Method for forming micro-electro-mechanical system (MEMS) device structure

Patent metadata

Field	Value
Publication number	US-10131539-B2
Application number	US-201715725752-A
Country	US
Kind code	B2
Filing date	Oct 5, 2017
Priority date	Nov 29, 2016
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

A method for forming a micro-electro-mechanical system (MEMS) device structure is provided. The method includes forming a second substrate over a first substrate, and a cavity is formed between the first substrate and the second substrate. The method includes forming a hole through the second substrate using an etching process, and the hole is connected to the cavity. The etching process includes a plurality of etching cycles, and each of the etching cycles includes an etching step, and the etching step has a first stage and a second stage. The etching time of each of the etching steps during the second stage is gradually increased as the number of etching cycles is increased.

First claim

What is claimed is:

1. A method for forming a micro-electro-mechanical system (MEMS) device structure, comprising:
forming a second substrate over a first substrate, wherein a cavity is formed between the first substrate and the second substrate;
forming a hole through the second substrate using an etching process, wherein the hole is connected to the cavity, and
the etching process comprises a plurality of etching cycles, and each of the etching cycles comprises an etching step, the etching step has a first stage and a second stage, wherein an etching time of each of the etching steps during the second stage is gradually increased as the number of etching cycles is increased.

2. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 1 , wherein the etching time of each of the etching steps during the first stage is a constant value.

3. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 1 , wherein the hole has a final depth after the etching cycles, and the etching process is changed from the first stage to the second stage when an intermediate depth of the hole is in a range from about 70% to about 80% of the final depth.

4. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 1 , wherein each of the etching cycles further comprises:
performing a deposition step; and
performing a stripping step after the deposition step, wherein the etching step is performed after the stripping step.

5. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 4 , wherein performing the deposition step comprises using a fluorocarbon gas comprising C 4 F 8 , CF 4 , CHF 3 , CH 2 F 2 or a combination thereof.

6. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 1 , further comprising:
performing a cleaning process on the hole after the etching process, wherein the cleaning process is performed using an oxygen (O 2 ) plasma.

7. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 6 , wherein the cleaning process does not comprise a wet cleaning process.

8. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 6 , wherein the cleaning process and the etching process are performed in the same chamber.

9. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 1 , further comprising:
filling a metal layer into the hole;
patterning the metal layer using a patterned photoresist layer as a mask; and
removing the patterned photoresist layer by performing a removal process, wherein the removal process comprises:
performing a first cleaning step using a first cleaning solution;
performing a second cleaning step using a second cleaning solution, wherein a contact angle between the second cleaning solution and the first cleaning solution is in a range from about 80 degrees to about 90 degrees.

10. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 9 , wherein the removal process further comprises a spin drying step after the second cleaning step.

11. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 9 , further comprising:
performing an exhaust process to exhaust air inside of the hole before the step of filling the metal layer into the hole.

12. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 1 , wherein forming the second substrate over the first substrate comprises bonding the second substrate to the first substrate by performing a fusion bonding process.

13. A method for forming a micro-electro-mechanical system (MEMS) device structure, comprising:
forming an electrode over a substrate;
forming a cavity over the electrode;
forming a MEMS substrate over the substrate, wherein the cavity is formed between the first substrate and the MEMS substrate; and
performing a dry etching process on the MEMS substrate to form a hole in the MEMS substrate, wherein the dry etching process comprises a plurality of etching cycles, each of the etching cycles comprising:
performing a deposition step to form a protection layer on the opening;
performing a stripping step to remove a portion of the protection layer; and
performing an etching step to etch a portion of the MEMS substrate.

14. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 13 , further comprising:
performing a cleaning process on the hole after the dry etching process, wherein the cleaning process is performed using an oxygen (O 2 ) plasma.

15. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 13 , wherein the etching step has a first stage and a second stage, wherein the etching time of each of the etching steps during the first stage is a constant value as the number of etching cycles is increased, and the etching time of each of the etching steps during the second stage is gradually increased as the number of etching cycles is increased.

16. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 13 , wherein each of the etching steps during the first stage has an etching gas with a flow rate that is a constant value as the number of etching cycles is increased, and each of the etching steps during the second stage has an etching gas with a flow rate that is gradually increased as the number of etching cycles is increased.

17. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 13 , further comprising:
filling a metal layer into the hole;
patterning the metal layer using a patterned photoresist layer as a mask; and
removing the patterned photoresist layer using a cleaning process, wherein the cleaning process comprises a spin drying step.

18. A method for forming a micro-electro-mechanical system (MEMS) device structure, comprising:
forming an interconnect structure over a first substrate;
forming an outgassing prevention layer over the interconnect structure;
forming a cavity adjacent to the outgassing prevention layer;
forming a MEMS substrate over the electrode, wherein the cavity is surrounded by the first substrate and the MEMS substrate;
forming a hole through the MEMS substrate using a dry etching process; and
performing a cleaning process on the hole after the dry etching process, wherein the cleaning process does not comprise a wet cleaning process.

19. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 18 , further comprising:
filling a metal layer into the hole;
patterning the metal layer using a patterned photoresist layer as a mask; and
removing the patterned photoresist layer by performing a removal process, wherein the removal process comprises a spin drying step.

20. The method for forming the micro-electro-mechanical system (MEMS) device structure as claimed in claim 19 , wherein performing the removal process further comprises:
performing a first cleaning step using a first cleaning solution; and
performing a second cleaning step using a second cleaning solution, wherein a contact angle between the second cleaning solution and the fi

Assignees

• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Meng Chin-Han
• Hsu Chih-Hsien
• Chung Chia-Chi
• Chiang Yu-Pei
• Chen Wen-Chih
• Huang Chen-Huang
• Xu zhi-sheng
• Chen Jr-Sheng
• Liu Kuo-Chin
• Huang Lin-Ching

Classifications

• B81C2201/0159

  Lithographic techniques not provided for in B81C2201/0157 · CPC title

• B81C1/00523

  Etching material · CPC title

• B81B3/0072

  For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers · CPC title

• H01G5/18 Primary

  due to change in inclination, e.g. by flexing, by spiral wrapping · CPC title

• B81C2201/0198

  for making a masking layer · CPC title