FACILITATING PROCESS MODEL ACCURACY BY MODELING MASK CORNER ROUNDING EFFECTS

• US 20090089736A1
• Filed: 09/28/2007
• Published: 04/02/2009
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: Synopsys Incorporated
• Original Assignee: Synopsys Incorporated
• Inventors: Huang, Jensheng, Melvin, Lawrence S. III, Kuo, Chun-chieh
• Granted Patent: US 7,707,539 B2
• Time in Patent Office: Days
• US Class Current: 716/50
• 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 7/70441 Optical proximity correction [OPC]
• 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: G03F 7/70675 Latent image, i.e. measuring the image of the exposed resist prior to development

Abstract

An embodiment provides systems and techniques for determining an improved process model which models mask corner rounding (MCR) effects. During operation, the system may receive a mask layout and process data which was generated by applying a photolithography process to the mask layout. The system may also receive an uncalibrated process model which may contain a set of MCR components. Next, the system may identify a set of corners in the mask layout. The system may then modify the mask layout in proximity to the set of corners to obtain a modified mask layout. Alternatively, the system may determine a set of mask layers. Next, the system may determine an improved process model by calibrating the uncalibrated process model using the modified mask layout and/or the set of mask layers, and the process data.

Claims

1. A method for determining an improved process model which models mask corner rounding effects, the method comprising:

receiving a mask layout;

receiving process data which was generated by applying a photolithography process to the mask layout;

receiving an uncalibrated process model;

identifying a set of corners in the mask layout;

modifying the mask layout in proximity to the set of corners to obtain a modified mask layout, wherein the modifications to the mask layout relate to mask corner rounding effects; and

determining the improved process model by calibrating the uncalibrated process model using the modified mask layout and the process data.

2. The method of claim 1, wherein modifying the mask layout includes adding a bevel artifact to a corner in the set of corners.

3. The method of claim 1, wherein modifying the mask layout includes adding a notch artifact to a corner in the set of corners.

4. The method of claim 1, wherein the set of corners includes an inner corner and an outer corner, and wherein modifying the mask layout includes:

adding a first artifact to the inner corner; and

adding a second artifact to the outer corner, wherein the second artifact is different from the first artifact.

5. The method of claim 4, wherein the first artifact'"'"'s size is different from the second artifact'"'"'s size.

6. The method of claim 4, wherein the first artifact'"'"'s shape is different from the second artifact'"'"'s shape.

7. A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for determining an improved process model which models mask corner rounding effects, the method comprising:

receiving a mask layout;

receiving process data which was generated by applying a photolithography process to the mask layout;

receiving an uncalibrated process model;

identifying a set of corners in the mask layout;

modifying the mask layout in proximity to the set of corners to obtain a modified mask layout, wherein the modifications to the mask layout relate to mask corner rounding effects; and

determining the improved process model by calibrating the uncalibrated process model using the modified mask layout and the process data.

8. The computer-readable storage medium of claim 7, wherein modifying the mask layout includes adding a bevel artifact to a corner in the set of corners.

9. The computer-readable storage medium of claim 7, wherein modifying the mask layout includes adding a notch artifact to a corner in the set of corners.

10. The computer-readable storage medium of claim 7, wherein the set of corners includes an inner corner and an outer corner, and wherein modifying the mask layout includes:

adding a first artifact to the inner corner; and

adding a second artifact to the outer corner, wherein the second artifact is different from the first artifact.

11. The computer-readable storage medium of claim 10, wherein the first artifact'"'"'s size is different from the second artifact'"'"'s size.

12. The computer-readable storage medium of claim 10, wherein the first artifact'"'"'s shape is different from the second artifact'"'"'s shape.

13. A method for determining an improved process model which models mask corner rounding effects, the method comprising:

receiving a mask layout;

receiving process data which was generated by applying a photolithography process to the mask layout;

receiving an uncalibrated process model which includes;

an optical component; and

a set of mask-corner-rounding (MCR) components, wherein each MCR component is designed to model MCR effects;

identifying a set of corners in the mask layout;

determining a set of mask layers which includes;

a first mask layer which includes substantially all patterns in the mask layout; and

a set of MCR mask layers, wherein substantially all patterns in each MCR mask layer relate to patterns in the mask layout that are in proximity to the set of corners, and wherein each MCR mask layer is associated with an MCR component; and

determining the improved process model by calibrating the uncalibrated process model using the set of mask layers and the process data.

14. The method of claim 13, wherein the set of MCR components includes:

an inner-corner component for modeling MCR effects of inner corners; and

an outer-corner component for modeling MCR effects of outer corners.

15. The method of claim 13, wherein the set of MCR mask layers includes:

an inner-corner mask layer, wherein substantially all patterns in the inner-corner mask layer relate to patterns in the mask layout that are in proximity to inner corners; and

an outer-corner mask layer, wherein substantially all patterns in the outer-corner mask layer relate to patterns in the mask layout that are in proximity to outer corners.

16. The method of claim 13, wherein determining the improved process model includes:

convolving the optical component with the first mask layer; and

convolving each MCR component with the associated MCR mask layer.

17. A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for determining an improved process model which models mask corner rounding effects, the method comprising:

receiving a mask layout;

receiving process data which was generated by applying a photolithography process to the mask layout;

receiving an uncalibrated process model which includes;

an optical component; and

a set of mask-corner-rounding (MCR) components, wherein each MCR component is designed to model MCR effects;

identifying a set of corners in the mask layout;

determining a set of mask layers which includes;

a first mask layer which includes substantially all patterns in the mask layout; and

a set of MCR mask layers, wherein substantially all patterns in each MCR mask layer relate to patterns in the mask layout that are in proximity to the set of corners, and wherein each MCR mask layer is associated with an MCR component; and

determining the improved process model by calibrating the uncalibrated process model using the set of mask layers and the process data.

18. The computer-readable storage medium of claim 17, wherein the set of MCR components includes:

an inner-corner component for modeling MCR effects of inner corners; and

an outer-corner component for modeling MCR effects of outer corners.

19. The computer-readable storage medium of claim 17, wherein the set of MCR mask layers includes:

an inner-corner mask layer, wherein substantially all patterns in the inner-corner mask layer relate to patterns in the mask layout that are in proximity to inner corners; and

an outer-corner mask layer, wherein substantially all patterns in the outer-corner mask layer relate to patterns in the mask layout that are in proximity to outer corners.

20. The computer-readable storage medium of claim 17, wherein determining the improved process model includes:

convolving the optical component with the first mask layer; and

convolving each MCR component with the associated MCR mask layer.

21. A computer-readable storage medium storing instructions that when executed by a computer cause the computer to perform a method for determining an improved process model, the method comprising:

receiving a mask layout;

receiving process data, wherein the process data is generated by measuring critical dimensions of features that were produced using the mask layout and a photolithography process;

receiving an uncalibrated process model which includes;

an optical component; and

a mask-corner-rounding (MCR) component which is designed to model MCR effects;

selecting a set of corners in the mask layout;

determining an MCR mask layer, wherein substantially all patterns in the MCR mask layer relate to patterns in the mask layout that are in proximity to the set of corners;

determining the improved process model by calibrating the uncalibrated process model using the mask layout, the MCR mask layer, and the process data; and

outputting the improved process model.

22. The computer-readable storage medium of claim 21, wherein determining the improved process model includes:

convolving the optical component with the mask layout; and

convolving the MCR component with the MCR mask layer.