MEMS device with non-planar features

Patent metadata

Field	Value
Publication number	US-9340415-B2
Application number	US-201514661830-A
Country	US
Kind code	B2
Filing date	Mar 18, 2015
Priority date	Mar 18, 2014
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

A MEMS device is formed with facing surfaces of a contoured substrate and a layer of material having complementary contours. In one fabrication approach, a first photoresist layer is formed over a substrate. Selected regions of the first photoresist layer are exposed using a patterning mask. The exposed regions of the first photoresist layer are thermally shrunk to pattern the first photoresist layer with a contour. A layer of material is formed over the contoured first photoresist layer.

First claim

What is claimed is:

1. A method of forming a MEMS device, comprising:
forming a photoresist layer over a substrate after the substrate is a contoured substrate;
exposing selected regions of the photoresist layer using a mask;
thermally shrinking the photoresist layer such that exposed regions of the photoresist layer form a contour in the photoresist layer; and
forming a layer of material over the contoured photoresist layer;
wherein facing surfaces of the contoured substrate and the layer of material have complementary contours.

2. The method of claim 1 , wherein the photoresist layer is a second photoresist layer, and the method further comprises:
prior to forming the second photoresist layer, forming a first photoresist layer over the substrate before the substrate is the contoured substrate;
exposing selected regions of the first photoresist layer using a mask;
thermally shrinking the first photoresist layer such that the exposed selected regions of the first photoresist layer form the contour in the first photoresist layer; and
etching the contoured first photoresist layer to transfer the contour to the underlying substrate to form the contoured substrate.

3. The method of claim 1 , further comprising removing the contoured photoresist layer after forming the layer of material.

4. The method of claim 2 , wherein the mask used to expose the first photoresist layer is the same mask used to expose the second photoresist layer at least in the area of the contour.

5. The method of claim 4 , wherein the layer of material is a second layer of material, and the method further comprises forming a first layer of material conformally over the contoured substrate prior to forming the second photoresist layer.

6. The method of claim 5 , wherein the first layer of material and the second layer of material comprise conductive material.

7. The method of claim 6 , wherein the first layer of material and the second layer of material comprise the same conductive material.

8. The method of claim 7 , wherein the same conductive material is selected from the group consisting of Al, Al alloy, TiN, SiN, and AlOx.

9. The method of claim 1 , wherein the contour comprises a series of parallel ridges and grooves.

10. The method of claim 9 , wherein the ridges and grooves of the series are spaced at equal intervals.

11. The method of claim 10 , wherein the contour comprises a plurality of areas, each area having a series of parallel ridges and grooves; and wherein the ridges and grooves of a first area are orthogonal to the ridges and grooves of a second area.

12. The method of claim 10 , wherein the contour comprises a multiplicity of areas, each area having a series of parallel ridges and grooves; and wherein the ridges and grooves of each area are orthogonal to the ridges and grooves of adjacent areas.

13. The method of claim 12 , wherein ones of the ridges and grooves of a first area intersect with ones of the ridges and grooves of a second area.

14. A method of forming a MEMS device, comprising:
forming a photoresist layer over a contoured substrate;
exposing selected regions of the photoresist layer using a first mask;
exposing a subset of the selected regions of the photoresist layer using a second mask;
thermally shrinking the photoresist layer after exposing the selected regions and exposing the subset of selected regions to form a multilayer contour in the photoresist layer;
forming a layer of material over the multilayer contour in the photoresist layer; and
removing the contoured photoresist layer after forming the layer of material,
wherein facing surfaces of the contoured substrate and the layer of material have complementary contours.

15. A method of forming a MEMS device, comprising:
forming a first photoresist layer over a substrate;
exposing selected regions of the first photoresist layer using a mask;
thermally shrinking the first photoresist layer such that the exposed selected regions of the first photoresist layer form a contour in the first photoresist layer;
etching the contoured first photoresist layer to transfer the contour to the substrate;
forming a second photoresist layer over the contoured substrate;
exposing selected regions of the second photoresist layer using a mask;
thermally shrinking the second photoresist layer such that the exposed selected regions form the contour in the second photoresist layer; and
forming a layer of material over the contoured second photoresist layer;
wherein facing surfaces of the contoured substrate and the layer of material have complementary contours.

Assignees

• Texas Instruments Inc

Inventors

• Baker James C
• Oden Patrick I
• Black Robert S

Classifications

• B81C1/00626 Primary

  Processes for achieving a desired geometry not provided for in groups B81C1/00563 - B81C1/00619 · CPC title

• B81C1/00198

  comprising elements which are movable in relation to each other, e.g. comprising slidable or rotatable elements · CPC title

• B81C2201/0198

  for making a masking layer · CPC title

• B81C1/00404

  Mask characterised by its size, orientation or shape · CPC title

• B81B2203/019

  characterized by their profile · CPC title