Computer-implemented methods for determining if actual defects are potentially systematic defects or potentially random defects

• US 7,975,245 B2
• Filed: 08/20/2008
• Issued: 07/05/2011
• Est. Priority Date: 08/20/2007
• Status: Active Grant

• Current Assignee: KLA-Tencor Corporation
• Original Assignee: KLA-Tencor Corporation
• Inventors: Florence, Glenn, Rose, Peter, Park, Allen
• Primary Examiner(s): LEVIN, NAUM B
• Application Number:
  US12/195,024
• Publication Number:
  US 20090055783A1
• Time in Patent Office: 1,049 Days
• Field of Search: 716/52, 716/112, 382/144
• US Class Current: 716/52
• CPC Class Codes: G01R 31/318314 Tools, e.g. program interfaces, test suite, test bench, simulation hardware, test compiler, test program languages simulation software G01R31/318357; emulators G06F11/261
• CPC Class Codes: G01R 31/318371 Methodologies therefor, e.g. algorithms, procedures
• CPC Class Codes: 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

Abstract

Various computer-implemented methods for determining if actual defects are potentially systematic defects or potentially random defects are provided. One computer-implemented method for determining if actual defects are potentially systematic defects or potentially random defects includes comparing a number of actual defects in a group to a number of randomly generated defects in a group. The actual defects are detected on a wafer. A portion of a design on the wafer proximate a location of each of the actual defects in the group and each of the randomly generated defects in the group is substantially the same. The method also includes determining if the actual defects in the group are potentially systematic defects or potentially random defects based on results of the comparing step.

Claims

1. A computer-implemented method for determining if actual defects are potentially systematic defects or potentially random defects, comprising:

comparing a number of actual defects in a group to a number of randomly generated defects in a group, wherein the actual defects are detected on a wafer, and wherein a portion of a design on the wafer proximate a location of each of the actual defects in the group and each of the randomly generated defects in the group is substantially the same; and

determining if the actual defects in the group are potentially systematic defects or potentially random defects based on results of said comparing, wherein said determining comprises determining that the actual defects in the group are potentially systematic defects if the number of the actual defects in the group is greater than the number of the randomly generated defects in the group and determining that the actual defects in the group are potentially random defects if the number of the actual defects in the group is not greater than the number of the randomly generated defects in the group, and wherein said comparing and said determining are performed using a computer system.

2. The method of claim 1, wherein said comparing comprises comparing a Pareto chart generated for the actual defects to a Pareto chart generated for the randomly generated defects.

3. The method of claim 1, wherein said comparing comprises determining a ratio of the number of the actual defects in the group to the number of the randomly generated defects in the group.

4. The method of claim 1, wherein the portion of the design corresponds to a design clip.

5. The method of claim 1, wherein the method is performed separately for different groups of actual defects detected on the wafer, and wherein a portion of the design on the wafer proximate a location of each of the actual defects in each of the different groups is substantially the same.

6. The method of claim 1, wherein the method is performed separately for all groups of actual defects detected on the wafer, and wherein a portion of the design on the wafer proximate a location of each of the actual defects in each of said all groups is substantially the same.

7. The method of claim 1, wherein the method is performed without user intervention.

8. The method of claim 1, wherein the actual defects are detected by inspection of a layer on the wafer, and wherein the randomly generated defects are generated once for an inspection recipe for the layer on the wafer and used for performing the method for defects detected on the layer of multiple wafers using the inspection recipe.

9. The method of claim 1, wherein said determining further comprises determining that the actual defects in the group are potentially systematic defects if the number of the actual defects in the group is statistically greater than the number of the randomly generated defects in the group and determining that the actual defects in the group are potentially random defects if the number of the actual defects in the group is not statistically greater than the number of the randomly generated defects in the group.

10. The method of claim 1, wherein, prior to said comparing, the method further comprises normalizing the number of the randomly generated defects in the group to the number of the actual defects in the group based on total number of the actual defects detected on the wafer and total number of the randomly generated defects.

11. The method of claim 1, further comprising comparing the number of the actual defects in the group to a number of different randomly generated defects in a different group, wherein a portion of the design proximate the location of each of the actual defects in the group and a location of each of the different randomly generated defects in the different group is substantially the same, wherein the randomly generated defects and the different randomly generated defects are separately generated, and wherein said determining further comprises determining if the actual defects in the group are potentially systematic defects or potentially random defects based on the results of said comparing the number of the actual defects in the group to the number of the randomly generated defects in the group and the number of the different randomly generated defects in the group.

12. A non-transitory computer-readable medium, comprising program instructions executable on a computer system for performing a computer-implemented method for determining if actual defects are potentially systematic defects or potentially random defects, wherein the computer-implemented method comprises:

comparing a number of actual defects in a group to a number of randomly generated defects in a group, wherein the actual defects are detected on a. wafer, and wherein a portion of a design on the wafer proximate a location of each of the actual defects in the group and each of the randomly generated detects in the group is substantially the same; and

determining if the actual defects in the group are potentially systematic defects or potentially random defects based on results of said comparing, wherein said determining comprises determining that the actual defects in the group are potentially systematic defects if the number of the actual defects in the group is greater than the number of the randomly generated defects in the group and determining that the actual defects in the group are potentially random defects if the number of the actual defects in the group is not greater than the number of the randomly generated defects in the group.

13. A system configured to determine if actual defects are potentially systematic defects or potentially random defects, comprising:

an inspection system configured to detect actual defects on a wafer; and

a computer system configured to;

compare a number of the actual defects in a group to a number of randomly generated defects in a group, wherein a portion of a design on the wafer proximate a location of each of the actual defects in the group and each of the randomly generated defects in the group is substantially the same; and

determine if the actual defects in the group are potentially systematic defects or potentially random defects based on results of the comparison, wherein determining if the actual defects in the group are potentially systematic defects or potentially random defects comprises determining that the actual defects in the group are potentially systematic defects if the number of the actual defects in the group is greater than the number of the randomly generated defects in the group and determining that the actual defects in the group are potentially random defects if the number of the actual defects in the group is not greater than the number of the randomly generated defects in the group.