Semiconductor Structure With Thermal Backside Core
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Solution Overview
Problem
Mobile power amplifiers face challenges in heat dissipation due to increasing thermal densities and series insertion loss, which are exacerbated by shrinking die and package sizes, leading to undesirable increases in thermal resistance and costs.
Innovation Solution
A semiconductor structure with a recessed thermally conductive core and heat sink configuration that reduces thermal resistance by minimizing the thickness of the semiconductor die substrate beneath the active devices and using a thermally conductive core in the recess, while maintaining mechanical rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the power amplifier die thickness is minimized to reduce thermal resistance, then thermal resistance is reduced, but yield loss increases due to thin wafer handling and breakage
Solution Approach 1:
The patent introduces a recess in the die substrate that extends downward, creating a third-dimensional thermal pathway. This allows the thermal conduction path to extend vertically into the recess rather than relying solely on minimizing the horizontal thickness of the die substrate, thus reducing thermal resistance without compromising mechanical integrity
Solution Approach 2:
The patent employs a composite structure combining the die substrate, recess formation, and thermal conduction path materials. The recess may be filled with thermally conductive materials or left as a cavity to enhance heat dissipation, creating a multi-material system that optimizes both thermal performance and mechanical strength
2Loss of energy
If the output area occupied by the power transistor is increased to reduce thermal resistance, then thermal resistance is reduced, but the overall power amplifier die area and package size increase
Solution Approach 1:
The patent utilizes vertical space by creating a recess in the die substrate. This allows the thermal management solution to extend in the vertical dimension rather than requiring increased horizontal area, thereby reducing thermal resistance without increasing the overall die footprint or package size
3Area of stationary object
If the power amplifier die size is reduced to decrease package size, then package size is reduced, but thermal density increases leading to worse heat dissipation
Solution Approach 1:
By creating a recess that extends vertically into the die substrate, the patent provides an additional thermal conduction pathway in the vertical dimension. This allows effective heat dissipation from a compact, small-area die by utilizing the third dimension for thermal management rather than requiring larger horizontal area
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 significantly reduces thermal resistance and improves heat dissipation efficiency, allowing for smaller, lower-cost power amplifier designs without compromising mechanical strength.
Implementation Method 1
A semiconductor structure with a recessed thermally conductive core and heat sink configuration that reduces thermal resistance
Data Source
AI summary
A semiconductor structure includes a semiconductor substrate having a recess disposed beneath a semiconductor device. The semiconductor structure also includes a thermally conductive core disposed in the recess, and a package substrate including a heat sink. The heat sink is in thermal contact with the thermally conductive core.