Circuit Board Solder Resist Openings for Residue-Free Plating Separation
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Solution Overview
Problem
The existing manufacturing processes for circuit boards, such as the dry film masking and LPR ink masking processes, are complicated and prone to process issues due to residue formation, with restrictions on pattern design and high likelihood of manufacturing defects.
Innovation Solution
A circuit board design and manufacturing method that utilizes laser processing to form openings in the solder resist layer and plating connection wiring, eliminating the need for separate dry films or LPR ink, thereby simplifying the process and reducing manufacturing costs and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dry film masking process or LPR ink masking process is used in etch-back process, then plating connection wiring can be connected to conductive pad, but manufacturing process becomes complicated and pattern design is restricted
Solution Approach 1:
The patent extracts and removes the plating connection wiring from the solder resist layer area after plating is completed. By using a lifting process that selectively removes the solder resist layer and associated plating wiring in the second opening region, the connection function is maintained while eliminating the need for complex masking processes and preventing residue issues.
Solution Approach 2:
The patent performs preliminary plating on the entire conductive pad area before selectively removing portions. The plating is first applied uniformly to ensure reliable electrical connection, then the excess plating wiring is removed in the second opening area through the lifting process, thus ensuring connection reliability before simplifying the final structure.
2Manufacturing precision
If dry film masking process or LPR ink masking process is used, then pattern design can be achieved, but residue of dry film or LPR ink causes process issues
Solution Approach 1:
The patent replaces the chemical masking processes (dry film or LPR ink application and removal) with a mechanical/laser-based lifting process. The second opening is formed by removing solder resist layer through lifting, and the plating wiring is subsequently removed by the same lifting process, eliminating chemical residues entirely while maintaining precise pattern definition.
Solution Approach 2:
The patent changes the state and properties of the solder resist layer in the second opening area by applying laser energy or chemical etching to reduce its adhesion strength. This parameter change allows the solder resist layer to be selectively removed along with the plating wiring through the lifting process, achieving precise pattern formation without residue.
3Reliability
If plating connection wiring is separated before electrical test using masking process, then electrical test can be performed, but manufacturing cost increases due to additional materials and processes
Solution Approach 1:
The lifting process serves multiple functions: it forms the second opening by removing solder resist layer, separates the plating connection wiring from the conductive pad area, and prepares the structure for electrical testing. This multi-functional approach eliminates the need for separate masking materials and processes, reducing manufacturing cost while ensuring reliable electrical testing.
Solution Approach 2:
The patent merges the opening formation process and the plating wiring separation process into a single lifting operation. By combining these functions into one process step using laser or chemical etching followed by mechanical lifting, the manufacturing cost is reduced while maintaining the ability to perform electrical tests reliably.
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 laser processing method allows for efficient separation of plating connection wiring without residue, minimizing process issues and reducing manufacturing costs while maintaining electrical integrity.
Implementation Method 1
forming a second opening by removing a portion of the solder resist layer overlapping the plating connection wiring using a laser processing process; and forming a plating lead-in wire by removing a portion of the plating connection wiring overlapping the second opening using the laser processing process
Data Source
AI summary
A circuit board according to an embodiment includes: an insulating layer; a conductive pad disposed on the insulating layer, a plating lead-in wire that is disposed on the insulating layer and is connected to the conductive pad; and a solder resist layer that is disposed on the insulating layer and includes a first opening overlapping the conductive pad and a second opening spaced apart from the first opening. The plating lead-in wire extends from the conductive pad to one side wall of the second opening, and a second portion of the insulating layer overlapping the second opening is thinner than a first portion of the insulating layer overlapping the first opening.