Semiconductor Lead Structure With Serrated Clips for Thermal Stress
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Solution Overview
Problem
Semiconductor devices experience thermal stress due to differences in linear expansion coefficients between the sealing resin and metal clips, leading to defects such as peeling and bonding failure.
Innovation Solution
The semiconductor device incorporates conductive members with serrated surfaces that enhance anchoring effects, improving the bond between the conductive members and the sealing resin, thereby reducing thermal stress and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sealing resin with greater linear expansion coefficient than metal clips is used, then the sealing resin can provide adequate sealing and coverage, but thermal stress is generated during temperature cycles causing peeling and bonding failure
Solution Approach 1:
The patent applies local quality by creating serrated surfaces at specific locations on the metal clips where they contact the sealing resin. This localized surface modification concentrates the anchoring effect at the critical bonding interface without altering the entire clip structure, thereby improving bond strength locally while maintaining the overall sealing performance of the resin.
Solution Approach 2:
The serrated surfaces introduce geometric curvature and irregularity to the otherwise flat metal clip surfaces. These curved, interlocking surface features mechanically engage with the sealing resin, creating a physical anchor that resists peeling forces generated by thermal expansion differences between materials with different linear expansion coefficients.
2Strength
If the bonding area between metal clips and sealing resin is increased, then adhesion is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent segments the bonding interface by creating multiple discrete serrated features distributed across the metal clip surface rather than using a single large bonding area. This segmentation increases the effective adhesion strength through multiple anchor points while keeping each individual feature simple and easy to manufacture, thereby avoiding increased device complexity.
3Ease of manufacture
If conventional smooth surfaces are used on metal clips, then manufacturing is simple, but thermal stress causes peeling and bonding failure
Solution Approach 1:
The patent changes the surface parameter of the metal clips from smooth to serrated. This parameter modification can be achieved through conventional manufacturing processes such as embossing, rolling, or machining, which alter the surface geometry without fundamentally changing the manufacturing method. The serrated surface parameter provides mechanical anchoring that significantly improves bond reliability under thermal stress while maintaining ease of manufacture.
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 serrated surfaces increase the surface area for better adhesion and heat radiation, resulting in improved reliability and reduced thermal stress-related defects.
Implementation Method 1
the first surface of the first portion has an uneven surface profile defined by a plurality of first recesses, the second surface of the first portion has an uneven surface profile defined by a plurality of second recesses... The first surface of the first portion is in contact with the sealing resin... The second surface of the first portion is in contact with the first bonding layer
Implementation Method 2
The serrated surfaces increase the surface area for better adhesion and heat radiation
Data Source
AI summary
A semiconductor device includes: a first lead including a base portion; a semiconductor element mounted on a first side of the base portion in the thickness direction and including a first electrode; a second lead spaced apart from the base portion in a first direction perpendicular to the thickness direction; a first conductive member electrically bonded to the first electrode and the second lead; and a sealing resin. The first conductive member includes a first portion bonded to the first electrode via a conductive first bonding layer. The first portion includes a first surface and a second surface respectively facing the first side and a second side in the thickness direction. The first portion includes a plurality of first recesses that are recessed from the first surface and a plurality of second recesses that are recessed from the second surface.