Micro-electro-mechanical system structure and method for forming the same

Patent metadata

Field	Value
Publication number	US-9950920-B2
Application number	US-201615003913-A
Country	US
Kind code	B2
Filing date	Jan 22, 2016
Priority date	Jan 22, 2016
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

A micro-electro-mechanical (MEMS) structure and a method for forming the same are disclosed. The MEMS structure includes a sacrificial layer, a lower dielectric film, an upper dielectric film, a plurality of through holes and a protective film. The sacrificial layer comprises an opening. The lower dielectric film is on the sacrificial layer. The upper dielectric film is on the lower dielectric film. The plurality of through holes passes through the lower dielectric film and the upper dielectric film. The protective film covers side walls of the upper dielectric film and the lower dielectric film and a film interface between the lower dielectric film and the upper dielectric film.

First claim

What is claimed is:

1. A micro-electro-mechanical system (MEMS) structure, comprising:
a sacrificial layer comprising an opening;
a lower dielectric film on the sacrificial layer;
an upper dielectric film on the lower dielectric film;
a plurality of through holes passing through the lower dielectric film and the upper dielectric film; and
a protective film covering side walls of the upper dielectric film and the lower dielectric film and a film interface between the lower dielectric film and the upper dielectric film,
wherein a silicon content of a silicon nitride in the protective film is larger than a silicon content of a silicon nitride in the lower dielectric film and a silicon content of a silicon nitride in the upper dielectric film.

2. The MEMS structure according to claim 1 , further comprising a conductive pattern between the lower dielectric film and the upper dielectric film.

3. The MEMS structure according to claim 2 , wherein the conductive pattern comprising a conductive mesh distributed among the through holes in the lower dielectric film and the upper dielectric film.

4. The MEMS structure according to claim 2 , further comprising a conductive layer electrically connecting with the conductive pattern.

5. The MEMS structure according to claim 1 , wherein the lower dielectric film comprises a plurality of protruding portions beyond a lower surface of the protective film.

6. The MEMS structure according to claim 5 , wherein the plurality of the protruding portions of the lower dielectric film is under the film interface between the lower dielectric film and the upper dielectric film.

7. The MEMS structure according to claim 1 , further comprising a conductive diagram comprising a plurality of apertures communicating with the opening of the sacrificial layer.

8. The MEMS structure according to claim 7 , further comprising a substrate and an insulating layer on the substrate, wherein the conductive diagram is on the insulating layer.

9. The MEMS structure according to claim 8 , wherein the substrate and the insulating layer comprising a cavity communicating with the plurality of the apertures of the conductive diagram.

10. The MEMS structure according to claim 7 , further comprising a conductive layer electrically connecting with the conductive diagram.

11. The MEMS structure according to claim 1 , wherein the lower dielectric film and the upper dielectric film are used as a back-plate for a microphone.

Assignees

• United Microelectronics Corp

Inventors

• Lin yuan-sheng
• Chen Weng-Yi
• Wang Kuan-Yu
• Liu Chih-Wei

Classifications

• H04R19/005

  using semiconductor materials · CPC title

• B81B2201/0257

  Microphones or microspeakers · CPC title

• H04R2201/003

  Mems transducers or their use · CPC title

• B81B2207/115

  Protective layers applied directly to the device before packaging · CPC title

• B81C1/00785

  Avoid chemical alteration, e.g. contamination, oxidation or unwanted etching (B81C1/00563 - B81C1/00595 take precedence) · CPC title