Manufacturing method of combined sensor

• US 8,438,718 B2
• Filed: 02/16/2011
• Issued: 05/14/2013
• Est. Priority Date: 02/26/2010
• Status: Expired due to Fees

• Current Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Inventors: Aono, Takanori, Suzuki, Kengo, Koide, Akira, Hayashi, Masahide
• Primary Examiner(s): Kim, Paul D
• Application Number:
  US13/028,592
• Publication Number:
  US 20110209815A1
• Time in Patent Office: 818 Days
• Field of Search: 294/28, 294/34, 294/69, 295/921, 295/94, 295/95, 296/091, 298/41, 298/55, 298/58, 735/041.2, 257/666, 257/682, 257/686, 156/146
• US Class Current: 29/595
• CPC Class Codes: B81B 2201/0235 Accelerometers
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 2207/096 through the substrate
• CPC Class Codes: B81B 7/02 containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] B81B7/04 takes precedence
• CPC Class Codes: B81C 1/00285 using materials for controlling the level of pressure, contaminants or moisture inside of the package, e.g. getters
• CPC Class Codes: B81C 2203/0118 Bonding a wafer on the substrate, i.e. where the cap consists of another wafer
• CPC Class Codes: B81C 2203/035 Soldering
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01C 19/5769 Manufacturing; Mounting; Housings
• CPC Class Codes: G01C 19/5783 Mountings or housings not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
• CPC Class Codes: G01P 15/0802 Details
• CPC Class Codes: G01P 2015/0882 for providing damping of vibrations
• CPC Class Codes: H01L 2224/48145 the bodies being stacked
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/92247 the second connecting process involving a wire connector
• 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
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/49007 Indicating transducer
• CPC Class Codes: Y10T 29/4908 Acoustic transducer
• CPC Class Codes: Y10T 29/49171 : with encapsulating
• CPC Class Codes: Y10T 29/49176 : with molding of electrically insulating material
• CPC Class Codes: Y10T 29/49826 : Assembling or joining

Abstract

A movable device of acceleration sensors and a vibration device of a gyroscope are formed on the same sensor wafer spaced apart from each other by a wall. A cap wafer having gaps corresponding to the movable mechanical components of the acceleration sensors and gyroscope is provided for the wafer and an adsorbent divided into a plurality of divisional portions is disposed in the gap for the gyroscope. After the sensor wafer and the cap wafer have been bonded together at a temperature of inactivation of the adsorbent and in an atmospheric pressure ambience of noble gas and activated gas, the adsorbent divisional portions are activated in sequence to adsorb the activated gas so as to adjust the pressure inside the gyroscope, thus manufacturing a combined sensor wafer.

Claims

1. A method of manufacturing a combined sensor having an angular rate detector adapted to detect an angular rate by using a vibration device, an acceleration detector adapted to detect an acceleration by using a mass and an adsorbent activated to adsorb a specified gas is an active gas, and a different gas is a noble gas or an inactive gas, comprising the steps of:

hermetically sealing said vibration device and said adsorbent in a first chamber and said mass in a second chamber in an ambience of said specified gas mixed with a different gas is the noble gas or the inactive gas at a predetermined ratio; and

activating thereafter said adsorbent.

2. The combined sensor manufacturing method according to claim 1, wherein said adsorbent is activated wholly or partly so that the pressure in said first chamber may amount to a desired level.

3. The combined sensor manufacturing method according to claim 2, wherein said adsorbent is divided into a plurality of divisional portions and one or ones are selected from said plurality of divisional portions so as to be activated to thereby set up a desired pressure in said first chamber.

4. The combined sensor manufacturing method according to claim 3, wherein said adsorbent is activated by conducting current to a heating element provided nearby said adsorbent or by irradiating a laser beam on said adsorbent.

5. The combined sensor manufacturing method according to claim 4, wherein a plurality of sets of said first and second chambers are formed by bonding or adhering a single silicon wafer formed with said vibration devices and said masses to another substrate.

6. The combined sensor manufacturing method according to claim 5, wherein said another substrate is made of glass or silicon.

7. The combined sensor manufacturing method according to claim 6, wherein after said adsorbent has been activated, said silicon wafer and said another substrate are diced to form a plurality of combined sensors each having a pair of said first chamber and said second chamber.