Multichip Module Adhesive Layer Thermal Expansion Control
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Solution Overview
Problem
Multichip modules face heat dissipation issues, leading to thermal expansion and deformation of chips and substrates, which can cause fatigue failure and shorten the module's lifespan.
Innovation Solution
A multichip module design featuring a base substrate, a silicon interposer with a specific wiring pattern, and an adhesive layer with a controlled coefficient of thermal expansion, where the adhesive layer's expansion coefficient is intermediate between the substrate and interposer, reducing thermal deformation and maintaining electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the build-up substrate is thinned by polishing or grinding to increase heat dissipation, then heat dissipation is improved, but the substrate becomes more susceptible to thermal deformation and fatigue failure
Solution Approach 1:
The patent introduces an adhesive layer as an intermediary between the base substrate and wiring board. This adhesive layer has a coefficient of thermal expansion that is intermediate between the base substrate and wiring board, acting as a buffer to reduce thermal stress and prevent fatigue failure while maintaining heat dissipation pathways.
Solution Approach 2:
The patent carefully selects and controls the coefficient of thermal expansion of the adhesive layer as a key parameter. By adjusting this parameter to be intermediate between the base substrate and wiring board, the system achieves optimal balance between heat dissipation and thermal stress reduction, preventing fatigue failure.
2Temperature
If chips and substrates are subjected to thermal expansion from heat generation, then heat dissipation occurs, but thermal deformation causes fatigue failure and shortens module lifespan
Solution Approach 1:
The adhesive layer serves as a mediator that absorbs and distributes thermal expansion stresses between the base substrate and wiring board. This intermediate layer prevents direct transmission of thermal stress, reducing fatigue failure and extending the operational lifespan of the multichip module.
Solution Approach 2:
The patent explicitly utilizes the principle of thermal expansion by selecting an adhesive layer with a coefficient of thermal expansion that is intermediate between the base substrate and wiring board. This allows the adhesive layer to expand and contract in a way that accommodates differential thermal expansion, preventing deformation and extending module lifespan.
3Adaptability or versatility
If a plurality of chips are mounted on a substrate to create a multichip module, then functional integration is improved, but heat generation increases causing thermal expansion and deformation
Solution Approach 1:
The adhesive layer acts as a thermal management intermediary that facilitates heat transfer from the chips while simultaneously managing thermal expansion stresses. This allows the multichip module to maintain high functional integration without suffering from excessive heat generation and thermal deformation.
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 design effectively suppresses thermal deformation, prolongs the module's lifespan, and reduces the bonding temperature, thereby minimizing damage and performance deterioration while maintaining electrical connectivity.
Implementation Method 1
a relationship between coefficients of thermal expansion is satisfied, wherein, assuming that α is a coefficient of thermal expansion of the wiring board, β is a coefficient of thermal expansion of the base substrate, and γ is a coefficient of thermal expansion of the adhesive layer
Data Source
AI summary
A multichip module comprising: a base substrate; a wiring board disposed on the base substrate and having a wiring pattern; an adhesive layer configured to bond the base substrate to the wiring board while maintaining an electrical connection between the base substrate and the wiring board; and a plurality of chips connected to a surface of the wiring board, the surface being opposite the adhesive layer, wherein, assuming that α is a coefficient of thermal expansion of the wiring board, &bgr; is a coefficient of thermal expansion of the base substrate, and γ is a coefficient of thermal expansion of the adhesive layer, the relationship α<γ<&bgr; is satisfied.