Resin Molded Semiconductor Device Corner Stress Management
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Solution Overview
Problem
Conventional resin-molded semiconductor devices face issues with stress generation at interfaces due to resin curing, leading to cracking of protective coating glass, detachment of interfaces, and breaking of bonding parts, especially at the corners of the circuit board, which can result in disconnecting of bonding parts and damage to mounted components.
Innovation Solution
A semiconductor device design featuring a circuit board with chamfered corners and a protective coating glass arrangement where the outer-peripheral end of the glass is positioned at a second distance larger than the first distance from the corners, ensuring strong bonding between the resin and the circuit board corners, thereby distributing stress and preventing detachment, while maintaining sufficient bonding strength to prevent cracking of the protective coating glass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the protective coating glass is positioned close to the corners of the circuit board, then the bonding strength between the protective coating glass and the circuit board is improved, but the stress concentration at the corners causes cracking of the protective coating glass and detachment at the interface
Solution Approach 1:
The patent applies asymmetry by positioning the protective coating glass such that the distance from its outer-peripheral end to each corner of the circuit board (second distance) is larger than the distance to each side (first distance). This asymmetric arrangement moves the glass away from corner positions where stress concentrates during resin curing, preventing cracking and interface detachment while maintaining adequate bonding strength at the interface.
2Reliability
If a flexible part with low Young's modulus (e.g., silicone resin) is applied between the protective coating glass and the molded resin, then the protective coating glass is prevented from cracking, but solder may crack due to difference in thermal expansion rates
Solution Approach 1:
The patent extracts the flexible intermediate layer (silicone resin) from the structure and replaces it with a direct bonding configuration. By positioning the protective coating glass at appropriate distances from the circuit board corners, the patent eliminates the need for a flexible intermediary while preventing glass cracking through proper stress distribution, thereby avoiding the solder joint problems that arise from thermal expansion mismatches in multi-layer flexible structures.
3Reliability
If the protective coating glass is positioned to allow direct contact between the resin and the circuit board corners, then stress distribution is improved and interface detachment is prevented, but the bonding strength at the corners may be insufficient
Solution Approach 1:
The patent uses the adhesive agent as an intermediary bonding layer between the circuit board and the molded resin. By positioning the protective coating glass to allow direct contact between the resin and circuit board corners, the adhesive agent mediates the bonding process, ensuring adequate bonding strength at the corners while maintaining proper stress distribution to prevent interface detachment.
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 design effectively reduces stress on the protective coating glass, preventing its cracking and maintaining strong bonding between the resin and the circuit board, thus preventing disconnecting of bonding parts and damage to mounted components, even under thermal stress.
Implementation Method 1
The wiring part is fixed to the circuit board through an adhesive agent and is electrically coupled with the pad
Implementation Method 2
The resin part seals the circuit board, the wiring part, and the protective coating glass
Implementation Method 3
The protective coating glass is disposed on the circuit board to cover the circuit wiring
Implementation Method 4
a circuit wiring electrically coupled with the mounted part, and a pad electrically coupled with the circuit wiring
Data Source
AI summary
A semiconductor device includes a circuit board, a wiring part, a protective coating glass, and a resin part. The circuit board has an approximately rectangular shape. The protective coating glass is disposed on the circuit board and is arranged on an inside of the circuit board in such a manner that an outer-peripheral end of the protective coating glass is away from each of four sides of the circuit board at a first distance and is away from each of four corners of the circuit board at a second distance that is larger than the first distance. The resin part seals the circuit board, the wiring part, and the protective coating glass in such a manner that an outer-peripheral end portion of the circuit board that is located on an outside of the protective coating glass directly contact with the resin part.