Method for removal of pattern resist over patterned metal having an underlying spacer layer

• US 7,354,865 B2
• Filed: 12/31/2003
• Issued: 04/08/2008
• Est. Priority Date: 12/31/2003
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: DiCarlo, Anthony, Wesneski, Lisa A.
• Primary Examiner(s): Vinh; Lan
• Application Number:
  US10/750,142
• Publication Number:
  US 20050148192A1
• Time in Patent Office: 1,560 Days
• Field of Search: 438/706, 438/710, 438/712, 438/745, 438/720, 134/1.1, 134/1.2, 430/312, 430/313
• US Class Current: 438/720
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G03F 7/422 using liquids only G03F7/421 takes precedence
• CPC Class Codes: G03F 7/427 using plasma means only

Abstract

A method of removing the pattern resist that remains on a microchip wafer after etching a patterned layer that is supported by a spacer layer. After the etch, the wafer is cleaned with a develop clean process that removes polymer residues from the pattern resist surface. Next is an ash to remove the hardened pattern resist surface, followed by removal of the pattern resist.

Claims

1. A method of removing pattern resist, comprising the steps of:

providing a wafer having an etched patterned layer and an overlying mask pattern resist outwardly from a spacer layer;

cleaning the wafer with a develop solution;

ashing the surface of the wafer;

photochemically removing the pattern resist that remains after the cleaning and ashing steps; and

selectively removing at least a majority of the spacer layer.

2. The method of claim 1, wherein the wafer is a micromechanical device wafer.

3. The method of claim 1, wherein the wafer is a DMD wafer.

4. The method of claim 1, wherein the cleaning step substantially removes polymer residue from the pattern resist.

5. The method of claim 1, wherein the ashing step substantially removes hardened skin from the pattern resist.

6. The method of claim 1, wherein the removing step is performed with an acetate strip process.

7. The method of claim 1, wherein the patterned layer is a metal layer.

8. A method, comprising the steps of:

depositing a sacrificial layer;

depositing material for a patterned layer;

depositing a pattern resist material;

etching the resist material and the material for the patterned layer;

cleaning the resist material and remaining material for the patterned layer with a develop solution after said etching step;

ashing the surface of the wafer after said cleaning step;

photochemically removing the pattern resist that remains after the cleaning and ashing steps; and

selectively removing the sacrificial layer.

9. The method of claim 8, wherein the wafer is a micromechanical device wafer.

10. The method of claim 8, wherein the wafer is a DMD wafer.

11. The method of claim 8, wherein the cleaning step substantially removes polymer residue from the pattern resist.

12. The method of claim 8, wherein the ashing step substantially removes hardened skin from the pattern resist.

13. The method of claim 8, wherein the removing step is performed with an acetate strip process.

14. The method of claim 8, wherein the patterned layer is a metal layer.

15. A method of forming a micromirror array, comprising the steps of:

forming control circuitry on a semiconductor substrate;

depositing a first spacer layer on the substrate;

patterning the first spacer layer to define hinge support vias and spring tip support vias;

depositing a hinge layer over the first spacer layer;

forming at least one hinge etch mask on the hinge layer;

patterning the hinge layer to form at least one hinge, wherein the pattern is formed using a pattern resist layer and an etch process;

removing pattern resist that remains after the preceding step by;

cleaning the wafer with a develop solution;

ashing the surface of the wafer; and

removing the pattern resist that remains after the cleaning and aching steps;

depositing a second spacer layer over the hinge layer;

patterning the second spacer layer to define mirror support vias;

depositing a metal mirror layer over the second spacer layer;

patterning the metal mirror layer to form an array of micro mirrors; and

removing the first and the second spacer layers.

16. The method of claim 15, wherein the cleaning step substantially removes polymer residue from the pattern resist.

17. The method of claim 15, wherein the ashing step substantially removes hardened skin from the pattern resist.

18. The method of claim 15, wherein the removing step is performed with an acetate strip process.