Method for fabricating phase shift mask

• US 5,766,805 A
• Filed: 09/13/1996
• Issued: 06/16/1998
• Est. Priority Date: 09/25/1995
• Status: Expired due to Term

• Current Assignee: LG Semico Company Limited (SK Hynix Inc.)
• Original Assignee: LG Semico Company Limited (SK Hynix Inc.)
• Inventors: Han, Oh Seok, Lee, Jun Seok
• Primary Examiner(s): ROSASCO, STEPHEN D
• Application Number:
  US08/710,234
• Time in Patent Office: 641 Days
• Field of Search: 430/5, 430/322, 430/324
• 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

Methods of fabricating phase shift masks, which facilitate easy adjustment of the light transmissivity of a field region and the thickness of a phase shift mask, to thereby simplify the production process, and increase its reliability and performance. Embodiments may include the steps of providing a transparent substrate, forming a conductive light shielding layer on the transparent substrate, implanting oxygen ions into the conductive light shielding layer to form a semitransparent film, and selectively etching the semitransparent film to form a phase shift film.

Claims

1. A method of fabricating a phase shift mask, comprising the steps of:

providing a transparent substrate;

forming a conductive light shielding layer on the transparent substrate;

implanting oxygen ions into the conductive light shielding layer to form a semitransparent film; and

selectively etching the semitransparent film,

wherein a phase shift film is formed.

2. The method as claimed in claim 1, wherein the conductive light shielding film comprises a metal.

3. The method as claimed in claim 2, wherein the metal comprises zinc.

4. The method as claimed in claim 1, wherein the semitransparent film is formed to have a light transmissivity of about 5% to 30% by controlling the oxygen injection density.

5. The method as claimed in claim 1, wherein a thickness d of the semitransparent film is determined to be d=λ

/2(n-1), where λ

is a wave length of a light source, and n is a refractive index.

6. The method as claimed in claim 1, wherein the semitransparent film is selectively etched prior to implanting oxygen ions.

7. A method of fabricating a phase shift mask, comprising the steps of:

providing a transparent substrate;

forming a translucent layer on the transparent substrate;

forming a conductive light shielding layer on the translucent layer;

implanting oxygen ions into the conductive light shielding layer to convert the light shielding layer into a semitransparent layer;

selectively removing the semitransparent layer to form a half-tone film, wherein a first aperture is formed in the semitransparent layer; and

selectively removing the a portion of the translucent layer positioned below the first aperture, wherein a second aperture is formed in the translucent layer;

wherein a phase shift film is formed.

8. The method as claimed in claim 7, wherein the conductive light shielding film comprises a metal.

9. The method as claimed in claim 8, wherein the metal comprises zinc.

10. The method as claimed in claim 7, wherein the translucent layer comprises an oxide film, wherein the oxide film is conductive and contains tin.

11. The method as claimed in claim 10, wherein the translucent layer comprises indium tin oxide.

12. The method as claimed in claim 7, wherein the semitransparent film is formed to have a light transmissivity of about 5% to 30% by controlling the oxygen injection density.

13. The method as claimed in claim 7, wherein the second aperture has a width that is smaller that a width of the first aperture.

14. A method of fabricating a phase shift mask, comprising the steps of:

providing a transparent substrate;

forming a translucent layer on the transparent substrate;

forming a conductive light shielding layer on the translucent layer;

implanting oxygen ions into the conductive light shielding layer to convert the conductive light shielding layer into a semitransparent layer;

selectively removing the semitransparent layer to form a half-tone film, wherein a first aperture is formed in the semitransparent layer;

forming insulating sidewalls at sides of the first aperture in the half-tone film; and

selectively removing a portion of the translucent layer positioned below the first aperture, wherein a second aperture is formed in the translucent layer, wherein the insulating sidewalls and the half-tone film serve as masks;

wherein a phase shift film is formed.

15. The method as claimed in claim 14, wherein the translucent layer comprises indium tin oxide.

16. The method as claimed in claim 14, wherein the conductive light shielding layer comprises a metal.

17. The method as claimed in claim 16, wherein the metal comprises zinc.

18. The method as claimed in claim 14, wherein the semitransparent film is formed to have a light transmissivity of about 5% to 30% by controlling the oxygen injection density.

19. The method as claimed in claim 14, wherein the insulating sidewalls are formed after forming the half-tone film by depositing an insulating film and etching back the insulating film.

20. The method as claimed in claim 14, wherein the second aperture has a width that is smaller that a width of the first aperture.