Lead Frame Terminal Resin Adhesion via Polygonal Geometry
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The adhesion between semiconductor terminals and sealing resin decreases with thinner package thickness and increased standoff, leading to unreliable semiconductor apparatus due to reduced terminal strength.
Innovation Solution
A lead frame with resin-sealed terminals having a polygonal or deformed columnar shape with notches or grooves, increasing the contact area with the resin, and varying terminal shapes to enhance bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the package thickness is thinned or standoff is increased, then the miniaturization and design flexibility are improved, but the adhesion between terminal and sealing resin decreases leading to reduced terminal strength
Solution Approach 1:
The terminal cross-section is designed with non-uniform geometry, featuring a resin-sealed portion with increased surface area through polygonal shapes (pentagonal or more) and deformed columnar shapes with notches or groove parts. This local geometric modification concentrates the adhesion enhancement exactly where the terminal contacts the sealing resin, without increasing the overall package thickness or standoff.
Solution Approach 2:
The invention transitions from a simple circular or quadrilateral terminal cross-section to complex three-dimensional geometries including polygonal columns and deformed shapes with vertical notches and grooves. This dimensional complexity increases the resin-contacting surface area in the radial and vertical directions, providing stronger adhesion within the same package volume constraints.
2Ease of manufacture
If conventional circular or quadrilateral terminal shapes are used, then the manufacturing process is simple, but the contact area with sealing resin is insufficient leading to poor adhesion
Solution Approach 1:
The terminal cross-sectional geometry parameters are changed from simple circles or quadrilaterals to polygonal shapes with five or more sides, and deformed columnar shapes featuring notches and grooves. These geometric parameter modifications increase the surface area available for resin adhesion while maintaining compatibility with existing etching and press processing manufacturing methods.
Data Source
AI summary
In a lead frame for a semiconductor apparatus 10, including plural terminals 13, one portions of the terminals 13 being sealed with a resin, a resin-sealed portion 16 of the terminal 13 has a polygonal columnar shape that is pentagonal or more or a deformed columnar shape having at least one notch or groove part extending vertically in a periphery. This resin-sealed portion 16 is formed by etching processing or press processing, and an exposed portion 18 of lower half of the terminal 13 is formed by the etching processing.