Multilayer Power Module Substrate for Better Heat Spreading
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Solution Overview
Problem
Conventional power module substrates, such as DBC, face challenges in efficiently dissipating heat from wide bandgap semiconductor devices like SiC and GaN due to their small active heat transfer area and vertical heat conduction, leading to poor performance in high-power applications.
Innovation Solution
A multilayer substrate configuration is introduced, featuring a ceramic dielectric layer with copper tiles of varying thicknesses sandwiched between the semiconductor device and a DBC substrate, enhancing heat spreading and dissipation through thermal coupling to a heat sink.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional DBC substrate is used with thin copper layers, then the structure is simple and low cost, but heat cannot spread and only transfers vertically, resulting in poor heat extraction capability
Solution Approach 1:
The patent transitions from vertical heat conduction in thin copper layers to horizontal heat spreading in a thick copper tile (0.5-2.5mm), adding a dimensional aspect to heat transfer. The copper tile creates a thermal spreading path that moves heat laterally across the substrate area before transferring to the cold plate, fundamentally changing the heat transfer geometry from 1D vertical to 2D/3D spreading-conduction pattern
Solution Approach 2:
The patent creates a composite thermal management structure combining the DBC substrate (ceramic insulator with thin copper layers) and a thick copper tile. This composite approach leverages the electrical insulation and structural support of the DBC substrate while adding the high thermal conductivity and heat spreading capability of the thick copper tile, achieving both manufacturing simplicity and improved heat extraction
2Temperature
If double-sided cooling with two DBC substrates is used, then heat extraction capability is improved, but manufacturing complexity and yield issues increase
Solution Approach 1:
The patent extracts the heat spreading function from the complex double-sided DBC substrate configuration and consolidates it into a single thick copper tile component. This extracted approach maintains the heat extraction improvement while eliminating the manufacturing complexity of assembling two DBC substrates, as the copper tile can be directly bonded to a single DBC substrate
Solution Approach 2:
The patent merges the heat spreading function (previously requiring a second DBC substrate) with the thermal conduction function into a single integrated copper tile structure. This unified component performs both heat distribution across its surface and vertical heat transfer to the cold plate, simplifying the overall assembly to one DBC substrate plus copper tile rather than two complete DBC substrates
3Temperature
If an insulated metal substrate (IMS) with thick top metal is used, then heat spreading is improved, but the substrate area must be large to compensate for low conductive insulating material, reducing adaptability for restricted space
Solution Approach 1:
The patent applies local quality by placing the thick copper tile specifically at the heat-generating region (under the semiconductor die) where heat spreading is most needed, rather than requiring the entire substrate to be large. The copper tile concentrates thermal management resources locally at the critical hot spot, enabling effective heat spreading in a compact overall footprint
Solution Approach 2:
The patent changes the thermal conductivity parameter of the insulating layer by selecting ceramic materials (Al2O3, AlN, or Si3N4) with higher thermal conductivity compared to conventional IMS materials. This parameter change allows the copper tile to be thinner (0.5-2.5mm vs. thicker in conventional IMS) while maintaining effective heat spreading, reducing the overall structure height and improving adaptability to space-constrained applications
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 provides a 10-20% improvement in heat extraction capability over conventional substrates, offering superior performance with lower complexity and cost, making it a viable alternative to double-sided cooling structures.
Implementation Method 1
a thermally conducting layer sandwiched between the first Cu layer of the substrate and the second side of the Cu tile
Implementation Method 2
The second Cu layer may be thermally coupled to a heat sink
Implementation Method 3
enhancing heat spreading and dissipation through thermal coupling to a heat sink
Data Source
AI summary
A multilayer substrate for a power module is provided. The multilayer substrate may include a copper tile soldered between an integrated circuit component and a direct bonded copper assembly in order to facilitate heat dissipation from the integrated circuit component.