Semiconductor Terminal Level Difference Prevents Resin Debonding
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Solution Overview
Problem
Interfacial debonding between the case and external connecting terminals in semiconductor devices leads to insulation failure and water ingress, causing corrosion and reliability issues, especially under thermal cycles.
Innovation Solution
A semiconductor device design featuring external connecting terminals with a flat plate shape, where the exposure region has parallel sides and a level difference between the front and rear surfaces, is embedded in a case with a terminal disposition portion that prevents the sealing resin from entering the debonding gap, ensuring strong embedding and insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If external connecting terminals are insert molded into the case, then the terminals are electrically connected to the semiconductor chips and external connections are enabled, but interfacial debonding occurs between the case and terminals under thermal cycles
Solution Approach 1:
The patent applies preliminary action by forming a protrusion on the external connecting terminal before insertion into the case. This protrusion is designed to prevent resin overflow during molding and to inhibit debonding under thermal cycles. The protrusion structure is pre-formed on the terminal surface, creating a mechanical interlock feature that anticipates and prevents future bonding failures.
Solution Approach 2:
The patent applies local quality by creating a protrusion at a specific location on the external connecting terminal - at a position that is not on the front surface and has a predetermined distance from the front surface. This localized structural modification concentrates the bonding strength enhancement at the critical interface region between the terminal and case, while leaving other areas unchanged.
2Adaptability or versatility
If the case material and terminal material are different, then manufacturing flexibility is improved, but interfacial debonding is more likely to occur
Solution Approach 1:
The protrusion structure creates a localized mechanical interlock at the terminal-case interface, providing enhanced bonding strength specifically where needed. This allows different materials to be used for the case and terminals while maintaining reliable bonding through the geometric feature rather than relying solely on material compatibility.
Solution Approach 2:
The patent effectively creates a composite structure at the interface by combining the terminal material with the case material through the protrusion design. The protrusion acts as a mechanical bridge between the two different materials, allowing them to work together as a composite system that maintains bonding strength despite material differences.
3Manufacturing precision
If debonding extent becomes large, then manufacturing tolerance is exceeded, but maintaining mutual insulation becomes difficult
Solution Approach 1:
The protrusion is pre-formed on the terminal to prevent resin overflow during the molding process. This preliminary structural feature ensures that the insulation resin does not extend into regions where it could create conductive paths, thereby maintaining circuit insulation from the manufacturing stage itself.
Solution Approach 2:
The protrusion creates a physical barrier that controls the flow and positioning of the insulation resin. By providing this geometric constraint, the design ensures that the resin film remains in appropriate positions and does not create unwanted conductive paths between circuits.
4Object-affected harmful factors
If water enters through interfacial debonding, then corrosion resistance is compromised, but device reliability decreases
Solution Approach 1:
The protrusion structure is designed in advance to prevent water ingress pathways. By controlling the interface geometry between the terminal and case, the protrusion eliminates gaps and voids where water could penetrate, thereby preventing corrosion before it can occur.
Solution Approach 2:
The protrusion creates a sealed interface structure that acts as a barrier to water penetration. The geometric feature ensures that insulation resin properly fills and seals the interface region, creating a protective film that prevents water from reaching and corroding internal components.
Data Source
AI summary
A case includes a terminal disposition portion which includes a disposition surface projecting from an inner wall surface toward an open area, exposes an exposure region on a front surface of an external connecting terminal, and embeds therein a rear surface of the external connecting terminal. In the case, at at least part of both sides along a pair of opposite sides of the exposure region, the disposition surface is located between the front surface and the rear surface to have a level difference to the front surface. In a semiconductor device with the above-described configuration, the case does not extend to the exposure region on the front surface of the external connecting terminal. Therefore, no encapsulation resin flows into an interfacial debonding gap between the external connecting terminal and the case, thus curbing further advance of the interfacial debonding.