Semiconductor Module Heat Base Layout for Torque-Stable Cooling
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Solution Overview
Problem
The use of phase change thermal grease in semiconductor modules can lead to a reduction in tightening torque between the heat dissipation base and the cooling module due to the generation of gaps between the heat dissipation base and screws during the phase change from solid to liquid, affecting the reliability and cooling performance of power converters.
Innovation Solution
Incorporating a solid heat dissipation member made of a phase change material and an elastic member on the rear surface of the heat dissipation base, with the elastic member surrounding the fastening holes and heat dissipation region, to maintain the gap and prevent torque reduction when the phase change material melts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If phase change thermal grease is used to fill gaps between heat dissipation base and cooling module, then heat dissipation performance is improved, but gaps are generated between heat dissipation base and screws during phase change, reducing tightening torque
Solution Approach 1:
The invention divides the thermal grease application area into two distinct regions: a heat dissipation region for filling gaps between the heat dissipation base and cooling module, and a loop-shaped region surrounding the heat dissipation region that remains free of thermal grease to maintain screw contact. This segmentation allows the thermal grease to improve heat dissipation while preventing it from interfering with screw tightening torque.
Solution Approach 2:
The invention applies thermal grease selectively to specific locations rather than uniformly across the entire heat dissipation base. The phase change material is confined to the heat dissipation region, while the loop-shaped region maintains a grease-free zone to ensure screws remain in direct contact with the heat dissipation base, preserving mechanical fastening reliability.
2Ease of manufacture
If phase change thermal grease is applied in paste form, then ease of application is improved, but it makes surroundings dirty during shipment
Solution Approach 1:
The invention utilizes the phase change property of the thermal grease, transitioning it from a solid state during shipment (preventing contamination) to a paste state during operation (enabling easy application and gap filling). This parameter change allows the material to exhibit different properties at different stages of the product lifecycle.
3Strength
If cooling module is joined to semiconductor module by screws, then mechanical fastening is achieved, but gaps between heat dissipation base and screws reduce tightening torque when phase change material melts
Solution Approach 1:
The invention segments the contact interface between the heat dissipation base and cooling module into two zones: a heat dissipation region where phase change material fills gaps, and a loop-shaped region where screws maintain direct metal-to-metal contact. This ensures mechanical fastening strength is preserved while enabling thermal grease to function in the heat dissipation area.
Solution Approach 2:
The loop-shaped region acts as an intermediary zone that mediates between the mechanical fastening function (screws) and the thermal management function (phase change material). By keeping this region free of thermal grease, the invention ensures screws maintain direct contact with the heat dissipation base, preserving tightening torque while allowing phase change material to function in the heat dissipation region.
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 ensures that the phase change material spreads without narrowing the gap, maintaining the tightening torque and preventing a reduction in heat dissipation and reliability of the semiconductor module and power converter.
Implementation Method 1
a phase change thermal grease is used instead of such a thermal grease. The phase change thermal grease keeps its solid state at room temperature and, when heated, changes into a paste.
Implementation Method 2
the phase change thermal grease is changed into a paste. According to the phase change of the phase change thermal grease from solid to liquid
Implementation Method 3
an elastic member on the rear surface of the heat dissipation base in the loop-shaped region
Implementation Method 4
a cooling module is provided on the rear surface of the heat dissipation base via a thermal grease
Data Source
AI summary
A semiconductor module includes an insulated circuit substrate including a semiconductor chip, an insulated circuit substrate including a wiring board provided on a front surface thereof, the wiring board having the semiconductor chip bonded thereto, a heat dissipation base having a front surface and a rear surface opposite to each other. The front surface has a substrate region to which the insulated circuit substrate is bonded. The rear surface has a heat dissipation region positioned overlapping the substrate region in a plan view of the semiconductor module and a loop-shaped region surrounding the heat dissipation region. The semiconductor module further includes a solid heat dissipation member made of a phase change material and provided on the rear surface of the heat dissipation base in the heat dissipation region, and an elastic member provided on the rear surface of the heat dissipation base in the loop-shaped region.