Capacitive sensor and manufacturing method of capacitive sensor

Patent metadata

Field	Value
Publication number	US-11662328-B2
Application number	US-202117358292-A
Country	US
Kind code	B2
Filing date	Jun 25, 2021
Priority date	Jul 8, 2020
Publication date	May 30, 2023
Grant date	May 30, 2023

Abstract

A capacitive sensor includes a sensing electrode, a first electrode pad, a substrate, and a second electrode pad. The sensing electrode outputs a signal corresponding to a capacitance between the sensing electrode and a detection target. The first electrode pad is coupled to the sensing electrode. The substrate includes a substrate surface portion and a step portion. On the substrate surface portion are the sensing electrode and the first electrode pad mounted. The step portion is provided at a position in the substrate lower than the substrate surface portion. The second electrode pad is mounted on the step portion and coupled to an external line.

First claim

What is claimed is:

1. A capacitive sensor comprising:
a sensing electrode configured to output a signal corresponding to a capacitance between the sensing electrode and a detection target;
a first electrode pad coupled to the sensing electrode;
a first substrate having a substrate surface portion and a step portion, the sensing electrode and the first electrode pad being mounted on the substrate surface portion, and the step portion being formed at a position lower than the substrate surface portion; and
a second electrode pad mounted on the step portion and coupled to an external line,
wherein a second substrate, on which the external line is formed, is flip-chip bonded onto the second electrode pad, and
a depth of the step portion is such that a sum of a thickness of the second substrate, a thickness of a bump that couples the second electrode pad and the second substrate, and a thickness of the second electrode pad does not exceed a height of the substrate surface portion.

2. The capacitive sensor according to claim 1 , wherein a line coupling the first electrode pad to the second electrode pad is formed along the step portion.

3. A manufacturing method of a capacitive sensor, the method comprising:
forming a step portion in a first substrate by etching an end region of the first substrate comprising a substrate surface portion on which a sensing electrode and a first electrode pad are mounted, wherein the sensing electrode is configured to output a signal corresponding to a capacitance between the sensing electrode and a detection target, and the first electrode pad is coupled to the sensing electrode;
forming a line extending from the first electrode pad to the step portion;
forming, in the step portion, a second electrode pad coupled to the line and an external line; and
flip-chip bonding, onto the second electrode pad, a second substrate on which the external line is formed,
wherein, in forming the step portion, a depth of the step portion is determined such that a sum of a thickness of the second substrate, a thickness of a bump that couples the second electrode pad and the second substrate, and a thickness of the second electrode pad does not exceed a height of the substrate surface portion.

Assignees

• Oht Inc
• Univ Tohoku

Inventors

• Yasuda Toshiro
• Kamibayashi Kazutoshi
• Sugawa Shigetoshi
• Kuroda Rihito
• Goto Tetsuya

Classifications

• G01R27/2605

  Measuring capacitance (capacitive sensors G01D5/24) · CPC title

• G01D5/24 Primary

  by varying capacitance · CPC title

• G01N27/24 Primary

  Investigating the presence of flaws · CPC title

• G01N27/228

  Circuits therefor (measuring capacitance per se G01R27/26) · CPC title

• G01N27/226 Primary

  Construction of measuring vessels; Electrodes therefor · CPC title