Odd-Layer PCB via formation using simultaneous etching
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Solution Overview
Problem
Existing multi-layer printed circuit boards (PCBs) are limited to even-numbered circuit layers, leading to increased thickness and unsuitability for portable electronic devices, and require complex processes like drilling or laser formation of via holes, which are costly and inefficient.
Innovation Solution
A method for manufacturing PCBs with odd-numbered circuit layers using an etching process to simultaneously form inner circuit layers and vias, eliminating the need for plating and reducing manufacturing steps, while using a metal substrate with different metal layers to prevent bending and improve heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional drilling or laser processes are used to form via holes in multi-layer PCBs, then via holes can be formed to connect circuit layers, but the manufacturing process becomes complex and costly
Solution Approach 1:
The patent extracts the via hole formation process from the conventional drilling/laser methodology and replaces it with an etching-based approach. The via holes are formed simultaneously with circuit patterns through a single etching process that creates both the conductive paths and the inter-layer connections, eliminating the need for separate drilling or laser drilling operations.
Solution Approach 2:
The patent merges the via hole formation process with the circuit pattern formation process. Both the circuit lines and the via holes are created in the same etching step, combining two previously separate manufacturing operations into one unified process, thereby reducing complexity and manufacturing steps.
2Reliability
If even-numbered circuit layers are used in multi-layer PCBs, then layers can be connected through via holes, but the substrate thickness increases
Solution Approach 1:
The patent inverts the conventional approach by using odd-numbered circuit layers instead of even-numbered layers. This inversion allows for a more efficient layer arrangement where the first and third layers (odd numbers) can be directly connected through via holes formed in the second insulating layer, achieving reliable layer connection while minimizing substrate thickness.
3Reliability
If plating method is used to form vias in multi-layer PCBs, then via holes can be filled with conductive material, but manufacturing cost increases
Solution Approach 1:
The patent replaces the expensive plating method with a more economical etching-based approach. Instead of using costly plating processes to fill via holes with conductive material, the invention uses a single etching process that simultaneously creates both the circuit patterns and the conductive via structures, significantly reducing manufacturing cost while maintaining via conductivity.
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 approach results in a lighter, slimmer PCB structure with improved heat dissipation and reduced manufacturing costs by forming odd-numbered circuit layers and vias through etching, without the need for plating, thus enhancing the PCB's suitability for portable devices.
Implementation Method 1
A method for manufacturing PCBs with odd-numbered circuit layers using an etching process to simultaneously form inner circuit layers and vias
Data Source
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AI summary
Disclosed are a printed circuit board and a method for manufacturing the same. The printed circuit board includes a core insulating layer, at least one via formed through the core insulating layer, an inner circuit layer buried in the core insulating layer, and an outer circuit layer on a top surface or a bottom surface of the core insulating layer. The via includes a first part, a second part below the first part, and a third part between the first and second parts, and the third part includes a metal different from a metal of the first and second parts. The inner circuit layer and the via are simultaneously formed so that the process steps are reduced. Since odd circuit layers are provided, the printed circuit board has a light and slim structure.