Silicon pressure micro-sensing device and the fabrication process

• US 6,541,834 B1
• Filed: 10/09/2001
• Issued: 04/01/2003
• Est. Priority Date: 10/09/2001
• Status: Expired due to Fees

• Current Assignee: Integrated Crystal Technology, Inc. (Silergy Corporation)
• Original Assignee: Integrated Crystal Technology, Inc. (Silergy Corporation)
• Inventors: Lin, Chun-te, Lin, Ji-cheng, Shie, Jin-shown, Peng, Chih-tang, Yu, Shih-han, Chiang, Kuo-ning
• Primary Examiner(s): Cuneo, Kamand
• Assistant Examiner(s): SARKAR, ASOK K
• Application Number:
  US09/975,125
• Publication Number:
  US 20030068838A1
• Time in Patent Office: 539 Days
• Field of Search: 737/21, 737/24, 737/27, 737/18, 737/54, 737/55, 737/75, 735/17.R, 257/414-419, 438/50-53
• US Class Current: 257/419
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2203/0127 Diaphragms, i.e. structures separating two media that can control the passage from one medium to another; Membranes, i.e. diaphragms with filtering function
• CPC Class Codes: B81B 2203/0315 Cavities
• 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 2201/014 by depositing an etch stop layer, e.g. silicon nitride, silicon oxide, metal
• CPC Class Codes: B81C 2201/016 Passivation
• CPC Class Codes: G01L 9/0054 integral with a semiconducting diaphragm

Abstract

The invention is a silicon pressure micro-sensing device and the fabrication process thereof. The silicon pressure micro-sensing device includes a pressure chamber, and is constituted of a P-type substrate with a taper chamber and an N-type epitaxial layer thereon. On the N-type epitaxial layer are a plurality of piezo-resistance sensing units which sense deformation caused by pressure. The fabrication pressure of the silicon pressure micro-sensing device includes a step of first making a plurality of holes on the N-type epitaxial layer to reach the P-type substrate beneath. Then, by an anisotropic etching stop technique, in which etchant pass through the holes, a taper chamber is formed in the P-type substrate. Finally, an insulating material is applied to seal the holes, thus attaining the silicon pressure micro-sensing device that is able to sense pressure differences between two ends thereof.

Claims

1. A silicon pressure micro-sensing device comprising:

an N-type epitaxial layer comprising;

a plurality of piezo-resistance sensing units, for sensing pressure, in said N-type epitaxial layer;

a passivation, for preventing inappropriate etching from etchant in the process, on an upper surface of said N-type epitaxial layer;

a plurality of device pads formed on an upper surface of the passivation and connected to leads of an external circuit;

a plurality of holes which go through said N-type epitaxial layer and passivation and act as passages for the etchant; and

an insulating membrane on the upper surface of said passivation to seal said plurality of holes; and

a P-type (100) substrate with a taper chamber and on a lower surface of said N-type epitaxial layer.

2. The silicon pressure micro-sensing device as described in claim 1, wherein said P-type (100) substrate further comprises a venthole at a bottom part of said taper chamber.