Disruptable Solder Coating to Prevent Spreading Bridges
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Solution Overview
Problem
Conventional solder structures face issues with unwanted solder spreading during the soldering process, leading to potential electrical connections between insulated portions of a package, which can result in undesired conductive bridges and reliability concerns.
Innovation Solution
A solder structure with a coating that inhibits solder spreading by partially or entirely disrupting upon establishing a solder connection, using a morphological adhesion promoter or oxide layer that acts as a barrier and self-destructs during soldering, eliminating the need for additional countermeasures like solder resist.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder material is applied to create solder connections, then electrical connections between functional bodies are established, but solder spreads into unwanted portions of the package creating conductive bridges
Solution Approach 1:
A coating layer is introduced as an intermediary between the solder material and the package surfaces. This coating acts as a controlled barrier that prevents unwanted solder spreading while allowing solder connection in designated areas. The coating is selectively disrupted only where solder connections are intended, maintaining reliability while controlling solder flow paths.
Solution Approach 2:
The coating is applied with spatial differentiation - it covers areas where solder spreading must be prevented while being absent or disrupted in areas where solder connections are required. This local variation in coating presence creates different functional zones: protected areas that resist solder flow and open areas that allow solder bonding, thereby solving the contradiction between preventing spreading and enabling connections.
2Manufacturing precision
If coating is applied to protect against solder spreading, then solder is confined to desired areas, but coating must be disrupted to establish solder connection
Solution Approach 1:
The coating is applied in advance to the package surfaces before the soldering process. This preliminary coating application establishes the solder confinement pattern beforehand, ensuring precise solder placement. The coating remains intact during assembly and is only disrupted during the actual soldering operation, separating the precision function from the connection function.
Solution Approach 2:
The coating's protective function is maintained by controlling its physical and chemical parameters (material composition, thickness, thermal stability). These parameters are selected so the coating resists solder spreading at soldering temperatures but can be selectively disrupted in controlled areas. By adjusting coating parameters, both precision and ease of manufacturing are optimized.
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 prevents solder from flowing into undesired regions, ensuring reliable electrical connections with low contact resistance and avoiding the formation of unwanted bridges, while maintaining adhesion and protecting against oxidation.
Implementation Method 1
a coating which at least partially coats the solder material and is configured for protecting the solder material against solder spreading
Implementation Method 2
being at least partially disrupted when establishing a solder connection between the solder material and a solderable structure
Implementation Method 3
at least partially (i.e. only partially or entirely) disrupting the coating in the solder connection region
Implementation Method 4
establishing a solder connection by the solder material in a solder connection region between the first functional body and the second functional body
Implementation Method 5
using a morphological adhesion promoter or oxide layer that acts as a barrier
Implementation Method 6
protecting against oxidation
Data Source
AI summary
A solder structure and method is disclosed. In one example, the solder structure includes a solder material, and a coating which at least partially coats the solder material and is configured for protecting the solder material against solder spreading. The coating is at least partially disrupted when establishing a solder connection between the solder material and a solderable structure.