Wiring Board Surface Roughening for Underfill Void Prevention
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Solution Overview
Problem
Existing methods for manufacturing wiring boards and semiconductor apparatuses face issues with insufficient wettability of the solder resist layer, leading to voids and peeling defects due to excessively flat surfaces, which affect the adhesion and flowability of underfill resin.
Innovation Solution
A method involving a roughening treatment on the support surface before forming the dielectric and wiring layers, which enhances adhesion and wettability, preventing voids and peeling by transferring the roughened surface onto the insulating or solder resist layer, thereby controlling underfill resin flowability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat support surface is used for manufacturing wiring boards, then the manufacturing process is simple, but the solder resist layer has insufficient wettability leading to voids and peeling defects
Solution Approach 1:
The support surface is subjected to roughening treatment (chemical etching, mechanical abrasion, or plasma treatment) before forming the dielectric and wiring layers. This preliminary action creates a roughened surface that enhances adhesion and wettability of subsequent layers, preventing voids and peeling defects while maintaining manufacturing simplicity
Solution Approach 2:
The surface roughness parameter of the support is deliberately changed from flat to rough through controlled etching or treatment processes. This parameter change improves the wettability of the solder resist layer and adhesion strength, resolving the contradiction between manufacturing simplicity and adhesion quality
2Reliability
If the support surface is roughened to improve adhesion, then wettability and adhesion are enhanced, but the manufacturing process becomes more complex
Solution Approach 1:
The roughening treatment is performed as a preliminary step before layer formation, integrating it into the existing manufacturing workflow. Common techniques like chemical etching using standard solutions or plasma treatment are employed, which are already part of typical PCB manufacturing processes, thus minimizing additional complexity
Solution Approach 2:
The surface roughness is controlled within specific ranges (Ra value) to achieve optimal adhesion without excessive complexity. By standardizing the roughening parameters and using conventional treatment methods, the process complexity is kept manageable while achieving reliable adhesion enhancement
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
This approach ensures improved adhesion between the support and dielectric layers, prevents voids and peeling, and enhances the quality of the wiring board and semiconductor apparatus by adjusting wettability and flowability of the underfill resin.
Implementation Method 1
a roughening treatment is carried out over a surface of a support
Implementation Method 2
enhances adhesion and wettability, preventing voids and peeling by transferring the roughened surface onto the insulating or solder resist layer
Data Source
AI summary
There are provided steps of providing a dielectric layer and a wiring layer on a surface of a support to form an intermediate body, removing the support from the intermediate body to obtain a wiring board, and carrying out a roughening treatment over a surface of the support before the intermediate body forming step.