Etch Resist Inkjet Ink for High Current PCBs
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Solution Overview
Problem
State-of-the-art etch resist inkjet inks fail to withstand the longer etching times required for high current PCBs, and improving adhesion to copper for better etching resistance often results in incomplete removal during the stripping step.
Innovation Solution
The development of an etch resist inkjet ink composition that includes specific photoinitiators, (meth)acrylamides, polymerizable compounds, and polyfunctional (meth)acrylates, which enhances etch resistance and strippability by optimizing the ink's properties for UV curing and copper adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the adhesion of etch resist inkjet ink to copper is improved to withstand longer etching times, then etch resistance is improved, but stripping behavior deteriorates (incomplete removal during stripping step)
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by incorporating specific additives including chelating agents, leveling agents, and anti-foaming agents. These parameter changes modify the ink's interaction with copper surface and etching solution, achieving both improved etch resistance and complete strippability without compromising either property
Solution Approach 2:
The invention creates a composite ink formulation that combines multiple functional components: photoinitiators, (meth)acrylamides, polymerizable compounds, polyfunctional (meth)acrylates, chelating agents, leveling agents, and anti-foaming agents. This composite material approach allows the ink to simultaneously achieve strong copper adhesion for etch resistance and complete removability during stripping
2Quantity of substance
If etching time is extended to remove thicker copper layers in high current PCBs, then copper removal completeness is improved, but etch resist durability is worsened (ink fails to withstand etching)
Solution Approach 1:
The patent modifies the chemical parameters of the etch resist ink by adding chelating agents that complex with metal ions, leveling agents that ensure uniform film formation, and anti-foaming agents that prevent bubbles during etching. These parameter changes enable the ink to maintain its protective function throughout extended etching periods required for thick copper layers
Solution Approach 2:
The ink formulation includes additives that prepare the copper surface and etching environment in advance. The chelating agents pre-bind metal ions, leveling agents pre-establish uniform coverage, and anti-foaming agents pre-prevent bubble formation, enabling the system to withstand prolonged etching without degradation
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 inkjet ink achieves improved etch resistance and strippability, allowing for effective copper removal during etching and complete removal during the stripping process, even with thicker copper layers used in high current PCBs.
Implementation Method 1
The inkjet ink achieves improved etch resistance and strippability, allowing for effective copper removal during etching and complete removal during the stripping process, even with thicker copper layers used in high current PCBs.
Implementation Method 2
improving adhesion of the etch resist inkjet inks to copper in order to withstand the longer etching times
Data Source
AI summary
An etch resist inkjet ink comprising: - one or more photoinitiators, wherein at least one photoinitiator is a thioxantone compound, - one or more acrylamides according to Formula I, wherein R represents H or CH3; R1 and R2 independently from each other represent an optionally substituted alkyl group; R1 and R2 may represent the necessary atom to form a 5 or 6 membered ring; - one or more polymerizable compounds according to Formula II, and wherein X = O, S or NH; R = H or CH3; L is an optionally substituted one to five atomic group divalent linking group; n is 0 or 1; and A is an optionally substituted aromatic group; - one or more polyfunctional (meth)acrylates.