Magnetic sensor and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-10062836-B2
Application number	US-201715458578-A
Country	US
Kind code	B2
Filing date	Mar 14, 2017
Priority date	Mar 15, 2016
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

The magnetic sensor includes a semiconductor substrate having Hall elements on a front surface of the semiconductor substrate, a conductive layer formed on a back surface of the semiconductor substrate, and a magnetic flux converging plate formed on the conductive layer. The magnetic flux converging plate is formed on the back surface of the semiconductor substrate through formation of the base conductive layer on the back surface of the semiconductor substrate, formation of a resist on the base conductive layer having an opening for forming the magnetic flux converging plate, formation of the magnetic flux converging plate in the opening of the resist by electroplating, removal of the resist, and removal of a part of the base conductive layer by etching with the magnetic flux converging plate as a mask.

First claim

What is claimed is:

1. A magnetic sensor, comprising:
a semiconductor substrate including Hall elements in the semiconductor substrate, the Hall elements having an exposed surface at a front surface of the semiconductor substrate;
a conductive layer on a back surface of the semiconductor substrate; and
a magnetic flux converging plate on the conductive layer adjacent to the back surface of the semiconductor substrate; and
a protective film contacting the front surface of the semiconductor substrate, wherein the exposed surface of the Hall elements contact the protective film and the magnetic flux converging plate is at an opposite side of the substrate from the protective film.

2. A magnetic sensor according to claim 1 , wherein the semiconductor substrate has a thickness of from 100 μm to 400 μm.

3. A magnetic sensor according to claim 1 , wherein the magnetic flux converging plate has a thickness of from 20 μm to 50 μm.

4. A method of manufacturing a magnetic sensor, the method comprising:
forming Hall elements in a semiconductor substrate, the Hall elements having an exposed surface at a front surface of the semiconductor substrate;
forming a protective film contacting the front surface of the semiconductor substrate and contacting the exposed surface of the Hall elements;
forming a base conductive layer on a back surface of the semiconductor substrate;
forming, on the base conductive layer, a resist having an opening for forming a magnetic flux converging plate;
forming a magnetic flux converging plate in the opening by performing electroplating under a state in which the resist is formed such that the magnetic flux converging plate is arranged adjacent to the back surface of the semiconductor substrate and at an opposite side to the protective film;
removing the resist; and
removing a part of the base conductive layer by etching with the magnetic flux converging plate as a mask.

5. A method of manufacturing a magnetic sensor according to claim 4 , further comprising grinding the back surface of the semiconductor substrate so that the semiconductor substrate has a thickness of from 100 μm to 400 μm.

6. A method of manufacturing a magnetic sensor according to claim 4 , wherein the magnetic flux converging plate has a thickness of from 20 μm to 50 μm.

Assignees

• Sii Semiconductor Corp
• Ablic Inc

Inventors

• Hioka Takaaki
• Ebihara Mika
• Takahashi Hiroshi
• Kishi Matsuo
• TAKAHAMA Miei

Classifications

• G01R33/0052 Primary

  Manufacturing aspects; Manufacturing of single devices, i.e. of semiconductor magnetic sensor chips (devices based on galvano-magnetic effect or the like H10N50/85) · CPC title

• H01L43/14

  Electricity · mapped topic

• G01R33/07 Primary

  Hall effect devices · CPC title

• H01L43/065 Primary

  Electricity · mapped topic

• G01R33/072 Primary

  Constructional adaptation of the sensor to specific applications · CPC title