METHOD FOR ADDING ASSIST FEATURES

• US 20190332019A1
• Filed: 11/23/2017
• Published: 10/31/2019
• Est. Priority Date: 12/30/2016
• Status: Active Application

• Current Assignee: Shanghai IC R&D Center Co., Ltd
• Original Assignee: Shanghai IC R&D Center Co., Ltd
• Inventors: HU, Hongmei
• Application Number:
  US16/475,116
• Publication Number:
  US 20190332019A1
• Time in Patent Office: Days
• CPC Class Codes: G03F 1/36 Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes
• CPC Class Codes: G03F 7/70441 Optical proximity correction [OPC]

Abstract

A method for adding Assist Feature comprises providing target patterns for OPC, selecting a rule in which only one Assist Feature can be added based on a Base AF rule, and establishing an Extra Assist Feature rule; making a global size-up of the target patterns, so that all sides of the target patterns extend outwards by a distance A; subtracting the distance value between the corresponding sides of the target patterns formatted under the Extra Assist Feature rule by a distance 2A based on the Extra Assist Feature rule; and carrying out the corresponding adjustment on other parameters which are affected by the overall sizing of the target patterns formatted under the Extra Assist Feature rule based on a distance A; operating the Extra Assist Feature rule to generate a first Assist Feature; executing the Base AF rule on the target patterns, generating a second Assist Feature by using the first Assist Feature as a newly-added reference feature, and superimposing the first Assist Feature, the second Assist Feature and the existing Assist Feature to form a final Assist Feature.

Claims

1. A method for adding Assist Features, comprising:

Step 01, providing target patterns for OPC, selecting a rule in which only one Assist Feature can be added based on a Base AF rule, and establishing an Extra Assist Feature rule;

wherein the target patterns already has Assist Feature;

Step 02, making a global size-up of the target patterns, so that all sides of the target patterns extend outwards by a distance A;

wherein the distance A is a non-negative number, and the unit of the distance A is a unit of length;

Step 03, subtracting the distance value between the corresponding sides of the target patterns formatted under the Extra Assist Feature rule by a distance 2A based on the Extra Assist Feature rule; and

carrying out the corresponding adjustment on other parameters which are affected by the overall sizing of the target patterns formatted under the Extra Assist Feature rule based on a distance A;

Step 04, operating the Extra Assist Feature rule to generate a first Assist Feature;

Step 05, executing the Base AF rule on the target patterns, generating a second Assist Feature by using the first Assist Feature as a newly added reference feature, and superimposing the first Assist Feature, the second Assist Feature and the existing Assist Feature to form a final Assist Feature.

2. The method for adding Assist Features of claim 1, wherein, in the Step 02, the distance A is less than ½

of the minimum space allowed by the target patterns.

3. The method for adding Assist Features of claim 1, wherein the Assist Features in the Rule-based Assist Feature and the Assist Features in the Extra Assist Feature rule are side bar Assist Features.

4. The method for adding Assist Features of claim 1, wherein, in the Step 01 and before the Extra Assist Feature rule is established, the method further includes:

establishing an initial Rule-based Assist Feature on the target patterns based on the Base AF rule;

in step 05, the method further comprises;

executing the Rule-based Assist Feature on the target patterns, generating a second Assist Feature by using the first Assist Feature, the initial Rule-based Assist Feature, the original input Assist Feature and the original input reference pattern as reference pattern;

the final Assist Feature is composed of the first Assist Feature, the second Assist Feature, the initial Rule-based Assist Feature and the original input Assist Feature.

5. The method for adding Assist Features of claim 4, wherein the initial Rule-based Assist Feature comprises side bar Assist Features and corner bar Assist Features.

6. The method for adding Assist Features of claim 1, wherein the target patterns include contact/hole target patterns.

7. The method for adding Assist Features of claim 1, wherein the Assist Feature is sub-resolution pattern.

8. The method for adding Assist Features of claim 1, wherein, further comprises a Step between the Step 04 and the Step 05, the Step is, replacing the target patterns after global sizing-up with the target patterns in Step 01.