Method of manufacturing an X-ray exposure mask and device for controlling the internal stress of thin films

• US 5,188,706 A
• Filed: 03/16/1990
• Issued: 02/23/1993
• Est. Priority Date: 03/18/1989
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Itoh, Masamitsu, Hori, Masaru
• Primary Examiner(s): Dang, Thi
• Application Number:
  US07/494,397
• Time in Patent Office: 1,075 Days
• Field of Search: 437/11, 437/13, 430/5, 378/35, 156/656, 156/659.1, 156/657, 156/643, 156/646
• US Class Current: 216/12
• CPC Class Codes: B81C 1/00666 Treatments for controlling internal stress or strain in MEMS structures
• CPC Class Codes: B81C 2201/017 Methods for controlling internal stress of deposited layers not provided for in B81C2201/0164 - B81C2201/0169
• CPC Class Codes: G03F 1/22 Masks or mask blanks for imaging by radiation of 100nm or shorter wavelength, e.g. X-ray masks, extreme ultraviolet [EUV] masks; Preparation thereof

Abstract

An X-ray mask can be manufactured by forming an X-ray transmitting thin film on a mask support, forming an X-ray absorber thin film on the X-ray transmitting thin film, and patterning the X-ray absorber thin film with a desired pattern to form an X-ray absorber pattern. Prior to the patterning, at least one inert element with an atomic number greater than that of neon is ion-implanted in the X-ray absorber thin film.

Claims

1. A method of manufacturing an X-ray msk comprising the steps of:

(a) forming an X-ray transmitting thin film on a mask support;

(b) form an X-ray absorber thin film on said X-ray transmitting thin film;

(c) patterning said X-ray absorbe thin film with a desired pattern to from an X-ray absorber pattern; and

(d) ion-implanting, prior to step (c), at least one inert element with an atomic number greater than that of neon in only a surface layer of said X-ray absorber thin film.

2. The method according to claim 1, wherein the inert element is at least one gas element chosen from the group consisting of argon, krypton and xenon.

3. The method according to claim 1, further comprising step (e) of conducting oblique ion implantation on the X-ray absorber pattern after step (C).

4. The method according to claim 3, wherein an inert element with an atomic number greater than that of neon is obliquely ion-implanted.

5. The method according to claim 3, wherein an element of the same type as the component elements of the X-ray absorber is obliquely ion-implanted.

6. The method according to claim 1, wherein the patterning is carried out by reactive plasma etching using an etching gas that contains a gas reactive with said X-ray absorber, thereby forming a gas infiltration-preventing film in the surface of the said X-ray absorber pattern.

7. The method according to claim 6, wherein the reactive gas is hydrocarbon gas or nitrogen.

8. The method according to claim 1, further comprising step (f) of plasma doping the top and sides of the X-ray absorber pattern after step (c).

9. A method of manufacturing an X-ray mask comprising the steps of:

(a) forming an X-ray absorber thin film on a transparent support;

(b) forming an X-ray absorber pattern by patterning said X-ray absorber thin film in desired pattern; and

(c) implanting ions in the top and sides of said pattern by oblique ion implantation to said X-ray absorber pattern.

10. The method according to claim 9, wherein at least one inert gas element chosen from the group consisting of argon, krypton and xenon is obliquely ion-implanted.

11. The method according to claim 9, wherein an element of the same type as the constituent element of said X-ray absorber is obliquely ion-implanted.

12. The method according to claim 9, wherein the patterning is carried out by reactive plasma etching using an etching gas that contains a gas reactive with said X-ray absorber, thereby forming a gas infiltration-preventing film in the surface of the said X-ray absorber pattern.

13. The method according to claim 12, wherein the reactive gas is ethylene or nitrogen.

14. The method according to claim 9, further comprising step (d) of plasma doping the top and sides of the X-ray absorber pattern after step (c).

15. A method of manufacturing an X-ray mask comprising the steps of:

(a) forming an X-ray transmitting thin film on a mask support,

(b) forming an X-ray absorber thin film on said X-ray transmitting thin film,

(c) patterning said X-ray absorber thin film to form an X-ray absorber pattern,

(d) ion implanting, prior to step (c), at least one inert gas element with an atomic number greater than that of neon in only a surface layer of said X-ray absorber thin film such that said X-ray absorber thin film has a compressive stress no greater than 2×

10⁸ dyn/cm², and

(e) heat-treating said X-ray absorber after process (d) such that the internal stress of said X-ray absorber pattern is no greater than 1×

10⁸ dyn/cm².

16. A method of manufacturing an X-ray mask comprising the steps of:

(a) forming an X-ray transmitting thin film on a mask support,

(b) forming an X-ray absorber thin film on said X-ray transmitting thin film,

(c) patterning said X-ray absorber thin film to form an X-ray absorber pattern, and

(d) while measuring the internal stress of said X-ray absorber thin film and controlling the quantity of ions implanted according to the measured internal stress, ion-implanting at least one inert gas element with an atomic number greater than that of neon in only a surface layer of said X-ray absorber thin film to reduce the internal stress of said X-ray absorber thin film so as to control said internal stress to a desired value.

17. A method of manufacturing an X-ray mask comprising the steps of:

(a) forming an X-ray transmitting thin film on a mask support;

(b) forming an X-ray absorber thin film on said X-ray transmitting thin film;

(c) patterning said X-ray absorber thin film with a desired pattern to form an X-ray absorber pattern; and

(d) ion-implanting, prior to step (c), at least one inert element having an atomic number greater than that of neon in a surface layer of said X-ray absorber thin film, thereby forming an internal stress-alleviating layer comprising said ion-implanted surface layer, leaving a non-implanted lower layer of said absorber thin film, said stress-alleviating layer reducing the internal stress of said X-ray absorber thin film by canceling its stress with the stress of said non-implanted lower layer.