Graded CTE Multi-Layer Substrate Warpage Control
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Solution Overview
Problem
Thermal mismatch between components in microelectronic systems due to mismatched coefficients of thermal expansion (CTE) leads to thermo-mechanical issues such as warpage and stress, which existing semiconductor packaging technologies fail to adequately address.
Innovation Solution
A multi-layer molded semiconductor substrate with a graded CTE across its layers, where the bottom layer has a higher CTE and the top layer has a lower CTE, optimized to distribute warpage and stress, using mold compounds with varying filler content and types to achieve desired CTE values, and incorporating conductive materials for electrical signal transmission and thermal dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer substrate with uniform CTE is used, then the manufacturing process is simple, but thermal mismatch causes warpage and stress between components
Solution Approach 1:
The substrate is divided into multiple layers, each with different CTE values, to create a graded CTE profile that reduces thermal mismatch stress between components while maintaining structural integrity
Solution Approach 2:
Different regions of the substrate (different layers) are assigned different CTE properties to match the thermal expansion characteristics of adjacent components at each interface, optimizing thermal performance locally throughout the structure
2Reliability
If mold compound with high filler content is used to reduce CTE, then thermal mismatch is reduced, but manufacturing complexity and cost increase
Solution Approach 1:
The filler distribution is segmented across multiple layers, with each layer containing specific filler types and concentrations optimized for its required CTE value, allowing precise thermal property control without overwhelming manufacturing complexity
Solution Approach 2:
The CTE parameters of the mold compound are systematically varied across layers by adjusting filler content and composition, creating a graded transition that optimizes thermal matching while maintaining manufacturability
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 graded CTE multi-layer substrate effectively reduces thermo-mechanical issues by distributing warpage and stress across the system, improving thermal performance and structural integrity while minimizing thermal mismatch between coupled components.
Implementation Method 1
mismatch in coefficient of thermal expansion (CTE) between interacting components, such as a die and a substrate
Implementation Method 2
conductive material configured to transmit electrical signals through or among different layers of the multi-layer molded substrate
Implementation Method 3
conductive materials for electrical signal transmission and thermal dissipation
Data Source
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AI summary
This document discusses, among other things, a multi-layer molded substrate having layers with a graded coefficients of thermal expansions (CTEs) to optimize thermal performance of the multi-layer molded substrate with first and second structures attached to top and bottom surfaces of the multi-layer molded substrate, respectively.