Humidity sensor and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-9239309-B2
Application number	US-201214115901-A
Country	US
Kind code	B2
Filing date	May 30, 2012
Priority date	Jun 6, 2011
Publication date	Jan 19, 2016
Grant date	Jan 19, 2016

Abstract

A humidity sensor includes a humidity detention section, a pad section, and a dam section. The humidity detention section includes a pair of detection electrodes facing each other on a predetermined surface of a substrate and a humidity-sensitive film covering the detection electrodes. The pad section is spaced from the humidity detection section on the surface and covered with a protection gel section. The dam section is located between the humidity detection section and the pad section on the surface. The dam section includes a dam wire that is made from the same material as the detection electrodes and a dam humidity-sensitive film that is made from the same material as the humidity-sensitive film and covers at least part of the dam wire.

First claim

What is claimed is:

1. A humidity sensor comprising:
a humidity detention section including a pair of detection electrodes and a humidity-sensitive film, the detection electrodes facing each other on a humidity detection section formation surface of a substrate, the humidity-sensitive film covering the detection electrodes and a gap between the detection electrodes;
a pad section as an external connection terminal, the pad section being spaced from the humidity detection section on the humidity detection section formation surface of the substrate and covered with a protection gel section under a condition where a bonding wire is connected to the pad section; and
a dam section located between the humidity detection section and the pad section on the humidity detection section formation surface of the substrate to restrain the protection gel section from flowing from the pad section side to the humidity detection section side, wherein
the dam section includes a dam wire and a dam humidity-sensitive film,
the dam wire is made from the same material as the detection electrodes and located on the same surface as the detection electrodes,
the dam humidity-sensitive film is made from the same material as the humidity-sensitive film and covers at least part of the dam wire,
a first recess is formed on the dam section to receive a portion of the protection gel section in a case where the protection gel section flows to the dam section; and
a second recess is formed at a location between the dam section and the humidity detection section to receive another portion of the protection gel section in a case where the protection gel section flows to the second recess formed at the location between the dam section and the humidity detection section.

2. The humidity sensor according to claim 1 , further comprising:
a plurality of dam wires including the dam wire and arranged side by side in a facing direction in which the humidity detection section and the pad section face each other, wherein
the first recess formed in the dam section is between adjacent dam wires.

3. The humidity sensor according to claim 2 , wherein
the dam humidity-sensitive film covers at least two adjacent dam wires and a gap between the at least two adjacent dam wires, and
the first recess is located between the at least two adjacent dam wires.

4. The humidity sensor according to claim 2 , wherein
at least one of the plurality of dam wires is exposed outside the dam humidity-sensitive film, and
the first recess is located between the exposed dam wire and the dam wire adjacent to the exposed dam wire.

5. The humidity sensor according to claim 4 , wherein
the exposed dam wire is located between the dam humidity-sensitive film and the humidity-sensitive film in the facing direction in which the humidity detection section and the pad section face each other.

6. The humidity sensor according to claim 1 , wherein
the detection electrodes, the pad section, and the dam wire are made from the same material,
surfaces of the detection electrodes and a surface of the dam wire are collectively covered with the protection layer, and
the humidity-sensitive film and the dam humidity-sensitive film are formed on the protection layer.

7. The humidity sensor according to claim 1 , wherein
the dam wire includes a dummy wire having no electrical connection function and electrically isolated from the detection electrodes and the pad section.

8. The humidity sensor according to claim 1 , further comprising:
a circuit section formed in the substrate and capable of processing an output signal of the humidity detection section, wherein
the dam wire includes a wire of the circuit section.

9. The humidity sensor according to claim 1 , wherein
the humidity-sensitive film and the dam humidity-sensitive film are separated from each other.

10. The humidity sensor according to claim 9 , wherein
the humidity detection section formation surface of the substrate has a rectangular shape, and
the dam humidity-sensitive film of the dam section extends from one side to another side opposite to the one side of the humidity detection section formation surface to divide the humidity detection section formation surface into two regions.

11. The humidity sensor according to claim 9 , wherein
the dam section surrounds the humidity detection section.

12. The humidity sensor according to claim 1 , wherein
the humidity-sensitive film and the dam humidity-sensitive film are integrated together through a connection humidity-sensitive film which is made from the same material as the humidity-sensitive film.

13. The humidity sensor according to claim 12 , wherein
the humidity detection section formation surface of the substrate has a rectangular shape,
the dam humidity-sensitive film of the dam section extends from one side to another side opposite to the one side of the humidity detection section formation surface to divide the humidity detection section formation surface into two regions,
a width of the dam humidity-sensitive film is smaller than a width of the humidity-sensitive film in a direction perpendicular to a longitudinal direction of the dam humidity-sensitive film, and
the connection humidity-sensitive film is connected to a portion of the dam humidity-sensitive film.

14. The humidity sensor according to claim 12 , wherein
the dam section has a rectangular C-shape in plan view and is located between the pad section and the humidity detection section, and
the dam section is located on both sides of the pad section in a direction perpendicular to the facing direction in which the humidity detection section and the pad section face each other.

15. The humidity sensor according to claim 1 , wherein
the humidity detection section detects a change in ambient humidity based on a change in capacitance between the detection electrodes.

16. A method of manufacturing a humidity sensor comprising:
an electrode formation step of forming a pair of detection electrodes on a predetermined surface of a substrate;
a humidity detection section formation step of forming a humidity detection section by forming a humidity-sensitive film to cover the detection electrodes and a gap between the detection electrodes; and
a pad section formation step of forming a pad section as an external connection terminal in such a manner that the pad section is spaced from the humidity detection section on the surface of the substrate and covered with a protection gel section under a condition where a bonding wire is connected to the pad section, wherein
the electrode formation step includes a dam wire formation step of forming a dam wire on the surface of the substrate between the humidity detection section and the pad section by using the same material as the detection electrodes, and the humidity detection section formation step includes a dam section formation step of forming a dam section, which restrains the protection gel section from flowing from the pad section side to the humidity detection section side, by forming a dam humidity-sensitive film to cover at least part of the dam wire by using the same material as the humidity-sensitive film,
a first recess is formed on the dam section to receive a portion of the protection gel section in a case where the protection gel section flows to the dam section; and
a second recess is formed at a location between the dam section and the humidity detection section to receive another portion of the protection gel section in a case where the protection gel section flows to the second recess formed at the locatio

Assignees

• Niimi Naohisa
• Sakai Minekazu
• Denso Corp

Inventors

• Niimi Naohisa
• Sakai Minekazu

Classifications

• G01N27/223 Primary

  for determining moisture content, e.g. humidity (rain detectors on vehicle windows B60S1/0825) · CPC title

• G01N27/121

  for determining moisture content, e.g. humidity, of the fluid (moisture content of the tested material G01N27/048) · CPC title