Patterned Inorganic Solder Mask for High-Temperature PCB Reliability
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Solution Overview
Problem
Conventional solder mask layers on printed circuit boards are prone to degradation at high temperatures, leading to corrosion and contamination issues, especially in urban environments and space applications, due to their organic composition and limited thickness and patterning resolution, as well as poor moisture barrier properties.
Innovation Solution
A method for forming a patterned solder mask layer using chemical vapor deposition with a water-soluble lift-off material, such as polyvinyl alcohol, and atomic layer deposition, which creates a conformal, inorganic, and optically transparent mask that is stable at high temperatures and provides precise patterning with thicknesses below 1 micrometer, effectively preventing corrosion and contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic polymer-based solder mask is used, then ease of manufacture is improved, but reliability deteriorates due to degradation at high temperatures causing corrosion and contamination
Solution Approach 1:
The patent changes the material parameter from organic polymer to inorganic material (such as silicon oxide, silicon nitride, or diamond-like carbon), which fundamentally alters the thermal stability and chemical resistance properties, eliminating degradation at high temperatures while maintaining manufacturability through CVD processes
Solution Approach 2:
The patent employs composite material structures combining inorganic solder mask layers with specific thickness configurations (mask layer thickness ratio of 0.5-2.0 relative to conductive layer) to achieve both manufacturing feasibility and superior reliability against corrosion and contamination
2Ease of manufacture
If screen-printing method is used for mask application, then ease of manufacture is improved, but manufacturing precision deteriorates with resolution limit of about 50 micrometers
Solution Approach 1:
The patent replaces the mechanical screen-printing process with chemical vapor deposition (CVD) methodology, substituting mechanical patterning limitations with chemical deposition precision that can achieve sub-micrometer resolution while maintaining ease of manufacture through established semiconductor fabrication processes
3Ease of manufacture
If polymer-based solder mask is used, then ease of manufacture is improved, but object-affected harmful factors worsen due to poor moisture barrier properties causing oxidation and corrosion
Solution Approach 1:
The patent changes the material composition parameter from organic polymer to inorganic material, which fundamentally improves moisture barrier properties by eliminating the hygroscopic nature of polymers, thereby preventing oxidation and corrosion of conductive layers while maintaining ease of manufacture through CVD processes
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 results in printed circuit boards and electrical components that are less susceptible to corrosion, with improved reliability and precision in solder mask application, allowing for high-resolution patterning and effective prevention of solder spread, while maintaining stability and moisture barrier properties.
Implementation Method 1
depositing an inorganic solder mask layer onto a substrate by a process of chemical vapor deposition
Implementation Method 2
and atomic layer deposition
Data Source
AI summary
A method for formation of a patterned solder mask (10) on a substrate is provided, in which method the mask is deposited by a process of chemical deposition in vapor phase. A method for manufacturing a printed circuit board and/or an electronic component comprising formation of said patterned solder mask is further provided.