Multiple TIMs for Semiconductor Die Thermal Management
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Solution Overview
Problem
In semiconductor packaging, existing thermal interface materials (TIMs) face challenges in accommodating the expansion and contraction of different package components while effectively conducting heat, as they often compromise between adhesion, flexibility, and thermal conductivity, especially when integrating multiple dies of varying sizes and thicknesses within a single package.
Innovation Solution
The use of multiple formulations of TIMs with customized particle sizes and filler loadings is employed to optimize thermal conductivity and compressibility for each die, allowing for varying bond line thicknesses and accommodating different z-heights, thereby improving thermal resistance and mechanical stress absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single type of thermal interface material is used for all dies, then manufacturing simplicity is maintained, but thermal performance and mechanical accommodation cannot be optimized for each die's specific requirements
Solution Approach 1:
The patent divides the thermal interface material selection into separate segments for each die, allowing each die to have a customized TIM formulation optimized for its specific thermal and mechanical requirements, rather than using a single uniform TIM for all dies in the package
Solution Approach 2:
The patent applies different TIM formulations with specific properties (particle sizes, filler loadings, viscosities) to different locations in the package based on each die's characteristics, ensuring local optimization of thermal conductivity and mechanical accommodation for each die-heat spreader interface
2Temperature
If thermal interface materials with high thermal conductivity are used, then heat conduction is improved, but adhesion and flexibility to accommodate expansion and contraction deteriorate
Solution Approach 1:
The patent modifies the physical and chemical parameters of the TIM formulations, including particle size distribution, filler loading concentrations, and base polymer composition, to achieve an optimal balance between thermal conductivity and mechanical properties such as adhesion and flexibility for each specific die application
Solution Approach 2:
The patent employs composite TIM formulations combining different filler materials (such as metal particles, ceramic particles, or polymer particles) with base adhesives to create materials that simultaneously provide high thermal conductivity and adequate adhesion flexibility to accommodate thermal expansion and contraction
3Manufacturing precision
If multiple different thermal interface materials are used for different dies, then thermal performance and mechanical accommodation are optimized, but manufacturing process complexity increases
Solution Approach 1:
The patent develops a universal manufacturing approach where a single dispensing system can handle multiple TIM formulations by sequentially dispensing different materials to different die locations, making the complex multi-TIM process as manageable as a single-TIM process while achieving optimized thermal and mechanical performance for each die
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 approach enhances the ability to cool semiconductor dies effectively, enabling higher performance and reduced thermal impedance, allowing for more dies to be integrated in a single package without increasing manufacturing costs or complexity, and supports operation in extreme environments.
Implementation Method 1
heat must be conducted away from the die so that it does not overheat during use
Implementation Method 2
Because a semiconductor die heats with use, the different parts of a package, including the die will expand and contract
Data Source
AI summary
A multiple chip package is described with multiple thermal interface materials. In one example, a package has a substrate, a first semiconductor die coupled to the substrate, a second semiconductor die coupled to the substrate, a heat spreader coupled to the die, wherein the first die has a first distance to the heat spreader and the second die has a second distance to the heat spreader, a first filled thermal interface material (TIM) between the first die and the heat spreader to mechanically and thermally couple the heat spreader to the die, and a second filled TIM between the second die and the heat spreader to mechanically and thermally couple the heat spreader to the second die.