METHOD OF CORRECTING FLARE AND METHOD OF PREPARING EXTREME ULTRA VIOLET MASK

• US 20120224156A1
• Filed: 03/02/2012
• Published: 09/06/2012
• Est. Priority Date: 03/03/2011
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Lee, Young-Mi, Kim, In-Sung, Park, Ji-Soong, Ahn, Byoung-Sup, Shin, Jae-Pil
• Granted Patent: US 9,116,438 B2
• Time in Patent Office: Days
• US Class Current: 355/52
• CPC Class Codes: G03F 1/22 Masks or mask blanks for imaging by radiation of 100nm or shorter wavelength, e.g. X-ray masks, extreme ultraviolet [EUV] masks; Preparation thereof
• 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 1/68 Preparation processes not covered by groups G03F1/20 - G03F1/50
• 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 1/84 Inspecting
• CPC Class Codes: G03F 7/70433 Layout for increasing efficiency or for compensating imaging errors, e.g. layout of exposure fields for reducing focus errors; Use of mask features for increasing efficiency or for compensating imaging errors
• CPC Class Codes: G03F 7/70441 Optical proximity correction [OPC]
• CPC Class Codes: G03F 7/70591 Testing optical components
• CPC Class Codes: G03F 7/70941 Stray fields and charges, e.g. stray light, scattered light, flare, transmission loss

Abstract

A method of correcting flare includes measuring flare of a test pattern, calculating point spread functions (PSFs) of the flare as a function of distance, and correcting the flare using corresponding PSFs for an influence range of the flare. The influence range is divided into a first range less than a predetermined distance and a second range equal to or greater than the predetermined distance, and corresponding PSFs are separately applied to the first and second ranges to correct the flare.

Claims

1. A method of correcting flare in extreme ultraviolet (EUV) lithography, the method comprising:

measuring flare of a test pattern;

calculating point spread functions (PSFs) of the flare as a function of distance; and

correcting the flare using the corresponding PSF for an influence range of the flare.

2. The method of claim 1, wherein the influence range is divided into a first range less than a predetermined distance and a second range equal to or greater than the predetermined distance.

3. The method of claim 2, wherein, when correcting the flare uses a same operation over the first and second influence ranges, corresponding PSFs are separately applied to the first and second ranges to perform optical proximity correction (OPC).

4. The method of claim 2, wherein, when correcting the flare uses different operations for each of the first and second influence ranges, a PSF of the flare in the first range is used for a chip level OPC correction, and a PSF of the flare in the second range is used for long-range flare correction or writing.

5. The method of claim 2, wherein the predetermined distance corresponds to a distance between full-fields on which an exposure is performed, or a width of a scribe lane of a wafer.

6. The method of claim 5, wherein the first range comprises a short-range and a middle-range, which are less than the width of the scribe lane, and the second range comprises a long-range equal to or greater than the width of the scribe lane.

7. The method of claim 1, wherein a shadow effect resulting from an oblique incidence of EUV is used with the OPC.

8. The method of claim 1, wherein the PSFs are convolved with a density map of the test pattern to yield a flare map, and are used for at least one of OPC, long-range flare correction, and writing.

9. The method of claim 8, wherein, when the PSFs are used for writing, the flare map is converted into a dose map.

10. A method of preparing an extreme ultraviolet (EUV) mask, the method comprising:

measuring a critical dimension (CD) and flare of a test pattern on a wafer formed using a test mask;

calculating point spread functions (PSFs) of the flare;

calibrating a model based on the CD, and preparing an algorithm for optical proximity correction (OPC);

performing and verifying OPC on a mask using the calibrated model and the algorithm;

performing mask tape-out (MTO) by transmitting OPC result data for mask preparation;

performing mask process correction (MPC) by correcting a mask process proximity effect based on the OPC result data;

dividing MPC result data into regions for the mask preparation; and

adjusting a mask preparation exposure dose based on the divided result data for each region,

wherein PSFs corresponding to an influence range are used to correct the flare.

11. The method of claim 10, wherein the influence range is divided into a first range less than a predetermined distance and a second range equal to or greater than the predetermined distance.

12. The method of claim 11, wherein, when correcting the flare uses a same operation over the first and second influence ranges, corresponding PSFs are separately applied to the first and second ranges for calibrating the model, performing OPC, and verifying the OPC.

13. The method of claim 11, wherein, when correcting the flare uses different operations for each of the first and second influence ranges, PSFs of the flare in the first range are used for a chip level correction comprising calibrating the model, performing OPC, and verifying OPC, and a PSF of the flare in the second range are used for any one of correcting long-range flare and adjusting the dose after performing MPC.

14. The method of claim 11, wherein the predetermined distance corresponds to a distance between full-fields on which an exposure is performed, or a width of a scribe lane of a wafer.

15. The method of claim 10, wherein a shadow effect resulting from an oblique incidence of EUV is used for calibrating the model, performing OPC, and verifying OPC.

16. A method of correcting flare in extreme ultraviolet (EUV) lithography, the method comprising:

providing point spread functions (PSFs) of flare of a test pattern as a function of distance; and

correcting the flare using the corresponding PSF for an influence range of the flare,

wherein the influence range is divided into a first range less than a predetermined distance and a second range equal to or greater than the predetermined distance, and corresponding PSFs are separately applied to the first and second ranges to correct the flare.

17. The method of claim 16, wherein correcting the flare comprises performing optical proximity correction (OPC) over the first and second influence ranges.

18. The method of claim 16, wherein correcting the flare comprises performing a chip level OPC correction in the first range, and long-range flare correction or writing in the second range.

19. The method of claim 18, further comprising convolving the PSFs with a density map of the test pattern to yield a flare map, and converting the flare map into a dose map when the PSFs are used for writing.