Metal Plating Levelers for Uniform Deposit in Small Holes

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Solution Overview

Problem

Metal plating compositions face challenges in achieving uniform distribution and sufficient thickness of metal deposits, particularly in small holes of printed wiring boards, leading to potential mechanical stress and failure during thermal processes.

Innovation Solution

Incorporating specific compounds with the formula R1-A-R3-A-[C(O)—R5—C(O)-A-R3-A]n-R2, where A is —NH— or —NH—R6—, and R1, R2, R3, R5, and R6 are defined chemical groups, into metal plating compositions to enhance leveling and throwing power, which are then used in conjunction with metal ions and other additives for improved plating performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional levelers are used in metal plating compositions, then some leveling performance is achieved, but throwing power remains insufficient and uniform distribution in small holes is not achieved

Engineering Contradiction:
Improveuniformity of metal deposit distributionVSAvoidthermal reliability of plated layers
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent modifies the chemical structure of levelers by introducing specific functional groups (carboxylic acid, hydroxyl, amino groups) and controlling molecular weight ranges (500-5000 Da). These parameter changes in the chemical composition enable the levelers to simultaneously improve uniformity of deposit distribution and enhance throwing power, thereby achieving both manufacturing precision and thermal reliability in small hole plating applications.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If metal plating is performed in small diameter holes (0.25 mm and smaller), then finer features are achieved, but uniform metal layer distribution becomes difficult and thickness is insufficient

Engineering Contradiction:
Improvecapability to plate small featuresVSAvoiduniformity of metal layer thickness
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs levelers with specific local chemical properties (functional groups positioned at particular locations in the molecule, controlled hydrophilicity/hydrophobicity balance) that enable differential adsorption behavior. This local quality control allows the levelers to preferentially adsorb on specific surface areas and deposit conditions, ensuring uniform metal distribution in small diameter holes while maintaining the capability to produce fine features.

Inventive Principle:
Principle #3Local quality

3Loss of time

If thin metal layers are deposited in through-holes and vias, then plating time is reduced, but the layers may tear under thermal or mechanical stress

Engineering Contradiction:
Improveplating timeVSAvoidmechanical strength of metal deposit
Core Design Contradiction:
Loss of timeVSStrength

Solution Approach 1:

The patent creates a composite plating system combining metal ions with specifically designed organic levelers (molecular weight 500-5000 Da with functional groups). This composite approach allows the formation of thin metal layers that incorporate organic molecules within the deposit structure, enhancing mechanical strength and stress resistance while maintaining reduced plating times and thin layer thickness.

Inventive Principle:
Principle #40Composite materials

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 use of these compounds results in improved leveling performance and throwing power, ensuring uniform and reliable metal deposition even in small features, enhancing the thermal reliability of printed circuit boards and other metal-plated components.

Implementation Method 1

various compounds have been used with varying performance... compounds having a formula... improve the performance of the metal plating compositions, such as leveling and throwing power

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentUS8337688B2Metal plating compositions
Publication Date: 2012.12.25 DUPONT ELECTRONIC MATERIALS INT LLC

AI summary

Disclosed are metal plating compositions for plating a metal on a substrate. The metal plating compositions include compounds which influence the leveling and throwing performance of the metal plating compositions. Also disclosed are methods of depositing metals on a substrate.