,

a surface of the transparent substrate in a formation region for the light-transmitting portion is exposed,

a first phase shift film that transmits the exposure light in a phase opposite to that of the light-transmitting portion is formed on the transparent substrate in a formation region for the peripheral portion,

the first phase shift film and a second phase shift film that transmits the exposure light in a phase opposite to that of the light-transmitting portion are laminated sequentially on the transparent substrate in a formation region for the semi-light-shielding portion, and

a multilayered structure of the first phase shift film and the second phase shift film has a transmittance that allows the exposure light to be transmitted partially and transmits the exposure light in a same phase as that of the light-transmitting portion.

2. The photomask according to claim 1,

wherein the first phase shift film has a first transmittance adjusting film and a first phase adjusting film formed on the first transmittance adjusting film,

the first transmittance adjusting film transmits the exposure light in a same phase as that of the light-transmitting portion and has a relatively low transmittance with respect to the exposure light, and

the first phase adjusting film transmits the exposure light in a phase opposite to that of the light-transmitting portion and has a relatively high transmittance with respect to the exposure light.

3. The photomask according to claim 1,

wherein the second phase shift film has a second transmittance adjusting film and a second phase adjusting film formed on the second transmittance adjusting film,

the second transmittance adjusting film transmits the exposure light in a same phase as that of the light-transmitting portion and has a relatively low transmittance with respect to the exposure light, and

the second phase adjusting film transmits the exposure light in a phase opposite to that of the light-transmitting portion and has a relatively high transmittance with respect to the exposure light.

4. The photomask according to claim 1,

wherein the peripheral portion is in contact with the light-transmitting portion.

5. The photomask according to claim 1,

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

6. The photomask according to claim 1,

wherein the first phase shift film has a first phase adjusting film that transmits the exposure light in a phase opposite to that of the light-transmitting portion,

the second phase shift film has a second phase adjusting film that is formed on the first phase adjusting film and transmits the exposure light in a phase opposite to that of the light-transmitting portion, and

a transmittance adjusting film having a lower transmittance than that of the phase adjusting films with respect to the exposure light is formed between the first phase adjusting film and the second phase adjusting film.

7. The photomask according to claim 1,

wherein a transmittance of the semi-light-shielding portion with respect to the exposure light is 6% or more and 15% or less.

8. 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.

9. The method for forming a pattern according to claim 8,

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

10. 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,

a surface of the transparent substrate in a formation region for the light-transmitting portion is exposed,

a semi-light-shielding film that has a transmittance allowing the exposure light to be transmitted partially and transmits the exposure light in a same phase to that of the light-transmitting portion is formed on the transparent substrate in the semi-light-shielding portion formation region, and

the semi-light-shielding film with a reduced thickness is formed on the transparent substrate in a formation region for the peripheral portion, the thickness being such an extent that the exposure light is transmitted in a phase opposite to that of the light-transmitting portion.

11. The photomask according to claim 10,

wherein the semi-light-shielding film has a transmittance adjusting film formed on the transparent substrate and a phase adjusting film formed on the transmittance adjusting film,

the transmittance adjusting film transmits the exposure light in a same phase as that of the light-transmitting portion and has a relatively low transmittance with respect to the exposure light, and

the phase adjusting film has a relatively high transmittance with respect to the exposure light,

the phase adjusting film in a formation region for the semi-light-shielding portion has a thickness that transmits the exposure light in a same phase as that of the light-transmitting portion, and

the phase adjusting film in a formation region for the peripheral portion has a thickness that transmits the exposure light in a phase opposite to that of the light-transmitting portion.

12. The photomask according to claim 10,

wherein the semi-light-shielding film has a phase adjusting film formed on the transparent substrate and a transmittance adjusting film formed only on the phase adjusting film in the semi-light-shielding portion formation region,

the transmittance adjusting film transmits the exposure light in a same phase as that of the light-transmitting portion and has a relatively low transmittance with respect to the exposure light, and

the phase adjusting film has a relatively high transmittance with respect to the exposure light,

the phase adjusting film in a formation region for the semi-light-shielding portion has a thickness that transmits the exposure light in a same phase as that of the light-transmitting portion, and

the phase adjusting film in a formation region for the peripheral portion has a thickness that transmits the exposure light in a phase opposite to that of the light-transmitting portion.

13. The photomask according to claim 10,

wherein the peripheral portion is in contact with the light-transmitting portion.

14. The photomask according to claim 10,

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

15. The photomask according to claim 10,

wherein a transmittance of the semi-light-shielding portion with respect to the exposure light is 6% or more and 15% or less.

16. A method for forming a pattern that uses the photomask according to claim 10, 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.

17. The method for forming a pattern according to claim 16,

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

18. 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,

a surface of the transparent substrate in a formation region for the light-transmitting portion is exposed,

a semi-light-shielding film that has a transmittance that allows the exposure light to be transmitted partially and transmits the exposure light in a same phase as that of the light-transmitting portion is formed on the transparent substrate in the semi-light-shielding portion, and

the transparent substrate in a formation region for the peripheral portion is dug down such that a thickness thereof is such an extent that the exposure light is transmitted in a phase opposite to that of the light-transmitting portion.

19. The photomask according to claim 18,

wherein the semi-light-shielding film has a transmittance adjusting film formed on the transparent substrate and a phase adjusting film formed on the transmittance adjusting film,

the transmittance adjusting film has a relatively low transmittance with respect to the exposure light, and

the phase adjusting film has a relatively high transmittance with respect to the exposure light.

20. The photomask according to claim 18,

wherein the peripheral portion is in contact with the light-transmitting portion.

21. The photomask according to claim 18,

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

22. The photomask according to claim 18,

wherein a transmittance of the semi-light-shielding portion with respect to the exposure light is 6% or more and 15% or less.

23. A method for forming a pattern that uses the photomask according to claim 18, 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.

24. The method for forming a pattern according to claim 23,

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

25. 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 first phase shift film that transmits the exposure light in a phase opposite to that of the light-transmitting portion on the transparent substrate, and

a second step of forming a second phase shift film that transmits the exposure light in a phase opposite to that of the light-transmitting portion on the first phase shift film,

a third step of removing the second phase shift film in a formation region for the light-transmitting portion and a formation region for the peripheral portion, and

a fourth step of removing the first phase shift film in the light-transmitting portion formation region after the third step,

wherein a multilayered structure of the first phase shift film and the second phase shift film formed on the transparent substrate in the semi-light-shielding portion formation region has a transmittance that allows the exposure light to be transmitted partially and transmits the exposure light in a same phase as that of the light-transmitting portion.

26. The photomask according to claim 25,

wherein a transmittance of the semi-light-shielding portion with respect to the exposure light is 6% or more and 15% or less.

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 first phase shift film that transmits the exposure light in a phase opposite to that of the light-transmitting portion on the transparent substrate, and

a second step of forming a second phase shift film that transmits the exposure light in a phase opposite to that of the light-transmitting portion on the first phase shift film,

a third step of removing the second phase shift film in a formation region for the peripheral portion, and

a fourth step of removing the second phase shift film and the first phase shift film in the light-transmitting portion formation region sequentially after the third step,

wherein a multilayered structure of the first phase shift film and the second phase shift film formed on the transparent substrate in the semi-light-shielding portion formation region has a transmittance that allows the exposure light to be transmitted partially and transmits the exposure light in a same phase as that of the light-transmitting portion.

28. The photomask according to claim 27,

wherein a transmittance of the semi-light-shielding portion with respect to the exposure light is 6% or more and 15% or less.