# US 10,760,929 B2 · Environmental sensor and manufacturing method thereof

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- Number: US 10,760,929 B2
- Document ID: US10760929B2
- Status: Granted
- Kind: B2
- Application number: 15/781,352
- Filed: 2015-12-14
- Published: 2018-12-13
- Granted: 2020-09-01
- Earliest claimed: 2015-12-04
- Assignees: Weifang Goertek Microelectronics Co., Ltd.
- Applicants: Weifang Goertek Microelectronics Co., Ltd.
- Inventors: Junkai Zhan; Mengjin Cai
- Web page: https://patentgrep.com/patent/US10760929B2

## CPC

- G01D 5/2417: {by varying separation}
- B81C 1/00182: {Arrangements of deformable or non-deformable structures, e.g. membrane and cavity for use in a transducer}
- B81C 1/00214: {Processes for the simultaneaous manufacturing of a network or an array of similar microstructural devices}
- G01K 7/34: using capacitative elements (capacitors per se H01G)
- G01L 9/0045: {Diaphragm associated with a buried cavity}
- G01L 9/0047: {Diaphragm with non uniform thickness, e.g. with grooves, bosses or continuously varying thickness}
- G01L 9/0073: {using a semiconductive diaphragm}
- B81B 2201/0214: Biosensors; Chemical sensors
- B81B 2201/0221: Variable capacitors
- B81B 2201/0264: Pressure sensors
- B81B 2201/0278: Temperature sensors
- B81B 2207/053: of movable structures
- G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- 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)
- G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00)
- G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G)
- B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00)

## Abstract

An environmental sensor and manufacturing method thereof. The environmental sensor comprises: a substrate comprising at least one recess disposed at an upper portion of the substrate; and a sensitive film layer disposed above the substrate, comprising a fixed portion fixed on an end surface of the substrate and a bent portion configured to extend inside the recess. The bent portion and a side wall of the recess form a capacitor configured to detect a signal. The bent portion, fixed portion, and the recess form a closed cavity. A conventional capacitive structure configured on a substrate surface is changed to a capacitive structure of the environmental sensor vertically extending into the inside of the substrate, increasing a depth of the recess, and in turn, increasing a sensing area between two polar plates of the capacitor, significantly shrinking a coverage area of the capacitor on the substrate, and satisfying a requirement of a modern compact electronic component.

## Claims

### Claim 1

An environmental sensor comprising:
a base material (1), wherein the upper end of the base material (1) is provided with at least one groove (1a); and
a sensitive film layer (3) on the base material (1), the sensitive film layer (3) comprises a fixed part (3b) fixed on the end surface of the base material (1) and a bending part (3a) extending into the groove (1a), the bending part (3a) and the side wall of the groove (1a) form a capacitor configured for signal detection;
wherein:
the bending part (3a), the fixed part (3b) and the groove (1a) form an airtight cavity, and
the sensitive film layer (3) further comprises a connecting part (3d) connected to two adjacent bending parts (3a), and the connecting part (3d) is suspended above the end surface of the base material (1).

### Claim 2 (depends on 1)

The environmental sensor according to claim 1, wherein the bending part (3a) is suspended in the groove (1a).

### Claim 3 (depends on 1)

The environmental sensor according to claim 1, wherein the bottom end of the bending part (3a) is fixed on the bottom end of the groove (1a) by a first sacrificial layer (2).

### Claim 4 (depends on 1)

The environmental sensor according to claim 1, wherein the connecting part (3d) is further provided with a hollow (3c), and the two adjacent bending parts (3a) are insulated by the hollow (3c); and the environmental sensor further comprises a second sacrificial layer (4) filling the hollow (3c).

### Claim 5

An environmental sensor comprising:
a base material (1), wherein the upper end of the base material (1) is provided with at least one groove (1a);
a fixed film layer (8) at least disposed on the side wall of the groove (1a) of the base material (1) by an insulating layer; and
a sensitive film layer (3) on the base material (1), the sensitive film layer (3) comprises a fixed part (3b) fixed on the end surface of the base material (1) and a bending part (3a) extending into the groove (1a), the bending part (3a) and the side wall of the fixed film layer (8) form a capacitor configured for signal detection;
wherein:
the bending part (3a), the fixed part (3b) and the groove (1a) form an airtight cavity, and
the sensitive film layer (3) further comprises a connecting part (3d) connected to two adjacent bending parts (3a), and the connecting part (3d) is suspended above the end surface of the base material (1).

### Claim 6 (depends on 5)

The environmental sensor according to claim 5, wherein the bending part (3a) is suspended in the groove (1a).

### Claim 7 (depends on 5)

The environmental sensor according to claim 5, wherein the bottom end of the bending part (3a) is fixed on the bottom end of the groove (1a) by a first sacrificial layer (2).

### Claim 8 (depends on 5)

The environmental sensor according to claim 5, wherein the connecting part (3d) is further provided with a hollow (3c), the two adjacent bending parts (3a) are insulated by the hollow (3c), and the environmental sensor further comprises a second sacrificial layer (4) filling the hollow (3c).

### Claim 9

A manufacturing method for an environmental sensor, the method comprising:
a) etching a groove (1a) in the upper end surface of a base material (1), and depositing a first sacrificial layer (2) on the upper end surface of the base material (1) and the inner wall of the groove (1a);
b) depositing a sensitive film layer (3) on the first sacrificial layer (2), wherein the sensitive film layer (3) comprises a fixed part (3b) fixed on the end surface of the base material (1) and a bending part (3a) extending into the groove (1a);
c) etching the sensitive film layer (3) on the end surface of the base material (1) to form a hollow (3c);
d) at least corroding the first sacrificial layer (2) located between the bending part (3a) and the side wall of the groove (1a) by the hollow (3c);
e) depositing a second sacrificial layer (4) on the sensitive film layer (3), wherein the second sacrificial layer (4) seals the hollow (3c); and
f) corroding the second sacrificial layer (4) located on the bending part (3a).

### Claim 10 (depends on 9)

The manufacturing method according to claim 9, wherein, between the step e) and the step f), the method further comprises etching the positions on the second sacrificial layer (4) on both sides of the hollow (3c) to form a side wall groove (4a), and depositing a protective layer (5) on the upper end of the second sacrificial layer (4), wherein the protective layer (5) is filled in the side wall groove (4a).

### Claim 11 (depends on 9)

The manufacturing method according to claim 9, wherein in the step d), the first sacrificial layer (2) between the bending part (3a) and the groove (1a) is completely corroded, such that the bending part (3a) is suspended in the groove (1a).

### Claim 12 (depends on 9)

The manufacturing method according to claim 9, wherein, before the first sacrificial layer (2) is deposited in the step a), the method further comprises depositing a third sacrificial layer (7) and a fixed film layer (8) on the inner wall of the groove (1a) in sequence.

### Claim 13 (depends on 9)

The manufacturing method according to claim 9, wherein the bending part (3a) comprises at least two bending parts (3a), the sensitive film layer (3) further comprises a connecting part (3d) connected to two adjacent of the bending parts (3a), and the connecting part (3d) is suspended above the end surface of the base material (1).

### Claim 14 (depends on 13)

The manufacturing method according to claim 13, wherein the two adjacent bending parts (3a) are insulated by the hollow (3c).