Method for the generation of variable pitch nested lines and/or contact holes using fixed size pixels for direct-write lithographic systems

• US 20060236295A1
• Filed: 06/15/2006
• Published: 10/19/2006
• Est. Priority Date: 05/16/2003
• Status: Active Grant

• Current Assignee: ASML Holding NV
• Original Assignee: ASML Holding NV
• Inventors: Baba-Ali, Nabila
• Granted Patent: US 7,589,819 B2
• Time in Patent Office: Days
• US Class Current: 716/52
• CPC Class Codes: G03F 7/70283 Mask effects on the imaging process
• CPC Class Codes: G03F 7/70291 Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices
• 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

Abstract

Provided is a method and system for developing a lithographic mask layout. The lithographic mask layout is adapted for configuring an array of micro-mirrors in a maskless lithography system. The method includes generating an ideal mask layout representative of image characteristics associated with a desired image. Next, an equivalent mask is produced in accordance with an average intensity of the ideal mask layout.

Claims

1. An apparatus for developing a lithographic mask layout, the lithographic mask layout being adapted for configuring an array of micro-mirrors in a maskless lithography system, the apparatus comprising:

means for generating an ideal mask layout representative of image characteristics associated with a desired image; and

means for producing an equivalent mask layout in accordance with an average intensity of the ideal mask layout.

2. The apparatus of claim 1, wherein the means for generating includes means for producing a binary mask layout representative of the image characteristics.

3. The apparatus of claim 2, wherein the characteristics include at least one of pitch and image position.

4. The apparatus of claim 1, wherein each mirror has a predetermined mirror width;

and

wherein the image characteristics are independent of the predetermined mirror width.

5. The apparatus of claim 1, wherein the ideal mask layout has a mask transmission that can vary continuously.

6. The apparatus of claim 5, wherein the means for producing includes (i) means for determining a pitch of the desired image and (ii) means for forming a mirror-based masked pattern, the mirror-based masked pattern being a function of the desired image pitch and the mirror width.

7. The apparatus of claim 6, wherein the equivalent mask layout is representative of the desired image in a wafer plane.

8. The apparatus of claim 7, wherein the mirror-based mask pattern corresponds to a number of pattern pixels;

and

wherein each of the pixels includes a width and an intensity value, each intensity value being determined by averaging intensity values of a corresponding portion of the ideal mask layout, each pixel intensity value being associated with a corresponding grey-tone level.

9. The apparatus of claim 1, further comprising means for producing one or more images in accordance with the equivalent mask layout.

10. The apparatus of claim 9, wherein the one or more images are simulated images produced based upon lithographic simulation tools.

11. The apparatus of claim 9, further comprising means for determining performance metrics of at least one of the one or more images.

12. The apparatus of claim 11, wherein the performance metrics include at least one from the group including critical dimension, normalized image log slope, and image position.

13. The apparatus of claim 12, further comprising means for optimizing the performance metrics when the performance metrics do not satisfy predetermined quality requirements.

14. The apparatus of claim 13, wherein the means for optimizing includes at least one from the group including (a) means for shifting the one or more simulated images in the wafer plane, (b) means for perturbing the grey-tone level of selected ones of the pixels, (c) means for converting the grey-tone levels to tilt angles when the mirrors are tiltable, and (d) means for perturbing tilt angles.