Thick-Silver Die Interface for CTE Stress and Heat Dissipation
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Solution Overview
Problem
Semiconductor devices face heat dissipation challenges due to high current and frequency operations, leading to potential failure from thermal stress caused by coefficient of thermal expansion (CTE) mismatches between materials, which existing solutions attempt to address with multiple layers that increase complexity and cost.
Innovation Solution
A semiconductor device design featuring a thick-silver layer between the thermal layer and semiconductor die, with a metallurgical die-attach directly contacting the silver layer, eliminating the need for additional barrier layers and reducing stress through silver's high ductility and low diffusion impact on die-attach strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple barrier layers are used between thermal layer and die to address CTE mismatch, then stress is reduced, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes unnecessary barrier layers from the traditional multi-layer structure, retaining only the essential thick-silver layer that provides both stress relief and thermal conduction functions, thereby simplifying the device structure while maintaining reliability
Solution Approach 2:
The thick-silver layer serves multiple functions simultaneously: it acts as a stress-relief layer due to its high ductility and CTE match with the die, while also functioning as a thermal conduction path, eliminating the need for separate barrier layers and simplifying the overall structure
2Reliability
If multiple barrier layers are used between thermal layer and die to address CTE mismatch, then stress is reduced, but manufacturing cost increases
Solution Approach 1:
The patent eliminates redundant barrier layers from the manufacturing process, reducing material costs and simplifying fabrication steps while maintaining the essential stress-relief functionality through the thick-silver layer
Solution Approach 2:
The patent combines the stress-relief function and thermal conduction function into a single thick-silver layer, reducing the total number of manufacturing steps and materials required, thereby lowering production costs while maintaining device reliability
3Temperature
If thermal layer material with high thermal conductivity is selected, then heat dissipation is improved, but CTE mismatch with die increases causing greater stress
Solution Approach 1:
The thick-silver layer acts as an intermediary between the die and the thermal layer, providing a transition zone that matches the CTE of the die while allowing effective heat transfer, thus mediating between the thermal requirements and the stress constraints
Solution Approach 2:
The patent changes the CTE parameter matching by introducing a silver layer whose CTE closely matches that of the die, while simultaneously maintaining high thermal conductivity, thus resolving the contradiction between heat dissipation and stress reduction
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
This configuration effectively manages CTE mismatches, enhances heat dissipation, and reduces stress, thereby improving the reliability and lifespan of semiconductor devices while simplifying the manufacturing process and reducing costs.
Implementation Method 1
The thermal conductivity of the material used to construct the thermal layer has a direct impact on the ability of the thermal layer to dissipate the heat
Implementation Method 2
CTE represents the physical amount of expansion or contraction a material will experience as the material heats up or cools down, respectively
Data Source
AI summary
A semiconductor device and a method of manufacturing the same include a die and a thermal layer, and a thick-silver layer disposed directly onto a first of the thermal layer, as well as a metallurgical die-attach disposed between the thick-silver layer and the die, the metallurgical die-attach directly contacting the thick-silver layer.