Multi-Chip Substrate Structure for Thermal Warpage Relief
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Solution Overview
Problem
Conductive traces in multi-chip devices experience stress, expansion, and warpage due to thermal expansion of the substrate, leading to potential cracks and breakage, which reduces device reliability and yield.
Innovation Solution
Replace a portion of the substrate material with a material having a lower coefficient of thermal expansion to reduce substrate expansion and warpage, thereby alleviating stress on conductive traces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the substrate material is used as-is, then the device structure is simple, but the conductive traces experience stress, expansion, and warpage leading to cracks and breakage
Solution Approach 1:
The patent applies local quality by replacing only a portion of the substrate material with a different material that has a lower coefficient of thermal expansion. This localized material substitution specifically targets the regions where conductive traces are most susceptible to thermal stress, rather than changing the entire substrate. The different material is strategically positioned to provide differential thermal expansion support where needed, reducing stress on conductive traces while maintaining overall substrate functionality.
Solution Approach 2:
The patent employs composite materials by combining the original substrate material with a different material having a lower coefficient of thermal expansion. This creates a composite substrate structure where the two materials work together to provide both mechanical support and thermal stability. The composite construction allows the substrate to maintain its structural integrity while the lower CTE material counteracts thermal expansion forces that would otherwise cause conductive trace failure.
2Reliability
If the substrate material is replaced with lower CTE material, then thermal stress on conductive traces is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the substrate into distinct regions: areas with the original substrate material and areas with the different lower CTE material. This segmentation allows each material to be optimized for its specific function - the original substrate provides overall structural support while the different material provides thermal stress relief in critical areas. The segmented approach simplifies manufacturing compared to creating a fully homogeneous alternative substrate, as each material region can be fabricated and integrated using established processes.
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
Reduces the potential for cracks and breakage in conductive traces, enhancing the reliability and yield of multi-chip devices by minimizing thermal stress.
Implementation Method 1
Replace a portion of the substrate material with a material having a lower coefficient of thermal expansion to reduce substrate expansion and warpage
Data Source
AI summary
A multi-chip device includes a first material within a substrate. The first material has a first coefficient of thermal expansion different than a second coefficient of thermal expansion of the substrate. A first chip overlies a first portion of the first material and a first portion of the substrate. A second chip overlies a second portion of the first material and a second portion of the substrate. The first material is between the first portion of the substrate and the second portion of the substrate.