Silver Plated Substrate Acicular Projections Resin Adhesion

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Solution Overview

Problem

Existing semiconductor packages face challenges in achieving high adhesion between columnar terminal portions and resin, leading to weak bonding and potential detachment, while also requiring thick undercoat plating layers that increase costs and reduce productivity.

Innovation Solution

A substrate with columnar terminal portions featuring a roughened silver plating layer having acicular projections as the outermost layer, which enhances adhesion to sealing resin and reduces the total thickness of plating layers, thereby improving productivity and cost-effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a thick undercoat plating layer is formed to create a roughened outer surface for improving adhesion to resin, then adhesion between columnar terminal portions and resin is improved, but total plating layer thickness increases and manufacturing cost rises

Engineering Contradiction:

Improveadhesion between columnar terminal portions and resinVSAvoidtotal plating layer thickness

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The invention changes the crystal orientation parameter of the silver plating layer, specifically making the <100> crystal direction occupy the largest proportion among the three crystal directions. This parameter change enables the formation of acicular projections on the surface that provide roughness for resin adhesion while maintaining a thin overall plating layer thickness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite structure by combining silver plating with a specific crystal structure that forms acicular projections, rather than using a thick undercoat plating layer. This composite approach achieves both adhesion improvement and thickness reduction

Inventive Principle:

Principle #40Composite materials

2Reliability

Engineering Contradiction:

Improveadhesion between columnar terminal portions and resinVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

By changing the crystal orientation parameter to make <100> the dominant direction, the invention achieves surface roughness with a thin silver plating layer, eliminating the need for expensive thick undercoat plating and reducing overall manufacturing cost

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention uses a thin layer of silver plating with controlled crystal structure as a cost-effective alternative to thick undercoat plating layers, achieving the desired adhesion function at lower material and processing costs

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

Engineering Contradiction:

Improveadhesion between columnar terminal portions and resinVSAvoidproductivity in forming roughened surface

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The invention changes the plating process parameters to control crystal growth orientation, making <100> the dominant crystal direction. This parameter control enables automatic formation of acicular projections during plating, eliminating the need for separate roughening processes and improving productivity

Inventive Principle:

Principle #35Parameter changes

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 substrate achieves remarkable adhesion to sealing resin, reduces processing costs, and minimizes the total thickness of plating layers, facilitating thinner semiconductor package designs with improved reliability and efficiency.

Implementation Method 1

a roughened silver plating layer having acicular projections, and the roughened silver plating layer has a crystal structure in which the crystal direction <100> occupies a largest proportion among the crystal directions <100>, <110>, and <111>

Methodology Applied

Scientific EffectElectroplating: Electroplating

Data Source

PatentUS11062983B2Substrate for mounting semiconductor element

Publication Date: 2021.07.13 CHANG WAH TECH

AI summary

A substrate for mounting a semiconductor element thereon has columnar terminal portions formed by concavities provided on an upper surface of a metal plate made of a copper-based material, and is provided with a roughened silver plating layer having acicular projections, applied, as the outermost plating layer, to top faces of the columnar terminal portions. The roughened silver plating layer has a crystal structure in which the crystal direction <101> occupies a largest proportion among the crystal directions <001>, <111> and <101>. The substrate for mounting a semiconductor element thereon facilitates thin design of semiconductor packages produced by flip-chip mounting, can be manufactured with improved productivity owing to reduction in cost and operation time, achieves remarkably high adhesion to sealing resin while keeping the total thickness of plating layers including the silver plating layer to be thin.