Jettable Solder Resist Composition for High-Temperature PCB Printing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing inkjet printing technologies for solder masks on printed circuit boards face limitations due to ink viscosity restrictions, which affect the choice of components and film thickness, and UV-curable inks struggle with compatibility with high-temperature soldering processes while maintaining physical properties.
Innovation Solution
A jettable composition comprising reactive monomers or prepolymers with epoxy or oxetane functional groups, free radical polymerizable compounds, thermal cross-linking agents like blocked isocyanates, and radical initiators, which are photocurable and thermosetting, allowing for higher viscosity inks suitable for inkjet printing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the viscosity of inkjet solder mask composition is increased to improve film thickness and mechanical properties, then the ink can no longer be deposited using conventional inkjet printheads which require low viscosity (5-15 mPa·s)
Solution Approach 1:
The patent changes the chemical composition parameters of the ink by incorporating epoxy or oxetane functional groups with specific molecular structures that provide both adequate viscosity for jetting and the required mechanical properties after curing. The composition includes reactive diluents that adjust viscosity while maintaining curability.
Solution Approach 2:
The patent creates a composite ink composition combining multiple components: epoxy/oxetane functional groups, free radical polymerizable compounds, thermal cross-linking agents, and radical initiators. This composite approach allows the ink to exhibit both jettable flow characteristics and cured mechanical strength.
2Reliability
If UV curable inks are used to achieve rapid cure and high crosslinking density, then chemical resistance and mechanical properties improve, but compatibility with high temperature soldering processes becomes difficult to maintain
Solution Approach 1:
The patent merges UV curability with thermal cross-linking capability in a single composition. The ink contains both photopolymerizable groups for rapid UV curing and epoxy/oxetane groups with thermal cross-linking agents for high-temperature stability during soldering. This combination allows the coating to withstand soldering temperatures while maintaining chemical resistance.
Solution Approach 2:
The patent applies a preliminary UV cure to form a protective layer before the soldering process, then uses the thermal cross-linking components to further strengthen the coating during the high-temperature soldering step. This sequential curing approach ensures both chemical resistance and temperature compatibility.
3Manufacturing precision
If conventional photolithographic developing processes are used to ensure precise patterning, then manufacturing precision is maintained, but the number of process steps and materials required increases
Solution Approach 1:
The patent extracts the patterning function from the complex photolithographic process by using inkjet printing to directly deposit the solder mask composition in the desired pattern. This eliminates the need for separate photoresist application, photolithographic exposure, and developing steps, reducing overall process complexity while maintaining precision through digital control.
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 composition enables efficient deposition of solder resist with improved film thickness and mechanical properties, ensuring compatibility with high-temperature soldering processes and maintaining chemical resistance.
Implementation Method 1
a free radical polymerizable compound; and a radical initiator
Implementation Method 2
UV curable inks are preferred for the design of solder mask inks as they allow rapid cure and a high degree of crosslinking
Implementation Method 3
a thermal cross-linking agent comprising an isocyanate compound
Data Source
AI summary
A jettable composition is described, comprising a reactive monomer, oligomer or prepolymer containing at least one epoxy or oxetane functional group; a free radical polymerizable compound; a thermal cross-linking agent; and a radical initiator, along with an electronic device having the composition jetted thereon and a method of manufacturing an electronic device.