Elastic Interconnect with Spacer for PoP Movement

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Solution Overview

Problem

The existing interconnects for Package on Package (PoP) assemblies, which use probe pins, restrict relative movement between packages and can damage solder balls and conductor pads during repeated use.

Innovation Solution

An interconnect comprising an elastic body with electric conductor particles and a spacer, which allows for relative movement between packages without damaging the solder balls and pads, ensuring a secure electrical connection through the use of an elastic body and electric conductor particles dispersed within, and a spacer that limits deformation and applies pressure to maintain mechanical and electrical integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If probe pins are used to connect packages, then electrical connection is achieved, but relative movement between packages is restricted and solder balls/pads may be damaged

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidrelative movement capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent uses a flexible interconnect structure that can bend and deform elastically to accommodate relative movement between packages while maintaining electrical connection. This flexible structure replaces the rigid probe pins, allowing the interconnect to absorb mechanical stress through elastic deformation rather than restricting package movement or damaging solder joints.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The interconnect's physical parameters (shape, length, stiffness) are designed to change dynamically in response to mechanical stress. The structure transitions between different deformation states while maintaining electrical conductivity, allowing it to adapt to package movement while preserving reliable electrical connection.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If probe pins are pressed into solder balls and pads, then electrical connection is established, but solder balls and pads may be damaged during repeated use

Engineering Contradiction:

Improveelectrical connection establishmentVSAvoidconnection durability

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The flexible interconnect structure is designed with built-in mechanical compliance that cushions and absorbs the forces applied during connection establishment and package movement. This pre-engineered compliance prevents excessive stress from being transmitted to the solder balls and pads, protecting them from damage during repeated connection cycles.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent replaces the rigid mechanical probe pin system with a flexible interconnect system that uses elastic deformation to establish and maintain electrical connection. This substitution eliminates the need for high-contact-force mechanical insertion, thereby preventing damage to solder balls and pads while maintaining reliable electrical connection over extended periods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 interconnect enables secure and durable electrical connections between integrated circuit packages, allowing for relative movement without damaging the components, thus enhancing the reliability and longevity of the connections.

Implementation Method 1

an elastic body, an electric conductor and a spacer... when the interconnect is compressed between first and second integrated circuit packages, the spacer limits the deformation of the elastic body

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

The electric conductor includes an elastic body and electric conductor particles disbursed in the elastic body... for contacting one of a plurality of balls of the first integrated circuit package and one of a plurality of conductor pads of the second integrated circuit package

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS8154113B2Interconnect and test assembly including an interconnect

Publication Date: 2012.04.10 YAMAICHI ELECTRONICS USA INC

AI summary

An interconnect includes an elastic body, an electric conductor and a spacer. The elastic body has a first surface, a second surface, a first hole extending from the first surface to the second surface, and a second hole extending from the first surface to the second surface. The electric conductor is disposed in the first hole of the insulating body for contacting one of a plurality of balls of the first integrated circuit package and one of a plurality of conductor pads of the second integrated circuit package. The electric conductor includes an elastic body and electric conductor particles disbursed in the elastic body. The spacer is disposed in the second hole.