Integrated GaN Power Module Layout for Thermal Contact Stability
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Solution Overview
Problem
Conventional power modules incorporating silicon carbide or gallium nitride face limitations in heat dissipation due to module configuration issues, such as thermal expansion mismatches between components, leading to warped baseplates and reduced thermal contact with heat sinks, which inhibits performance and increases thermal resistance.
Innovation Solution
The use of insulated metal substrates with copper bases and ceramic layers, along with solder-plated copper spacers and direct-bonded copper substrates, allows for closer coupling of semiconductor devices to heat-transfer substrates, accommodating thermal expansion differences and improving heat dissipation by maintaining a planar profile and reducing component spacing, thereby enhancing thermal conductivity and operational efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional module configuration is used with silicon carbide or gallium nitride components, then the module structure is simple, but thermal expansion mismatches cause warped baseplates and reduced thermal contact with heat sinks
Solution Approach 1:
The patent introduces a compliant underfill material as an intermediary substance between the semiconductor device and the substrate. This underfill accommodates thermal expansion mismatches between different materials, preventing warping and maintaining reliable thermal contact between the power module components and the heat sink, thereby resolving the contradiction between heat dissipation and thermal contact reliability
Solution Approach 2:
The patent employs composite material structures including the combination of gallium nitride semiconductor devices with compliant underfill materials and metal substrates. This composite approach allows each material to contribute its optimal properties: the gallium nitride provides high power density, the underfill provides thermal expansion accommodation, and the metal substrate provides heat sinking, collectively resolving the thermal contact issue
2Power
If component spacing is reduced to improve power density, then power density increases, but thermal management becomes more difficult
Solution Approach 1:
The patent merges multiple functions into the underfill material, which simultaneously provides electrical insulation, mechanical compliance for thermal expansion, and thermal conduction pathways. This allows reduced component spacing for higher power density while the integrated underfill system manages the increased heat generation through maintained thermal contact
3Power
If gallium nitride switches operate at wider current and voltage ranges, then power density increases, but dv/dt and di/dt losses increase
Solution Approach 1:
The patent implements preliminary thermal management through the compliant underfill structure that maintains optimal thermal contact from the outset of operation. This preliminary thermal pathway control helps manage the rate of change of voltage and current by ensuring efficient heat removal, thereby reducing dv/dt and di/dt losses even when operating at wider current and voltage ranges
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 enables improved heat rejection and faster switching speeds for gallium nitride switches, allowing them to operate over wider current and voltage ranges with increased power density and reduced dv/dt and di/dt losses, thus enhancing overall device performance.
Implementation Method 1
one or more spacers coupled between and soldered to each of the printed circuit board and the heat-transfer substrate. The one or more spacers may include solder-plated copper spacers. At least one spacer may be coupled with a via formed through the printed circuit board, and configured to transfer heat from the one or more surface-mounted components to the heat-transfer substrate.
Implementation Method 2
one or more gallium nitride transistors coupled between and soldered to each of the second surface of the printed circuit board and the heat-transfer substrate
Implementation Method 3
The heat-transfer substrate may be an insulated metal substrate. The insulated metal substrate may include a copper base and one or more insulation layers.
Implementation Method 4
The heat-transfer substrate may be a direct-bonded copper board. The direct-bonded copper board may include a first copper layer coupled with the one or more gallium nitride transistors, a second copper layer, and a ceramic layer.
Data Source
AI summary
Integrated power modules according to the present technology may include a printed circuit board characterized by a first surface and a second surface. The integrated power modules may include one or more surface-mounted components coupled with the first surface of the printed circuit board. The integrated power modules may include a heat-transfer substrate. The integrated power modules may include one or more gallium nitride transistors coupled between and soldered to each of the second surface of the printed circuit board and the heat-transfer substrate. The integrated power modules may include one or more spacers coupled between and soldered to each of the printed circuit board and the heat-transfer substrate.