Semiconductor Lead Recess Geometry to Block Delamination
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Solution Overview
Problem
In semiconductor devices, delamination at the interface between the lead and the sealing material often propagates orthogonally, leading to potential failure due to the shape of recesses on the lead's surface.
Innovation Solution
The semiconductor module incorporates a lead with polygonal recesses on its surface, where the bottom surface is not orthogonal to the lead's sides, and barbed portions protrude from the recess walls, enhancing the contact area with the sealing material and preventing delamination propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If recesses with wall surfaces parallel to the lead side or arranged orthogonally are formed on the lead surface, then delamination prevention is attempted, but delamination propagation occurs in the direction orthogonal to the lead side
Solution Approach 1:
The patent applies asymmetry by forming recesses with bottom surfaces having sides extending in directions not orthogonal to the lead sides. This asymmetric configuration prevents delamination from propagating orthogonally along the lead side by creating non-uniform stress distribution and blocking the propagation path through the angled recess geometry.
Solution Approach 2:
The patent employs curved or angled surfaces in the recess configuration rather than purely orthogonal flat surfaces. The bottom surface of each recess has sides extending at angles not orthogonal to the lead side, creating a geometric structure that deflects and blocks delamination propagation through the angled interfaces.
2Ease of manufacture
If conventional orthogonal recesses are used on the lead surface, then manufacturing is simplified, but delamination occurs and propagates causing device failure
Solution Approach 1:
The asymmetric recess configuration with bottom surfaces having non-orthogonal sides provides both manufacturing feasibility through standard molding processes and improved reliability by preventing delamination propagation. The asymmetry is achieved through the angular orientation of recess sides rather than complex multi-step processing.
Data Source
AI summary
A semiconductor module, including: a circuit board including a semiconductor element having an electrode on an upper surface thereof; a lead bonded to the electrode by a bonding material; and a sealing material that seals the semiconductor element and the lead. The lead includes: a bonding portion bonded to the electrode, the bonding portion having a lower surface facing the electrode, and an upper surface opposite to the lower surface, and a plurality of recesses formed on the upper surface of the bonding portion. In a plan view of the semiconductor module, the bonding portion has a plurality of sides, and each recess has a bottom surface of a planar shape, the planar shape having a side extending in a direction that is not orthogonal to any of the sides of the bonding portion. Each of the recesses a barbed portion protruding from a wall surface thereof.