Polyimide Siloxane Plating Component for High-Density PCB Adhesion
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Solution Overview
Problem
Current methods fail to achieve strong adhesion of electroless plating films to smooth surfaces on printed circuit boards, which is essential for high-density wiring and high-frequency electrical signal transmission, due to low surface roughness and inadequate adhesion strength, especially when incorporating inorganic fillers that increase surface roughness and reduce insulation.
Innovation Solution
A component for electroless plating using a polyimide resin with a siloxane structure is applied to the surface, providing a smooth interface with a surface roughness of 0.5 μm or less, and an insulating sheet with multiple layers, including a polyimide resin layer for electroless plating and a thermosetting resin layer for circuit-facing, ensures strong adhesion and low linear expansion, while maintaining processability and heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If inorganic fillers are added to the insulating sheet to reduce linear expansion, then linear expansion is reduced, but surface roughness increases and adhesion to electroless plating film deteriorates
Solution Approach 1:
The insulating sheet is divided into two distinct layers: a first layer (circuit board layer) containing inorganic fillers for low linear expansion, and a second layer (smooth surface layer) without fillers to provide surface smoothness and adhesion. This segmentation allows each layer to independently fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the insulating sheet are given different properties: the first layer has high filler content for dimensional stability, while the second layer has no filler or reduced filler content to maintain surface smoothness and adhesion properties. This local differentiation resolves the contradiction between bulk stability and surface quality.
2Strength
If the surface roughness is increased to improve adhesion of electroless plating film, then adhesion strength is improved, but surface smoothness required for high-density wiring is compromised
Solution Approach 1:
The insulating sheet is divided into two distinct layers: a first layer (circuit board layer) containing inorganic fillers for low linear expansion, and a second layer (smooth surface layer) without fillers to provide surface smoothness and adhesion. This segmentation allows each layer to independently fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the insulating sheet are given different properties: the first layer has high filler content for dimensional stability, while the second layer has no filler or reduced filler content to maintain surface smoothness and adhesion properties. This local differentiation resolves the contradiction between bulk stability and surface quality.
3Device complexity
If a single-layer insulating sheet is used to simplify structure, then device complexity is reduced, but it cannot simultaneously achieve low linear expansion and surface smoothness for high-density wiring
Solution Approach 1:
The insulating sheet is divided into two distinct layers: a first layer (circuit board layer) containing inorganic fillers for low linear expansion, and a second layer (smooth surface layer) without fillers to provide surface smoothness and adhesion. This segmentation allows each layer to independently fulfill its specific function without compromising the other.
Solution Approach 2:
The two-layer insulating sheet structure serves multiple functions simultaneously: the first layer provides dimensional stability and mechanical strength, while the second layer provides surface smoothness and adhesion. This multi-functionality allows a single component to meet multiple requirements that would otherwise require separate elements.
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 achieves high adhesion strength to electroless plating films on smooth surfaces, supports high-density circuit formation, and maintains low linear expansion and heat resistance, enabling reliable transmission of high-frequency electrical signals without compromising surface smoothness or increasing surface roughness.
Implementation Method 1
a component for electroless plating, the component having at least a surface a for electroless plating, the surface a having a surface roughness of 0.5 μm or less in terms of arithmetic average roughness measured with a cutoff value of 0.002 mm, and the surface a containing a polyimide resin having a siloxane structure
Implementation Method 2
Electroless plating for depositing a metal on a base by decomposing a reductant in an aqueous solution of a metal salt and then reducing the metal salt without electrical energy
Implementation Method 3
an insulating sheet with multiple layers, including a polyimide resin layer for electroless plating and a thermosetting resin layer for circuit-facing, ensures strong adhesion and low linear expansion, while maintaining processability and heat resistance
Data Source
AI summary
It is an object of the present invention to provide a component for plating suitably used in, for example, producing a printed circuit board, a solution, and a printed circuit board including the component, the component for plating having satisfactory adhesion to an electroless plating film provided on a surface of the component even when the surface roughness of the surface of the component is small. The object is achieved by a component for electroless plating including at least a surface a for electroless plating, the surface a having a surface roughness of 0.5 μm or less in terms of arithmetic average roughness measured with a cutoff value of 0.002 mm, and the surface a containing a polyimide resin having a siloxane structure.