Heat-Conductive Silicone Composition for Miniaturized Semiconductor Packages
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Solution Overview
Problem
Conventional heat-dissipating greases for semiconductor packages face challenges in miniaturization, where reaction retarders can volatilize, leading to poor crushability and insufficient heat-dissipating performance due to accelerated curing and inadequate spreading over fine patterns with reduced application amounts.
Innovation Solution
A silicone composition comprising organopolysiloxane, aluminum and zinc oxide powders, organohydrogenpolysiloxane, and a platinum group metal catalyst, optimized to provide a cured product with specific storage and loss elastic moduli, ensuring excellent crushability, spreadability, and heat conductivity, even when applied to fine patterns with minimal amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reaction retarder is added to prevent outflow of grease, then reliability is improved, but the reaction retarder volatilizes under miniaturization conditions, leading to accelerated curing and poor crushability
Solution Approach 1:
The patent changes the chemical parameters of the curing system by selecting specific organopolysiloxane (A) with controlled viscosity (60-100,000 mm²/s) and functional groups, and organohydrogenpolysiloxane (C) with controlled SiH group content (ratio 0.5-1.5), to achieve appropriate curing speed without relying on volatile reaction retarders
Solution Approach 2:
The patent creates a composite curing system combining organopolysiloxane (A), organohydrogenpolysiloxane (C), and platinum group metal catalyst (D) in specific proportions, where the interaction between components provides controlled curing characteristics that prevent both outflow and ensure crushability
2Volume of moving object
If the application amount of heat-dissipating grease is reduced for miniaturization, then device size is reduced, but the grease cannot sufficiently spread over the whole heat-generating part, resulting in insufficient heat-dissipating performance
Solution Approach 1:
The patent adjusts the viscosity parameter of organopolysiloxane (A) to a specific range (60-100,000 mm²/s) and controls the ratio of SiH groups to aliphatic unsaturated hydrocarbon groups (0.5-1.5) to optimize the balance between spreadability and curing characteristics, enabling sufficient coverage with minimal application amount
Solution Approach 2:
The patent creates a dynamically adjustable system where the grease maintains appropriate fluidity during application for sufficient spreading, then transitions to controlled curing after application, achieving both good spreadability and crushability through the dynamic curing process
3Reliability
If the curing reaction is accelerated to improve heat-dissipating performance, then heat conductivity is improved, but the grease cannot be compressed into desired thickness, resulting in poor crushability
Solution Approach 1:
The patent carefully controls the concentration of platinum group metal catalyst (D) at 0.1-500 ppm to moderate the curing speed, and adjusts the ratio of SiH groups to aliphatic unsaturated hydrocarbon groups (0.5-1.5) to achieve balanced curing characteristics that allow both heat dissipation and thickness control
Solution Approach 2:
The patent implements a staged curing process where the grease first spreads over the heat-generating part in a fluid state, then gradually cures to achieve desired thickness, and finally completes curing to achieve final mechanical properties, allowing sequential achievement of spreadability, thickness control, and heat-dissipating performance
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 silicone composition allows for effective compression and spreading of heat-dissipating grease over heat-generating parts, achieving sufficient heat-dissipating performance by controlling the curing process and preventing outflow, thus addressing the limitations of conventional greases.
Implementation Method 1
a silicone composition comprising: (A) 100 parts by mass of an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups per molecule... (C) an organohydrogenpolysiloxane having two or more silicon-bonded hydrogen atoms... (D) a platinum group metal catalyst
Implementation Method 2
a platinum group metal catalyst in an amount of 0.1 to 500 ppm in terms of platinum with respect to the component (A)
Implementation Method 3
if there is a space between the heat-generating member and the cooling member, thermal conduction does not proceed smoothly because of the presence of air, which is poor in heat conductivity
Data Source
AI summary
A silicone composition that contains an organopolysiloxane having at least two aliphatic unsaturated hydrocarbon groups per molecule, a filler containing an aluminum powder and a zinc oxide powder, an organohydrogenpolysiloxane having two or more SiH groups per molecule, and a platinum group metal catalyst, in which when a storage and loss elastic modulus G″ of the silicone composition is measured by means a viscoelasticity measurement apparatus capable of measuring shear modulus, the silicone composition can provide a cured product wherein G′ after 3,000 seconds from the start of holding is 10,000 Pa or less, G′ after 7,200 seconds from the start of holding is 100,000 Pa or less, and G′ exceeds G″ after 800 seconds or more from the start of holding. As a result, there is provided a silicone composition excellent in crushability, spreadability, and heat conductivity.