Environmental sensor and manufacturing method thereof

• US 10,760,929 B2
• Filed: 12/14/2015
• Issued: 09/01/2020
• Est. Priority Date: 12/04/2015
• Status: Active Grant

• Current Assignee: Weifang Goertek Microelectronics Co., Ltd. (Goertek Incorporated)
• Original Assignee: Weifang Goertek Microelectronics Co., Ltd. (Goertek Incorporated)
• Inventors: Zhan, Junkai, Cai, Mengjin
• Primary Examiner(s): Le, Son T
• Application Number:
  US15/781,352
• Publication Number:
  US 20180356255A1
• Time in Patent Office: 1,723 Days
• CPC Class Codes: B81B 2201/0214 Biosensors; Chemical sensors
• CPC Class Codes: B81B 2201/0221 Variable capacitors
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2201/0278 Temperature sensors
• CPC Class Codes: B81B 2207/053 of movable structures
• CPC Class Codes: B81C 1/00182 Arrangements of deformable or non-deformable structures, e.g. membrane and cavity for use in a transducer
• CPC Class Codes: B81C 1/00214 Processes for the simultaneaous manufacturing of a network or an array of similar microstructural devices
• CPC Class Codes: G01D 5/2417 by varying separation
• CPC Class Codes: G01K 7/34 using capacitative elements capacitors per se H01G
• CPC Class Codes: G01L 9/0045 Diaphragm associated with a buried cavity
• CPC Class Codes: G01L 9/0047 Diaphragm with non uniform thickness, e.g. with grooves, bosses or continuously varying thickness
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm

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

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).

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

3. 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).

4. 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).

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).

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

7. 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).

8. 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).

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).

10. 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).

11. 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).

12. 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.

13. 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).

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