Semiconductor Pad Trench Design for High-Temperature Reliability
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Solution Overview
Problem
The existing connection structure between semiconductor pads and metal wires in semiconductor devices experiences short-circuit defects due to the diffusion of material at high temperatures, leading to alloy layer formation that breaks through the insulating film, especially in high-temperature applications like automotive products where increased current flow and high temperatures are common.
Innovation Solution
A trench is formed on the surface of the pad between the metal ball and adjacent pads to suppress the diffusion of gold from the ball into the pad, reducing the growth of the alloy layer and preventing it from breaking through the insulating film, thereby preventing short-circuit defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wire connection structure using a ball is adopted to connect pads and terminals, then electrical connection between semiconductor elements and external circuits is achieved, but material diffusion occurs at high temperatures forming alloy layers that break through insulating films causing short-circuit defects
Solution Approach 1:
The pad surface is segmented into multiple regions by forming trenches that divide the pad into first and second regions. This segmentation prevents the continuous diffusion path of gold atoms from the ball to adjacent pads, thereby blocking alloy layer growth that would otherwise cause short-circuit defects.
Solution Approach 2:
Trenches filled with insulating material serve as intermediary barriers between the ball region and adjacent pads. These trenches act as diffusion barriers that intercept and block the movement of diffusing gold atoms, preventing them from reaching and alloying with adjacent pad regions.
2Productivity
If the distance between adjacent pads is reduced to increase functionality and reduce device size, then device integration is improved, but the risk of short-circuit defects increases due to alloy layer growth
Solution Approach 1:
By segmenting each pad into multiple regions separated by trenches, the invention creates isolated zones that can be closely spaced without risking alloy layer connectivity. This allows pads to be positioned closer together while maintaining reliability through the trench barriers.
Solution Approach 2:
The trench structure introduces localized differentiation within each pad, creating regions with different functions: the first region contacts the ball and wire, while the second region remains isolated to prevent alloy layer spread. This local quality variation enables closer pad spacing without compromising reliability.
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 solution effectively reduces the occurrence of short-circuit defects by limiting the diffusion of gold and the growth of alloy layers, ensuring reliable operation of semiconductor devices even at elevated temperatures.
Implementation Method 1
the diffusion of material at high temperatures, leading to alloy layer formation
Data Source
AI summary
Technique capable of achieving reliability improvement of a semiconductor device even if temperature rising of an operation guarantee temperature of the semiconductor device is performed is provided. Gap portions are provided among a plurality of pads, and a glass coat composed of, for example, a silicon oxide film or a silicon nitride film is embedded in the gap portions. The glass coat is provided in order to secure electrical insulation among the pads, and coats outer edge portions of the pads. Trenches are formed so as to be adjacent to regions, which are coated with the glass coat, of the outer edge portions of the pads.