Circuit Board Electrode Structure Without Seed Layer Delamination
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Solution Overview
Problem
Conventional circuit boards face issues with low adhesion between the seed layer and the protective layer, leading to separation of the electrode part from the circuit pattern, and contamination of the protective layer during the de-smear process, which affects the physical and electrical reliability and integration of the circuit board.
Innovation Solution
The circuit board design incorporates a connection part, such as solder, between the electrode part and the circuit pattern, eliminating the need for a seed layer and allowing for higher metal density and improved adhesion, thereby enhancing physical and electrical reliability and reducing the separation distance between electrode parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seed layer is used to connect the circuit pattern and electrode part through electroless chemical plating, then the electrode part can be formed, but the adhesion with the protective layer is low causing the seed layer to fall off
Solution Approach 1:
The patent removes the seed layer entirely from the structure. Instead of using a separate seed layer for electroless plating, the circuit pattern itself serves as the base for electrolytic plating of the electrode part, eliminating the adhesion problem between seed layer and protective layer
Solution Approach 2:
The patent merges the function of the seed layer with the circuit pattern. The circuit pattern directly serves as the foundation for electrode part formation through electrolytic plating, combining what were previously separate functional layers
2Reliability
If a seed layer is formed through electroless chemical copper plating to connect circuit pattern and electrode part, then the electrode part can be manufactured, but the electrode part separates from the circuit pattern due to low adhesion
Solution Approach 1:
The patent extracts and removes the seed layer from the manufacturing process. The circuit pattern directly serves as the substrate for electrolytic plating, eliminating the weak adhesion interface between seed layer and both the circuit pattern and protective layer
Solution Approach 2:
The patent uses the circuit pattern itself as the intermediary between the protective layer and electrode part, eliminating the need for a separate seed layer mediator that had poor adhesion properties
3Ease of manufacture
If the de-smear process is performed to remove the seed layer after electrode part formation, then the seed layer can be removed, but the protective layer is damaged or contaminated
Solution Approach 1:
The patent removes the seed layer from the process entirely, eliminating the need for the de-smear process and thereby preventing damage and contamination to the protective layer that occurs during seed layer removal
Solution Approach 2:
Instead of forming a seed layer and then removing it through de-smearing, the patent inverts the approach by directly forming the electrode part on the circuit pattern through electrolytic plating without a preliminary seed layer formation step
4Productivity
If the electrode part width is reduced to increase circuit integration, then the pitch between electrode parts can be reduced, but the adhesion and reliability may be compromised
Solution Approach 1:
The patent changes the plating method from electroless chemical plating to electrolytic plating, which enables better control over the electrode part dimensions and composition, allowing reduced width while maintaining adhesion reliability through optimized plating parameters
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 design improves the physical and electrical reliability of the circuit board by preventing separation and contamination, allowing for reduced electrode part width and increased circuit integration, and eliminates the need for a de-smear process, resulting in a more reliable and compact circuit board.
Implementation Method 1
the first connection part includes a solder
Implementation Method 2
the electrode part is formed by performing electrolytic plating on a circuit pattern
Data Source
AI summary
A circuit board according to an embodiment includes an insulating layer, a first circuit pattern disposed on the insulating layer, a first protective layer disposed on the insulating layer and including an opening that vertically overlaps an upper surface of the first circuit pattern; a first connection part disposed in the opening; and an electrode part disposed on the first connection part, and wherein a width of an upper surface of the electrode part is smaller than a width of the opening of the first protective layer.