Laser-Sintered Chip Contact Connection for High-Current Durability
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Solution Overview
Problem
Existing chip arrangements for power transistors face durability issues due to high thermal and electrical stresses, leading to component failure and increased production costs, especially when used in applications with temperature fluctuations, and require multiple contact conductors to transmit high currents.
Innovation Solution
A method involving the application of silver or copper paste on both chip contact surfaces and conductor material tracks, followed by sintering using laser energy to form a robust contact connection, which reduces sensitivity to temperature fluctuations and eliminates the need for multiple contact conductors, allowing for cost-effective production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple contact conductors are used to transmit high currents, then current transmission capability is improved, but device complexity and production cost increase
Solution Approach 1:
The patent combines multiple contact conductors into a single conductor material web that directly contacts the chip contact surface. The conductor material web is formed as a continuous structure with increased cross-sectional area, eliminating the need for multiple separate contact conductors while maintaining high current transmission capability. This merging approach reduces device complexity and production cost.
Solution Approach 2:
The conductor material web is formed as a composite structure with increased cross-sectional area, combining multiple conductor material strands into a unified web. This composite structure provides both the necessary current transmission capability and mechanical strength, replacing multiple individual contact conductors with a single integrated component.
2Ease of manufacture
If soldering is used to connect contact conductors, then ease of manufacture is improved, but reliability deteriorates due to temperature limitations and susceptibility to thermal stress
Solution Approach 1:
The patent replaces the soldering process with a direct mechanical contact system using the conductor material web. The web is positioned to directly contact the chip contact surface without requiring thermal processing, eliminating the temperature limitations and thermal stress issues associated with soldering while maintaining manufacturing simplicity.
Solution Approach 2:
The conductor material web acts as an intermediary element between the chip contact surface and the external circuit. This web provides a direct mechanical and electrical connection that eliminates the need for solder joints, thereby improving reliability while maintaining ease of manufacture through simple positioning and attachment processes.
3Ease of manufacture
If bond wires are used to connect chip contact pads, then ease of manufacture is improved, but reliability deteriorates under high thermal and electrical stresses
Solution Approach 1:
The patent merges the functions of multiple bond wires into a single conductor material web that directly contacts the chip contact surface. This web has increased cross-sectional area and is specifically designed to withstand high thermal and electrical stresses, eliminating the reliability issues of thin bond wires while maintaining manufacturing simplicity through direct placement.
Solution Approach 2:
The patent changes the physical parameters of the connection element by using a conductor material web with significantly increased cross-sectional area compared to traditional bond wires. This parameter change enhances the web's ability to withstand thermal and electrical stresses while maintaining ease of manufacture through straightforward positioning and attachment processes.
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 method enhances the durability of contact connections, enabling operation at higher temperatures (up to 300 °C) and reduces production costs by minimizing the number of contact conductors required, while maintaining high current transmission capabilities.
Implementation Method 1
the contact connection is formed by sintering the silver paste or the copper paste using laser energy
Implementation Method 2
the contact connection is formed by sintering the silver paste or the copper paste using laser energy
Implementation Method 3
a solvent contained in the silver paste or the copper paste is at least partially evaporated by heating
Data Source
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AI summary
The invention relates to a chip arrangement (10) and a method for forming a contact connection (11) between a chip (18), in particular a power transistor or the like, and a conductor material strip (14), said conductor material strip being formed on a non-conductive substrate (12) and the chip being arranged on the substrate or on a conductor material strip (15). A silver paste (29) or copper paste is applied to a chip contact surface (25) of the chip and of the conductor material strip (28), a contact conductor (30) is dipped into the silver paste or the copper paste on the chip contact surface and into the silver paste or the copper paste on the conductor material strip, and a solvent contained in the silver paste or the copper paste is at least partially evaporated by heating. The silver paste or the copper paste is then sintered by means of laser energy, thereby forming the contact connection.