Power Module Integration via Direct Copper Bonding
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Solution Overview
Problem
Current HDI technology for integrating power electronics faces limitations in cost reduction and increased integration and compactness due to high stray inductances and heat constraints, which hinder mass production and reliability in power modules.
Innovation Solution
A method involving the production of laminated subassemblies with matching profiled copper metal base-forming plates, where insulating and conductive inner layers are formed using IMS techniques, and electronic chips are implanted and bonded through press-fitting and resin polymerization, allowing for reduced stray inductances and enhanced heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If HDI technology with tapes and microvias is used to increase integration level, then the size of power modules is reduced, but stray inductances increase which oppose higher cutoff frequencies
Solution Approach 1:
The patent extracts and eliminates the harmful interconnection elements (tapes and microvias) that generate stray inductances. By removing these traditional HDI interconnection methods and replacing them with direct copper-to-copper bonding, the invention eliminates the source of stray inductances while maintaining compact module size.
Solution Approach 2:
The patent replaces the mechanical HDI interconnection system (tapes, microvias, laser drilling) with a direct metallurgical bonding system. The copper plates are bonded directly to each other through sintering or diffusion bonding, substituting the complex mechanical interconnection structure with a simpler direct metal-to-metal contact that eliminates stray inductances.
2Productivity
If HDI technology with laser drilling and welding is used to increase integration, then component density increases, but manufacturing cost reduction is hindered due to lack of parallelization
Solution Approach 1:
The patent segments the manufacturing process into independent parallel steps. Multiple copper plates with pre-formed circuit patterns can be manufactured separately and then bonded together in a single sintering or diffusion bonding operation, enabling parallel production and reducing manufacturing costs compared to sequential HDI processes.
Solution Approach 2:
The patent changes the bonding parameter from traditional welding temperatures to lower sintering or diffusion bonding temperatures. This parameter change enables the use of copper plates with pre-formed circuits and allows for parallel processing, reducing manufacturing complexity and cost while maintaining high component density.
3Speed
If switching frequency is increased to reduce heat and improve compactness, then power density increases, but stray inductances generate more heat and risk of overvoltages increases
Solution Approach 1:
The patent converts the potential harm of high-frequency switching by eliminating stray inductances through direct copper bonding. The same high switching frequency that would normally generate harmful overvoltages and heat in HDI systems becomes beneficial, enabling faster switching with reduced losses and improved efficiency due to the absence of stray inductances.
4Volume of moving object
If integration level is increased to improve compactness, then heat dissipation becomes more constrained, but efficient cooling is necessary to maintain reliability
Solution Approach 1:
The patent merges the electrical interconnection function with the thermal management function by using the same copper plates for both purposes. The copper plates serve as both the electrical conductors and the heat dissipation pathways, eliminating the need for separate interconnection layers and improving thermal management in compact designs.
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 approach enables increased integration and compactness while reducing manufacturing costs and heat constraints, improving the reliability and performance of power modules by minimizing stray inductances and facilitating efficient heat extraction.
Implementation Method 1
maintaining pressure until finalization of the mechanical bonds by resin polymerization
Implementation Method 2
press-fitting the first and second blanks in order to produce the laminated subassembly
Data Source
AI summary
The method comprises the steps of 1) producing first and second blanks (EB1, EB2) by laminating insulating and conductive inner layers (PP, CP, E1) on copper plates forming a base (MB1, MB2), at least one electronic chip (MT, MD) being sandwiched between the blanks, said blanks being produced such that their upper lamination surfaces have matching profiles, 2) stacking and fitting the blanks via their matching profiles, and 3) press-fitting the blanks to form a laminated sub-assembly for an integrated power electronics device. The method uses IMS-type techniques.