Wiring Board Conductive Post Formation via Plating Resist
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Solution Overview
Problem
Existing methods for manufacturing wiring boards with conductive posts face challenges in productivity and fine wiring pattern formation due to interference from conductive posts during the manufacturing process, particularly when dealing with band-shaped pads, which are traditionally difficult to work with.
Innovation Solution
A method involving surface treatment of pads, application of a plating resist layer with resist openings to expose post connecting portions, electrolytic plating to form conductive posts, and subsequent removal of the plating resist layer, along with the use of pad protection sheets to prevent seed layer lamination between pads and improve conductive post formation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conductive posts are formed early in the manufacturing process, then connectivity is established, but productivity decreases due to interference with subsequent pad processing
Solution Approach 1:
The patent applies preliminary action by forming the conductive posts before the solder resist layer is applied, but scheduling the electrolytic plating operation after the solder resist is in place. This allows the posts to be pre-positioned in the substrate while delaying their electrical formation until it becomes convenient, eliminating interference with pad surface treatment and enabling parallel processing of different board sections.
2Reliability
If surface treatment is applied to pads, then solderability is improved, but conductive post formation becomes difficult due to interference
Solution Approach 1:
The patent segments the manufacturing process into distinct phases: first applying surface treatment to pads, then applying the solder resist layer that covers the treated pads while leaving post connecting portions exposed, and finally forming conductive posts in the exposed areas. This segmentation allows each operation to be performed on isolated regions without interfering with previously completed steps.
Solution Approach 2:
The solder resist layer acts as an intermediary that protects the surface-treated pads from subsequent conductive post formation operations. By applying the solder resist after pad treatment but before post formation, it creates a physical barrier that prevents plating solution from affecting the pads while allowing post formation to proceed in the exposed post connecting portions.
3Manufacturing precision
If band-shaped pads are processed, then fine wiring patterns are achieved, but manufacturing complexity increases due to interference with conductive posts
Solution Approach 1:
The patent uses preliminary action by establishing the precise band-shaped pad patterns and applying the solder resist layer before forming the conductive posts. This sequence allows the fine wiring patterns to be created and protected first, then the conductive posts to be formed in the surrounding post connecting portions without risking damage to the delicate pad structures.
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 method enhances productivity by allowing efficient surface treatment and conductive post formation around pads without interference, enabling the creation of fine wiring patterns and improving the manufacturing efficiency of wiring boards with conductive posts, especially for semiconductor chips with band-shaped pads.
Implementation Method 1
applying electrolytic plating on the post connecting portions such that conductive posts rising from the post connecting portions are formed in the resist opening portions
Data Source
AI summary
A method for manufacturing a wiring board having conductive posts includes preparing a wiring board including electronic circuit and a solder resist layer covering the electronic circuit and having first openings and second openings surrounding the first openings such that the first openings are exposing pad portions of the electronic circuit and that the second openings are exposing post connecting portions of the electronic circuit surrounding the pad portions, applying surface treatment to the pad portions, forming a plating resist layer on the wiring board after the surface treatment of the pad portions such that the plating resist layer has resist openings exposing the post connecting portions, applying electrolytic plating on the post connecting portions such that conductive posts rising from the post connecting portions are formed in the resist openings, and removing the plating resist layer from the wiring board after forming the conductive posts in the resist openings.