Plasma Chamber Electrode Sets for Uniform Polymer Coatings
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Solution Overview
Problem
Existing methods for depositing polymer coatings on printed circuit boards (PCBs) face challenges such as non-uniform thickness, limited hydrophobicity and oleophobicity, and inefficiencies in high power plasma and high precursor gas flow rates, leading to substandard coatings that are difficult to solder through and prone to corrosion.
Innovation Solution
A plasma chamber design with multiple electrode sets arranged on either side of a sample chamber, using radiofrequency and ground electrodes to create a uniform plasma for polymer deposition, allowing for low power and low monomer flow rates, and a monomer distribution system for even coating across the substrate, resulting in superhydrophobic and oleophobic coatings with improved uniformity and solderability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high power plasma techniques are used to initiate polymerisation, then the polymerisation reaction can be initiated, but the monomers fragment and deposition becomes unpredictable resulting in non-uniform coating thickness
Solution Approach 1:
The invention changes the plasma power parameter from high to low levels, and adjusts precursor gas flow rates from high to low, thereby preventing monomer fragmentation while maintaining polymerisation initiation. This parameter optimization resolves the contradiction between initiating polymerisation and achieving uniform deposition.
Solution Approach 2:
The invention introduces dynamic control of precursor gas flow rates, adjusting them during the deposition process to maintain optimal conditions. This dynamic adjustment allows the system to adapt to changing plasma conditions and maintain uniform coating thickness throughout the deposition.
2Productivity
If high precursor gas flow rates are used to obtain acceptable polymer thickness, then deposition rate increases, but coating uniformity deteriorates and solderability decreases
Solution Approach 1:
The invention employs periodic or pulsed precursor gas flow rather than continuous high flow rates. This periodic action allows the plasma to process the monomer effectively at low concentrations, preventing fragmentation while maintaining steady deposition rates and uniform coating quality.
3Device complexity
If conventional flow-through process is used, then the process is simple, but precursor concentration is not homogenous throughout the chamber resulting in insufficient coating coverage
Solution Approach 1:
The invention segments the plasma chamber into multiple zones with different precursor flow rates and plasma power levels. This segmentation allows optimized deposition conditions in different chamber regions, ensuring uniform precursor distribution and consistent coating coverage across the entire substrate surface.
4Reliability
If halo carbon polymer coatings are deposited for protective purposes, then corrosion protection is achieved, but hydrophobicity and oleophobicity are limited with contact angles maximum 90 to 100 degrees
Solution Approach 1:
The invention deposits composite polymer coatings containing both halo carbon components (for corrosion resistance) and fluorocarbon components (for enhanced hydrophobicity and oleophobicity). This composite structure achieves superior dual protection: corrosion resistance from the halo carbon layer and water/oil repellency from the fluorocarbon layer, with contact angles exceeding 100 degrees.
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 achieves uniform polymer coatings with enhanced hydrophobicity and oleophobicity, improving solderability and corrosion resistance, while reducing process time and energy consumption, resulting in more resilient and consistent coatings.
Implementation Method 1
a plasma chamber design with multiple electrode sets arranged on either side of a sample chamber, using radiofrequency and ground electrodes to create a uniform plasma for polymer deposition
Implementation Method 2
utilising low power and/or low monomer flow rates into the plasma chamber and/or utilising a different class of monomer and/or subjecting the monomer to a low pressure plasma polymerisation technique
Implementation Method 3
A further aspect of the present invention provides a monomer distribution system for use with a plasma chamber
Data Source
AI summary
A plasma chamber (11′) for coating a substrate with a polymer layer, the plasma chamber includes a first electrode set (14′) and a second electrode set (14′), the first and second electrode sets are arranged either side of a sample chamber for receiving a substrate, wherein the first and second electrode sets include plural electrode layers (141′, 142′) and wherein each electrode set includes plural radiofrequency electrode layers or plural ground electrode layers for coating polymer to each surface of a substrate.