Conductive Paste Interconnect for Embedded Power Devices
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Solution Overview
Problem
Current methods for connecting power devices to substrates, such as copper vias and electro-less copper plating, face limitations in achieving optimal electrical and thermal contact due to thickness constraints and compatibility issues with PCB processes.
Innovation Solution
A method involving embedding a power die in a dielectric substrate with metallization layers, etching cavities, plating conductive material, filling with a conductive paste, stabilizing the paste, and sealing with additional conductive layers to ensure both electrical and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electro-less copper plating is used to connect power die electrodes, then electrical connection is achieved, but the copper layer thickness is limited to a few tens of μm resulting in insufficient thermal conductivity
Solution Approach 1:
The patent combines electro-less copper plating with electrodeposition to create a multi-layer copper structure. The electro-less plating provides initial coverage and adhesion, while the subsequent electrodeposition adds significant copper thickness to achieve both electrical and thermal conductivity requirements.
Solution Approach 2:
The electro-less copper plating is performed as a preliminary step before electrodeposition. This preliminary copper layer serves as a base for subsequent electrodeposition processes, ensuring proper adhesion and coverage before adding the thicker copper layer needed for thermal management.
2Reliability
If copper vias are used to connect embedded power devices, then electrical connection is achieved, but the process is not compatible with standard PCB manufacturing processes
Solution Approach 1:
The patent employs electro-less copper plating and electrodeposition techniques that are already widely used in standard PCB manufacturing processes. This approach allows the power device interconnection to be integrated into existing PCB production lines without requiring specialized via drilling or plating equipment, achieving both electrical connection and PCB process compatibility.
3Temperature
If foam copper is grown on wafer level and sintered on substrate, then thermal contact is improved, but the multiple deposition steps and sintering process are expensive and require conditions not compatible with PCB processing
Solution Approach 1:
The patent replaces the expensive foam copper growth and sintering process with electro-less plating and electrodeposition, which use readily available copper salts and standard PCB electroplating equipment. This substitution significantly reduces material and process costs while achieving the necessary copper thickness for thermal management.
Solution Approach 2:
The patent changes the process parameters from high-temperature sintering (required for foam copper) to electrochemical deposition processes that operate at lower temperatures compatible with PCB manufacturing. The electrodeposition process allows precise control of copper thickness and morphology to achieve optimal thermal and electrical properties.
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 provides a reliable and efficient method for connecting power devices, enhancing both electrical and thermal contact while being compatible with PCB processes, thus addressing the limitations of existing methods.
Implementation Method 1
stabilizing the conducting paste in order to evaporate or burn out the additives of the conducting paste
Implementation Method 2
plating a conductive material on the whole surface of the cavities to connect the power die electrodes with the conductive material layer on the top and bottom surfaces of the dielectric material
Data Source
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AI summary
The present invention concerns a method and a system for interconnecting a power device embedded in a substrate using conducting paste into cavities. The present invention: - embeds the power die in a substrate composed of a dielectric material comprising a metallization layer on the top and bottom surfaces of the dielectric material, - etches the substrate on the top and bottom surfaces of the power die, - plates a conductive material on the whole surface of the cavities to connect the power die electrodes with the conductive material layer on the top and bottom surfaces of the dielectric material, - fills the plated cavities with a paste made of electrical and thermal conductive material and additive components, - stabilizes the conducting paste in order to evaporate or burn out the additives of the conducting paste, - plates a conductive material on the top and on the bottom of the substrate.