Methodology for post-integration awareness in optical proximity correction

Patent metadata

Field	Value
Publication number	US-10386715-B2
Application number	US-201715730830-A
Country	US
Kind code	B2
Filing date	Oct 12, 2017
Priority date	Oct 12, 2017
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

A method of creating an optical proximity correction (OPC) model and assessing the model through optical rule checking (ORC) includes the introduction of post-integration, i.e., post-metallization data. High density critical dimension scanning electron microscopy and backscattered electron scanning electron microscopy from a metallized structure are used during development and verification of the model to accurately predict post-integration behavior.

First claim

What is claimed is:

1. A method of verifying an optical proximity correction (OPC) rule set, comprising:
collecting critical dimension scanning electron microscope (CDSEM) data from a post-integration structure, wherein the post-integration structure includes:
a first metal level having a first conductive structure, and
a second metal level above the first metal level and having a second conductive structure horizontally separated from the first conductive structure;

constructing a post-integration OPC model using the post-integration CDSEM data;
performing optical rule checking (ORC) on the optical proximity correction (OPC) rule set using the post-integration OPC model to identify post-integration weak points within the structure, wherein at least one of the post-integration weak points includes a bridge defect between the first conductive structure and the second conductive structure;
verifying the post-integration weak points to create a verified OPC rule set; and
producing a photomask using the verified OPC rule set.

2. The method of claim 1 , wherein the CDSEM data comprises a backscattered critical dimension scanning electron microscope (BSE CDSEM) compositional image including the first metal level and the second metal level.

3. The method of claim 1 , wherein the post-integration CDSEM data corresponds to a metal trench pattern.

4. The method of claim 1 , wherein the first conductive structure includes a lower metal wire, and wherein the second conductive structure includes an upper via.

5. The method of claim 4 , wherein verifying the post-integration weak points comprises measuring a distance between a top surface of the lower metal wire and a bottom surface of the upper via within the structure.

6. The method of claim 5 , wherein the measured distance includes a horizontal component and a vertical component.

7. The method of claim 1 , wherein verifying the post-integration weak points utilizes at least one metrology technique selected from a group consisting of high energy critical dimension scanning electron microscopy, transmission electron microscopy and electron beam spectroscopy.

8. A method of verifying an optical proximity correction (OPC) rule set, comprising:
collecting image data from a post-integration structure, wherein the post-integration structure includes:
a first metal level having a first conductive structure, and
a second metal level above the first metal level and having a second conductive structure horizontally separated from the first conductive structure;

generating a post-integration OPC model using the image data of the post-integration structure;
performing optical rule checking (ORC) on the optical proximity correction (OPC) rule set using the post-integration OPC model to identify post-integration weak points within the structure, wherein at least one of the post-integration weak points includes a bridging region between the first conductive structure and the second conductive structure;
modifying the OPC rule set to correct for the identified post-integration weak points; and
producing a photomask using the modified OPC rule set.

9. The method of claim 8 , wherein the image data of the post-integration structure comprises a backscattered critical dimension scanning electron microscope (BSE CDSEM) image.

10. The method of claim 8 , wherein the image data of the post-integration structure corresponds to a metal trench pattern.

11. The method of claim 8 , wherein the first conductive structure includes a lower metal wire, and wherein the second conductive structure includes an upper via.

12. The method of claim 11 , further comprising verifying the post-integration weak points.

13. The method of claim 12 , wherein verifying the post-integration weak points comprises measuring a distance between a top surface of the lower metal wire and a bottom surface of the upper via within the structure.

14. The method of claim 13 , wherein the measured distance includes a horizontal component and a vertical component.

15. The method of claim 12 , wherein verifying the post-integration weak points utilizes at least one metrology technique selected from a group consisting of high energy critical dimension scanning electron microscopy, transmission electron microscopy and electron beam spectroscopy.

Assignees

• Globalfoundries Inc

Inventors

• Wang Feng
• Zhang Hongxin
• Gao Shaowen
• Chen Norman

Classifications

• G03F1/36 Primary

  Masks having proximity correction features; Preparation thereof, e.g. optical proximity correction [OPC] design processes · CPC title