Semiconductor Package Corner Pads for Thermal Stress Resistance
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Solution Overview
Problem
Semiconductor packages face stress issues due to thermal expansion and contraction differences between the package and the substrate, leading to potential breakage or peeling off of solder balls at the corners, which existing technologies have not adequately addressed.
Innovation Solution
A semiconductor device design featuring L-shaped non-signal pads and pins with increased bonding areas, using solder balls and pastes to form bonding members that enhance stress resistance without requiring protective resins, thereby reducing costs and facilitating repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder balls are used at terminal pads including corner pads, then electrical connection is achieved, but stress concentration causes breakage or peeling off due to thermal expansion differences
Solution Approach 1:
The terminal pads are segmented into signal pads (with circular solder balls) and non-signal pads (with L-shaped solder balls). This segmentation allows different solder ball shapes to be used in different locations, with the L-shaped solder balls at non-signal pads providing extended bonding area to resist stress while circular solder balls at signal pads maintain electrical connection functionality.
Solution Approach 2:
Different pad configurations are applied locally based on functional requirements: signal pads use circular solder balls for electrical connection, while non-signal pads use L-shaped solder balls specifically at corner positions where stress concentration occurs. This local quality approach targets stress resistance exactly where needed without compromising overall electrical functionality.
2Reliability
If protective resins are applied to protect solder balls, then stress resistance improves, but manufacturing complexity and cost increase
Solution Approach 1:
The protective resin layer is extracted/removed from the package structure. Instead of adding a separate protective layer, the patent uses the L-shaped solder ball configuration itself to provide stress resistance, eliminating the need for additional protective resins and simplifying the overall package structure.
Solution Approach 2:
The L-shaped solder balls serve as both the electrical connection element and the stress-resistant protective element. Rather than using expensive protective resins that require additional manufacturing steps, the patent uses the solder ball geometry itself to provide protection, reducing material costs and manufacturing complexity.
3Reliability
If L-shaped non-signal pads are used, then bonding area increases and stress resistance improves, but manufacturing precision requirements increase
Solution Approach 1:
The L-shaped pad configuration is pre-designed and pre-fabricated into the substrate before solder ball attachment. This preliminary action ensures that the extended bonding area is already in place, allowing standard solder ball placement processes to be used without requiring high-precision alignment for complex geometries during the bonding process.
Solution Approach 2:
Instead of making the solder ball complex in shape to increase bonding area, the patent inverts the approach by making the pad L-shaped while keeping the solder ball geometry simple. This reversal simplifies the manufacturing process, as the complex geometry is in the pad (which is part of the substrate and easier to form) rather than in the solder ball (which requires precise placement).
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 design improves stress resistance of bonding members between non-signal pads and pins, eliminating the need for protective resins and simplifying defect recovery, while maintaining effective bonding and reducing costs.
Implementation Method 1
solder balls and pastes to form bonding members
Implementation Method 2
solder balls and pastes to form bonding members
Implementation Method 3
difference between expansion or contraction that is caused by a temperature change
Implementation Method 4
difference between expansion or contraction that is caused by a temperature change
Data Source
AI summary
A semiconductor device includes a substrate including a signal pad and a non-signal pad, a semiconductor housing portion including a signal pin and a first non-signal pin, and first bonding members configured to bond the signal pad and the signal pin and to bond the first non-signal pad and the first non-signal pin. The first non-signal pad and the first non-signal pin each have an L shape in a plan view.