Terminal Assembly with Differential Solderability
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Solution Overview
Problem
Existing technologies face challenges in making reliable, non-permanent electrical connections between substrates, particularly for Ball Grid Array (BGA) and Land Grid Array (LGA) packages, which are difficult to replace or interchange once soldered to a printed circuit board.
Innovation Solution
An intercoupling component with an electrically conductive terminal assembly featuring a core member obstructing an axial hole, where the core member and terminal body have different solderability materials, allowing for secure and reversible connections between substrates using solder balls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal body is made entirely of a solderable material, then solderability is improved, but manufacturing cost increases due to the need for expensive materials like gold or tin throughout the entire structure
Solution Approach 1:
The terminal assembly applies local quality by providing a solderable coating (first material) only on specific surfaces where solder contact is required (core member outer surface and terminal body outer surface), while the interior and bulk structure use a different, less expensive material composition. This resolves the contradiction by concentrating expensive solderable materials only where functionally necessary.
Solution Approach 2:
The terminal assembly uses composite materials by combining a core member made of one material with a terminal body made of another material, and further combining these with different coating materials (solderable first material versus non-solderable second material). This multi-material construction allows optimization of both solderability at contact points and cost through material selection in non-critical areas.
2Ease of manufacture
If the terminal body is made entirely of a non-solderable material to reduce cost, then manufacturing cost decreases, but solderability and connection reliability deteriorate
Solution Approach 1:
The terminal assembly applies local quality by providing a solderable coating (first material) only on specific surfaces where solder contact is required (core member outer surface and terminal body outer surface), while the interior and bulk structure use a different, less expensive material composition. This resolves the contradiction by concentrating expensive solderable materials only where functionally necessary.
3Reliability
If solder flows freely along the terminal body during soldering, then complete wetting is achieved, but solder joints become unreliable due to excessive solder distribution and potential bridging
Solution Approach 1:
The terminal assembly applies local quality by providing a solderable coating (first material) only on specific surfaces where solder contact is required (core member outer surface and terminal body outer surface), while the interior and bulk structure use a different, less expensive material composition. This resolves the contradiction by concentrating expensive solderable materials only where functionally necessary.
Solution Approach 2:
The terminal assembly extracts the solderability function from the entire terminal structure and concentrates it only on the surfaces that contact solder balls. The core member and terminal body use non-solderable materials that prevent unwanted solder flow, effectively separating the soldering function from the structural function.
4Ease of manufacture
If a single material is used for the entire terminal assembly, then manufacturing process is simplified, but the ability to control solder flow and selectivity is reduced
Solution Approach 1:
The terminal assembly applies local quality by providing a solderable coating (first material) only on specific surfaces where solder contact is required (core member outer surface and terminal body outer surface), while the interior and bulk structure use a different, less expensive material composition. This resolves the contradiction by concentrating expensive solderable materials only where functionally necessary.
Solution Approach 2:
The terminal assembly uses composite materials by combining a core member made of one material with a terminal body made of another material, and further combining these with different coating materials (solderable first material versus non-solderable second material). This multi-material construction allows optimization of both solderability at contact points and cost through material selection in non-critical areas.
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
Enables reliable, non-permanent electrical connections between substrates, reducing manufacturing costs through selective plating and assembly, while maintaining high solderability and preventing solder flow along peripheral sides during reflow.
Implementation Method 1
at least an outer surface of the core member includes a first material and at least an outer surface of the body includes a second material, the first material having greater solderability than the second material
Data Source
AI summary
An intercoupling component is provided which permits reliable, non-permanent electrical connection between a first substrate and a second substrate. The intercoupling component includes an electrically conductive terminal including a first end and a second end opposed to the first end. The first and second ends are configured to receive a solder ball. An axial hole extends inward from the first end of the terminal, and an electrically conductive core member is disposed within the hole. The core member is sized and shaped to obstruct the hole. In addition, at least an outer surface of the core member includes a first material and at least an outer surface of the body includes a second material, the first material having greater solderability than the second material.