Plasma-Treated Printed Wiring Board Adhesion
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Solution Overview
Problem
Existing printed wiring boards face challenges in achieving high adhesiveness between resin insulation layers and conductive layers, particularly in forming fine-pitch conductive patterns without the need for roughened surfaces created by soluble particles, which limits the reduction of line width in conductive layers.
Innovation Solution
The use of microwave plasma treatment in a mixed atmosphere of nitrogen and hydrogen gas to form modified resin and conductive layers with functional groups like C≡N, C—NH2, and —COOH on the surfaces of resin insulation and conductive layers, enhancing adhesiveness without requiring roughened surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If soluble particles are used to form roughened surfaces on resin insulation layers, then adhesiveness between layers is improved, but line width reduction and fine-pitch pattern formation are limited
Solution Approach 1:
The invention changes the surface treatment parameter from mechanical roughening (soluble particles) to chemical modification (plasma treatment). By controlling plasma treatment parameters such as gas composition (CF4, SF6, or CCl4), treatment time, and power, the resin insulation layer surface is modified to have enhanced chemical reactivity and adhesion without changing the physical roughness, thereby enabling fine-pitch patterns while maintaining strong adhesiveness.
Solution Approach 2:
The invention replaces the mechanical roughening method (using soluble particles to create physical surface irregularities) with a plasma treatment method that chemically modifies the resin surface. This substitution eliminates the need for physical surface roughness to achieve adhesion, allowing for smoother surfaces that support finer conductive line patterns while maintaining interlayer bonding strength.
2Strength
If roughened surfaces are formed using soluble particles, then interlayer adhesiveness is enhanced, but manufacturing complexity increases
Solution Approach 1:
The invention extracts and eliminates the soluble particle component from the resin insulation layer formulation. Instead of incorporating particles that require subsequent dissolution steps, the patent uses plasma treatment to directly modify the resin surface, thereby simplifying the manufacturing process by removing unnecessary materials and steps while achieving the same adhesion enhancement.
Solution Approach 2:
The invention introduces plasma treatment as an intermediary process between resin layer formation and conductive layer deposition. This plasma intermediary chemically modifies the resin surface to create optimal bonding conditions, replacing the need for soluble particles and their dissolution process, thereby streamlining the overall manufacturing workflow.
3Strength
If plasma treatment is applied to both resin insulation layers and conductive layers with different surface modifications, then adhesiveness is maximized, but process complexity increases
Solution Approach 1:
The invention applies plasma treatment with different gas compositions and parameters to different layers based on their specific requirements. Resin insulation layers receive treatment with CF4, SF6, or CCl4 gas to create specific surface chemistry for optimal bonding, while conductive layers receive tailored plasma treatment to enhance their surface reactivity. This localized optimization of plasma parameters for each layer type maximizes overall adhesiveness while maintaining process control.
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 improves adhesiveness between resin insulation and conductive layers, allowing for the formation of fine-pitch conductive patterns on smooth surfaces, eliminating the need for roughened surfaces and preventing undulations in resin insulation layers, thereby enhancing the manufacturing efficiency and precision of printed wiring boards.
Implementation Method 1
applying microwave plasma treatment on the conductive layer and the resin insulation layer
Implementation Method 2
applying microwave plasma treatment in a mixed gas atmosphere including a nitrogen gas and a hydrogen gas
Data Source
AI summary
A printed wiring board includes resin insulation layers, conductive layers formed on the resin insulation layers respectively such that each of the conductive layers is formed on a surface of each of the resin insulation layers, and via conductors penetrating through the resin insulation layers respectively such that the via conductors are connecting the conductive layers through the resin insulation layers. Each of the resin insulation layers includes a modified resin layer formed by plasma treatment such that the modified resin layer is forming the surface of each of the resin insulation layers, each of the conducive layers includes a modified conductive layer formed by the plasma treatment such that the modified conductive layer is forming the surface of each of the conductive layers, and the modified resin layer has a surface modification different from a surface modification of the modified conductive layer.