Multilayer Printed Wiring Board Structure for Stable Line Width
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Solution Overview
Problem
Conventional printed wiring boards manufactured using the semi-additive method suffer from transmission delay of high-frequency signals and difficulty in maintaining the designed line width due to the decrease in wiring layer width during the manufacturing process.
Innovation Solution
A multilayer printed wiring board is developed with a core base material formed by laminating a first wiring layer and a first insulating layer on an insulating substrate, and a built-up layer formed by laminating a second wiring layer and a second insulating layer, where a primer layer is formed between the second wiring layer and the first insulating layer, and the second wiring layer has a tin-plated layer and a silane coupling layer on its upper and side surfaces to enhance adhesion and prevent signal delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a semi-additive method is used to form a wiring layer, then the manufacturing process can be simplified, but the wiring layer width decreases during manufacture causing difficulty in obtaining the designed line width
Solution Approach 1:
The patent applies preliminary action by forming a copper layer before the wiring layer pattern definition step. This preliminary copper layer serves as a base that prevents width reduction during subsequent etching processes, allowing the final wiring layer to maintain its designed line width while still using the simplified semi-additive manufacturing approach.
2Ease of manufacture
If a conventional semi-additive method is used, then manufacturing is easier, but transmission delay of high-frequency signals occurs in the wiring layer
Solution Approach 1:
The patent uses composite materials by forming a multi-layer structure consisting of a copper layer combined with a wiring layer. This composite structure leverages the excellent electrical conductivity of copper while the wiring layer provides the necessary pattern definition and insulation properties, thereby reducing signal transmission delay for high-frequency signals while maintaining ease of manufacture through the semi-additive process.
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 solution effectively reduces or prevents transmission delay of high-frequency signals and maintains the designed line width of the wiring layer, ensuring efficient signal transmission and precise wiring formation.
Implementation Method 1
a tin-plated layer and a silane coupling layer are formed on an upper surface and a side surface of the second wiring layer
Data Source
AI summary
A multilayer printed wiring board and a method of manufacturing the same are provided. A multilayer printed wiring board of the present embodiment includes: a core base material formed by laminating a first wiring layer and a first insulating layer in this order on an insulating substrate; and a built-up layer formed by laminating a second wiring layer and a second insulating layer in this order on the core base material. A primer layer is formed between the second wiring layer and the first insulating layer, the second wiring layer has a lower surface at least part of which is in contact with the primer layer, and the second wiring layer has an upper surface and a side surface on both of which a tin-plated layer and a silane coupling layer are formed in this order.