SEMICONDUCTOR PRESSURE SENSOR

• US 20190273200A1
• Filed: 09/19/2018
• Published: 09/05/2019
• Est. Priority Date: 03/05/2018
• Status: Active Grant

• Current Assignee: Mitsubishi Electric Corporation
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: SATO, Kimitoshi
• Granted Patent: US 10,454,017 B2
• Time in Patent Office: Days
• CPC Class Codes: B81B 3/0072 For controlling internal stress or strain in moving or flexible elements, e.g. stress compensating layers
• CPC Class Codes: G01L 9/0047 Diaphragm with non uniform thickness, e.g. with grooves, bosses or continuously varying thickness
• CPC Class Codes: G01L 9/008 using piezoelectric devices piezoelectric resonators G01L9/0022; surface acoustic waves G01L9/0025
• CPC Class Codes: H10N 30/10513 characterised by the underlying bases, e.g. substrates
• CPC Class Codes: H10N 30/1071 with electrical and mechanical input and output, e.g. having combined actuator and sensor parts
• CPC Class Codes: H10N 30/302 Sensors
• CPC Class Codes: H10N 30/308 Membrane type
• CPC Class Codes: H10N 30/875 Further connection or lead arrangements, e.g. flexible wiring boards, terminal pins
• CPC Class Codes: H10N 30/88 Mounts; Supports; Enclosures; Casings
• CPC Class Codes: H10N 30/883 Further insulation means against electrical, physical or chemical damage, e.g. protective coatings
• CPC Class Codes: H10N 39/00 Integrated devices, or assemblies of multiple devices, comprising at least one piezoelectric, electrostrictive or magnetostrictive element covered by groups H10N30/00 – H10N35/00

Abstract

A semiconductor pressure sensor includes: a first semiconductor substrate having a surface; an oxide film provided on the surface of the first semiconductor substrate and having a cavity; a second semiconductor substrate bonded to the first semiconductor substrate via the oxide film and having a diaphragm above the cavity; and a piezoelectric device provided on the diaphragm, wherein no recess is provided in the surface of the first semiconductor substrate within a region of the diaphragm, and a stress mitigating groove is provided in the oxide film outside and around the diaphragm.

Claims

1. A semiconductor pressure sensor comprising:

a first semiconductor substrate having a surface;

an oxide film provided on the surface of the first semiconductor substrate and having a cavity;

a second semiconductor substrate bonded to the first semiconductor substrate via the oxide film and having a diaphragm above the cavity; and

a piezoelectric device provided on the diaphragm,

wherein no recess is provided in the surface of the first semiconductor substrate within a region of the diaphragm, and

a stress mitigating groove is provided in the oxide film outside and around the diaphragm.

2. The semiconductor pressure sensor according to claim 1, wherein a cavity extension space connected to the cavity is provided in the surface of the first semiconductor substrate outside the region of the diaphragm.

3. The semiconductor pressure sensor according to claim 2, wherein a pressure introduction hole which extends from a backside of the first semiconductor substrate and reaches the cavity extension space is provided.