Physical quantity sensor

Patent metadata

Field	Value
Publication number	US-11054326-B2
Application number	US-201916511115-A
Country	US
Kind code	B2
Filing date	Jul 15, 2019
Priority date	Feb 28, 2017
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

In a physical quantity sensor, a first substrate has a recess depressed from a second surface to provide a thin film section adjacent to a first surface, and a second substrate has a first surface bonded to the first surface of the first substrate, and has a hollow depressed from the first surface and facing the recess. The recess and the hollow have such sizes that a projected line defined by projecting an end of a bottom surface in the recess to the first surface of the first substrate surrounds an open end of the hollow. When the thin film section is displaced toward the hollow, a maximum tensile stress is generated at a position on a rear surface of the thin film section intersecting an extended line along a normal direction to the first surface of the first substrate and passing through the open end of the hollow.

First claim

What is claimed is:

1. A physical quantity sensor comprising:
a first substrate having a first surface and a second surface opposite to each other, and having a recess depressed from the second surface to provide a thin film section adjacent to the first surface; and
a second substrate having a first surface bonded to the first surface of the first substrate, and having a hollow depressed from the first surface at a portion facing the recess, wherein
the recess and the hollow have such sizes that a projected line defined by projecting an end of a bottom surface in the recess to the first surface of the first substrate surrounds an open end of the hollow,
the thin film section has a front surface on the first surface of the first substrate and a rear surface that is opposite to the front surface and is closer to the second surface of the first substrate than the front surface is, and
when a position on the rear surface of the thin film section intersecting an extended line that is along a normal direction to the first surface of the first substrate and passes through the open end of the hollow is defined as a specific position, the thin film section is configured so that a maximum tensile stress is generated at the specific position when the thin film section is displaced toward the hollow.

2. The physical quantity sensor according to claim 1 , wherein
when the specific position is defined as a first position and the end on the bottom surface of the recess is defined as a second position, the thin film section is configured so that greater tensile stress is generated at the first position than at the second position when the thin film section is displaced toward the hollow.

3. The physical quantity sensor according to claim 1 , wherein
the end of the bottom surface in the recess has a circular shape, and
the open end of the hollow has a circular shape.

4. A physical quantity sensor comprising:
a first substrate having a first surface and a second surface opposite to each other, and having a recess depressed from the second surface to provide a thin film section adjacent to the first surface; and
a second substrate having a first surface bonded to the first surface of the first substrate, and having a hollow depressed from the first surface at a portion facing the recess, wherein
the recess and the hollow have such sizes that a projected line defined by projecting an end of a bottom surface in the recess to the first surface of the first substrate surrounds an open end of the hollow,
the thin film section has a front surface on the first surface of the first substrate and a rear surface that is opposite to the front surface and is closer to the second surface of the first substrate than the front surface is, and
when a position on the rear surface of the thin film section intersecting an extended line that is along a normal direction to the first surface of the first substrate and passes through the open end of the hollow is defined as a first position, the end of the bottom surface in the recess is defined as a second position, a shortest distance between the first position and the second position is defined as L [μm], and a thickness of the thin film section is define as d [μm], L>1.28×d+0.53 is satisfied.

5. The physical quantity sensor according to claim 4 , wherein
the end of the bottom surface in the recess has a circular shape, and
the open end of the hollow has a circular shape.

Assignees

• Denso Corp

Inventors

• Hayakawa Yutaka
• Yokura Hisanori

Classifications

• G01L9/00 Primary

  Measuring steady of quasi-steady pressure of fluid or fluent solid material by electric or magnetic pressure-sensitive elements {(G01L11/004 takes precedence)}; Transmitting or indicating the displacement of mechanical pressure-sensitive elements, used to measure the steady or quasi-steady pressure of a fluid or fluent solid material, by electric or magnetic means (measuring differences of two or more pressure values G01L13/00; measuring two or more pressure values simultaneously G01L15/00) · CPC title

• G01P15/0802

  Details · CPC title

• G01L9/0054

  integral with a semiconducting diaphragm · CPC title

• G01L9/0042 Primary

  Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms (details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively) · CPC title

• G01L9/0045

  Diaphragm associated with a buried cavity · CPC title