Heat Slug Recess Design for Semiconductor Package Thermal Stress
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Solution Overview
Problem
Semiconductor packages face defects due to cracking in the encapsulant caused by differences in coefficients of thermal expansion between the heat slug, bonding material, and encapsulant, leading to reduced heat dissipation performance.
Innovation Solution
A semiconductor package design featuring a heat slug with a side surface forming a recess with the electronic component, increasing the contact area and reducing stress, combined with an oxide coating layer to enhance bonding, and heat transfer members for improved heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat slug is bonded to an electronic component using a bonding material, then heat dissipation performance is improved, but cracking occurs in the encapsulant due to difference in coefficients of thermal expansion
Solution Approach 1:
The heat slug side surface is formed with different regions having different properties: a first region with a first coefficient of thermal expansion and a second region with a second coefficient of thermal expansion. This local quality variation allows different parts of the heat slug to accommodate different thermal expansion requirements, reducing stress on the encapsulant while maintaining effective heat dissipation.
Solution Approach 2:
The heat slug is constructed as a composite structure with multiple regions having different coefficients of thermal expansion. This composite material approach enables the heat slug to simultaneously achieve good thermal conductivity for heat dissipation and compatible thermal expansion characteristics to prevent encapsulant cracking.
2Stress or pressure
If the heat slug has a larger upper surface area than lower surface area, then stress distribution is improved, but manufacturing complexity increases
Solution Approach 1:
The heat slug side surface includes curved surfaces with specific radii of curvature. The first curved surface has a first radius of curvature and the second curved surface has a second radius of curvature. This curvature design gradually transitions the cross-sectional area from the lower surface to the upper surface, improving stress distribution while providing a manufacturable geometric form.
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 reduces defects and enhances heat dissipation performance by dispersing thermal stress and improving bonding between the heat slug and encapsulant, while maintaining efficient heat transfer.
Implementation Method 1
The semiconductor package may further include an oxide coating layer disposed on the side surface of the heat slug
Implementation Method 2
A heat slug made of a metal material having a high thermal conductivity may be bonded to an electronic component by a bonding material to increase heat dissipation from the electronic component
Implementation Method 3
a bonding material bonding the heat slug to the upper surface of the electronic component
Data Source
AI summary
A semiconductor package includes a substrate, an electronic component mounted on an upper surface of the substrate so that a lower surface of the electronic component faces the upper surface of the substrate, a heat slug disposed on an upper surface of the electronic component so that a lower surface of the heat slug faces the upper surface of the electronic component, a bonding material bonding the heat slug to the upper surface of the electronic component, and an encapsulant in which the heat slug and the electronic component are embedded. A side surface of the heat slug extending between an edge of the lower surface of the heat slug and an edge of an upper surface of the heat slug forms a recess with the upper surface of the electronic component.