Thermally Conductive Die Attach Film for Low-Temperature Void-Free Curing
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Solution Overview
Problem
Conventional film-like adhesives face challenges in curing at lower temperatures, leading to insufficient void discharge between the adhesive and the wiring board, which affects the thermal conductivity and reliability of semiconductor packages.
Innovation Solution
A thermally conductive film-like adhesive with specific compositions and properties, including an epoxy resin, epoxy resin curing agent, polymer component, and inorganic filler, is developed to achieve efficient curing at lower temperatures, ensuring effective void discharge and enhanced thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the film-like adhesive is highly filled with thermally conductive filler having small particle diameter, then thermal conductivity is improved, but fluidity decreases and voids are generated at interface
Solution Approach 1:
The patent changes the particle size parameter of the thermally conductive filler from small particle diameter to large particle diameter (d50: 3.0-10.0 μm). This parameter change resolves the contradiction by improving fluidity and reducing void generation while maintaining adequate thermal conductivity through optimized filler content (40-70 wt%).
Solution Approach 2:
The patent creates a composite adhesive composition combining epoxy resin, polymer component, and large particle thermally conductive filler with specific surface treatments. This composite approach allows the filler particles to disperse uniformly without aggregating, maintaining both fluidity for void-free bonding and thermal conductivity for heat dissipation.
2Use of energy by stationary object
If curing temperature is reduced, then energy consumption and damage to semiconductor package are reduced, but void discharge becomes insufficient
Solution Approach 1:
The patent changes the curing temperature parameter from conventional high temperature (180°C) to lower temperature (100-150°C). This parameter change is made possible by optimizing the adhesive composition with specific resin systems and filler content, allowing sufficient void discharge and curing at lower temperatures, thus reducing energy consumption and thermal damage risk.
Solution Approach 2:
The patent utilizes the porous structure formed during low-temperature curing to facilitate void discharge. The optimized adhesive composition creates a controlled porous state that allows trapped air and volatiles to escape before the adhesive fully cures, ensuring reliable bonding even at reduced curing temperatures.
3Length of stationary object
If film thickness is reduced, then packaging density is improved, but adhesion strength and heat dissipation capability decrease
Solution Approach 1:
The patent optimizes the adhesive film thickness parameter to a specific range (1-10 μm). This parameter optimization maintains packaging density while ensuring adequate adhesion strength and heat dissipation. The thin film achieves sufficient bonding through optimized composition rather than relying on thickness.
Solution Approach 2:
The patent employs a composite adhesive formulation with epoxy resin, polymer component, and thermally conductive filler that enables thin film construction. The synergistic combination of these materials provides both strong adhesion and effective thermal conduction even at 1-10 μm thickness, eliminating the need for thicker films.
4Temperature
If inorganic filler content is increased, then thermal conductivity is improved, but viscosity increases and fluidity decreases
Solution Approach 1:
The patent changes the filler particle size parameter to large particle diameter (d50: 3.0-10.0 μm), which reduces the number of particles needed for a given volume fraction. This parameter change allows higher filler content (40-70 wt%) without excessive viscosity increase, maintaining both thermal conductivity and fluidity.
Solution Approach 2:
The patent applies surface treatment to the inorganic filler particles to modify their local surface properties. This surface treatment reduces inter-particle friction and improves dispersion, allowing high filler loading while maintaining adequate fluidity for bonding operations.
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 adhesive enables sufficient curing and void discharge at lower temperatures, improving the thermal conductivity and reliability of semiconductor packages by controlling capillary rheometer viscosity and differential scanning calorimetry measurements.
Implementation Method 1
sufficient curing and void discharge at lower temperatures
Implementation Method 2
enhanced thermal conductivity
Data Source
AI summary
Provided is a thermally conductive film-like adhesive capable of sufficiently advancing a curing reaction under milder conditions, capable of effectively suppressing residual voids between the adhesive and a wiring board in a semiconductor package to be obtained when used as a die attach film, and capable of obtaining a semiconductor package excellent in heat releasing property inside the package. In addition, provided are a semiconductor package using the thermally conductive film-like adhesive and a method of producing the same.