Process of exactly patterning layer to target configuration by using photo-resist mask formed with dummy pattern

• US 5,763,143 A
• Filed: 12/13/1995
• Issued: 06/09/1998
• Est. Priority Date: 12/28/1994
• Status: Expired due to Fees

• Current Assignee: NEC Compound Semiconductor Devices, Ltd. (NEC Corporation)
• Original Assignee: NEC Corporation
• Inventors: Sakura, Naoki
• Primary Examiner(s): CHAPMAN, MARK A
• Application Number:
  US08/571,535
• Time in Patent Office: 909 Days
• Field of Search: 430/330, 430/5, 430/313
• US Class Current: 430/330
• CPC Class Codes: G03F 7/20 Exposure; Apparatus therefor photographic printing apparatus for making copies G03B27/00
• CPC Class Codes: G03F 7/40 Treatment after imagewise removal, e.g. baking

Abstract

Tension takes place in a surface of a photo-resist mask due to a shrinkage in a post-development bake, and a recess formed in the photo-resist mask takes up the tension so as to maintain the adhesion to a semiconductor substrate and prevent a resist pattern from undesirable deformation.

Claims

1. A process for etching a given pattern in a first layer, comprising the steps of:

a) depositing a resist layer on said first layer;

b) transferring a mask pattern to said resist layer, said mask pattern having a main pattern image corresponding to said given pattern and a stress-relief pattern image corresponding to a stress-relief pattern comprising at least one recess to be formed in said resist layer;

c) developing said main pattern image and said stress-relief pattern image in said resist layer so as to form said resist layer into a resist mask having said at least one recess spaced from said first layer by a bottom portion of said photo-resist mask;

d) baking said resist mask so as to increase an adhesion; and

e) etching said given pattern into said first layer by using said resist mask.

2. The process as set forth in claim 1, in which said step b) includes the sub-steps of:

b-1) covering said resist layer with a photo-mask having said mask pattern, and

b-2) radiating light through said photo-mask to said resist layer so as to make said resist layer partially soluble in a developing solution, a first portion of said resist layer radiated through said main pattern image being soluble over a thickness of said resist layer, a second portion of said resist layer radiated through said stress-relief pattern being soluble to a depth less than said thickness.

3. The process as set forth in claim 2, in which said stress-relief pattern image has an open area transferring an amount of said light onto said resist layer insufficient to render the resist layer soluble over said thickness.

4. The process as set forth in claim 3, in which said open area is narrower than a limit of resolution capable of proportionally transferring an image.

5. The process as set forth in claim 1, in which said main pattern image has a plurality of first slits arranged in parallel at intervals, and said stress-relief pattern image has a second slit narrower than said plurality of first slit located in the vicinity of said plurality of first slits.

6. The process as set forth in claim 5, in which a distance between adjacent two of said plurality of first slits is equal to a distance between one of said plurality of first slits and said second slit.

7. The process as set forth in claim 1, in which said main pattern image has a rectangular open area, and said stress-relief pattern image has a frame-like open area provided outside of said rectangular open area.

8. A process of forming an etched pattern on a first layer, said etched pattern having a given configuration, comprising the steps of:

a) forming the first layer;

b) coating said layer with a photo-resist layer;

c) covering said photo-resist layer with a photo-mask, the photo-mask having a main pattern image corresponding to said given configuration, and having a stress-relief pattern image corresponding to a pattern of stress relief recesses to be formed on said photo-resist layer;

d) radiating a light through said photo-mask to said photo-resist layer so as to make a first portion of said photo-resist layer radiated through said main pattern image soluble, in a developing solution, over a thickness of said photo-resist layer, and a second portion of said photo-resist layer radiated through said stress-relief pattern image soluble to a depth less than said thickness;

e) developing said main pattern image and said stress-relief pattern image in said photo-resist layer so as to form said photo-resist layer into a photo-resist mask having an open area exposing a portion of said first layer in said first portion, and having at least one recess in said second portion, said recess spaced from said first layer by a bottom portion of said photo-resist mask;

f) baking said photo-resist mask so as to increase an adhesion between said first layer and said photo-resist mask; and

g) etching the exposed portion of said first layer so as to form said pattern in said first layer to said given configuration.

9. A process of forming a layer to a given pattern, comprising the steps of:

a) forming a conductive layer on a substrate;

b) coating said conductive layer with a photo-resist layer;

c) covering said photo-resist layer with a photo-mask, the photo-mask having a main pattern image corresponding to said given configuration, and having a stress-relief pattern image corresponding to a pattern of stress relief recesses to be formed on said photo-resist layer;

d) radiating a light through said photo-mask to said photo-resist layer so as to make a first portion of said photo-resist layer radiated through said main pattern image soluble, in a developing solution, over a thickness of said photo-resist layer, and a second portion of said photo-resist layer radiated through said stress-relief pattern image soluble to a depth less than said thickness;

e) developing said main pattern image and said stress-relief pattern image in said photo-resist layer so as to form said photo-resist layer into a photo-resist mask having an open area located within said first portion exposing a part of said conductive layer, and having at least one recess located within said second portion, said recess spaced from said first layer by a bottom portion of said photo-resist mask;

f) baking said photo-resist mask so as to increase an adhesion between said conductive layer and said photo-resist mask;

g) depositing a substance on said part of said conductive layer so as to form at least one column of said substance;

h) removing said photo-resist mask; and

l) forming said conductive layer to said given configuration by using said at least one column of said substance as a mask.