Power Module Solder Barrier Structure Against Bridging Shorts
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Solution Overview
Problem
Solder bridging between electronic components in power modules leads to electrical failures due to excess molten solder wetting, causing shorting and other electrical issues, despite efforts to minimize solder usage.
Innovation Solution
Incorporating a solder repellent or solder wetting structure on the substrate's metallic surface, positioned between sensitive components, which repels or attracts excess molten solder, preventing it from bridging to critical areas like shunt resistors, using materials such as aluminum or copper ribbons/wires that are non-wettable or readily wettable to manage solder flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If excess solder is used for attaching electronic components to substrate, then solder wetting and adhesion are improved, but solder bridging to adjacent components increases causing electrical shorting
Solution Approach 1:
The substrate surface is segmented into different functional zones: a solder wetting zone (first region) that attracts and absorbs excess solder, and a solder repellent zone (second region) that prevents solder adhesion. This segmentation allows the system to handle excess solder constructively in one area while protecting sensitive components in another area from solder bridging.
Solution Approach 2:
Different regions of the substrate are given different local properties: the first region has solder-wetting characteristics (e.g., copper material) to attract excess solder, while the second region has solder-repellent characteristics (e.g., nickel or tin coating) to prevent solder adhesion. This local differentiation enables simultaneous solder absorption and solder protection within the same substrate structure.
2Reliability
If minimum solder is used for attaching electronic component to substrate, then solder bridging to neighbouring structure is reduced, but solder wetting of component may be non-ideal leading to solder voids
Solution Approach 1:
The first region acts as an intermediary structure between the solder joint and the sensitive second region. It provides a controlled path for excess solder to adhere, serving as a buffer that protects the second region from solder bridging while ensuring adequate solder is available for proper wetting of the electronic component.
3Reliability
If solder repellent structure is added to prevent solder bridging, then electrical shorting is reduced, but device complexity increases
Solution Approach 1:
The solder management function is merged into the substrate structure itself through the formation of distinct regions with different materials or coatings during the substrate manufacturing process. This integration approach avoids adding separate external solder management components, thereby reducing overall device complexity while still providing effective solder bridging prevention.
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
Effectively reduces solder bridging and shorting by repelling or redirecting excess solder away from sensitive components, ensuring reliable electrical performance in power modules.
Implementation Method 1
a solder repellent structure configured to repel molten solder
Implementation Method 2
a solder wetting structure configured such that excess solder squeezed out from under the electronic component adheres to the solder wetting structure
Data Source
AI summary
A power module is disclosed herein. In one embodiment, the power modules includes a solder repellent structure that adjoins a metallic surface of a substrate outside a perimeter of an electronic component attached to the metallic surface of the substrate and positioned adjacent to one or more sides of the electronic component, the solder repellent structure being configured to repel molten solder. In another embodiment, the power modules includes a solder wetting structure that adjoins a metallic surface of a substrate outside a perimeter of an electronic component attached to the metallic surface of the substrate and positioned adjacent to one or more sides of the electronic component, where excess solder adheres to the solder wetting structure.