Method of Performing Proximity Correction

• US 20090204936A1
• Filed: 02/11/2008
• Published: 08/13/2009
• Est. Priority Date: 02/11/2008
• Status: Abandoned Application

• Current Assignee: Qimonda AG (Infineon Technologies AG)
• Original Assignee: Qimonda AG (Infineon Technologies AG)
• Inventors: Bodendorf, Christof, Jacobs, Werner, Kersch, Alfred
• Application Number:
  US12/029,280
• Publication Number:
  US 20090204936A1
• Time in Patent Office: Days
• US Class Current: 716/53
• 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 1/80 Etching

Abstract

A method of performing proximity correction of a mask layout is used during the generation of a masking structure for performing a processing step. The masking structure includes at least one opening that is delimited by a sidewall and that exposes an area that is to be processed. The method includes the steps of a) determining a value representing a flux of particles to a target portion, wherein the target portion is at least one of the group of a portion of the sidewall and a portion of the uncovered area and wherein the particles are generated during the processing of the area; and b) determining a corrected mask layout dependent on the value determined in step a).

Claims

1. A method of performing proximity correction of a mask layout that is used during generation of a masking structure for performing a processing step, the masking structure comprising at least one opening that is delimited by a sidewall and that exposes an area that is to be processed, the method comprising:

determining a value representing a flux of particles to a target portion, wherein the target portion is a portion of the sidewall and/or a portion of the exposed area, and wherein the particles are generated during the processing of the exposed area; and

determining a corrected mask layout depending on the determined value.

2. The method according to claim 1, wherein the processing step comprises an etching step.

3. The method according to claim 1, wherein the determined value is proportional to an absolute value of the flux of particles to the target portion.

4. The method according to claim 1, wherein the value representing the flux of particles to the target portion is determined assuming that the particles emerge from a part of a cross section of the opening that is visible from the target portion.

5. The method according to claim 4, wherein a cross section that is parallel to the exposed area to be processed and that is located in a region of an upper side of the opening is assumed.

6. The method according to claim 1, wherein the value representing the flux of particles is determined assuming that the particles arrive at the target portion without being reflected.

7. The method according to claim 1, wherein the value representing the flux of particles is determined assuming that the particles are reflected before arriving at the target portion.

8. The method according to claim 1, wherein the target portion is a point located on the sidewall and in the plane of the exposed area to be processed.

9. The method according to claim 4, wherein the value representing the flux of particles is determined by summarizing a plurality of values representing different partial flux to the target portion emerging from different portions of the visible cross section.

10. The method according to claim 9, wherein the value is determined by calculating an integral of a function representing a flux emerging from differential areas of the visible cross section, the integral being evaluated over the visible cross section.

11. The method according to claim 10, wherein the value representing the flux of particles to the target portion is denoted F and is calculated according to

12. The method according to claim 11, wherein the integral is calculated using a contour integral method, wherein a contour of the cross section is represented by a polygon.

13. The method according to claim 12, wherein the opening comprises a trench with width s, length w and height h and the value F is calculated from

14. The method according to claim 13, wherein the length w is assumed to be infinite and the value F is calculated from

15. The method according to claim 14, wherein

a plurality of correction values for a plurality of openings with different widths is measured;

the measured correction values are fitted with an expression based on the equation of claim 14 related to a first target portion in order to determine a value of height h; and

a value representing a flux to a second target portion is determined using the determined value of height h.

16. The method according to claim 1, wherein a correction value is calculated dependent on the determined value, the correction value being used to correct a measure of the mask layout.

17. The method according to claim 16, wherein the correction value is calculated as a polynomial function of the determined value.

18. The method according to claim 1, wherein the sidewall comprises a curved or tilted sidewall.

19. The method according to claim 1, wherein the method steps are represented by a programming code that can be executed on a computer.

20. A storage medium comprising programming code that represents the method steps of claim 1.

21. A programmable device programmed to perform the method according to claim 1.