Semiconductor Solder Flow Prevention via Laser Oxide
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Solution Overview
Problem
Existing methods for preventing solder flow in power semiconductor devices are inadequate, as they either require acute groove angles that are difficult to maintain or involve time-consuming and costly laser scanning for forming copper oxide films, leading to reduced productivity and increased costs.
Innovation Solution
The implementation of finely roughened oxide material surfaces in solder flow prevention areas, created by laser irradiation, between chip and bonding regions on the circuit substrate to effectively prevent solder spread during high-temperature processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grooves are formed by laser irradiation to prevent solder flow, then solder flow is prevented, but the upper corner rounding reduces effectiveness and requires acute angles that are difficult to maintain
Solution Approach 1:
The invention changes the surface parameters of the metal circuit layer by forming an oxide film through laser irradiation. The oxide film creates a naturally rounded upper corner with sufficient width without requiring acute angles, maintaining solder flow prevention effectiveness while eliminating the manufacturing precision issue of angle maintenance
Solution Approach 2:
The invention uses laser irradiation to accelerate the oxidation of the metal circuit layer surface, forming a copper oxide film. This oxidized surface provides the desired rounded geometry that prevents solder flow without requiring difficult-to-maintain acute angles
2Reliability
If the entire surface is scanned by laser light to form copper oxide film, then solder flow is prevented, but the process takes much time reducing productivity and increasing cost
Solution Approach 1:
The invention applies laser irradiation only to specific local areas where solder flow prevention is needed, rather than scanning the entire surface. This localized approach maintains the necessary oxide film formation at critical locations while significantly reducing processing time and improving productivity
3Adaptability or versatility
If chip and bonding region are placed at short distance for high integration, then device integration is improved, but solder flow may reach bonding region causing assembly failure
Solution Approach 1:
The invention introduces an oxide film as an intermediary barrier between the chip solder region and the bonding region. This oxide film layer acts as a physical and chemical barrier that prevents solder flow while allowing the chip and bonding region to be placed at short distances for high integration
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 enhances the reliability of semiconductor devices by preventing solder flow, even at high integration densities, thereby reducing assembly failures and maintaining high productivity while minimizing costs.
Implementation Method 1
by laser irradiation
Implementation Method 2
forming a copper oxide film
Implementation Method 3
oxide material finely roughened at the surface... effectively preventing solder spread
Data Source
AI summary
In a semiconductor device where a metal circuit layer is disposed over a main planar surface of an insulating substrate, a semiconductor chip is connected by way of a solder over the metal circuit layer, and a metal wiring is connected over the metal circuit layer, in which a solder flow prevention area comprising a linear oxide material is formed between the semiconductor chip and the ultrasonic metal bonding region over the metal circuit layer.