Semiconductor Package Stress Relaxation Layer Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The production of semiconductor packages using metal substrates faces internal stress issues due to the difference in thermal expansion coefficients between the metal substrate and the encapsulation material, leading to warping and reliability concerns.
Innovation Solution
A semiconductor package design that incorporates a stress relaxation layer with a lower elastic modulus and coefficient of thermal expansion, formed of an insulating material, between the metal substrate and the encapsulation material, to alleviate internal stress and improve reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal substrate is used for the semiconductor package, then electromagnetic shielding properties and thermal characteristics are improved, but internal stress is caused due to the difference in the coefficient of thermal expansion between the metal substrate and the encapsulation material, resulting in warping of the encapsulation material
Solution Approach 1:
The patent introduces a stress relaxation layer as an intermediary component between the metal substrate and the encapsulation material. This intermediate layer has a coefficient of thermal expansion that is lower than that of the encapsulation material, serving as a buffer to reduce the thermal expansion mismatch stress. The stress relaxation layer absorbs and distributes the internal stress, preventing warping of the encapsulation material while maintaining the electromagnetic shielding and thermal characteristics of the metal substrate.
Solution Approach 2:
The patent employs a composite structure consisting of multiple layers with different material properties: the metal substrate layer, the stress relaxation layer, and the encapsulation material layer. Each layer is designed with specific material characteristics to fulfill its function. The composite structure allows the package to simultaneously achieve electromagnetic shielding, thermal management, and stress relaxation, resolving the contradiction between improved reliability and structural stability.
2Temperature
If the coefficient of thermal expansion difference between the metal substrate and encapsulation material is large, then thermal characteristics are improved, but the internal stress increases causing warping
Solution Approach 1:
The patent changes the physical parameter (coefficient of thermal expansion) of the stress relaxation layer to be lower than that of the encapsulation material. This parameter selection is crucial: by choosing a material with appropriate thermal expansion characteristics, the stress relaxation layer can compensate for the thermal expansion difference between the metal substrate and encapsulation material, thereby reducing internal stress while maintaining good thermal characteristics across the package structure.
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 stress relaxation layer effectively reduces internal stress and warping, enhancing the reliability and stability of the semiconductor package by matching the thermal expansion properties and elastic modulus of the substrate and encapsulation material.
Implementation Method 1
there is a problem in the production of a semiconductor package using a metal substrate that an internal stress is caused due to the difference in the coefficient of thermal expansion (CTE) between the metal substrate and an encapsulation material
Data Source
AI summary
A semiconductor package includes a support substrate; a stress relaxation layer provided on a main surface of the support substrate; a semiconductor device located on the stress relaxation layer; an encapsulation material covering the semiconductor device, the encapsulation material being formed of an insulating material different from that of the stress relaxation layer; a line running through the encapsulation material and electrically connected to the semiconductor device; and an external terminal electrically connected to the line. Where the support substrate has an elastic modulus of A, the stress relaxation layer has an elastic modulus of B, and the encapsulation material has an elastic modulus of C under a same temperature condition, the relationship of A>C>B or C>A>B is obtained.