Thermally Conductive Resin Sheet for Reflow-Stable Insulation
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Solution Overview
Problem
Conventional heat dissipation resin sheets used in power semiconductor devices face issues with thermal expansion and contraction, leading to interface peeling and insufficient withstand voltage performance, especially during high-temperature reflow steps, and they lack sufficient moisture absorption reflow tolerance and high thermal conductivity.
Innovation Solution
A thermally conductive resin sheet comprising a crystalline thermoplastic resin with a melting point of 300°C or higher, such as polyetherketone-based resin, combined with boron nitride agglomerated particles as a thermally conductive filler, which provides excellent moisture absorption reflow tolerance and high thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional heat dissipation resin sheets are used, then thermal conductivity is provided, but interface peeling occurs due to thermal expansion and contraction during high-temperature reflow steps
Solution Approach 1:
The patent changes the chemical composition parameters of the resin by incorporating specific inorganic fillers (alumina, aluminum nitride, boron nitride) in controlled amounts to modify the thermal expansion coefficient and enhance high-temperature stability, preventing interface peeling during reflow
Solution Approach 2:
The patent creates a composite material system combining organic resin with inorganic fillers (alumina, aluminum nitride, boron nitride) to achieve both thermal conductivity and dimensional stability at high temperatures, resolving the contradiction between temperature resistance and interface bonding
2Temperature
If ceramic substrates are used for heat dissipation, then high thermal conductivity is achieved, but the substrates are easily broken by impact and difficult to thin film and downsize
Solution Approach 1:
The patent replaces fragile ceramic substrates with a resin-based heat dissipation sheet that offers comparable thermal performance but with superior impact resistance and flexibility, enabling thin-film and downsized applications
Solution Approach 2:
The patent uses composite materials combining resin with inorganic fillers to achieve ceramic-level thermal conductivity while maintaining the inherent flexibility and impact resistance of polymer materials
3Temperature
If thermosetting resin with inorganic filler is used, then heat dissipation is improved, but withstand voltage performance becomes insufficient under high-temperature and high-humidity conditions
Solution Approach 1:
The patent optimizes the resin composition parameters including glass transition temperature (Tg≥150°C) and moisture absorption characteristics to maintain electrical insulation properties at high temperatures while preserving heat dissipation capability
Solution Approach 2:
The patent selects specific resin types with appropriate Tg values and moisture absorption rates to ensure electrical performance stability under harsh conditions without sacrificing thermal management capability
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 thermally conductive resin sheet exhibits improved withstand voltage performance and maintains high thermal conductivity even after moisture absorption reflow tests, reducing the risk of interface peeling and foaming, and ensuring reliable performance under high-temperature and high-humidity conditions.
Implementation Method 1
a thermally conductive resin sheet comprising a resin composition containing a crystalline thermoplastic resin having a melting point of 300°C or higher and a thermally conductive filler comprising boron nitride agglomerated particles
Implementation Method 2
exhibits improved withstand voltage performance and maintains high thermal conductivity even after moisture absorption reflow tests
Data Source
Figure 1~2
Figure 3
AI summary
Provided is a thermally conductive resin sheet having sufficient withstand voltage performance and excellent moisture absorption reflow tolerance that comprises a resin composition containing a crystalline thermoplastic resin having a melting point of 300°C or higher and a thermally conductive filler, the thermally conductive filler comprising boron nitride agglomerated particles. In addition, the thermally conductive resin sheet according to another embodiment of the present invention comprises a resin composition containing 15% by mass or more and 40% by mass or less of a crystalline thermoplastic resin having a melting point of 300°C or higher and 60% by mass or more and 85% by mass or less of a thermally conductive filler, a thermal conductivity of the thermally conductive resin sheet in the thickness direction at 25°C being 5.0 W/m·K or more.