# US 11,079,685 B2 · Method of manufacturing photo masks

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- Number: US 11,079,685 B2
- Document ID: US11079685B2
- Status: Granted
- Kind: B2
- Application number: 15/966,962
- Filed: 2018-04-30
- Published: 2019-05-16
- Granted: 2021-08-03
- Earliest claimed: 2017-11-14
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Co., Ltd.
- Inventors: Ken-Hsien Hsieh; Ru-Gun Liu; Wei-Shuo Su
- Web page: https://patentgrep.com/patent/US11079685B2

## CPC

- G03F 7/70466: {Multiple exposures, e.g. combination of fine and coarse exposures, double patterning or multiple exposures for printing a single feature (stitching G03F7/70475)}
- G03F 1/36: Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes
- G03F 1/70: Adapting basic layout or design of masks to lithographic process requirements, e.g., second iteration correction of mask patterns for imaging
- G06F 30/398: Design verification or optimisation, e.g. using design rule check [DRC], layout versus schematics [LVS] or finite element methods [FEM] (optical proximity correction [OPC] design processes G03F1/36)
- H10P 50/73: {using masks for insulating materials}
- G06F 2119/18: Manufacturability analysis or optimisation for manufacturability
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

In a method of manufacturing a photo mask used in a semiconductor manufacturing process, a mask pattern layout in which a plurality of patterns are arranged is acquired. The plurality of patterns are converted into a graph having nodes and links. It is determined whether the nodes are colorable by N colors without causing adjacent nodes connected by a link to be colored by a same color, where N is an integer equal to or more than 3. When it is determined that the nodes are colorable by N colors, the nodes are colored with the N colors. The plurality of patterns are classified into N groups based on the N colored nodes. The N groups are assigned to N photo masks. N data sets for the N photo masks are output.

## Claims

### Claim 1

A method of generating photo mask data for photo masks used in a semiconductor manufacturing process, the method comprising:
acquiring a mask pattern layout in which a plurality of patterns are arranged;
converting the plurality of patterns into a graph having nodes and links, wherein each of the plurality of patterns are converted and the graph includes one or more pre-colored nodes;
determining whether the nodes are colorable with respect to a degree defined by a number of the links to the nodes by N colors without removing the one or more pre-colored nodes and without causing adjacent nodes connected by a link to be colored by a same color, N being an integer equal to or more than 3, wherein the graph includes a node of which the degree is 1 or 2;
when it is determined that the nodes are colorable by N colors, coloring the nodes with the N colors;
classifying the plurality of patterns into N groups based on the N colored nodes;
assigning the N groups to N photo masks; and
outputting N data sets for the N photo masks.

### Claim 2 (depends on 1)

The method of claim 1, wherein in the converting:
when a minimum distance between two patterns is equal to or smaller than a threshold distance, nodes representing the two patterns are connected by a link, and
when a distance between two patterns is greater than the threshold distance, nodes representing the two patterns are not connected by a link.

### Claim 3 (depends on 2)

The method of claim 2, wherein in the determining:
the graph is simplified by repeating a removal of a node having less than N links from the graph, and
when all nodes are removed, it is determined that the nodes are colorable by N colors.

### Claim 4 (depends on 3)

The method of claim 3, wherein:
when all nodes are not removed, it is determined whether a remaining graph is a known N-colorable pattern, and
when it is determined that the remaining graph is a known N-colorable pattern, it is determined that the nodes are colorable by N colors.

### Claim 5 (depends on 3)

The method of claim 3, wherein:
when all nodes are not removed, it is determined whether a remaining graph is colorable by the N colors, and
when it is determined that the remaining graph is colorable by the N colors, it is determined that the nodes are colorable by N colors.

### Claim 6 (depends on 2)

The method of claim 2, wherein:
the plurality of patterns include one or more designated patterns,
in the determining, the graph is simplified by repeating a removal of a node having less than N links from the graph but one or more nodes corresponding to the one or more designated patterns are not removed, and
when all nodes except for one or more nodes corresponding to the one or more designated patterns are removed, it is determined that the nodes are colorable by N colors.

### Claim 7 (depends on 2)

The method of claim 2, wherein in each of the N data sets, any adjacent two patterns have a distance greater than the threshold distance.

### Claim 8 (depends on 7)

The method of claim 7, wherein in each of the N data sets, a minimum distance between any adjacent two patterns is N time the threshold distance.

### Claim 9

A method of manufacturing photo masks used in a semiconductor manufacturing process, the method comprising:
acquiring a mask pattern layout in which a plurality of patterns are arranged;
converting the plurality of patterns into a graph having nodes and links, wherein each of the plurality of patterns are converted and the graph includes one or more pre-colored nodes;
determining whether the nodes are colorable with respect to a degree defined by a number of the links to the nodes by N colors without removing the one or more pre-colored nodes and without causing adjacent nodes connected by a link to be colored by a same color, N being an integer equal to or more than 3, wherein the graph includes a node of which the degree is 1 or 2;
when it is determined that the nodes are colorable by N colors, coloring the nodes with the N colors;
classifying the plurality of patterns into N groups based on the N colored nodes;
assigning the N groups to N photo masks;
outputting N data sets for the N photo masks; and
fabricating the N photo masks by using the N mask data sets.

### Claim 10 (depends on 9)

The method of claim 9, wherein in the converting:
when a minimum distance between two patterns is equal to or smaller than a threshold distance, nodes representing the two patterns are connected by a link, and
when a distance between two patterns is greater than the threshold distance, nodes representing the two patterns are not connected by a link.

### Claim 11

An apparatus for analyzing a photo mask data for photo masks used in a semiconductor manufacturing process, the apparatus comprising:
a processor; and
a non-transitory, computer-readable storage medium storing a program, the program, when executed by the processor, causes the processor to perform:
acquiring a mask pattern layout in which a plurality of patterns are arranged;
converting the plurality of patterns into a graph having nodes and links, wherein each of the plurality of patterns are converted and the graph includes one or more pre-colored nodes;
determining whether the nodes are colorable with respect to a degree defined by a number of the links to the nodes by N colors without removing the one or more pre-colored nodes and without causing adjacent nodes connected by a link to be colored by a same color, N being an integer equal to or more than 3, wherein the graph includes a node of which the degree is 1 or 2 and one or more pre-colored nodes;
when it is determined that the nodes are colorable by N colors, coloring the nodes with the N colors;
classifying the plurality of patterns into N groups based on the N colored nodes;
assigning the N groups to N photo masks; and
outputting N data sets for the N photo masks.

### Claim 12 (depends on 11)

The apparatus of claim 11, wherein:
the program, when executed by the processor, further causes the processor to perform, when it is determined that the nodes are colorable by N colors:
coloring the nodes with the N colors;
classifying the plurality of patterns into N groups based on the N colored nodes;
assigning the N groups to N photo masks; and
outputting N data sets for the N photo masks.

### Claim 13 (depends on 12)

The apparatus of claim 12, wherein in the converting:
when a minimum distance between two patterns is equal to or smaller than a threshold distance, nodes representing the two patterns are connected by a link, and
when a distance between two patterns is greater than the threshold distance, nodes representing the two patterns are not connected by a link.

### Claim 14 (depends on 13)

The apparatus of claim 13, wherein in the determining:
the graph is simplified by repeating a removal of a node having less than N links from the graph, and
when all nodes are removed, it is determined that the nodes are colorable by N colors.

### Claim 15 (depends on 14)

The apparatus of claim 14, wherein:
when all nodes are not removed, it is determined whether a remaining graph is a known N-colorable pattern, and
when it is determined that the remaining graph is a known N-colorable pattern, it is determined that the nodes are colorable by N colors.

### Claim 16 (depends on 14)

The apparatus of claim 14, wherein:
when all nodes are not removed, it is determined whether a remaining graph is colorable by the N colors, and
when it is determined that the remaining graph is colorable by the N colors, it is determined that the nodes are colorable by N colors.

### Claim 17 (depends on 13)

The apparatus of claim 13, wherein:
the plurality of patterns include one or more designated patterns,
in the determining, the graph is simplified by repeating a removal of a node having less than N links from the graph but one or more nodes corresponding to the one or more designated patterns are not removed, and
when all nodes except for one or more nodes corresponding to the one or more designated patterns are removed, it is determined that the nodes are colorable by N colors.

### Claim 18 (depends on 13)

The apparatus of claim 13, wherein in each of the N data sets, any adjacent two patterns have a distance greater than the threshold distance.

### Claim 19 (depends on 18)

The apparatus of claim 18, wherein in each of the N data sets, a minimum distance between any adjacent two patterns is N times the threshold distance.

### Claim 20 (depends on 12)

The apparatus of claim 12, wherein the mask pattern layout and the N data are in GDS-II stream format or in Open Artwork System Interchange Standard format.