PROCESS CONTROL MONITORS FOR INTERFEROMETRIC MODULATORS

• US 20080003352A1
• Filed: 08/20/2007
• Published: 01/03/2008
• Est. Priority Date: 09/27/2004
• Status: Abandoned Application

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Inventors: Cummings, William, Gally, Brian
• Application Number:
  US11/841,635
• Publication Number:
  US 20080003352A1
• Time in Patent Office: Days
• US Class Current: 427/99.2
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81C 99/004 during manufacturing
• CPC Class Codes: G01N 21/55 Specular reflectivity
• CPC Class Codes: G01N 21/9501 Semiconductor wafers manufacturing processes per se of semiconductor devices implementing a measuring step H01L22/10
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26

Abstract

Process control monitors are disclosed that are produced using at least some of the same process steps used to manufacture a MEMS device. Analysis of the process control monitors can provide information regarding properties of the MEMS device and components or sub-components in the device. This information can be used to identify errors in processing or to optimize the MEMS device. In some embodiments, analysis of the process control monitors may utilize optical measurements.

Claims

1. A method of manufacturing an apparatus comprising a micro-electro-mechanical system (MEMS) and a process control monitor, comprising:

forming a MEMS structure, wherein forming the MEMS structure includes one or more material deposition and patterning steps; and

forming a process control monitor, wherein forming the process control monitor includes one or more of the material deposition and patterning steps, wherein the process control monitor comprises less than all components present in the MEMS structure.

2. The method of claim 1, wherein the process control monitor is formed during formation of the MEMS structure.

3. The method of claim 1, wherein the MEMS structure is an interferometric modulator.

4. The method of claim 1, wherein the process control monitor comprises an etalon.

5. The method of claim 4, wherein no substantial air gap exists between reflecting surfaces in the etalon.

6. The method of claim 1, wherein the process control monitor comprises a non-modulating interferometer.

7. The method of claim 1, wherein the process control monitor comprises at least three components present in the MEMS structure.

8. The method of claim 1, wherein the deposition steps comprise:

depositing a layer of partially reflective material;

depositing one or more dielectric layers; and

depositing a layer of substantially totally reflective material.

9. The method of claim 1, wherein a final layer of material formed in the process control monitor is substantially reflective.

10. The method of claim 9, wherein layers other than the final layer formed in the process control monitor are substantially transparent.

11. The method of claim 1, wherein the patterning steps comprises applying at least one pattern to the process control monitor that is different from a pattern applied to the MEMS structure.

12. The method of claim 11, wherein the different pattern results in a deposited layer being completely etched away in the process control monitor but not completely etched away in the MEMS structure.

13. The method of claim 11, wherein the different pattern results in a deposited layer being completely etched away in the MEMS structure but not completely etched away in the process control monitor.

14. The method of claim 1, wherein the MEMS structure and process control monitor are formed on a single wafer.

15. The method of claim 1, wherein the MEMS structure and process control monitor are formed on a same substantially transparent substrate.

16. The method of claim 14, further comprising cutting the substrate to separate the process control monitor from the MEMS structure.

17. A method of manufacturing a combined micro-electro-mechanical system (MEMS) and process control monitor structure, comprising:

forming at least one MEMS structure on a first side of a substrate through a series of deposition and patterning steps; and

forming at least one process control monitor on the first side of the substrate during formation of the MEMS structure utilizing one or more of the series of deposition and patterning steps, wherein the process control monitor comprises less than all components present in the MEMS structure.

18. The method of claim 17, wherein the MEMS structure is an interferometric modulator.

19. A method of manufacturing a wafer, comprising:

providing a substantially transparent substrate;

depositing one or more layers on the substrate; and

selectively removing portions of the one or more layers so as to form an interferometric modulator and a process control monitor on the substrate, wherein the process control monitor comprises less than all of the deposited layers.

20. The method of claim 19, wherein the process control monitor comprises an etalon.

21. The method of claim 20, wherein no substantial air gap exists between reflecting surfaces in the etalon.

22. The method of claim 19, wherein the process control monitor comprises a non-modulating interferometer.

23. The method of claim 19, wherein the process control monitor comprises at least three components present in the interferometric modulator.

24. The method of claim 19, further comprising cutting the substrate to separate the process control monitor from the interferometric modulator.