Granted Patent B2

US 7,376,260 · App. 11/011,384 · Granted May 20, 2008

Assignee: LSI Logic Corporation

Abstract

Claims (63)

1. A method for performing post-optical proximity correction (OPC) multi layer overlay quality inspection, comprising:

generating a virtual target mask for a first mask and a second mask overlay using design rules at least partially defining the relationship between the first mask and the second mask;

creating a composite aerial image representing a first mask image formed from the first mask and a second mask image formed by the second mask by performing imaging of the first mask and the second mask and overlaying the second mask image onto the first mask image;

generating an overlay image map of the composite aerial image using the design rules at least partially defining the relationship between the first mask and the second mask; and

comparing the overlay image map area and the virtual target mask area, wherein the step of comparing the overlay image map area and the virtual target mask area comprises:

calculating the area of the overlay image map;

calculating the area of the virtual target mask; and

determining if the area calculated for the overlay image map matches the area calculated for the virtual target mask within the predetermined tolerance.

2. The method as claimed in claim 1 , further comprising:

introducing an overlay error in the second mask;

creating a second composite aerial image representing the first mask image and the second mask image having the introduced error by performing imaging of the first mask and the second mask having the introduced error and overlaying the second mask image having the introduced error onto the first mask image;

generating a second overlay image map of the second composite aerial image using the predetermined design rules defining the relationship between the first mask and the second mask having the introduced error; and

comparing the second overlay image map area and the virtual target mask area.

3. The method as claimed in claim 2 , wherein the introduced overlay error comprises at least one of an alignment error, a rotational error, a magnification error, or the like.

4. The method as claimed in claim 2 , wherein the step of comparing the second overlay image map area and the virtual target mask area comprises:

calculating the area of the second overlay image map;

calculating the area of the virtual target mask; and

determining if the area calculated for the second overlay image map matches the area calculated for the virtual target mask within the predetermined tolerance.

5. The method as claimed in claim 1 , wherein the relationship between the first mask and the second mask comprises a Boolean operation.

6. The method as claimed in claim 1 , wherein the virtual target mask comprises a diffusion/poly post overlay target.

7. The method as claimed in claim 1 , wherein the virtual target mask comprises a contact/metal mask overlay target.

8. A computer-readable medium having computer-executable instructions for executing a method for performing post-optical proximity correction (OPC) multi layer overlay quality inspection, the method comprising:

generating a virtual target mask for a first mask and a second mask overlay using design rules at least partially defining the relationship between the first mask and the second mask;

creating a composite aerial image representing a first mask image formed from the first mask and a second mask image formed by the second mask by performing imaging of the first mask and the second mask and overlaying the second mask image onto the first mask image;

generating an overlay image map of the composite aerial image using the design rules at least partially defining the relationship between the first mask and the second mask; and

comparing the overlay image map area and the virtual target mask area, wherein the step of comparing the overlay image map area and the virtual target mask area comprises:

calculating the area of the overlay image map;

calculating the area of the virtual target mask; and

determining if the area calculated for the overlay image map matches the area calculated for the virtual target mask within the predetermined tolerance.

9. The computer readable medium as claimed in claim 8 , wherein the method further comprises:

introducing an overlay error in the second mask;

creating a second composite aerial image representing the first mask image and the second mask image having the introduced error by performing imaging of the first mask and the second mask having the introduced error and overlaying the second mask image having the introduced error onto the first mask image;

generating a second overlay image map of the second composite aerial image using the predetermined design rules defining the relationship between the first mask and the second mask having the introduced error; and

comparing the second overlay image map area and the virtual target mask area.

10. The computer readable medium as claimed in claim 9 , wherein the introduced error comprises at least one of an alignment error, a rotational error, a magnification error, or the like.

11. The computer readable medium as claimed in claim 9 , wherein the step of comparing the second overlay image map area and the virtual target mask area comprises:

calculating the area of the second overlay image map;

calculating the area of the virtual target mask; and

determining if the area calculated for the second overlay image map matches the area calculated for the virtual target mask within a second predetermined tolerance.

12. The computer readable medium as claimed in claim 8 , wherein the relationship between the first mask and the second mask comprises a Boolean operation.

13. The computer readable medium as claimed in claim 8 , wherein the virtual target mask comprises a diffusion/poly post-OPC mask overlay target.

14. The computer readable medium as claimed in claim 8 , wherein the virtual target mask comprises a contact/metal post-OPC mask overlay target.

15. A semi-conductor integrated circuit device manufactured refined masks using a method for performing post-optical proximity correction (OPC) multi layer overlay quality inspection, the method comprising:

generating a virtual target mask for a first mask and a second mask overlay using design rules at least partially defining the relationship between the first mask and the second mask;

creating a composite aerial image representing a first mask image formed from the first mask and a second mask image formed by the second mask by performing imaging of the first mask and the second mask and overlaying the second mask image onto the first mask image;

generating an overlay image map of the composite aerial image using the design rules at least partially defining the relationship between the first mask and the second mask; and

comparing the overlay image map area and the virtual target mask area, wherein the step of comparing the overlay image map area and the virtual target mask area comprises:

calculating the area of the overlay image map;

calculating the area of the virtual target mask; and

determining if the area calculated for the overlay image map matches the area calculated for the virtual target mask within a predetermined tolerance.

16. The semi-conductor integrated circuit device as claimed in claim 15 , wherein the method further comprises:

introducing an overlay error in the second mask;

creating a second composite aerial image representing the first mask image and the second mask image having the introduced error by performing imaging of the first mask and the second mask having the introduced error and overlaying the second mask image having the introduced error onto the first mask image;

generating a second overlay image map of the second composite aerial image using the predetermined design rules defining the relationship between the first mask and the second mask having the introduced error; and

comparing the second overlay image map area and the virtual target mask area.

17. The semi-conductor integrated circuit device as claimed in claim 16 , wherein the introduced overlay error comprises at least one of an alignment error, a rotational error, a magnification error, or the like.

18. The semi-conductor integrated circuit device as claimed in claim 16 , wherein the step of comparing the second overlay image map area and the virtual target mask area comprises:

calculating the area of the second overlay image map;

calculating the area of the virtual target mask; and

determining if the area calculated for the second overlay image map matches the area calculated for the virtual target mask within a predetermined tolerance.

19. The semi-conductor integrated circuit device as claimed in claim 15 , wherein the relationship between the first mask and the second mask comprises a Boolean operation.

20. The semi-conductor integrated circuit device as claimed in claim 15 , wherein the virtual target mask comprises a diffusion/poly post-OPC mask overlay target.

21. The semi-conductor integrated circuit device as claimed in claim 15 , wherein the virtual target mask comprises a contact/metal post-OPC mask overlay target.

Assignments (8)

Continuity (2)