Glass Core Circuit Board Copper Wiring Without Etch Undercuts
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Solution Overview
Problem
The formation of copper wiring on a glass core circuit board is hindered by undercuts in the electrolytic copper plating layer, leading to cracking and damage during the manufacturing process, particularly when using alkaline etching agents and electroless nickel plating layers with high phosphorus content.
Innovation Solution
A method involving a glass core with a first electrolytic copper plating layer, a dielectric layer, a second metal layer, an electroless nickel plating layer with a phosphorus content of less than 5 mass %, and a second electrolytic copper plating layer, where acidic etching is used to prevent glass damage and cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an electroless nickel plating layer with high phosphorus content is used, then the etching of unnecessary parts can be performed, but the glass plate may break during the manufacturing process due to damage caused by alkaline etching agents
Solution Approach 1:
The invention changes the phosphorus content parameter of the electroless nickel plating layer from high (conventional) to low (5 mass% or less), which fundamentally alters the etching chemistry required. This parameter change enables the use of acidic etching agents instead of alkaline ones, thereby protecting the glass plate from damage while maintaining etching capability.
Solution Approach 2:
The invention converts the previously harmful effect of low phosphorus content (which made etching difficult) into a benefit by discovering that low phosphorus content enables acidic etching, which is gentler on glass plates. What was once a manufacturing limitation becomes a protective feature against glass damage.
2Ease of manufacture
If an alkaline etching agent is used to etch the electroless nickel plating layer, then the etching can be performed, but undercuts in the electrolytic copper plating layer occur causing defects
Solution Approach 1:
The invention changes the etching agent type parameter from alkaline to acidic, which is enabled by the low phosphorus content of the electroless nickel plating layer. This parameter change eliminates the formation of undercuts in the electrolytic copper plating layer, thereby improving manufacturing precision without sacrificing etching capability.
3Adaptability or versatility
If a conventional semi-additive process is applied to form wires on a glass plate, then multiple layers of wires can be formed, but the process cannot be applied when a dielectric layer is provided on the glass plate
Solution Approach 1:
The invention changes the phosphorus content parameter of the electroless nickel plating layer to less than 5 mass%, which enables acidic etching. This parameter change allows the development of a modified semi-additive process that can be applied over dielectric layers, thereby improving process adaptability to multi-layer configurations with dielectric insulation.
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 enables the appropriate formation of copper wiring on the glass core circuit board, reducing cracking and manufacturing complexity while preventing glass breakage and defects in the electrolytic copper plating layer.
Implementation Method 1
an electroless nickel plating layer with a phosphorus content of less than 5 mass %
Implementation Method 2
a first electrolytic copper plating layer disposed on the first metal layer... a second electrolytic copper plating layer disposed on the electroless nickel plating layer
Implementation Method 3
acidic etching is used to prevent glass damage and cracking
Data Source
AI summary
A glass core, a multilayer circuit board, and a method of manufacturing a glass core that appropriately form copper wiring, and suppresses crack and the like, a glass core includes: a glass plate; a first metal layer provided on the glass plate; a first electrolytic copper plating layer provided on the first metal layer; a dielectric layer provided above the first electrolytic copper plating layer; a second metal layer provided on the dielectric layer; an electroless nickel plating layer provided on the second metal layer and having a phosphorus content of less than 5 mass %; and a second electrolytic copper plating layer provided on the electroless nickel plating layer.