# US 2016/0257559 A1 · Method of fabricating mems devices using plasma etching and device therefor

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- Number: US 2016/0257559 A1
- Document ID: US20160257559A1
- Status: Published application
- Kind: A1
- Application number: 14/658,114
- Filed: 2015-03-13
- Published: 2016-09-08
- Earliest claimed: 2014-03-14
- Assignees: mCube Inc.
- Applicants: MCube Inc.
- Inventors: Ben (Wen-Pin) Chuang; MH (Ming-Hong) Kuo; WJ (Wen-Chih) Chen; Tse-Hsi “Terrence” Lee
- Web page: https://patentgrep.com/patent/US20160257559A1

## CPC

- B81B 3/0051: {For defining the movement, i.e. structures that guide or limit the movement of an element (mechanical arrangements for preventing or damping vibration or shock H01H3/60)}
- B81B 7/0006: {Interconnects}
- B81B 7/0077: {Other packages not provided for in groups B81B7/0035 - B81B7/0074}
- B81C 1/00531: {Dry etching}
- G01P 15/0802: {Details}
- G01P 15/125: by capacitive pick-up
- B81B 2201/0235: Accelerometers
- B81B 2201/0242: Gyroscopes
- B81B 2203/0307: Anchors
- B81B 2203/04: Electrodes
- B81C 2203/0109: Bonding an individual cap on the substrate
- G01P 2015/0871: {using stopper structures for limiting the travel of the seismic mass}
- B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00)
- 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)
- G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G})

## Abstract

A method for fabricating a MEMS sensor device. The method can include providing a substrate, forming an IC layer overlying the substrate, forming an oxide layer overlying the IC layer, forming a metal layer coupled to the IC layer through the oxide layer, forming a MEMS layer having a pair of designated sense electrode portions and a designated proof mass portion overlying the oxide layer, forming a via structure within each of the designated sense electrode portions, and etching the MEMS layer to form a pair of sense electrodes and a proof mass from the designated sense electrode portions and proof mass portions, respectively. The via structure can include a ground post and the proof mass can include a sense comb. The MEMS sensor device formed using this method can result is more well-defined edges of the proof mass structure.

## Claims

### Claim 1

A method of fabricating a MEMS device, the method comprising:
providing a substrate member;
forming an IC (Integrated Circuit) layer overlying the substrate member;
forming an oxide layer overlying the IC layer;
forming a metal layer coupled to the IC layer through the oxide layer;
forming a MEMS layer having a pair of designated sense electrode portions and a designated proof mass portion;
forming a via structure within each of the designated sense electrode portions; and
etching the MEMS layer to form a pair of sense electrodes and a proof mass from the designated sense electrode portions and proof mass portions, respectively;
wherein each of the sense electrodes includes a ground post and the proof mass includes a sense comb.

### Claim 2 (depends on 1)

The method of claim 1 wherein the MEMS layer comprises a device selected from a group consisting of: an accelerometer and a gyroscope.

### Claim 3 (depends on 1)

The method of claim 1 wherein the pair of sense electrodes are anchored to the oxide layer.

### Claim 4 (depends on 3)

The method of claim 3 further comprising:
forming a cap layer comprising a plurality of stops; and
disposing the cap layer on top of the MEMS layer to thereby encapsulate the MEMS layer.

### Claim 5 (depends on 4)

The method of claim 4 wherein at least one of the plurality of stops in the cap layer is initially disposed above, but not in contact with, an anchor portion of the proof mass.

### Claim 6 (depends on 4)

The method of claim 4 wherein at least one of the plurality of stops in the cap layer is initially disposed above, but not in contact with, at least a sense electrode from the pair of sense electrodes.

### Claim 7 (depends on 4)

The method of claim 4 wherein at least one of the plurality of stops in the cap layer is initially disposed above, but not in contact with, the proof mass.

### Claim 8 (depends on 1)

The method of claim 1 wherein the via structure extends into the oxide layer and reaches a metallic layer.

### Claim 9 (depends on 8)

The method of claim 8 further comprising disposing a metal material within the via structure in contact with the metallic layer to form the ground post.

### Claim 10

The method of claim wherein the etching of the MEMS layer to form a pair of sense electrodes and a proof mass comprises electrically separating portions of the MEMS layer.

### Claim 11

A MEMS device, the method comprising:
a substrate member;
an IC (Integrated Circuit) layer overlying the substrate member;
an oxide layer overlying the IC layer;
a metal layer coupled to the IC layer through the oxide layer;
a MEMS layer having a first portion having a pair of designated sense electrode portions and a second portion having a proof mass portion, wherein the first portion is electrically separated from the second portion;
wherein a ground post is formed in a via structure formed within each of the designated sense electrode portions; and
wherein the proof mass includes a sense comb.

### Claim 12 (depends on 11)

The device of claim 11 wherein the MEMS layer comprises a device selected from a group consisting of: an accelerometer and a gyroscope.

### Claim 13 (depends on 11)

The device of claim 11 wherein the pair of sense electrodes are anchored to the oxide layer.

### Claim 14 (depends on 13)

The device of claim 13 further comprising:
a cap layer comprising a plurality of stops disposed on top of the MEMS layer to thereby encapsulate the MEMS layer.

### Claim 15 (depends on 14)

The device of claim 14 wherein at least one of the plurality of stops in the cap layer is initially disposed above, but not in contact with, an anchor portion of the proof mass.

### Claim 16 (depends on 14)

The device of claim 14 wherein a first stop from the plurality of stops in the cap layer is initially disposed above, but not in contact with, at least a sense electrode from the pair of sense electrodes.

### Claim 17 (depends on 16)

The device of claim 16 wherein a second stop from the plurality of stops in the cap layer is initially disposed above, but not in contact with, the proof mass.

### Claim 18 (depends on 17)

The device of claim 17 wherein a height of the first stop and a height of the second stop are substantially similar.

### Claim 19 (depends on 11)

The device of claim 11 wherein the via structure extends into the oxide layer and reaches a metallic layer.

### Claim 20 (depends on 11)

The device of claim 11 wherein at least one sense comb of the proof mass is disposed between the pair of designated sense electrode portions.