Pressure sensor with tapered stem

Patent metadata

Field	Value
Publication number	US-12018992-B2
Application number	US-202017437736-A
Country	US
Kind code	B2
Filing date	Mar 6, 2020
Priority date	Mar 11, 2019
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

A pressure sensor configured to prevent tearing or cracking of an insulating film for insulating between a stem and a detection circuit from occurring. A stem having a planar outer bottom surface, an outer side surface intersecting the outer bottom surface, and a pressure receiving inner surface that is the opposite surface to the outer bottom surface and receives pressure from a fluid to be measured; and a detection circuit provided to the outer bottom surface with an insulating film interposed therebetween. The stem has a foot part that: is formed to surround the outer bottom surface; consists of a surface which, when observed parallel to the outer bottom surface, faces a direction different from the direction of the outer bottom surface and the outer side surface; and connects between the outer bottom surface and the outer side surface. The insulating film covers a portion of the foot part.

First claim

The invention claimed is:

1. A pressure sensor comprising:
a stem including (i) a planar outer bottom surface, (ii) an outer side surface extending in a direction intersecting the outer bottom surface, (iii) a pressure receiving inner surface that is an opposite surface to the outer bottom surface and configured to receive pressure from a fluid to be measured and (iv) a skirt portion that (a) surrounds the outer bottom surface, (b) has a surface facing a direction different from facing directions of the outer bottom surface and the outer side surface when viewed from a direction parallel to the outer bottom surface and (c) connects the outer bottom surface and the outer side surface;
a detection circuit on the outer bottom surface; and
an insulating film interposed between the outer bottom surface and the detection circuit,
wherein
the insulating film covers the outer bottom surface, the skirt portion, and at least a part of the outer side surface.

2. The pressure sensor according to claim 1 , wherein a length from a first boundary between the outer bottom surface and the skirt portion to a second boundary between the skirt portion and the outer side surface viewing from a direction perpendicular to the outer bottom surface is 10 μm or more and 1 mm or less.

3. The pressure sensor according to claim 1 , wherein the skirt portion includes an inclined surface formed so as to surround the outer bottom surface and forming an angle of 30 degrees to 60 degrees with respect to the outer bottom surface viewing in a cross section orthogonal to the outer bottom surface.

4. The pressure sensor according to claim 3 , wherein the inclined surface is directly connected to the outer bottom surface or is connected to the outer bottom surface via a connection surface forming an angle smaller than that of the inclined surface.

5. The pressure sensor according to claim 3 , wherein the inclined surface forms a predetermined angle with respect to the outer bottom surface viewing in a cross section orthogonal to the outer bottom surface.

6. The pressure sensor according to claim 4 , wherein the inclined surface forms a predetermined angle with respect to the outer bottom surface viewing in a cross section orthogonal to the outer bottom surface.

7. The pressure sensor according to claim 3 , wherein the inclined surface changes so that an angle formed with respect to the outer bottom surface increases as a distance from the outer bottom surface increases viewing in a cross section orthogonal to the outer bottom surface.

8. The pressure sensor according to claim 4 , wherein the inclined surface changes so that an angle formed with respect to the outer bottom surface increases as a distance from the outer bottom surface increases viewing in a cross section orthogonal to the outer bottom surface.

9. The pressure sensor according to claim 1 , wherein the skirt portion has a curved surface shape whose angle formed with respect to the outer bottom surface increases transitionally as a distance from a first boundary between the outer bottom surface and the skirt portion increases viewing in a cross section orthogonal to the outer bottom surface.

10. The pressure sensor according to claim 1 , wherein the outer side surface is substantially perpendicular to the outer bottom surface.

Assignees

• Tdk Corp

Inventors

• Kobayashi Masanori
• Unno Ken

Classifications

• G01L19/145

  with stress relieving means · CPC title

• G01L9/0055

  bonded on a diaphragm · CPC title

• G01L19/06

  Means for preventing overload or deleterious influence of the measured medium on the measuring device or vice versa · CPC title

• G01L9/0052 Primary

  of piezoresistive elements (circuits therefor G01L9/06) · 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