System and method of predicting problematic areas for lithography in a circuit design

• US 8,001,495 B2
• Filed: 04/17/2008
• Issued: 08/16/2011
• Est. Priority Date: 04/17/2008
• Status: Expired due to Fees

• Current Assignee: Mentor Graphics Corporation (Siemens AG)
• Original Assignee: International Business Machines Corporation
• Inventors: Liegl, Bernhard R., Brunner, Timothy A., Greco, Stephen E., Xiang, Hua
• Primary Examiner(s): ROSSOSHEK, YELENA
• Application Number:
  US12/104,585
• Publication Number:
  US 20090265679A1
• Time in Patent Office: 1,216 Days
• Field of Search: 716/1, 716/2, 716/4, 716/5, 716/6, 716/19, 716/20, 716/21, 355/55, 355/67, 430/5, 430/30, 430/394
• US Class Current: 716/55
• 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 1/70 Adapting basic layout or design of masks to lithographic process requirements, e.g., second iteration correction of mask patterns for imaging
• CPC Class Codes: G03F 7/705 Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions
• CPC Class Codes: G06F 30/30 Circuit design

Abstract

A system and method is provided which predicts problematic areas for lithography in a circuit design, and more specifically, which uses modeling data from a modeling tool to accurately predict problematic lithographic areas. The method includes identifying surface heights of plurality of tiles of a modeled wafer, and mathematically mimicking a lithographic tool to determine best planes of focus for exposure for the plurality of tiles.

Claims

1. A method of predicting problematic areas for lithography comprising:

identifying, by a processor, surface heights of a plurality of tiles of a modeled wafer; and

mathematically mimicking a lithographic tool to determine best planes of focus for exposure for the plurality of tiles,

wherein an average distance of the surface heights is for a plurality of fields of exposure for each tile which is a three dimensional representation of a surface texture at a location on the modeled wafer.

2. The method of claim 1, wherein the identifying is performed by a modeling tool prior to reticle and wafer fabrication.

3. The method of claim 1, further comprising identifying tiles with an average focus offset with a value above a certain specification distance related to a depth of focus for a lithography process.

4. The method of claim 3, further comprising providing the calculated average offset data to a mask tool.

5. A method of predicting problematic areas for lithography comprising:

identifying, by a processor, surface heights of a plurality of tiles of a modeled wafer; and

mathematically mimicking a lithographic tool to determine best planes of focus for exposure for the plurality of tiles,

wherein the identifying surface heights of the plurality of tiles determines a three dimensional texture of the modeled wafer.

6. A method of predicting problematic areas for lithography comprising:

identifying, by a processor, surface heights of a plurality of tiles of a modeled wafer;

mathematically mimicking a lithographic tool to determine best planes of focus for exposure for the plurality of tiles; and

predicting an average distance of the surface heights if for a plurality of fields of exposure for each of the plurality of tiles comprises calculating a predetermined number of focal planes for each tile in a reticle field.

7. The method of claim 6, wherein each of the predetermined number of focal planes contributes to an equal percentage of exposure dose for an entire tile.

8. The method of claim 6, wherein the predetermined number of focal planes are used to measure surface irregularity in three dimensions.

9. The method of claim 6, wherein the predetermined number of focal planes are different planes of exposure.

10. The method of claim 6, wherein each of the plurality of fields of exposure is calculated to find an average focus offset by calculating an average distance along an axis of illumination from a best average focal plane.