Semiconductor Pressure Sensor Adhesive Sealing for Hermetic Integrity

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional semiconductor pressure sensors face issues with hermetic sealing and corrosion due to minute gaps between the sensor module and the outer case, leading to air infiltration, moisture contamination, and leakage, which compromise measurement accuracy.

Innovation Solution

A semiconductor pressure sensor design where the sensor module is integrally molded with a first thermosetting resin and an outer case with a second thermoplastic resin, with exposed portions sealed using an adhesive to prevent moisture and gas infiltration, ensuring reliable sealing and corrosion protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the sensor module is integrally molded with the outer case using thermosetting and thermoplastic resins, then the device size is reduced and manufacturing is simplified, but minute gaps form between the sensor module and outer case due to thermal expansion differences, leading to air infiltration and moisture contamination

Engineering Contradiction:

Improvedevice sizeVSAvoidhermetic sealing

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

A sealing member (adhesive layer) is introduced as an intermediary substance between the sensor module and outer case. This sealing member fills the minute gaps formed due to thermal expansion differences, preventing air and moisture infiltration while maintaining the integral mold structure's compact size and manufacturing simplicity.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sealing member is incorporated into the molding process beforehand, during which it is positioned to anticipate and compensate for the gaps that will form after thermal cycling. This pre-positioning ensures hermetic sealing is maintained despite subsequent thermal expansion and contraction.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Ease of operation

If the sensor module is exposed from the outer case for terminal connection, then electrical connection is enabled, but gaps form at the exposed portion due to resin volume shrinkage during solidification, causing moisture infiltration and corrosion

Engineering Contradiction:

Improveelectrical connectionVSAvoidmoisture infiltration and corrosion

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The sealing member acts as an intermediary that fills gaps at the exposed portion of the sensor module where terminals connect to the outer case. This prevents moisture infiltration and corrosion at the vulnerable interface while preserving electrical connection functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of operation

If a conventional construction with separate mounting portion and connector portion is used, then terminal connection is achieved, but the device becomes markedly large-sized due to the required mating portion for bonding lid and outer case

Engineering Contradiction:

Improveterminal connectionVSAvoiddevice size

Core Design Contradiction:

Ease of operationVSVolume of moving object

Solution Approach 1:

The mounting portion and connector portion are merged into a single integral mold structure. The terminal is molded integrally with the outer case, eliminating the need for separate mating portions and bonding operations, thereby reducing device size while maintaining electrical connection capability.

Inventive Principle:

Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively prevents corrosion and air-tightness faults, enhancing the reliability of the semiconductor pressure sensor by sealing the boundary between the sensor module and the outer case with an adhesive, thereby maintaining accurate pressure measurements.

Implementation Method 1

the exposed portion of the sensor module from the second resin, and the boundary between the exposed portion of the sensor module and the second resin are covered with an adhesive

Methodology Applied

Scientific EffectAdhesive sealing: Adhesive

Implementation Method 2

a sensor module in which a semiconductor pressure sensor part is contained is integrally molded with a first thermosetting resin

Methodology Applied

Scientific EffectThermosetting resin curing:

Implementation Method 3

an outer case in which mentioned sensor module is contained, and mentioned sensor module is further insert-molded with a second resin to form a connector portion

Methodology Applied

Scientific EffectThermoplastic resin molding:

Implementation Method 4

a semiconductor pressure sensor part that converts a pressure to an electrical signal

Methodology Applied

Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentUS7603908B2Semiconductor pressure sensor, manufacturing method thereof, and die for molding semiconductor pressure sensor

Publication Date: 2009.10.20 MITSUBISHI ELECTRIC MOBILITY CORP

AI summary

A semiconductor pressure sensor is provided with a semiconductor pressure sensor part that converts a pressure to an electrical signal, a sensor module in which said semiconductor pressure sensor part and a terminal of which part is extended to the outside are insert-molded with a first resin, and an outer case in which said sensor module is contained, and said sensor module is further insert-molded with a second resin to form a connector portion, and the semiconductor pressure sensor is characterized in that the exposed portion of the sensor module from the second resin, and the boundary between the exposed portion of the sensor module and the second resin are covered with an adhesive.