Grooved Lead Structure for Resin Adhesion in Semiconductor Packages
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Solution Overview
Problem
Existing semiconductor devices face issues with the adhesion between leads and sealing resins due to thermal stress, leading to peeling and cracking, which can cause pitting corrosion on bonding wires.
Innovation Solution
The semiconductor device incorporates leads with recessed grooves on their surfaces to enhance adhesion with the sealing resin, providing an anchoring effect and resistance to shear stress, thereby improving bonding strength and reducing thermal stress impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing resin is applied directly on the smooth pad surface, then the manufacturing process is simple, but the adhesion between the sealing resin and lead is insufficient under thermal stress
Solution Approach 1:
The lead surface is modified locally by forming grooves only in specific regions where the sealing resin contacts the lead. This local modification enhances adhesion at the critical interface without changing the entire lead structure, resolving the contradiction between improved reliability and device complexity.
Solution Approach 2:
The grooves formed on the lead surface create curved surfaces that enhance the mechanical interlocking between the sealing resin and lead. The curved groove surfaces provide better anchoring compared to flat surfaces, improving adhesion while maintaining relatively simple manufacturing processes.
2Reliability
If grooves are formed near the peripheral edge of the lead to maximize adhesion, then the bonding strength is improved, but the structural integrity and stress distribution are compromised
Solution Approach 1:
Grooves are positioned in the central region of the lead rather than at the peripheral edge, concentrating the adhesion enhancement where the semiconductor element and bonding wires are located. This local placement maintains structural integrity at the edges while providing sufficient bonding strength in the functional area.
Solution Approach 2:
Instead of placing grooves at the peripheral edge (one-dimensional approach), the invention positions grooves in the central region (two-dimensional positioning), optimizing both adhesion and structural integrity by considering the spatial distribution of thermal and mechanical stresses across the lead surface.
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 grooved leads enhance the adhesion between the lead and sealing resin, preventing peeling and cracking, while also reducing laser machining time and improving heat dissipation and thermal conductivity.
Implementation Method 1
the lead is formed with a plurality of grooves that are recessed from the main surface... the plurality of grooves are located away from a peripheral edge of the main surface
Data Source
AI summary
There is provided a technique that includes: a lead having a main surface facing in a thickness direction; a semiconductor element mounted over the main surface; and a sealing resin that is in contact with the main surface and covers the semiconductor element, wherein the lead is formed with a plurality of grooves that are recessed from the main surface and are located apart from each other, and wherein the plurality of grooves are located away from a peripheral edge of the main surface.