Semiconductor device embedded with pressure sensor and manufacturing method thereof

• US 7,451,656 B2
• Filed: 07/23/2007
• Issued: 11/18/2008
• Est. Priority Date: 10/01/2004
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Yokoyama, Natsuki, Goto, Yasushi, Machida, Shuntaro
• Primary Examiner(s): Allen; Andre J
• Assistant Examiner(s): JENKINS, JERMAINE L
• Application Number:
  US11/878,243
• Publication Number:
  US 20070262401A1
• Time in Patent Office: 484 Days
• Field of Search: 73700-756
• US Class Current: 73/754
• CPC Class Codes: G01L 9/0073 using a semiconductive diaphragm
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/181 Encapsulation

Abstract

The method for promoting the size reduction, the performance improvement and the reliability improvement of a semiconductor device embedded with pressure sensor is provided. In a semiconductor device embedded with pressure sensor, a part of an uppermost wiring is used as a lower electrode of a pressure detecting unit. A part of a silicon oxide film formed on the lower electrode is a cavity. On a tungsten silicide film formed on the silicon oxide film, a silicon nitride film is formed. The silicon nitride film has a function to fill a hole or holes and suppress immersion of moisture from outside to the semiconductor device embedded with pressure sensor. A laminated film of the silicon nitride film and the tungsten silicide film forms a diaphragm of the pressure sensor.

Claims

1. A semiconductor device, comprising:

an electronic circuit having MOS transistors formed on a semiconductor substrate and multilevel wiring layers formed over said semiconductor substrate, and

a sensor having a fixed electrode, a diaphragm formed over said fixed electrode and a cavity formed between said fixed electrode and said diaphragm,

wherein said fixed electrode of said sensor is formed by using one of said multilevel wiring layers of said electronic circuit, and

wherein said diaphragm of said sensor is formed by using a conductive layer upper than said one of said multilevel wiring layers.

2. The semiconductor device according to claim 1, wherein said electronic circuit comprises a digital circuit and an analog circuit, and

wherein said sensor is formed above a formation area of said digital circuit.

3. The semiconductor device according to claim 2, wherein said sensor is not formed above a formation area of said analog circuit.

4. The semiconductor device according to claim 1, wherein said sensor detects pressure by measuring a capacitance between said fixed electrode and said diaphragm.

5. The semiconductor device according to claim 1, wherein said device is installed in a tire and is used for detecting pressure inside said tire.

6. The semiconductor device according to claim 1, wherein said diaphragm comprises a tungsten silicide film or a tungsten film.

7. The semiconductor device according to claim 6, wherein said tungsten silicide film or said tungsten film has a tensile stress.

8. The semiconductor device according to claim 1, wherein the sensor is a pressure sensor.

9. The semiconductor device according to claim 1, wherein the sensor is a capacitive pressure sensor.