Spring-Loaded Clamp Interconnect for CTE Mismatch
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Solution Overview
Problem
Interconnect technologies in integrated optical circuits face issues due to high shear stress from coefficient of thermal expansion (CTE) mismatch, leading to increased interconnection defects and limited reworkability, especially with solder connections which are costly and permanent.
Innovation Solution
A clamp interconnect system with a filler metal provides a solderless connection between components with different CTEs, allowing the interposer to move and maintain electrical communication without interruption, reducing shear stress and enabling reworkability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solder connections are used to achieve electrical communication between circuits, then electrical connection is achieved, but high shear stress from CTE mismatch increases interconnection defects and makes connections permanent and costly
Solution Approach 1:
The patent applies the dynamics principle by using a spring-loaded clamp instead of a rigid solder connection. The spring mechanism allows the interconnect to dynamically adjust to thermal expansion and contraction, providing continuous electrical contact while accommodating CTE mismatch between components. This dynamic adaptation eliminates the permanence and brittleness of solder joints while maintaining reliable electrical connection.
Solution Approach 2:
The patent uses a filler metal as an intermediary material between the clamp and the circuit components. This filler metal mediates the mechanical and thermal stresses, providing a compliant interface that reduces shear stress from CTE mismatch while maintaining electrical conductivity. The intermediary layer protects both the clamp and the circuit board from direct stress transmission.
2Reliability
If solder connections are used to achieve electrical communication between circuits, then electrical connection is achieved, but high shear stress from CTE mismatch leads to increased interconnection defects
Solution Approach 1:
The spring-loaded clamp provides a dynamic connection that can accommodate thermal expansion and contraction of components with different CTEs. As temperatures change, the spring compresses or extends to maintain contact pressure, preventing the high shear stresses that would occur with rigid solder joints. This dynamic compliance eliminates the harmful shear stress effect.
Solution Approach 2:
The patent changes the mechanical parameters of the connection by using a spring mechanism with specific force constants and a filler metal with appropriate compliance. These parameter changes allow the connection to maintain optimal contact pressure across temperature variations while reducing shear stress below threshold levels that would cause defects.
3Ease of manufacture
If wire bonds are used for interconnection between integrated circuits, then cost effectiveness is achieved, but the speed of the device is limited
Solution Approach 1:
The patent segments the interconnection system into distinct functional elements: a rigid clamp structure for mechanical support, a spring element for dynamic compliance, and a filler metal for stress distribution. This segmentation allows each element to be optimized for its specific function while maintaining overall cost-effectiveness and high-speed performance.
Solution Approach 2:
The patent employs composite construction by combining different materials with complementary properties: conductive materials for electrical connection, spring steel or similar for the clamp mechanism, and compliant filler metal. This composite approach achieves both cost-effectiveness and high-speed signal transmission by optimizing each material for its specific role.
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 system effectively reduces shear stress and allows for the expansion and contraction of components with different CTEs, maintaining continuous electrical communication and enabling cost-effective reworkability of integrated optical circuits.
Implementation Method 1
the interposer to be capable of movement about the filler metal. Such movement allows for the interconnect, connected to components having different CTEs, to expand and contract without interruption of the electrical connection
Data Source
AI summary
An apparatus including a bridge member and a clamp is disclosed. The bridge member is positioned in a first plane and has a substrate with a first surface and a second surface; and a plurality of distinct conductive pillars formed on the second surface of the substrate. The clamp has a body, a proximal end and a distal end. The body is positioned in a second plane above the first plane with the second plane being within 2 degrees of parallel to the first plane. The proximal end is positioned along the second plane; and the distal end has a plurality of prongs. The distal end is offset from the second plane in a direction toward the bridge member such that each prong contacts the first surface of the substrate.