Power Semiconductor Device Adhesive Sheet Flow Prevention Frame
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Solution Overview
Problem
The existing methods for bonding power modules and support members using adhesive sheets suffer from uneven internal pressure distribution, leading to increased voids and reduced reliability in adhesiveness, heat dissipation, and insulation, which affects the overall performance of power semiconductor devices.
Innovation Solution
Incorporating a flow prevention frame between the power module and support member to ensure uniform internal pressure distribution across the adhesive sheet, reducing the number and size of voids by controlling the flow of the adhesive material during thermal pressure bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a screw fixing method with heat dissipation grease is used to connect the power module and support member, then heat dissipation is improved, but the device size increases and insulation deteriorates due to grease deterioration
Solution Approach 1:
The patent changes the material parameters by selecting a thermosetting resin with specific properties (thermal conductivity ≥1.0 W/m·K, tensile strength ≥5.0 MPa, elongation ≥5%) to replace grease, achieving both heat dissipation and insulation reliability through parameter optimization
Solution Approach 2:
The patent uses a composite adhesive sheet combining organic thermosetting resin and inorganic filler particles, where the inorganic substance provides thermal conductivity while the resin matrix provides insulation and structural integrity, achieving multiple functions simultaneously
2Strength
If a thermosetting resin adhesive sheet is used to join the power module and support member, then adhesiveness and heat dissipation are improved, but voids remain in the adhesive sheet causing internal cracks and reduced reliability
Solution Approach 1:
The patent applies preliminary action by pre-heating the adhesive sheet to 80-150°C before bonding to reduce viscosity and improve flow characteristics, and by optimizing the inorganic filler particle size distribution (0.1-2.0 mm) beforehand to prevent void formation during the bonding process
Solution Approach 2:
The patent addresses void issues by carefully controlling the porosity of the adhesive sheet through optimized inorganic filler content (30-70 vol%) and particle size distribution, transforming the potentially harmful porous structure into a controlled feature that maintains strength while minimizing void-related reliability issues
3Strength
If pressure is applied to the adhesive sheet during bonding, then adhesiveness is improved, but deformation of the power module or support member occurs due to excessive pressing force
Solution Approach 1:
The patent changes the temperature parameter by heating the adhesive sheet to 80-150°C before bonding, which reduces the resin viscosity and allows effective bonding at lower pressing forces (0.01-0.1 MPa), thereby preventing component deformation while maintaining adhesiveness
4Area of stationary object
If the adhesive sheet is made thin to reduce mounting area, then mounting area is reduced, but insulation reliability decreases due to partial discharge from voids
Solution Approach 1:
The patent changes the material composition parameters by optimizing the inorganic filler content (30-70 vol%) and particle size distribution (0.1-2.0 mm) to eliminate voids in thin adhesive sheets, enabling reliable insulation even at reduced thickness (0.1-1.0 mm) by preventing partial discharge
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
This configuration enhances the adhesiveness, heat dissipation, and insulation reliability of the power semiconductor device by minimizing voids and maintaining consistent internal pressure, thereby improving the overall reliability and reducing the mounting area and cost.
Implementation Method 1
a heat dissipation adhesive sheet having high thermal conductivity is selected as the adhesive sheet
Implementation Method 2
the adhesive sheet is required to have insulation
Implementation Method 3
a method for heating an uncured adhesive sheet and applying pressure to the adhesive sheet during curing is used
Data Source
AI summary
A power semiconductor device includes a power module unit, an adhesive sheet, a support member, and a flow prevention frame. The adhesive sheet is bonded to the power module unit. The support member is connected to the power module unit with the adhesive sheet therebetween. The flow prevention frame is sandwiched between the power module unit and the support member, and is placed around the adhesive sheet. The adhesive sheet has an outer peripheral surface adjoining an inner peripheral surface of the flow prevention frame. A value obtained by dividing a maximum value of the internal pressure on the outer peripheral surface by a minimum value of the internal pressure is less than or equal to 10.