Selective NiPdAu Plating on Leadframe for Mold Adhesion

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Solution Overview

Problem

Electronic devices with lead-free soldering surfaces, such as those plated with nickel/palladium/gold, face reduced adhesion to molding compounds, posing a challenge in maintaining reliable connections and adhesion without using heavy metals.

Innovation Solution

A leadframe with selectively roughened mold adhesion and die attachment surfaces, and plated soldering and bonding surfaces with nickel/palladium/gold, allowing for enhanced adhesion while maintaining smooth bonding and soldering surfaces for good bondability and solderability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the soldering surface is plated with nickel/palladium/gold to avoid lead, then environmental safety is improved, but adhesion to molding compound deteriorates

Engineering Contradiction:

Improveenvironmental safetyVSAvoidadhesion to molding compound

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent applies different surface treatments to different regions of the leadframe: nickel/palladium/gold plating is applied to soldering surfaces for environmental safety, while mold adhesion surfaces are left roughened copper for strong bonding. This local differentiation resolves the contradiction by allowing each surface to have the properties needed for its specific function.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The leadframe surface is segmented into functionally distinct regions: plated soldering surfaces and roughened mold adhesion surfaces. This segmentation allows the patent to optimize each region independently - using plated materials where environmental safety is needed and roughened copper where adhesion is critical.

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 solution enhances mold adhesion and maintains safety by avoiding heavy metals in soldering materials, ensuring reliable connections and extended durability under various environmental conditions without compromising bondability or solderability.

Implementation Method 1

plated with nickel/palladium/gold

Methodology Applied

Scientific EffectElectroplating: Electroplating

Implementation Method 2

roughened to increase the surface area for attachment

Methodology Applied

Scientific EffectSurface roughening: Abrasion

Data Source

PatentUS7504712B2Electronic device with selective nickel palladium gold plated leadframe and method of making the same

Publication Date: 2009.03.17 QPL LTD

AI summary

An electronic device comprises a leadframe attached to a die and embedded in a mold packaging with enhanced adhesion property. The leadframe comprises a bonding surface, a soldering surface, a mold adhesion surface, and a die attachment surface wherein the soldering surface and bonding surface are selectively plated with nickel/palladium/gold. The mold adhesion surface and the die attachment surface are roughened for better attachment to a mold and a die respectively.