Variable Thickness Heat Spreader for Weight Reduction
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Solution Overview
Problem
Heat spreaders used in electronic packages add weight and induce stress in semiconductor chips, which is problematic for consumer electronics and satellite applications, while also affecting thermal dissipation efficiency.
Innovation Solution
Optimized heat spreader designs with reduced thickness in non-critical regions, such as the transition bottom and outer top periphery, to minimize weight while maintaining effective thermal dissipation, using a combination of thermal interface materials and strategically placed thinner material to reduce mass without compromising heat transfer capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat spreader is used to remove heat from semiconductor chips, then thermal dissipation efficiency is improved, but weight of the chip package increases
Solution Approach 1:
The heat spreader employs variable thickness design where the central region has maximum thickness for optimal heat dissipation, while peripheral regions have reduced thickness to minimize weight. This local differentiation allows the structure to have different thicknesses in different areas, achieving both thermal performance and weight reduction.
Solution Approach 2:
The invention changes the geometric parameter of the heat spreader by transitioning from uniform thickness to variable thickness. The thickness parameter varies spatially, being thickest at the center and thinner at the edges, which optimizes the balance between heat dissipation capability and overall weight.
2Temperature
If a heat spreader is used to remove heat from semiconductor chips, then thermal dissipation efficiency is improved, but stress in the circuit layers and interconnects increases
Solution Approach 1:
The variable thickness design creates a stress distribution optimization where the thicker central region provides structural support directly over the chip, while thinner peripheral regions reduce overall stress on the circuit layers and interconnects.
Solution Approach 2:
The heat spreader incorporates curved transition regions between the thick central area and thin peripheral areas. These smooth transitions help distribute stress more evenly throughout the structure, preventing stress concentration that would occur with abrupt thickness changes.
3Weight of moving object
If heat spreader weight is reduced by thinning material in selected regions, then weight is reduced, but thermal dissipation capability may be compromised
Solution Approach 1:
The design strategically places reduced thickness only in peripheral regions where thermal dissipation requirements are lower, while maintaining maximum thickness in the central region directly over the heat-generating chip. This localized material reduction achieves weight loss without compromising the critical heat dissipation function.
Solution Approach 2:
The invention transitions from a two-dimensional uniform thickness approach to a three-dimensional variable thickness profile. By adding the thickness dimension as a variable parameter, the design optimizes both weight and thermal performance simultaneously through spatially differentiated material distribution.
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 optimized heat spreader design achieves reduced weight and stress on the chip package while maintaining high thermal dissipation efficiency, suitable for various electronic applications.
Implementation Method 1
heat generated by the chip is transported into the heat spreader though a thermal interface material
Data Source
AI summary
A heat spreader is disclosed with regions where material is absent to reduce the mass/weight of the heat spreader without substantially reducing the temperature of the semiconductor chip and without substantially affecting the warpage and mechanical stress/strain in the electronic package.