Direct Metallization Carbon Dispersion Removal

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Solution Overview

Problem

Existing direct metallization processes for printed wiring boards face challenges in effectively removing excess carbon dispersion without redeposition and in minimizing the need for microetching to achieve clean copper surfaces.

Innovation Solution

The process involves applying a conductive carbon dispersion to the substrate and using non-absorbent rollers to remove excess solution, followed by passing the substrate through a vacuum extraction chamber to prevent redeposition and enhance surface cleanliness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional direct metallization processes are used to apply carbon dispersion, then the substrate can be prepared for electroplating, but excess carbon dispersion cannot be effectively removed without causing redeposition on the substrate

Engineering Contradiction:
Improvesurface cleanlinessVSAvoidredeposition prevention
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The removal process is segmented into two distinct stages: first, non-absorbent rollers mechanically remove excess carbon dispersion from the substrate surface; second, a vacuum extraction chamber removes remaining excess dispersion. This segmentation allows each stage to address specific aspects of excess material removal without causing redeposition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A vacuum extraction chamber is introduced as an intermediary device between the carbon dispersion application and drying steps. This intermediary system creates a controlled vacuum environment that extracts excess carbon dispersion through suction, preventing it from redepositing on the substrate while maintaining surface cleanliness.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If microetching is performed to achieve clean copper surfaces, then subsequent electroplating quality is improved, but the process complexity and time are increased

Engineering Contradiction:
Improvecopper surface cleanlinessVSAvoidprocess steps
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The vacuum extraction system performs preliminary removal of excess carbon dispersion before the substrate undergoes drying or subsequent processing. By removing excess material in advance, the need for aggressive microetching is reduced, as the copper surfaces are already cleaner and require less chemical etching to achieve the desired cleanliness for electroplating.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The vacuum extraction chamber actively extracts and removes excess carbon dispersion from the substrate surface through suction. This extraction process selectively removes unwanted material without requiring additional chemical etching steps, thereby simplifying the overall process while maintaining copper surface cleanliness.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If more extensive excess carbon dispersion removal is performed, then redeposition is reduced, but the process time and complexity increase

Engineering Contradiction:
Improveredeposition preventionVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The mechanical roller removal system and vacuum extraction chamber are combined into an integrated excess dispersion removal system. The rollers perform initial removal while the vacuum system simultaneously or sequentially extracts remaining excess material, achieving thorough redeposition prevention in a single integrated operation rather than requiring multiple separate processing steps.

Inventive Principle:
Principle #5Merging (Combining)

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

This method effectively removes excess carbon dispersion, reduces redeposition, and minimizes the requirement for microetching, resulting in cleaner copper surfaces and improved substrate preparation for subsequent electroplating steps.

Implementation Method 1

passing the substrate through a vacuum extraction chamber to extract excess carbon dispersion remaining on surfaces of the substrate

Methodology Applied
Scientific EffectVacuum suction: Vacuum

Implementation Method 2

contacting the substrate with at least one non-absorbent roller to remove excess carbon-containing dispersion from the substrate

Methodology Applied
Scientific EffectMechanical removal:

Data Source

PatentEP2326751B1Direct metallization process
Publication Date: 2013.04.03 MACDERMID INC

AI summary

An improved method of providing a carbon dispersion coating on surfaces of a substrate in a direct metallization process, wherein the substrate comprises conductive and non-conductive portions. The method comprises the steps of contacting the substrate with the carbon dispersion to coat the substrate with the carbon-containing dispersion and at least one of moving a non-absorbent roller over at least a portion of a substantially planar surface of the substrate to remove excess carbon dispersion from the substantially planar surface of the substrate and passing the substrate through a vacuum extraction chamber to extract excess carbon dispersion remaining on surfaces of the substrate. The method provides cleaner copper surfaces to minimize the microetch requirement and also prevents the carbon dispersion from undesirably redepositing on surfaces of the substrate.