Semiconductor Chip Adhesive Layout for Heat Dissipation and Peel Resistance
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Solution Overview
Problem
The adhesive used to bond a semiconductor chip to a substrate, when containing a high proportion of highly heat-conductive material, faces challenges in expanding with the substrate due to differences in thermal expansion, leading to peeling and reduced thermal conductivity.
Innovation Solution
Incorporating a lattice pattern of second portions made of a material with high thermal conductivity and elastic modulus within the adhesive layer, connecting the chip and substrate, allowing the adhesive to expand while maintaining effective heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the proportion of highly heat-conductive material in the adhesive is increased, then thermal conductivity is improved, but the adhesive cannot expand with the substrate due to high elastic modulus, causing peeling
Solution Approach 1:
The adhesive layer is designed with spatially varying properties: a first region containing resin material with low elastic modulus for stress absorption and expansion compatibility, and a second region containing highly heat-conductive material with high elastic modulus for thermal conduction. This local differentiation allows simultaneous achievement of thermal conductivity and adhesion stability.
Solution Approach 2:
The adhesive layer is formed as a composite structure combining two distinct materials with complementary properties: resin material providing flexibility and expansion capability, and highly heat-conductive material providing thermal conduction. This composite approach resolves the contradiction between thermal conductivity and adhesion stability.
2Temperature
If the proportion of resin material with low elastic modulus is decreased, then thermal conductivity is improved, but the adhesive cannot expand in accordance with substrate expansion, leading to peeling
Solution Approach 1:
Different regions of the adhesive layer are assigned different material properties: the first region uses resin material with low elastic modulus specifically for expansion adaptability, while the second region uses highly heat-conductive material for thermal conduction. This localized functional assignment resolves the contradiction.
Solution Approach 2:
The adhesive layer is segmented into functionally distinct regions: a first region for mechanical compliance and expansion accommodation, and a second region for thermal conduction. This segmentation allows each region to optimize its specific function without compromising the other.
3Temperature
If highly heat-conductive material is used to improve heat dissipation, then thermal conductivity is improved, but stress from moisture absorption reflow or temperature cycle test causes peeling
Solution Approach 1:
The adhesive layer employs local quality differentiation where the first region's resin material with low elastic modulus absorbs expansion stress during moisture absorption reflow and temperature cycling, protecting the bond interface. The second region's highly heat-conductive material efficiently dissipates heat. This spatial differentiation resolves the contradiction between heat dissipation efficiency and resistance to peeling stress.
Solution Approach 2:
The first region of resin material acts as a cushioning layer that absorbs expansion stress beforehand during moisture absorption reflow or temperature cycle tests, preventing this stress from reaching and causing peeling at the adhesive-substrate interface. This protective function enables the second region to focus on heat conduction without compromising bond strength.
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 solution ensures efficient heat dissipation and prevents peeling by absorbing stress from thermal expansion, maintaining thermal conductivity and adhesion during moisture absorption and temperature cycles.
Implementation Method 1
the adhesive is formed by blending a highly heat-conductive material, such as silver filler, which has high thermal conductivity, into a resin material
Implementation Method 2
The substrate expands due to heat transmitted from the semiconductor chip
Data Source
AI summary
A semiconductor device according to an embodiment includes a semiconductor chip, a substrate, and an adhesive layer. The substrate supports the semiconductor chip. The adhesive layer is disposed between the semiconductor chip and the substrate. The adhesive layer bonds the semiconductor chip and the substrate. The adhesive layer has a first portion and a plurality of second portions. The first portion is formed of a first material. The plurality of second portions are formed of a second material. The second material has a greater elastic modulus and a greater thermal conductivity than the first material. The second portions are located inside the first portion. Each of the second portions is in contact with and connects the semiconductor chip and the substrate.