# US 2014/0153074 A1 · Moems apparatus and a method for manufacturing same

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- Number: US 2014/0153074 A1
- Document ID: US20140153074A1
- Status: Published application
- Kind: A1
- Application number: 14/174,367
- Filed: 2014-02-06
- Published: 2014-06-05
- Earliest claimed: 2011-11-16
- Assignees: STMicroelectronics International N.V.
- Applicants: STMicroelectronics International N.V.
- Inventors: Moshe Medina; Pinchas Chaviv; Yaron Fein
- Web page: https://patentgrep.com/patent/US20140153074A1

## CPC

- G02B 26/08: for controlling the direction of light (in light guides G02B6/35)
- B81C 1/00603: {Aligning features and geometries on both sides of a substrate, e.g. when double side etching}
- G02B 26/0841: {the reflecting element being moved or deformed by electrostatic means}
- H02N 1/008: {Laterally driven motors, e.g. of the comb-drive type}
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- B81C: PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS (making microcapsules or microballoons B01J13/02; processes or apparatus specially adapted for the manufacture or treatment of piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/01)
- H02N: ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR

## Abstract

An apparatus is formed from a double active layer silicon on insulator (DSOI) substrate that includes first and second active layers separated by an insulating layer. An electrostatic comb drive is formed from the substrate to include a first comb formed from the first active layer and a second comb formed from the second active layer. The comb drive may be used to impart a tilting motion to a micro-mirror. The method of manufacturing provides comb teeth exhibiting an aspect ratio greater than 1:20, with an offset distance between comb teeth of the first and second combs that is less than about 6 μm.

## Claims

### Claim 1

An apparatus, comprising:
a double active layer silicon on insulator substrate including a first active layer separated from a second active layer by an insulating layer;
a first plurality of comb teeth formed in the first active layer and defined by a first plurality of cavities;
a second plurality of comb teeth formed in the second active layer and defined by a second plurality of cavities;
wherein an aspect ratio of the first and second pluralities of cavities defining the first and second pluralities of comb teeth is greater than 1:20.

### Claim 2 (depends on 1)

The apparatus of claim 1, wherein the first and second pluralities of comb teeth are components of a drive selected from the group consisting of a vertical comb drive or an in-plane comb drive.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein an aspect ratio of the cavities defining the first and second pluralities of comb teeth is greater than 1:40.

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein a distance between a tooth in the first plurality of comb teeth and an adjacent tooth in the second plurality of comb teeth is less than 6 μm.

### Claim 5 (depends on 1)

The apparatus of claim 1, further comprising:
a marker cavity formed in the first active layer; and
an additional cavity formed in the second active layer opposite the marker cavity.

### Claim 6 (depends on 5)

The apparatus of claim 5, wherein the marker cavity has a smaller opening than the additional cavity.

### Claim 7 (depends on 1)

The apparatus of claim 1, wherein the second plurality of comb teeth in the second active layer are positioned complementary of the first plurality of comb teeth in the first active layer.

### Claim 8

An apparatus, comprising;
a double active layer silicon on insulator substrate that includes first and second active layers separated by an insulating layer, wherein the first active layer has a first plurality of designed shapes and at least one first cavity adapted to be used as a marker, and the second active layer has a second plurality of designated shapes and at least one second cavity;
wherein the second cavity is arranged at a location that essentially corresponds to a location of said first cavity; and
wherein the insulating layer extends between the first and the second cavities and is practically transparent so as to allow identification, through said second cavity, said first marker cavity and a reference point; and
wherein the second plurality of designated shapes are located at a pre-determined distance from said at least one reference point.

### Claim 9 (depends on 8)

The apparatus according to claim 8, wherein said apparatus is an electro-static comb drive is selected from among a vertical comb drive or an in-plane comb drive.

### Claim 10 (depends on 8)

The apparatus according to claim 8, wherein each of said rotor and stator have an alignment accuracy of ±0.5 μm.

### Claim 11 (depends on 8)

The apparatus according to claim 8, wherein the first plurality of designed shapes comprises a stator of an electrostatic comb drive and the second plurality of designed shapes comprises a rotor.