# US 12,180,064 B2 · Curved cantilever design to reduce stress in MEMS actuator

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- Number: US 12,180,064 B2
- Document ID: US12180064B2
- Status: Granted
- Kind: B2
- Application number: 18/437,345
- Filed: 2024-02-09
- Published: 2024-06-06
- Granted: 2024-12-31
- Earliest claimed: 2022-01-13
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Ting-Jung Chen
- Web page: https://patentgrep.com/patent/US12180064B2

## CPC

- B81B 3/0072: {For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers}
- B81B 7/02: containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] (B81B7/04 takes precedence)
- B81C 1/00666: {Treatments for controlling internal stress or strain in MEMS structures}
- G02B 27/646: {compensating for small deviations, e.g. due to vibration or shake (movement of one or more optical elements for control of motion blur in cameras, projectors or printers G03B2205/0007; image stabilisation in cameras peculiar to the presence or use of an electronic image sensor H04N23/68)}
- H04N 23/54: Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
- H04N 23/68: for stable pick-up of the scene, e.g. compensating for camera body vibrations
- H04N 23/687: {by shifting the lens or sensor position}
- B81B 2201/033: Comb drives
- B81B 2201/042: Micromirrors, not used as optical switches
- B81B 2203/0118: Cantilevers
- B81B 2203/0163: Spring holders
- B81B 2203/019: characterized by their profile
- B81B 2203/0307: Anchors
- B81B 2203/058: Rotation out of a plane parallel to the substrate
- B81C 2201/0105: Sacrificial layer
- B81C 2201/0178: Oxidation
- G02B 7/021: {for more than one lens}
- 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)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

The present disclosure relates to an integrated chip structure. The integrated chip structure includes a MEMS (microelectromechanical systems) actuator. The MEMS actuator has an anchor. A proof mass continuously wraps around the anchor in a closed loop. One or more curved cantilevers are coupled between the proof mass and a frame. The frame wraps around the proof mass. The one or more curved cantilevers include curved outer surfaces arranged directly between a sidewall of the frame and a sidewall of the proof mass, as viewed in a top-view.

## Claims

### Claim 1

An integrated chip structure, comprising:
a MEMS (microelectromechanical systems) actuator, comprising:
an anchor;
a proof mass that continuously wraps around the anchor in a closed loop;
one or more curved cantilevers coupled between the proof mass and a frame, the frame wrapping around the proof mass; and
wherein the one or more curved cantilevers comprise curved outer surfaces arranged directly between a sidewall of the frame and a sidewall of the proof mass, as viewed in a top-view.

### Claim 2 (depends on 1)

The integrated chip structure of claim 1, wherein the one or more curved cantilevers comprise one or more of silicon, polysilicon, and silicon dioxide.

### Claim 3 (depends on 1)

The integrated chip structure of claim 1, wherein the one or more curved cantilevers comprise silicon, polysilicon arranged along a sidewall of the silicon, and silicon dioxide arranged over the silicon and the polysilicon.

### Claim 4 (depends on 1)

The integrated chip structure of claim 1, wherein the anchor comprises interior sidewalls interleaved directly with interior sidewalls of the proof mass.

### Claim 5 (depends on 1)

The integrated chip structure of claim 1,
wherein the anchor comprises a first plurality of protrusions extending in a first direction and a second plurality of protrusions extending in a second direction that is perpendicular to the second direction as viewed in the top-view; and
wherein both the first plurality of protrusions and the second plurality of protrusions are alternatively interspersed between protrusions of the proof mass.

### Claim 6 (depends on 1)

The integrated chip structure of claim 1, wherein the proof mass and the anchor engage with each other by overlapping or by fitting together projections and recesses within a plurality of interdigitated quadrants.

### Claim 7 (depends on 1)

The integrated chip structure of claim 1, further comprising:
a base underlying the anchor and the proof mass, wherein the anchor is fixed to the base.

### Claim 8 (depends on 7)

The integrated chip structure of claim 7, further comprising:
a CMOS-image sensor disposed over the anchor and the proof mass, wherein the CMOS-image sensor is fixed to the proof mass.

### Claim 9 (depends on 8)

The integrated chip structure of claim 8, further comprising:
a gyroscope fixed to the base; and
an accelerometer fixed to the base.

### Claim 10

An integrated chip structure, comprising:
a proof mass;
one or more curved cantilevers coupled between the proof mass and a frame, the frame wrapping around the proof mass;
wherein the one or more curved cantilevers comprise curved outer surfaces arranged between the frame and the proof mass, as viewed in a top-view; and
wherein the frame, the one or more curved cantilevers, and the proof mass comprise a same material that continuously extends from within the frame, to within the one or more curved cantilevers, and to within the proof mass.

### Claim 11 (depends on 10)

The integrated chip structure of claim 10, wherein the one or more curved cantilevers comprise:
a first curved cantilever extending in a first direction past one or more interior sidewalls of the proof mass; and
a second curved cantilever extending in a second direction past one or more additional interior sidewalls of the proof mass, the first direction being substantially perpendicular to the second direction.

### Claim 12 (depends on 10)

The integrated chip structure of claim 10, wherein the one or more curved cantilevers comprise:
a first curved cantilever extending away from the proof mass in a first direction; and
a second curved cantilever extending away from the proof mass in a second direction opposite the first direction, the first curved cantilever overlapping the second curved cantilever over the first direction.

### Claim 13 (depends on 10)

The integrated chip structure of claim 10, wherein the proof mass is asymmetric about a line bisecting a height or a width of the proof mass.

### Claim 14 (depends on 13)

The integrated chip structure of claim 13, wherein the proof mass is substantially symmetric about a 90-degree rotational symmetry.

### Claim 15

A method of forming an integrated chip structure, comprising:
providing a substrate;
patterning the substrate to remove a first region of the substrate laterally between a proof mass region and a cantilever region;
patterning the substrate to remove a second region of the substrate laterally between the cantilever region and a frame region; and
wherein removing the first region and the second region forms one or more curved cantilevers separated from a proof mass and a frame by non-zero spaces.

### Claim 16 (depends on 15)

The method of claim 15, wherein the one or more curved cantilevers have curved sidewalls that continuously extend between the proof mass and the frame.

### Claim 17 (depends on 15)

The method of claim 15, further comprising:
patterning the substrate to form a plurality of trenches; and
forming polysilicon within the plurality of trenches prior to patterning the substrate to remove the first region.

### Claim 18 (depends on 17)

The method of claim 17, wherein patterning the substrate to remove the first region exposes sidewalls of the polysilicon.

### Claim 19 (depends on 15)

The method of claim 15, further comprising:
forming a masking dielectric over the proof mass region, the frame region, and the cantilever region prior to patterning the substrate to remove the first region.

### Claim 20 (depends on 15)

The method of claim 15,
wherein the substrate comprises a lower semiconductor region separated from an upper semiconductor region by an insulating region; and
wherein patterning the substrate to remove the first region exposes an upper surface of the insulating region, the upper surface of the insulating region continuously extending below the cantilever region, the frame region, and the proof mass region.