Press-fit Pin Design for Semiconductor Package Contact

Solution Overview

Problem

Existing press-fit pin structures face challenges in achieving a balance between easy insertion and increased contact area with the external substrate, leading to high contact resistance and reduced heat transfer efficiency, while also risking substrate damage due to excessive force requirements.

Innovation Solution

A press-fit pin design featuring two press-fitting pieces extending in different directions, with one piece forming a convex portion and the other forming a complementary shape to the contact hole, along with a bending structure and steps to prevent excessive insertion and distribute insertion impact, enhancing contact area and heat transfer efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the contact area between the press-fit pin and the contact hole is increased, then the contact resistance is reduced and heat transfer efficiency is improved, but a large amount of external force is required to insert the press-fit pin which may cause cracks in the substrate

Engineering Contradiction:

Improvecontact resistanceVSAvoidinsertion force

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

The press-fit pin is divided into a body portion and multiple press-fitting pieces (first and second press-fitting pieces) that extend from the body. This segmentation allows the contact function to be distributed across multiple pieces rather than requiring a single large contact area, reducing the insertion force needed while maintaining good electrical and thermal contact.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The press-fitting pieces are configured with specific geometries (convex portions, complementary shapes) that concentrate the contact function at specific locations within the contact hole. This local optimization allows effective contact with reduced overall force requirements compared to a uniform large-area contact design.

Inventive Principle:

Principle #3Local quality

2Temperature

If the contact area between the press-fit pin and the contact hole is increased, then the heat transfer efficiency through the substrate is increased, but a large amount of external force is required to insert the press-fit pin

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidinsertion force

Core Design Contradiction:

TemperatureVSForce

Solution Approach 1:

The press-fit pin is divided into a body portion and multiple press-fitting pieces (first and second press-fitting pieces) that extend from the body. This segmentation allows the contact function to be distributed across multiple pieces rather than requiring a single large contact area, reducing the insertion force needed while maintaining good electrical and thermal contact.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The press-fit pin structure combines the body portion material with the press-fitting pieces material to create a composite structure that optimizes both mechanical insertion properties and thermal conduction properties, achieving good heat transfer efficiency without requiring excessive insertion force.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If a general press-fit pin structure with simple configuration is used, then the structure is simple and easy to manufacture, but the elastic force locally acts on only two points in the contact hole so that damages such as cracks may be generated on the external substrate

Engineering Contradiction:

Improvestructural simplicityVSAvoidsubstrate damage

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The press-fit pin is divided into a body portion and multiple press-fitting pieces (first and second press-fitting pieces) that extend from the body. This segmentation distributes the elastic force across multiple contact points within the contact hole rather than concentrating it at only two points, reducing the risk of substrate cracks while maintaining manufacturing simplicity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The press-fitting pieces are configured with specific geometries (convex portions, complementary shapes) that distribute the contact function at specific locations within the contact hole. This local optimization allows effective contact with reduced overall force requirements compared to a uniform large-area contact design.

Inventive Principle:

Principle #3Local quality

4Reliability

If a protrusion is added to the press-fit pin body to increase contact surface area, then the contact resistance is reduced and heat transfer efficiency is increased, but the press-fitting of the press-fitting piece is hampered making it difficult to insert

Engineering Contradiction:

Improvecontact resistanceVSAvoidinsertability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The press-fit pin is divided into a body portion and multiple press-fitting pieces (first and second press-fitting pieces) that extend from the body. This segmentation allows the contact function to be distributed across multiple pieces rather than requiring a single large contact area, reducing the insertion force needed while maintaining good electrical and thermal contact.

Inventive Principle:

Principle #1Segmentation

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 effectively increases the contact area between the press-fit pin and the external substrate, reducing contact resistance and improving heat transfer efficiency while preventing substrate damage and excessive insertion.

Implementation Method 1

The press-fit pin has a structure having an elastic force acting on a transverse direction and when the press-fit pin is inserted in a longitudinal direction, the press-fit pin is fixed to the contact hole of the external substrate by the elastic force

Methodology Applied

Scientific EffectElastic force: Elasticity

Data Source

PatentUS10541197B2Press-fit pin and semiconductor package including the same

Publication Date: 2020.01.21 JMJ KOREA CO LTD

AI summary

A press-fit pin increases contact area with the contact hole to provide appropriate contact pressure, reduce contact resistance, and increase heat transfer efficiency. The press-fit pin is of a semiconductor package including an end portion and a press unit extending from the end portion and is divided into a first press-fitting piece and a second press-fitting piece, the first press-fitting piece forming a convex portion in a first direction perpendicular to the direction of the press-fit pin and bending to a second direction perpendicular to the direction of the press-fit pin and forming 30-110 degrees with the first direction and the second press-fitting piece forming a convex portion in a third direction perpendicular to the direction of the press-fit pin and being 180 degrees with the first direction and bending to a fourth direction perpendicular to the direction of the press-fit pin and forming 250-330 degrees with the first direction.