# US 2021/0278433 A1 · Method for Manufacturing Three-Dimensionally Structured Member, Method for Manufacturing Acceleration Pickup, Accesleration Pickup, and Acceleration Sensor

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- Number: US 2021/0278433 A1
- Document ID: US20210278433A1
- Status: Published application
- Kind: A1
- Application number: 17/261,213
- Filed: 2019-07-16
- Published: 2021-09-09
- Earliest claimed: 2018-07-17
- Assignees: Tokyo Keiki Co., Ltd.
- Applicants: Tokyo Keiki Inc.
- Inventors: Kazuaki TANI; Takayoshi YAMAGUCHI; Takayuki TAMAKI
- Web page: https://patentgrep.com/patent/US20210278433A1

## CPC

- B81C 1/00555: {Achieving a desired geometry, i.e. controlling etch rates, anisotropy or selectivity (B81C1/00023 - B81C1/0019 take precedence)}
- B81B 3/0027: {Structures for transforming mechanical energy, e.g. potential energy of a spring into translation, sound into translation}
- B81C 1/0015: {Cantilevers (switches using MEMS H01H1/0036; electrostatic relays using micromechanics H01H59/0009; microelectro-mechanical resonators H03H9/02244)}
- B81C 1/00515: {Bulk micromachining techniques not provided for in B81C1/00507}
- B81C 1/00547: {Etching processes not provided for in groups B81C1/00531 - B81C1/00539}
- B81C 99/0095: {Aspects relating to the manufacture of substrate-free structures, not covered by groups B81C99/008 - B81C99/009}
- G01P 15/0802: {Details}
- G01P 15/125: by capacitive pick-up
- G01P 15/131: {with electrostatic counterbalancing means}
- B81B 2201/0235: Accelerometers
- B81B 2203/058: Rotation out of a plane parallel to the substrate
- B81C 1/00388: {Etch mask forming}
- B81C 2201/013: Etching
- B81C 2201/0133: Wet etching
- G01P 2015/0828: {the mass being of the paddle type being suspended at one of its longitudinal ends}
- 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)
- B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00)
- 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

The purpose of the present invention is to provide a method for manufacturing a three-dimensionally structured member which can be made by a simpler process. The method for manufacturing a three-dimensionally structured member includes shaping a flat plate-shaped base member to produce a three-dimensionally structured member having a plurality of sections that are different from one another in thickness. The manufacturing method comprises: a mask formation step for forming a mask over the whole of at least one main surface of the base member; a mask removal step for removing a part of the mask; and an etching step for etching an exposed part of the base member, wherein a combination of the mask removal step and the etching step is performed on the mask and the base member that correspond to each of the plurality of sections of the three-dimensionally structured member, in the order from thinnest to the thickest of thicknesses of the three-dimensionally structured members.

## Claims

### Claim 1

A method for manufacturing a three-dimensional structural member including a plurality of portions different in thickness by molding a flat plate-like base, the method comprising:
a mask forming step of forming a mask over at least one principal surface of the base;
a mask removing step of removing a part of the mask; and
an etching step of etching an exposed portion of the base,
wherein a combination of the mask removing step and the etching step is performed to the mask and the base corresponding to each of the plurality of portions of the three-dimensional structural member in an order of thinnest to thickest of the three-dimensional structural member.

### Claim 2 (depends on 1)

The method for manufacturing a three-dimensional structural member according to claim 1, wherein
the mask in the mask forming step is a positive resist, and
a part of the mask is exposed to light and thereby removed in the mask removing step.

### Claim 3

A method for manufacturing a three-dimensional structural member including four portions different in thickness by molding a flat plate-like base, the method comprising:
a mask forming step of forming a mask over at least one principal surface of the base;
a first mask removing step of removing a part of the mask corresponding to a thinnest portion of the three-dimensional structural member;
a first etching step of etching an exposed portion of the base corresponding to the thinnest portion of the three-dimensional structural member;
a second mask removing step of removing a part of the mask corresponding to a second thinnest portion of the three-dimensional structural member;
a second etching step of etching exposed portions of the base corresponding to the second thinnest portion and the thinnest portion of the three-dimensional structural member;
a third mask removing step of removing a part of the mask corresponding to a third thinnest portion of the three-dimensional structural member; and
a third etching step of etching exposed portions of the base corresponding to the third thinnest portion, the second thinnest portion, and the thinnest portion of the three-dimensional structural member.

### Claim 4 (depends on 3)

The method for manufacturing a three-dimensional structural member according to claim 3, wherein
the mask in the mask forming step is a positive resist, and
a part of the mask is exposed to light and thereby removed in the first mask removing step, the second mask removing step, and the third mask removing step.

### Claim 5

A method for manufacturing an acceleration pickup member for use in an acceleration sensor by molding a flat plate-like base, the acceleration pickup member including a pendulum section, a hinge section coupled to the pendulum section, a support section supporting the pendulum section through the hinge section, and a through groove section between the pendulum section and the support section, the method comprising:
a mask forming step of forming a mask over each principal surface of the base;
a first mask removing step of removing a part of the mask corresponding to the through groove section;
a first etching step of etching an exposed portion of the base corresponding to the through groove section;
a second mask removing step of removing a part of the mask corresponding to the hinge section;
a second etching step of etching exposed portions of the base corresponding to the hinge section and the through groove section;
a third mask removing step of removing a part of the mask corresponding to the pendulum section; and
a third etching step of etching exposed portions of the base corresponding to the pendulum section, the hinge section, and the through groove section.

### Claim 6 (depends on 5)

The method for manufacturing an acceleration pickup member according to claim 5, wherein
the mask in the mask forming step is a positive resist, and
a part of the mask is exposed to light and thereby removed in the first mask removing step, the second mask removing step, and the third mask removing step.

### Claim 7

An acceleration pickup member for use in an acceleration sensor, the acceleration pickup member comprising:
a pendulum section swinging in accordance with acceleration;
a hinge section coupled to the pendulum section;
a support section supporting the pendulum section through the hinge section; and
a through groove section between the pendulum section and the support section, wherein
an interior angle of a center section in a thickness direction in a side surface opposite to the support section of the pendulum section is 90°±10°, and
an interior angle in a boundary between the pendulum section and the hinge section is 120°±10°.

### Claim 8 (depends on 7)

A MEMS acceleration sensor comprising:
the acceleration pickup member according to claim 7;
a movable electrode provided on each principal surface of the pendulum section of the acceleration pickup member; and
a fixed electrode provided opposite to the movable electrode, an alternating voltage being supplied to the fixed electrode.