Landless Via Formation in High-Density PCB Manufacturing
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Solution Overview
Problem
Conventional methods for manufacturing printed circuit boards with high-density circuit patterns face issues such as deviations in hole shape during via hole formation and over-etching, leading to thickness and pitch deviations in circuit lines.
Innovation Solution
A method involving a carrier with a barrier of different material, where a circuit pattern is formed on the carrier, pressed into an insulator, and a hole is processed to form a landless via, with conductive material filled inside using electroplating, and the barrier and seed layers are efficiently removed to achieve precise high-density circuit formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser drilling is used to form via holes, then interlayer connections can be established, but excessive energy causes holes to deviate from the desired shape
Solution Approach 1:
A carrier is introduced as an intermediary component during the via formation process. The carrier supports the circuit pattern formation and serves as a reference for via hole positioning, enabling precise hole formation without direct laser processing of the final structure, thus maintaining both reliability and precision
2Ease of manufacture
If electroplating is performed to form circuit patterns, then conductive traces can be created, but thickness deviations occur after copper electroplating
Solution Approach 1:
The circuit pattern is preliminarily formed on a carrier before being transferred to the insulator. This preliminary formation allows for precise thickness control during electroplating, and the pattern is then transferred to the final substrate, maintaining thickness precision in the finished product
3Ease of manufacture
If etching is performed to remove seed layers and copper foils, then circuit patterns can be finalized, but over-etching increases deviations in circuit-line thickness and pitch
Solution Approach 1:
A carrier serves as an intermediary that protects and supports the circuit pattern during etching operations. The carrier prevents over-etching by providing a stable base, allowing precise removal of excess material without compromising the precision of the final circuit dimensions
4Reliability
If conventional via formation methods are used, then interlayer connections can be made, but via lands occupy space that could be used for wiring
Solution Approach 1:
The via land structure is extracted and removed from the design. Vias are formed directly through the insulator without requiring additional land areas, allowing the via holes to be positioned precisely at circuit intersections without occupying extra space, thereby increasing wiring density
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 enables precise formation of high-density circuit patterns with reduced deviations in thickness and pitch, ensuring reliable interlayer connections and increased wiring density without via lands.
Implementation Method 1
forming a barrier on one side of a carrier that is made of a different material from that of the carrier
Implementation Method 2
forming the circuit pattern on the first seed layer by electroplating
Implementation Method 3
forming a hole penetrating through the insulator by processing one end of the circuit pattern
Data Source
AI summary
Disclosed is a method of manufacturing a printed circuit board. The method of manufacturing a printed circuit board having a via for interlayer connection can include forming a circuit pattern on one side of a carrier, pressing one side of the carrier into one side of the insulator, removing the carrier, forming a hole penetrating through the insulator by processing one end of the circuit pattern, and forming a conductive material inside the hole to have the conductive material correspond to the via.