Mems device manufacturing method, mems device, and shutter apparatus using the same

Patent metadata

Field	Value
Publication number	US-2021024352-A1
Application number	US-201917040106-A
Country	US
Kind code	A1
Filing date	Feb 22, 2019
Priority date	Mar 28, 2018
Publication date	Jan 28, 2021
Grant date	—

Abstract

Provided is a method including at least the thermal treatment step of thermally treating a SOI substrate having a first silicon layer at a first temperature that the diffusion flow rate of an interstitial silicon atom in a silicon single crystal is higher than the diffusion flow rate of an interstitial oxygen atom and the processing step of processing the SOI substrate after the thermal treatment step to obtain a displacement enlarging mechanism.

First claim

1 . A MEMS device manufacturing method comprising: at least
a thermal treatment step of thermally treating a substrate having a silicon layer at a first temperature that a diffusion flow rate of an interstitial silicon atom in a silicon single crystal is higher than a diffusion flow rate of an interstitial oxygen atom; and a processing step of processing the substrate after the thermal treatment step to obtain a MEMS device.

2 . The MEMS device manufacturing method according to claim 1 , wherein
at the step performed after the thermal treatment step, a temperature applied to the silicon layer is equal to or lower than a second temperature that the diffusion flow rate of the interstitial oxygen atom in the silicon single crystal is higher than the diffusion flow rate of the interstitial silicon atom and precipitated oxide contained in the silicon layer does not substantially grow.

3 . The MEMS device manufacturing method according to claim 1 , wherein
the substrate is a multilayer bonded substrate configured such that a handle layer, an insulating layer, and a device layer are stacked on each other in this order, and the device layer is the silicon layer, and is formed using a silicon substrate manufactured by a Czochralski (CZ) method.

4 . The MEMS device manufacturing method according to claim 1 , wherein
the silicon layer contains a predetermined concentration of oxygen, and the predetermined concentration is in a range of 5×10 17 /cm 3 to 1×10 18 /cm 3 .

5 . The MEMS device manufacturing method according to claim 1 , further comprising:
a substrate preparation step of preparing a substrate having a silicon layer whose stacking fault density is equal to or greater than 1×10 4 /cm 2 , wherein at the processing step, the substrate prepared at the substrate preparation step is processed to obtain the MEMS device.

6 . The MEMS device manufacturing method according to claim 1 , further comprising:
a substrate preparation step of preparing a substrate having a silicon layer whose precipitated oxide density is equal to or less than 5×10 5 /cm 2 , wherein at the processing step, the substrate prepared at the substrate preparation step is processed to obtain the MEMS device.

7 . The MEMS device manufacturing method according to claim 1 , further comprising:
a substrate preparation step of preparing a substrate having a silicon layer whose precipitated oxide density is equal to or less than 5×10 5 /cm 2 and whose stacking fault density is equal to or greater than 1×10 4 /cm 2 , wherein at the processing step, the substrate prepared at the substrate preparation step is processed to obtain the MEMS device.

8 . The MEMS device manufacturing method according to claim 5 , wherein
at the step performed after the substrate preparation step, a temperature applied to the silicon layer is equal to or lower than a second temperature that a diffusion flow rate of an interstitial oxygen atom in a silicon single crystal is higher than a diffusion flow rate of an interstitial silicon atom and precipitated oxide contained in the silicon layer does not substantially grow.

9 . The MEMS device manufacturing method according to claim 5 , wherein
the substrate is a multilayer bonded substrate configured such that a handle layer, an insulating layer, and a device layer are stacked on each other in this order, the device layer is the silicon layer, and is formed using a silicon substrate manufactured by a Czochralski (CZ) method, and at the step performed after the substrate preparation step, the temperature applied to the silicon layer is equal to or lower than the second temperature that the diffusion flow rate of the interstitial oxygen atom in the silicon single crystal is higher than the diffusion flow rate of the interstitial silicon atom and the precipitated oxide contained in the silicon layer does not substantially grow.

10 . The MEMS device manufacturing method according to claim 5 , wherein
the silicon layer contains a predetermined concentration of oxygen, and the predetermined concentration is in a range of 5×10 17 /cm 3 to 1×10 18 /cm 3 .

11 . The MEMS device manufacturing method according to claim 5 , wherein
the processing step includes at least a mask pattern formation step of forming a mask pattern for processing the silicon layer; and a silicon layer processing step of patterning the silicon layer by means of the mask pattern, and the mask pattern includes a thermally-oxidized film formed on a surface of the substrate at the thermal treatment step.

12 . The MEMS device manufacturing method according to claim 1 , wherein
the MEMS device includes at least a thermal actuator configured to generate heat by current application to displace in a predetermined direction according to a generated heat temperature and a drive target member coupled to the thermal actuator.

13 . A MEMS device comprising: at least
a substrate having a silicon layer; a fixing portion formed on the substrate; a thermal actuator coupled to the fixing portion and configured to generate heat by current application to displace in a predetermined direction according to a generated heat temperature; and a drive target member coupled to the thermal actuator, wherein a precipitated oxide density of the silicon layer is equal to or less than 5×10 5 /cm 2 , and a member forming the thermal actuator is the silicon layer.

14 . A MEMS device comprising: at least
a substrate having a silicon layer; a fixing portion formed on the substrate; a thermal actuator coupled to the fixing portion and configured to generate heat by current application to displace in a predetermined direction according to a generated heat temperature; and a drive target member coupled to the thermal actuator, wherein a stacking fault density of the silicon layer is equal to or greater than 1×10 4 /cm 2 , and a member forming the thermal actuator is the silicon layer.

15 . A MEMS device comprising: at least
a substrate having a silicon layer; a fixing portion formed on the substrate; a thermal actuator coupled to the fixing portion and configured to generate heat by current application to displace in a predetermined direction according to a generated heat temperature; and a drive target member coupled to the thermal actuator, wherein a precipitated oxide density of the silicon layer is equal to or less than 5×10 5 /cm 2 , and a stacking fault density of the silicon layer is equal to or greater than 1×10 4 /cm 2 , and a member forming the thermal actuator is the silicon layer.

16 . The MEMS device according to claim 13 , wherein
the substrate is a multilayer bonded substrate configured such that a handle layer, an insulating layer, and a device layer are stacked on each other in this order, and the device layer is the silicon layer, and is formed using a silicon substrate manufactured by a Czochralski (CZ) method.

17 . The MEMS device according to claim 13 , wherein
the silicon layer contains a predetermined concentration of oxygen, and the predetermined concentration is in a range of 5×10 17 /cm 3 to 1×10 18 /cm 3 .

18 . The MEMS device according to claim 13 , wherein
a member forming the drive target member includes the silicon layer.

19 . A shutter apparatus for closing or opening an optical path by a drive target member, comprising:
the MEMS device according to claim 13 ; and first and second electrodes arranged on the fixing portion and electrically connected to both end portions of the thermal actuator.

Assignees

• Sumitomo Precision Prod Co

Inventors

• Matsuoka Gen
• Kiuchi Mario

Classifications

• B81C1/00825

  Protect against mechanical threats, e.g. against shocks, or residues (B81C1/00261 take precedence) · CPC title

• B81C1/00682

  Treatments for improving mechanical properties, not provided for in B81C1/00658 - B81C1/0065 · CPC title

• B81B2201/047

  Optical MEMS not provided for in B81B2201/042 - B81B2201/045 · CPC title

• G02B26/04 Primary

  by periodically varying the intensity of light, e.g. using choppers (shutters, diaphragms for cameras G03B9/00; devices for eliminating or reducing the effect of flicker in projection systems G03B21/40) · CPC title

• B81C1/00666 Primary

  Treatments for controlling internal stress or strain in MEMS structures · CPC title