Printed Wiring Board Plating Adhesion on Low Roughness Resin
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Solution Overview
Problem
Highly functional and integrated printed wiring boards with low surface roughness face challenges in achieving sufficient plating adhesion and require pretreatment agents with excellent penetrability and storage stability.
Innovation Solution
A method involving ultraviolet irradiation or modified swelling and roughening treatments followed by treatment with a silane coupling agent and glycol ethers to achieve surface roughness of 0.2 μm or less, improving plating adhesion and solution stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional desmear treatment is used on highly functional printed wiring boards, then the manufacturing process is simple, but plating adhesion becomes insufficient
Solution Approach 1:
The surface treatment process is divided into multiple distinct stages: (1) swelling treatment to expand the resin substrate, (2) roughening treatment to create surface irregularities, (3) reduction treatment to neutralize oxidized surfaces, and (4) silane coupling agent treatment to enhance adhesion. This segmentation allows each stage to optimize specific aspects of surface preparation, collectively achieving superior plating adhesion without overwhelming complexity
Solution Approach 2:
The patent applies preliminary swelling and roughening treatments before the main plating process. By pre-preparing the surface in this manner, the subsequent electroless copper plating can proceed more effectively, achieving better adhesion without requiring complex in-process adjustments during plating
2Manufacturing precision
If surface roughness is reduced to achieve high functionality, then integration density improves, but plating adhesion deteriorates
Solution Approach 1:
The patent changes multiple surface parameters through controlled treatment: swelling ratio, roughening degree, surface chemistry (via silane coupling agents), and surface energy. By adjusting these parameters systematically, the surface can maintain low roughness (Ra ≤ 0.2 μm) while achieving excellent plating adhesion through chemical modification rather than relying solely on mechanical roughness
Solution Approach 2:
The patent creates a composite surface structure by combining the resin substrate with deposited layers including roughening layers, reduction layers, and silane coupling agent layers. This composite structure provides both the smoothness needed for high functionality and the chemical/physical properties needed for strong plating adhesion
3Reliability
If pretreatment agent penetrability is increased to treat low roughness surfaces, then plating adhesion improves, but solution storage stability deteriorates
Solution Approach 1:
The patent introduces a silane coupling agent as an intermediary substance between the resin substrate and the electroless plating solution. This intermediary first modifies the substrate surface through chemical bonding, creating a stable interface that then accepts the plating solution, thereby achieving good adhesion without requiring the plating solution itself to have excessive penetrability that would compromise stability
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 method ensures excellent plating adhesion and high penetrability on resin substrates with low surface roughness, enhancing the manufacturing process for printed wiring boards.
Implementation Method 1
irradiating ultraviolet ray having wave length of 350 nm or less to a surface of the resin substrate
Implementation Method 2
roughening treatment for etching a surface of the resin substrate by immersing the substrate in a roughening solution containing an oxidizing agent
Implementation Method 3
treating the resin substrate by a silane coupling agent having amino group
Data Source
AI summary
A present invention provides a method for manufacturing a printed wiring board having excellent plating adhesion to a resin substrate having low surface roughness such as having surface roughness Ra of 0.2 μm or less, having excellent treating solution stability, and having high penetrability into the resin substrate. The method for manufacturing a resin substrate includes a step 1A or a step 1B; and a step 2 after the step 1A or the step 1B; and the steps are conducted before conducting electroless plating.