SiC Semiconductor Adhesion via Stress Relaxation Resin
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Solution Overview
Problem
Silicon carbide (SiC) semiconductor devices face challenges in adhering to sealant resins due to the SiC substrate's surface properties, leading to poor adhesive strength and increased peeling and cracking under thermal stress.
Innovation Solution
A method involving the application of a stress relaxation resin, such as polyimide or polyamide resin, to cover the peripheral end portions of SiC semiconductor devices before sealing with a sealant resin, enhancing the adhesive strength and reducing thermal stress-induced peeling and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a silane based resin film is deposited on SiC semiconductor device surface, then adhesive strength should be enhanced, but the SiC surface properties prevent effective film deposition and adhesion
Solution Approach 1:
The patent introduces a silane coupling agent as an intermediary substance that chemically bonds to both the SiC semiconductor device surface and the sealant resin. The silane coupling agent forms a bridge between the inorganic SiC surface and the organic sealant resin, enabling effective adhesion despite the incompatible surface properties of SiC. This mediator overcomes the fundamental adhesion problem by creating a chemical bridge between dissimilar materials.
Solution Approach 2:
The patent changes the chemical parameters of the SiC surface by treating it with a silane coupling agent, which modifies the surface chemistry to enable better adhesion. The treatment alters the surface energy, roughness, and chemical composition of the SiC surface, transforming it from a non-adhesive state to an adhesive state that can bond effectively with the sealant resin.
2Productivity
If the semiconductor device is diced with a dicing blade, then individual chips are obtained, but the insulating layer is not provided in the dicing region to avoid clogging the blade
Solution Approach 1:
The patent applies different treatments to different regions of the semiconductor device. The insulating layer is selectively formed only in the non-dicing regions where adhesion is needed, while the dicing regions remain free of insulating material to allow blade passage. This local differentiation enables both efficient dicing and adequate adhesion in respective areas.
3Power
If the semiconductor device operates at high voltage, then power control function is achieved, but thermal stress causes peeling at the adhesive interface due to coefficient of thermal expansion difference
Solution Approach 1:
The patent changes the thermal and mechanical parameters of the adhesive interface by applying silane coupling agent treatment and optimizing the sealant resin composition. This creates a transition layer with intermediate thermal expansion properties that gradually bridge the gap between the SiC device and the sealant resin, reducing thermal stress concentration at the interface.
Solution Approach 2:
The patent creates a composite adhesive structure consisting of multiple layers with different properties: the silane coupling agent layer, the sealant resin layer, and the SiC substrate. This composite structure combines the advantages of each material to achieve both strong adhesion and thermal stress resistance, with each layer contributing specific functional properties.
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 approach significantly enhances the reliability of semiconductor apparatus by reducing peeling and cracking caused by thermal stress, allowing for more reliable operation of SiC semiconductor devices.
Implementation Method 1
the semiconductor device generates heat, which causes thermal stress between the semiconductor device and the sealant resin. This thermal stress is caused as the semiconductor chip and the sealant resin have their respective coefficients of thermal expansion with a difference therebetween
Data Source
AI summary
A plurality of semiconductor devices provided on a silicon carbide substrate are provided with electrode layers, respectively. The silicon carbide substrate is cut at a region of an exposed surface of the silicon carbide substrate that separates the electrode layers to individually separate the semiconductor devices. A stress relaxation resin is applied to each individually separated semiconductor device to cover the exposed surface at a peripheral end portion of that surface of the semiconductor device which has the electrode layer thereon. A semiconductor apparatus can thus be obtained that also allows a semiconductor device with a silicon carbide or similar compound semiconductor substrate to adhere to a sealant resin via large adhesive strength and thus allows the sealant resin to be less crackable, less peelable and the like by thermal stress caused in operation.