Interposer Contact Structure With Nonlinear Spring Force for Signal Integrity
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Solution Overview
Problem
The increasing density of connections in interconnection systems poses challenges in simultaneously meeting mechanical and signal integrity requirements, particularly in high-density electronic devices, where excessive force can lead to warpage and disconnection of contacts.
Innovation Solution
An interposer design featuring a contact with a curved beam that slides in opposite directions upon compression, allowing for a non-linear spring rate reduction and providing a rigid connection, with a housing that allows for clearance and a fixed positional relationship, reducing impedance and insertion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the density of connections in interconnection systems is increased to provide greater bandwidth, then the number of connections and signal capacity improve, but the difficulty of simultaneously satisfying mechanical requirements and signal integrity requirements increases
Solution Approach 1:
The contact is divided into multiple functional segments: a curved beam portion with first and second contact portions, a landing strip, and a rigid connection portion. This segmentation allows each segment to independently address specific requirements - the curved beam provides compliance for mechanical tolerance, while the rigid connection ensures signal integrity for high-density connections.
Solution Approach 2:
The contact combines different material properties within a single component - the curved beam portion is designed to be compliant and elastic to accommodate mechanical variations, while the connection portions provide rigid electrical contact. This composite approach enables simultaneous satisfaction of mechanical and electrical requirements in high-density interconnection systems.
2Reliability
If excessive force is applied to ensure reliable electrical connections, then connection reliability improves, but warpage and disconnection of contacts occur
Solution Approach 1:
The contact incorporates a dynamic curved beam portion that can elastically deform under compression. Instead of applying excessive static force, the curved beam dynamically adjusts its compliance based on the applied load, providing sufficient contact force for reliable electrical connection while preventing excessive force that would cause warpage or disconnection.
Solution Approach 2:
The spring rate of the curved beam is specifically designed to decrease non-linearly with compression. This parameter change ensures that the contact provides high initial force for reliable connection establishment, then automatically reduces force as compression increases, preventing warpage and disconnection while maintaining connection reliability throughout the compression range.
3Manufacturing precision
If a rigid connection structure is used to ensure signal integrity, then impedance variation and insertion loss reduce, but the ability to accommodate fabrication tolerances and mechanical variations decreases
Solution Approach 1:
The contact is segmented into a compliant curved beam portion and rigid connection portions. The curved beam segment absorbs mechanical variations and fabrication tolerances through elastic deformation, while the rigid connection segments maintain precise geometric relationships for controlled impedance and minimal insertion loss, thus satisfying both manufacturing precision and adaptability requirements.
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 design enhances signal integrity by minimizing impedance variation, insertion loss, and return loss, while preventing warpage by reducing maximum spring force, thus ensuring reliable connections across varying fabrication tolerances.
Implementation Method 1
a curved beam comprising: a first contact portion; and a second contact portion configured to contact the landing strip in response to compression of the curved beam
Implementation Method 2
providing a rigid connection, with a housing that allows for clearance and a fixed positional relationship, reducing impedance and insertion loss
Data Source
AI summary
An interposer configured for creating multiple connections between electrical components is described. Contacts of the interposer are configured to produce a nonlinear force when compressed. A high spring rate is achieved from zero force to an acceptable force for establishing sufficient electrical connection between the electrical components; and then a lower spring rate is achieved for the remainder of the deflection to minimize the maximum force at the maximum designed compression. The contact includes a curved beam, a tail, and a landing strip. It may also include a solder ball connected to the tail. When the contact is compressed, the curved beam traces an arc in one direction, while the part of the contact touching the landing strip slides along the landing strip in the other direction, thereby reducing the force produced by the contact.