Method and apparatus for creating a phase step in mirrors used in spatial light modulator arrays

• US 7,279,110 B2
• Filed: 12/27/2004
• Issued: 10/09/2007
• Est. Priority Date: 12/27/2004
• Status: Expired due to Fees

• Current Assignee: ASML Holding NV
• Original Assignee: ASML Holding NV
• Inventors: Roux, Stephen
• Primary Examiner(s): Ahmed; Shamim
• Application Number:
  US11/020,138
• Publication Number:
  US 20060139729A1
• Time in Patent Office: 1,016 Days
• Field of Search: 216/2, 216/24, 216/41, 216/58, 216/17, 216/66, 216/19
• US Class Current: 216/24
• CPC Class Codes: G02B 26/0833 the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD G02B26/0825 takes precedence; micromechanical devices in general B81B

Abstract

A method and apparatus for patterning an array of SLM mirrors with a phase step is disclosed. Additional embodiments of the present invention describe a method for processing a substrate, wherein the processed substrate is used in the apparatus for patterning an array of SLM mirrors with a phase step. The processed substrate is then placed in close proximity to the mirrors and the etching/deposition process is then done through openings in the substrate. In embodiments in which the processed substrate does not have a high enough density of openings, a stepping and repeating process is used in order to achieve complete process coverage of every mirror in an array of SLM mirrors.

Claims

1. A method for manufacturing a spatial light modulator (SLM) mirror, comprising:

(a) creating a plurality of cavities on a first major side of a wafer;

(b) patterning a second major side of the wafer with an etch-resistant layer;

(c) etching portions of the wafer not patterned with the etch-resist layer to create openings between the first major side and the second major side of the wafer; and

(d) passing a material through a first opening in the wafer to cause the material to impinge upon a predetermined area of the SLM mirror that is aligned with the first opening, wherein the material causes a phase step to form on the SLM mirror.

2. The method of claim 1, wherein step (a) comprises:

creating a plurality of cavities, each cavity having a width of approximately 0.1 millimeters to 1 millimeters.

3. The method of claim 1, wherein step (a) comprises:

creating a plurality of cavities, each cavity having a width of approximately 0.42 millimeters.

4. The method of claim 1, wherein step (c) comprises:

etching openings in the wafer, each opening having a width of approximately 2 micrometers to 6 micrometers.

5. The method of claim 1, wherein step (c) comprises:

etching openings in the wafer, each opening having a width of approximately 3 micrometers.

6. The method of claim 1, wherein step (a) comprises:

anisotropically etching the first major side of the wafer.

7. The method of claim 1, wherein step (a) comprises creating a plurality of cavities on the first major side of the wafer, wherein the wafer comprises one of a silicon wafer and a molybdenum wafer.

8. The method of claim 1, wherein step (d) comprises etching a phase step in the mirrors by using one of an ion beam and a reactive ion beam as the material that impinges upon the predetermined area of the SLM mirror.

9. The method of claim 8, wherein the reactive ion beam is substantially more reactive with a reflective coating of the SLM mirror than the wafer.

10. The method of claim 1, wherein step (d) comprises depositing a phase step on the SLM mirror by using aluminum as the material that impinges upon the SLM mirror.

11. The method of claim 1, wherein the SLM mirror is one of a plurality of SLM mirrors included in an array of SLM mirrors, the method further comprising:

(e) moving the array of SLM mirrors in discrete steps along a first direction; and

(f) at each discrete step, passing the material through the first opening in the wafer to cause the material to impinge upon a predetermined area of another SLM mirror in the array of SLM mirrors that is aligned with the first opening, wherein the material causes a phase step to form on the other SLM mirror aligned with the first opening.

18. The method of claim 1, wherein the SLM mirror is one of a plurality of SLM mirrors included in an array of SLM mirrors, the method further comprising:

(e) moving the wafer in discrete steps along a first direction; and

(d) at each discrete step, passing the material through the first opening in the wafer to cause the material to impinge upon a predetermined area of another SLM mirror in the array of SLM mirrors that is aligned with the first opening, wherein the material causes a phase step to form on the other SLM mirror aligned with the first opening.

12. A method for manufacturing a spatial light modulator (SLM) mirror, comprising:

(a) providing a mask having a plurality of openings formed therein; and

(b) passing a material through a first opening in the mask to cause the material to impinge upon a predetermined area of the SLM mirror that is aligned with the first opening, wherein the material causes a phase step to form on the SLM mirror.

13. The method of claim 12, wherein step (b) comprises etching a phase step in the SLM mirror by using one of an ion beam and a reactive ion beam as the material that impinges upon the SLM mirror.

14. The method of claim 13, wherein the reactive ion beam is substantially more reactive with a reflective coating of the SLM mirror than the mask.

15. The method of claim 12, wherein step (b) comprises depositing a phase step on the SLM mirror by using aluminum as the material that impinges upon the SLM mirror.

16. The method of claim 12, wherein the SLM mirror is one of a plurality of SLM mirrors included in an array of SLM mirrors, the method further comprising:

(c) moving the array of SLM mirrors in discrete steps along a first direction; and

(d) at each discrete step, passing the material through the first opening in the mask to cause the material to impinge upon a predetermined area of another SLM mirror in the array of SLM mirrors that is aligned with the first opening, wherein the material causes a phase step to form on the other SLM mirror aligned with the first opening.

17. The method of claim 12, wherein the SLM mirror is one of a plurality of SLM mirrors included in an array of SLM mirrors, the method further comprising:

(c) moving the mask in discrete steps along a first direction; and

(d) at each discrete step, passing the material through the first opening in the mask to cause the material to impinge upon a predetermined area of another SLM mirror in the array of SLM mirrors that is aligned with the first opening, wherein the material causes a phase step to form on the other SLM mirror aligned with the first opening.