Dual-Filler Semiconductor Device Suppressing Air Bubbles
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In semiconductor devices using silicone gel as a filler, air bubbles form at higher temperatures, degrading insulation performance due to increased gas insolubility and external environmental influences, and injecting high-viscosity adhesives into narrow gaps is challenging, leading to reliability issues.
Innovation Solution
A semiconductor device design incorporating a dual-filler system where a softer silicone gel is used to seal the semiconductor elements and a harder silicone rubber surrounds the peripheral edge of the insulating substrate, filling the gap between the ceramic substrate and base plate to prevent air bubble formation and enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If silicone gel is used as filler at higher temperatures, then the usage temperature range is enlarged, but air bubbles are generated due to decreased gas solubility, degrading insulation performance
Solution Approach 1:
The patent changes the physical state parameter of the filler from gel to rubber, which has different gas solubility characteristics. The rubber material maintains gas solubility at higher temperatures unlike silicone gel, preventing air bubble generation while enabling extended temperature range operation
Solution Approach 2:
The patent uses a composite filling structure combining rubber material and silicone gel in different regions. The rubber material (higher gas solubility) is placed in the lower region where air bubbles tend to form, while silicone gel is used in the upper region, creating a composite system that prevents bubble generation while maintaining insulation performance
2Strength
If adhesive with high viscosity is injected into narrow gap between base plate and ceramic substrate, then adhesion strength is improved, but air bubbles are generated during injection, degrading insulation reliability
Solution Approach 1:
The patent changes the viscosity parameter of the adhesive material by selecting rubber material with appropriate flow characteristics. This material can flow into narrow gaps easily like low-viscosity materials, then cures to provide strong adhesion like high-viscosity materials, eliminating air bubble generation during injection while maintaining adhesion strength
Solution Approach 2:
The patent applies different material properties to different regions: the rubber material is specifically placed in the narrow gap region between base plate and ceramic substrate where adhesion is needed, while allowing different properties in other regions. This localized application ensures proper filling of narrow gaps without compromising overall insulation reliability
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
This design effectively suppresses air bubble generation and improves insulation reliability by ensuring proper filling and adhesion, maintaining insulation performance across varying temperatures.
Implementation Method 1
the amount of gas that can be dissolved in the silicone gel is decreased as the temperature is increased
Implementation Method 2
a rubber material in which air bubbles cannot be generated or grown into the material when the semiconductor device is used
Data Source
AI summary
A semiconductor device including: an insulating substrate having a conductor layer on the upper face and the lower face and a semiconductor element mounted on the upper conductor layer; a base plate bonded to the lower conductor layer; a case member surrounding the insulating substrate and bonded to the surface of the base plate to which the conductor layer bonded to the lower face; a first filler being a silicone composition filled in a region surrounded by the base plate and the case member; and a second filler being injected into a region below the first filler and surrounding a peripheral edge portion of the insulating substrate, whose height from the base plate is higher than the upper face and is lower than a bonding face between the semiconductor element and the upper conductor layer.