PCB Buried Circuit Plating Uniformity via Dummy Patterns
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Solution Overview
Problem
The formation of buried circuit patterns in printed circuit boards using plating leads to non-uniform etching, resulting in shorts between adjacent patterns and errors in signal transmission due to differences in plating thickness between patterned and non-patterned areas.
Innovation Solution
The introduction of uniformly formed dummy patterns in a dummy area alongside active circuit patterns, allowing for simultaneous formation and uniform plating processes that prevent over-grinding and ensure consistent etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plating is used to form buried circuit patterns, then circuit patterns can be formed on the insulating substrate, but non-uniform plating thickness occurs between patterned and non-patterned areas
Solution Approach 1:
The patent applies preliminary action by forming dummy patterns in advance in non-patterned areas before the actual plating process. These dummy patterns serve as placeholders that ensure uniform plating deposition across the entire substrate surface, preventing the non-uniform plating thickness that would otherwise occur between circuit pattern areas and empty areas.
Solution Approach 2:
The patent applies local quality by creating different local structures - dummy patterns in non-circuit areas versus actual circuit patterns in functional areas. This local differentiation allows the plating process to deposit uniformly across all areas while maintaining the specific functional requirements of circuit regions versus non-circuit regions.
2Manufacturing precision
If etching is performed after non-uniform plating, then circuit patterns are defined, but short circuits occur between adjacent patterns and signal transmission errors result
Solution Approach 1:
The dummy patterns are formed in advance to establish uniform plating thickness before etching. This preliminary uniform plating prevents the short circuits and signal transmission errors that would result from etching non-uniformly plated areas, as the etching process now acts on uniformly deposited material.
3Manufacturing precision
If dummy patterns are uniformly formed in the dummy area, then plating thickness uniformity is improved, but the device structure becomes more complex
Solution Approach 1:
The dummy patterns are preliminary structures formed only in non-circuit areas to facilitate uniform plating. They are later removed after serving their purpose, so they do not remain as permanent structural complexity in the final product. This temporary addition resolves the plating uniformity issue without permanently increasing device complexity.
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 reduces plating thickness differences and prevents over-grinding, ensuring accurate and uniform formation of circuit patterns without shorts or signal transmission errors.
Implementation Method 1
a circuit pattern 3 is formed by burying the buried pattern groove 2 using plating
Implementation Method 2
upon etching after plating, the etching is not uniformly performed
Data Source
AI summary
Provided is a printed circuit board, including a plurality of buried circuit patterns which are formed in an active area; and a plurality of buried dummy patterns which are uniformly formed in a dummy area except the active area. Thus, since when the circuit patterns are formed, the dummy patterns are also uniformly formed, a difference in plating can be reduced. Also, since the dummy patterns are uniformly formed in the dummy area, a difference in grinding between the dummy area and the active area can be reduced, thereby enabling the circuit patterns to be formed in the active area without the occurrence of over-grinding.