Wiring Board Surface Treatment for Adhesiveness and Low Transmission Loss
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Solution Overview
Problem
Wiring boards face challenges in achieving both high adhesiveness and electrical insulation properties due to surface roughening for transmission loss reduction and oxide layer formation during heat resistance tests, which deteriorate adhesiveness and insulation reliability.
Innovation Solution
A method involving surface treatments with organic components to enhance adhesiveness between wiring and insulating material layers, including electroless plating, electrolytic plating, and heat treatment above the glass transition temperature of the insulating material, to form a calcined layer for improved adhesiveness and insulation reliability without excessive surface roughening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the wiring surface is roughened by etching to improve adhesiveness, then the adhesiveness between wiring and insulating material is improved, but the transmission loss is increased due to skin effect
Solution Approach 1:
The patent changes the surface treatment parameters by controlling the average roughness Ra to be 0.03 μm or less through specific etching conditions, transforming the surface state from rough to extremely smooth while maintaining adhesiveness through chemical treatments
Solution Approach 2:
The patent introduces an intermediary surface treatment process that includes chemical etching followed by smoothness restoration, acting as a mediator between the wiring surface and insulating material to achieve both adhesiveness and low transmission loss
2Loss of energy
If the wiring surface is kept smooth to reduce transmission loss, then the transmission loss is reduced, but the adhesiveness to the insulating material is deteriorated
Solution Approach 1:
The patent applies a continuous surface treatment process that maintains smoothness while continuously providing chemical activation for adhesiveness, ensuring both low transmission loss and good bonding throughout the manufacturing process
Solution Approach 2:
The patent creates a composite surface structure combining extreme smoothness with chemical treatment layers, achieving a dual-characteristic surface that provides both low transmission loss and high adhesiveness
3Reliability
If long-term heat resistance tests are performed to ensure reliability, then the insulation reliability is verified, but a thick oxide layer is formed on the wiring surface which deteriorates adhesiveness
Solution Approach 1:
The patent performs preliminary surface treatments including chemical etching and smoothness restoration before heat resistance tests, creating a protective surface state that maintains adhesiveness even after prolonged thermal exposure and oxide formation
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 sufficient adhesiveness and heat resistance while maintaining low transmission loss and excellent insulation reliability, suitable for high-density packaging applications.
Implementation Method 1
forming a seed layer on a surface of the first insulating material layer by electroless plating
Implementation Method 2
forming a wiring part including a pad and wiring by electrolytic plating in a region exposed from the resist pattern
Implementation Method 3
heating the second insulating material layer to a temperature equal to or higher than the glass transition temperature of the second insulating material layer
Implementation Method 4
forming a calcined layer for improved adhesiveness and insulation reliability
Data Source
AI summary
A method for producing a wiring board according to the present disclosure includes: (A) forming a first insulating material layer on a supporting substrate; (B) forming a first opening part in the first insulating material layer; (C) forming a seed layer on the first insulating material layer; (D) providing a resist pattern on a surface of the seed layer; (E) forming a wiring part including a pad and wiring; (F) removing the resist pattern; (G) removing the seed layer; (H) applying a first surface treatment to the surface of the pad; (I) forming a second insulating material layer; (J) forming a second opening part in the second insulating material layer; (K) applying a second surface treatment to the surface of the pad; and (L) heating the second insulating material layer to a temperature equal to or higher than the glass transition temperature of the second insulating material layer.