Film-like Adhesive for Semiconductor Packages
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Solution Overview
Problem
Conventional die attach films with high thermal conductivity fillers pose a risk of partial fracture to semiconductor chips, substrates, or heat sinks during thermocompression bonding due to their hardness.
Innovation Solution
A film-like adhesive comprising epoxy resin, epoxy resin curing agent, phenoxy resin, and heat-conductive filler material with specific properties, including a particle size of 0.1 to 10.0 μm, compression ratio at break of 5 to 50%, fracture strength of 0.01 to 2.0 GPa, and thermal conductivity of 30 W/m·K or higher, is used to prevent fractures and ensure effective heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high thermal conductivity fillers with high hardness are used in die attach films, then thermal conductivity is improved, but the risk of partial fracture to semiconductor chips, substrates, or heat sinks during thermocompression bonding increases
Solution Approach 1:
The invention changes the physical parameters of the filler particles by controlling their size to 10 μm or smaller and adjusting their compression ratio at break to 5-50% of their average particle size. This parameter optimization allows the fillers to maintain high thermal conductivity while having reduced hardness and lower risk of causing fractures during bonding processes.
Solution Approach 2:
The invention uses composite filler particles consisting of a core material coated with a shell material. The core provides high thermal conductivity, while the shell material (such as resin or metal) reduces the overall hardness and brittleness of the filler particles. This composite structure enables the filler to maintain thermal performance while minimizing damage risk to bonded components.
2Object-affected harmful factors
If filler particle size is reduced to lower hardness, then fracture risk is reduced, but thermal conductivity may be compromised
Solution Approach 1:
The invention optimizes the filler particle size to 10 μm or smaller, which reduces hardness and fracture risk while maintaining effective thermal conductivity. The specific size range balances the trade-off between mechanical softness and thermal performance, ensuring both safety during bonding and effectiveness in heat dissipation.
Solution Approach 2:
By creating composite filler structures with core-shell architecture, the invention maintains high thermal conductivity through the core material while the shell reduces overall particle hardness. This allows smaller particle sizes to be used without sacrificing thermal performance, as the composite structure compensates for the reduced size effect on conductivity.
3Object-affected harmful factors
If compression ratio at break is increased to reduce filler hardness, then fracture risk is reduced, but bonding strength may be affected
Solution Approach 1:
The invention sets the compression ratio at break to a specific range of 5-50% of the average particle size, which optimizes the balance between filler softness and bonding strength. This controlled compression ratio ensures fillers are soft enough to prevent fractures but maintain sufficient structural integrity to support bonding strength requirements.
Solution Approach 2:
The composite filler structure with core-shell architecture allows the shell material to be optimized for bonding interface strength while the core maintains thermal conductivity. The shell acts as a bonding medium that adheres to substrates and chips, compensating for any reduction in overall particle strength due to increased compression ratio.
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 prevents partial fractures during thermocompression bonding and provides sufficient heat dissipation, maintaining the integrity of semiconductor packages while ensuring reliable bonding and thermal management.
Implementation Method 1
die attach films containing fillers having high thermal conductivity, such as conductive powders of gold, platinum, silver, copper, nickel, palladium, iron, aluminum, and stainless steel; and non-conductive powders of silicon oxide, aluminum nitride, boron nitride, aluminum borate, aluminum oxide, magnesium oxide, and diamond
Implementation Method 2
an epoxy resin (A), an epoxy resin curing agent (B)
Implementation Method 3
affixing a heat sink to the back surface of the semiconductor chip
Data Source
AI summary
Provided are a film-like adhesive that can prevent the back surface of a semiconductor chip, the front surface of a substrate, or the front surface of a heat sink from being partially fractured by a filler; and a method for producing a semiconductor package using the film-like adhesive.The film-like adhesive includes an epoxy resin (A), an epoxy resin curing agent (B), a phenoxy resin (C), and a heat-conductive filler material (D), in which the heat-conductive filler (D) has an average particle size of 0.1 to 10.0 μm, a compression ratio at break in a microcompression test of 5 to 50% of the average particle size of the sample, a fracture strength in a microcompression test of 0.01 to 2.0 GPa, and a thermal conductivity of 30 W/m·K or higher, the content of component (D) is 10 to 70 vol % with respect to the total amount of the components (A) to (D), and the thermal conductivity after thermal curing is 1.0 W/m·K or higher.