Embedded Mold Materials for Warpage Control in Electronic Packages
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electronic packaging methods face challenges in controlling warpage and stress due to coefficient of thermal expansion mismatches between semiconductor dies and mold compounds, leading to potential cracking and increased production costs.
Innovation Solution
The implementation of an electronic package with embedded materials in a molded structure, where a first material with different modulus and thermal expansion properties is deposited on a substrate and embedded within a second mold material, such as epoxy, to create a mold cap with customized warpage and stress responses, including the use of an undercut die seal to reduce stress at the die-to-mold interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mold compound is used to encapsulate the semiconductor die, then the interconnect reliability is improved, but warpage and stress occur due to coefficient of thermal expansion mismatch
Solution Approach 1:
The patent applies local quality by creating a multi-layer mold compound structure where different layers have different material properties. Specifically, a first mold compound layer is applied directly to the semiconductor die with different CTE than a second mold compound layer applied over it. This local differentiation of material properties allows the structure to better accommodate thermal expansion differences at the critical die interface while maintaining overall package integrity.
Solution Approach 2:
The patent uses composite materials by combining multiple mold compound layers with different coefficients of thermal expansion. The first mold compound layer and second mold compound layer are both mold compounds but with different CTE values, creating a composite structure that can be engineered to match the thermal expansion characteristics of the semiconductor die more closely, thereby reducing stress.
2Reliability
If a mold compound is used to encapsulate the semiconductor die, then the interconnect reliability is improved, but warpage occurs on the substrate
Solution Approach 1:
The patent applies local quality by creating a multi-layer mold compound structure where different layers have different material properties. Specifically, a first mold compound layer is applied directly to the semiconductor die with different CTE than a second mold compound layer applied over it. This local differentiation of material properties allows the structure to better accommodate thermal expansion differences at the critical die interface while maintaining overall package integrity.
Solution Approach 2:
The patent uses composite materials by combining multiple mold compound layers with different coefficients of thermal expansion. The first mold compound layer and second mold compound layer are both mold compounds but with different CTE values, creating a composite structure that can be engineered to match the thermal expansion characteristics of the semiconductor die more closely, thereby reducing stress.
3Adaptability or versatility
If different CTE materials are used for mold compound and substrate, then the package can accommodate thermal changes, but stress and warpage increase during temperature cycling
Solution Approach 1:
The patent applies local quality by creating a multi-layer mold compound structure where different layers have different material properties. Specifically, a first mold compound layer is applied directly to the semiconductor die with different CTE than a second mold compound layer applied over it. This local differentiation of material properties allows the structure to better accommodate thermal expansion differences at the critical die interface while maintaining overall package integrity.
Solution Approach 2:
The patent uses composite materials by combining multiple mold compound layers with different coefficients of thermal expansion. The first mold compound layer and second mold compound layer are both mold compounds but with different CTE values, creating a composite structure that can be engineered to match the thermal expansion characteristics of the semiconductor die more closely, thereby reducing stress.
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 effectively reduces warpage and stress in electronic packages, enhancing reliability and minimizing production costs by customizing the warpage response and stress distribution across the package.
Implementation Method 1
The mold compound and the substrate can have different coefficients of thermal expansion, glass transition temperatures, shrink rates, and/or mechanical rigidity, which can cause warping and/or stresses on the semiconductor die and/or on the substrate when there are room temperature changes or during temperature cycling
Implementation Method 2
The first and second materials can have different modulus and/or coefficient of thermal expansion. The embedded material can be used to control warpage and/or stress in the electronic package
Data Source
AI summary
A method and system are provided for an electronic package with embedded materials in a molded structure to control warpage and stress. A first material can be deposited on a substrate with a semiconductor die. The substrate can be a coreless substrate. The substrate with the semiconductor die can be placed in a mold tool that when closed defines a space about the semiconductor die. A second material, such as an epoxy mold compound, for example, can be applied to the defined space to produce a mold cap in which the first material is at least partially embedded in the second material. The first and second materials can have a different modulus and/or coefficient of thermal expansion. The first material can be used to cover electrical components on a surface of the substrate. In some instances, more than one material can be at least partially embedded in the second material.