Balancing mask loading

Patent metadata

Field	Value
Publication number	US-9360750-B2
Application number	US-201414300152-A
Country	US
Kind code	B2
Filing date	Jun 9, 2014
Priority date	Aug 31, 2012
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

Among other things, techniques for balancing mask loading are provided for herein. In some embodiments, one or more windows are defined within a layout. Based upon polygons comprised within respective windows, a localized mask loading is computed for the layout. In some embodiments, a global mask loading is also computed for the layout. Using the localized mask loading and the global mask loading, if computed, a loading effect of a plurality of mask pattern schemes is evaluated to identify a mask pattern scheme having a desired loading effect.

First claim

What is claimed is:

1. A method, comprising:
receiving a layout comprising a set of polygons associated with a semiconductor device;
defining a first window within the layout, a first subset of the set of polygons at least partially situated within the first window;
defining a second window within the layout, a second subset of the set of polygons at least partially situated within the second window;
for a first mask pattern scheme describing a first assignment of the set of polygons to masks:
computing a first localized mask loading for the first window and the second window;

for a second mask pattern scheme describing a second assignment of the set of polygons to the masks:
computing a second localized mask loading for the first window and the second window;

assigning the first mask pattern scheme or the second mask pattern scheme to the layout based upon the first localized mask loading and the second localized mask loading, wherein a distribution of holes across the masks is specified by the first mask pattern scheme when the first mask pattern scheme is assigned to the layout and is specified by the second mask pattern scheme when the second mask pattern scheme is assigned to the layout; and
forming the masks according to:
the first mask pattern scheme when the first mask pattern scheme is assigned to the layout; and
the second mask pattern scheme when the second mask pattern scheme is assigned to the layout.

2. The method of claim 1 , wherein,
the first mask pattern scheme is assigned to the layout if the first localized mask loading is less than the second localized mask loading; and
the second mask pattern scheme is assigned to the layout when the second localized mask loading is less than the first localized mask loading.

3. The method of claim 1 , the computing a first localized mask loading comprising:
for the first window:
computing a first area difference for a first portion of a first color net represented in the first window.

4. The method of claim 3 , the computing a first localized mask loading comprising:
for the first window:
computing a second area difference for a first portion of a second color net represented in the first window; and
summing the first area difference and the second area difference to yield a first window mask loading.

5. The method of claim 4 , the computing a first localized mask loading comprising:
for the second window:
computing a third area difference for a second portion of the first color net represented in the second window; and

summing the first window mask loading with the third area difference to yield the first localized mask loading.

6. The method of claim 1 , the computing a first localized mask loading comprising:
computing a first window mask loading for the first window; and
computing a second window mask loading for the second window.

7. The method of claim 6 , the computing a first localized mask loading comprising:
applying a first window weight to the first window mask loading to yield a first weighted window mask loading;
applying a second weight to the second window mask loading to yield a second weighted window mask loading; and
summing the first weighted window mask loading and the second weighted window mask loading to yield the first localized mask loading.

8. The method of claim 1 , the first mask pattern scheme providing for assigning a first mask to a first portion of the first subset and assigning a second mask to a second portion of the first subset.

9. The method of claim 1 , comprising:
computing a first global mask loading for the layout if the first mask pattern scheme is assigned to the layout; and
computing a second global mask loading for the layout if the second mask pattern scheme is assigned to the layout.

10. The method of claim 9 , wherein the assigning is further based the first global mask loading and the second global mask loading.

11. The method of claim 1 , wherein the first window at least partially overlaps the second window.

12. A method, comprising:
receiving a layout comprising a set of polygons associated with a semiconductor device;
defining a plurality of windows within the layout, a first subset of the set of polygons at least partially situated within a first window of the plurality of windows;
for a first mask pattern scheme describing a first assignment of the set of polygons to masks:
determining a first window mask loading for the first window; and determining a first global mask loading for the layout

using the first window mask loading and the first global mask loading to evaluate a loading effect of the first mask pattern scheme on the layout; and
forming the masks according to the first mask pattern scheme when the loading effect of the first mask pattern scheme is less than or equal to a loading effect of a desired mask pattern scheme.

13. The method of claim 12 , comprising:
for a second mask pattern scheme:
determining a second window mask loading for the first window; and
determining a second global mask loading for the layout;

using the second window mask loading and the second global mask loading to evaluate a loading effect of the second mask pattern scheme;
comparing the loading effect of the first mask pattern scheme to the loading effect of the second mask pattern scheme; and
assigning the first mask pattern scheme or the second mask pattern scheme to the layout based upon the comparing.

14. The method of claim 12 , the using comprising:
applying a window weight to the first window mask loading; and
applying a global weight to the first global mask loading.

15. The method of claim 12 , comprising:
for the first mask pattern scheme:
determining a second window mask loading for a second window of the plurality, a second subset of the set at least partially situated within the second window, wherein the using comprises:
using the second window mask loading to evaluate the loading effect of the first mask pattern scheme.

16. The method of claim 15 , the using comprising summing the first window mask loading and the second window mask loading to yield a first localized mask loading.

17. The method of claim 16 , comprising, for the first mask pattern scheme:
determining a first global mask loading for the layout, wherein the using comprises:
summing the first localized mask loading and the first global mask loading to evaluate the loading effect of the first mask pattern scheme.

18. The method of claim 17 , the using comprising, before the summing the first localized mask loading and the first global mask loading:
applying a localized weight to the first localized mask loading; and
applying a global weight to the first global mask loading.

19. A method, comprising:
receiving a layout comprising a set of polygons associated with a semiconductor device;
defining a first window within the layout, a first subset of the set of polygons at least partially situated within the first window;
defining a second window within the layout, a second subset of the set of polygons at least partially situated within the second window;
for a first mask pattern scheme:
computing a first window mask loading for the first window;
computing a second window mask loading for the second window;
applying a first window weight to the first window mask loading to yield a first weighted window mask loading;
applying a second window weight to the second window mask loading to yield a second weighted window mask loading;
summing the first weighted wind

Assignees

• Taiwan Semiconductor Mfg

Inventors

• Lin Hunglung
• Hsu Chin-Chang
• YANG Wen-ju

Classifications

• G03F1/70 Primary

  Adapting basic layout or design of masks to lithographic process requirements, e.g., second iteration correction of mask patterns for imaging · CPC title