Power Module Substrate Zoning for Lower DBC Material Cost
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Solution Overview
Problem
Existing power modules using direct bonded copper (DBC) substrates are expensive due to their high thermal conductivity requirements, which are not necessary in areas with low heat generation, leading to unnecessary cost.
Innovation Solution
A power module design incorporating a rigid insulated substrate mounted on a baseplate with an additional circuit carrier having lower rigidity, such as a printed circuit board (PCB) or flexible circuit board, reduces costs by minimizing the area of the rigid insulated substrate and utilizing less expensive materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a DBC substrate is used throughout the power module, then thermal conductivity is improved, but cost increases
Solution Approach 1:
The patent applies different substrate types in different regions: DBC substrate is used only in areas with high power density and heat generation, while areas with low power density use alternative substrates. This local differentiation optimizes thermal management where needed while reducing costs in areas where high thermal conductivity is not critical.
Solution Approach 2:
The power module is segmented into different functional zones with different thermal requirements. The DBC substrate is segmented to cover only the necessary high-power areas, while other areas use different substrate materials, allowing cost optimization without compromising overall thermal performance.
2Temperature
If the area of rigid insulated substrate is increased, then thermal management is improved, but cost increases
Solution Approach 1:
The patent implements local quality by matching substrate material properties to the thermal requirements of specific functional areas. High thermal conductivity substrates are applied only where heat generation is significant, while low-cost substrates are used in low-power areas, optimizing the balance between heat dissipation and cost.
3Ease of manufacture
If a flexible circuit board is used, then cost is reduced, but rigidity decreases
Solution Approach 1:
The patent applies flexible circuit boards in areas where mechanical rigidity is not critical and cost reduction is prioritized, while maintaining rigid substrates in areas requiring structural support. This selective application resolves the contradiction between cost and rigidity by matching material properties to functional requirements.
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 design achieves cost reduction by using a combination of rigid and flexible circuit carriers, maintaining effective thermal management while reducing material costs.
Implementation Method 1
DBC substrates are selected as circuit material for bare semiconductor chips in power modules as they efficiently dissipate the waste heat from the semiconductors
Implementation Method 2
A solder layer, a sinter layer or glue (thermally and/or electrically conducting) may be used to electrically connect and mechanically fasten the rigid insulated substrate and the additional circuit carrier to the baseplate
Data Source
AI summary
A power module (2) including a rigid insulated substrate (10) mounted on a baseplate (4) is disclosed. An additional circuit carrier (6, 8) is mounted on the baseplate (4) adjacent to the rigid insulated substrate (10). The additional circuit carrier (6, 8) has a rigidity which is less than that of the rigid insulated substrate (10).