LDS Substrate Plating Control via Thiol Treatment

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Solution Overview

Problem

The Laser Direct Structure (LDS) process for creating molded interconnect devices (MIDs) often results in extraneous plating on rough or mechanically damaged areas of non-conductive substrates, leading to undesirable plating outcomes.

Innovation Solution

A treatment composition comprising an aqueous mixture of a thiol functional organic compound, surfactant, and xanthan gum is applied to the substrate, followed by selective laser activation and electroless plating, preventing extraneous plating by controlling the plating process to only activated areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the LDS process is used to create MIDs with laser activation, then the manufacturing simplicity and resolution are improved, but extraneous plating occurs on rough or mechanically damaged areas

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidplating precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies a treatment composition containing a thiol functional organic compound to the substrate before laser activation. This preliminary treatment modifies the surface chemistry of rough or mechanically damaged areas, making them resistant to extraneous plating while preserving the effectiveness of subsequent laser activation on intended areas.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The treatment composition selectively modifies different areas of the substrate based on their surface characteristics. Rough or mechanically damaged areas receive a chemical treatment that prevents plating, while smooth, intact areas remain receptive to laser activation and subsequent plating, creating locally different plating properties across the substrate surface.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the treatment composition is applied to prevent extraneous plating, then plating precision is improved, but the process complexity increases

Engineering Contradiction:
Improveplating precisionVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The treatment composition acts as an intermediary substance that mediates between the substrate surface and the plating process. The thiol functional organic compound in the composition selectively binds to rough or damaged areas, creating a chemical barrier that prevents plating without interfering with the laser activation process on intended areas.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the chemical parameters of the substrate surface by applying a treatment composition with specific chemical properties (thiol functional organic compound). This parameter change selectively modifies the surface chemistry of rough areas to prevent plating, while the process remains relatively simple and can be integrated into existing manufacturing workflows.

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 method effectively minimizes extraneous plating on non-conductive substrates, ensuring precise and controlled metal deposition only on intended areas, enhancing the quality and reliability of MIDs.

Implementation Method 1

treating the non-conductive substrate with an aqueous composition comprising: a thiol functional organic compound

Methodology Applied
Scientific EffectSelf-assembly: Self-Assembly

Implementation Method 2

the aqueous composition comprising: a thiol functional organic compound

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 3

selectively laser activating portions of a surface of the non-conductive substrate such that the portions are activated to accept plating thereon

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 4

activating the non-conductive material with a laser, such that the metal compound is broken down into its associated metal which acts as a seed layer for subsequent electroless plating thereon

Methodology Applied
Scientific EffectPhotodissociation: Photodissociation

Implementation Method 5

contacting the substrate with an electroless plating bath, such that areas of the substrate, which were contacted by the laser, plate

Methodology Applied
Scientific EffectElectroless plating:

Implementation Method 6

electroless plating of the activated portions of the non-conductive substrate

Methodology Applied
Scientific EffectChemical reduction: Reduction

Data Source

PatentEP2529395B1Method for improving plating on non-conductive substrates
Publication Date: 2019.08.07 MACDERMID ACUMEN INC

AI summary

A method of treating a laser-activated thermoplastic substrate having a metal compound dispersed therein is described. The substrate is contacted with an aqueous composition comprising: (i) a thiol functional organic compound; (ii) an ethoxylaied alcohol surfactant; and (ill) xanthan gum. By use of the treatment composition, when the substrate is subsequently laser-activated and plated by electroless plating, extraneous plating of the substrate is substantially eliminated.