Boron Nitride Resin Sheet for Heat-Conductive Insulation
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Solution Overview
Problem
Existing heat dissipation resin sheets for power semiconductor devices face challenges in achieving high thermal conductivity, insulating properties, and handleability while maintaining heat resistance and avoiding voids that reduce reliability and efficiency.
Innovation Solution
A resin composition with a high volume percentage of boron nitride filler, specifically aggregated boron nitride particles, combined with a thermosetting epoxy resin of high molecular weight and controlled weight per epoxide equivalent, to create a cured product with enhanced thermal conductivity, insulating properties, and improved mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the amount of inorganic filler is increased to improve thermal conductivity, then thermal conductivity is improved, but the resin composition becomes difficult to handle and voids may form
Solution Approach 1:
The patent changes the molecular weight parameter of the epoxy resin to 5,000 or more, which fundamentally alters the viscosity and flow characteristics of the resin composition. This parameter change enables the composition to maintain high filler content (50% or more by volume) while remaining handleable, resolving the contradiction between thermal conductivity improvement and ease of operation.
2Temperature
If the amount of inorganic filler is increased to improve thermal conductivity, then thermal conductivity is improved, but insulating property may be reduced due to voids
Solution Approach 1:
By changing the molecular weight parameter of the epoxy resin to 5,000 or more, the patent achieves a resin composition that can accommodate high filler content without forming voids. The higher molecular weight resin provides better viscosity control and filling characteristics, ensuring complete mold filling and void-free curing, thus maintaining insulating property while improving thermal conductivity.
Solution Approach 2:
The patent creates a composite material system consisting of high molecular weight epoxy resin (molecular weight 5,000 or more) and inorganic filler (50% or more by volume). This composite structure leverages the synergistic effects of the resin matrix and filler particles to achieve both high thermal conductivity and maintained insulating property, resolving the contradiction between these two properties.
3Ease of operation
If high molecular weight epoxy resin is used to improve handleability, then handleability is improved, but crosslinking density and mechanical strength may be reduced
Solution Approach 1:
The patent carefully selects the molecular weight parameter of the epoxy resin to be 5,000 or more, which provides optimal handleability while maintaining sufficient crosslinking density. This specific parameter range ensures that the resin has appropriate viscosity for handling and filling, yet still forms a dense crosslinked network upon curing, achieving both handleability and mechanical strength.
Solution Approach 2:
The patent applies the concept of local quality by having different molecular weight epoxy resins serve different functions: higher molecular weight resins (5,000 or more) provide handleability and flow characteristics, while the crosslinking chemistry ensures sufficient local crosslinking density for mechanical strength. This local differentiation of molecular weight functions resolves the contradiction between handleability and strength.
4Ease of operation
If high molecular weight epoxy resin is used to improve handleability, then handleability is improved, but heat resistance may be reduced
Solution Approach 1:
The patent optimizes the molecular weight parameter of the epoxy resin to 5,000 or more, which provides excellent handleability while maintaining sufficient heat resistance. This parameter selection ensures that the resin has appropriate viscosity for processing yet forms a crosslinked network with adequate thermal stability, resolving the contradiction between handleability and heat resistance.
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 resin composition achieves high thermal conductivity, insulating properties, and heat resistance while maintaining handleability, effectively addressing the limitations of previous compositions by reducing voids and improving crosslinking density and mechanical strength.
Implementation Method 1
a resin composition comprising: an inorganic filler; and a thermosetting resin
Implementation Method 2
the inorganic filler contains 82% by volume or more of a boron nitride filler (A)... the thermal conductivity in the thickness direction of the sheet is excellent
Data Source
AI summary
The present invention provides a resin composition with high thermal conductivity, high insulating property, high heat resistance, and excellent handleability of a sheet; a cured product sheet; a composite molded body; and a semiconductor device. The resin composition contains an inorganic filler and a thermosetting resin, in which the amount of the inorganic filler in solid contents of the resin composition is 50% by volume or more, and the inorganic filler contains 82% by volume or more of a boron nitride filler (A), the boron nitride filler includes an aggregated filler, the thermosetting resin contains an epoxy resin having a mass-average molecular weight of 5,000 or more, a weight per epoxide equivalent (WPE) of resin components in the resin composition satisfies 100≤WPE≤300, and a storage modulus E′ of a cured product of the resin composition satisfies 1≥(E′ at 270° C.)/(E′ at 30° C.)≥0.2.