Laser Copper Surface Modification for Uniform Immersion Plating
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Solution Overview
Problem
Mechanical roughening of copper surfaces for improved adhesion and uniformity in plating processes is time-consuming and inefficient.
Innovation Solution
A laser surface modification method that cleans and slightly melts the copper surface to create uniform topography with variations up to one micron, enhancing adhesion without mechanical roughening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical roughening is performed to increase adhesion and uniformity, then plating adhesion is improved, but processing time increases
Solution Approach 1:
The patent replaces mechanical roughening systems with a laser-based system that uses optical energy to modify the copper surface. The laser beam melts and resolidifies the surface to create the desired roughness profile, eliminating mechanical contact and significantly reducing processing time while maintaining adhesion improvements.
Solution Approach 2:
The patent changes the physical state of the copper surface through controlled laser heating, melting, and resolidification. By controlling laser parameters (power, speed, pulse duration), the surface undergoes phase changes that create the required micro-roughness without mechanical intervention, resolving the time-adhesion contradiction.
2Reliability
If mechanical roughening is performed to improve adhesion, then uniformity of plating is improved, but operator intervention is required
Solution Approach 1:
The patent replaces manual or mechanically-controlled roughening with an automated laser system that can be programmed and controlled through software. The laser beam is precisely directed and moved across the surface using automated positioning systems, eliminating the need for operator intervention while maintaining uniform plating results.
Solution Approach 2:
The laser system is designed to automatically control its own parameters and positioning, with feedback mechanisms that ensure consistent surface modification without continuous operator input. The system self-regulates to maintain the required surface uniformity for consistent plating.
3Area of stationary object
If laser beam is applied to modify surface, then surface area is increased by variations, but energy consumption occurs
Solution Approach 1:
The patent uses pulsed laser operation rather than continuous beam application. The laser emits short, periodic pulses that melt and resolidify the surface in discrete intervals, creating surface variations while allowing cooling between pulses. This periodic action reduces overall energy consumption compared to continuous laser application while achieving the required surface area increase.
Solution Approach 2:
The patent exploits the phase transition of copper from solid to liquid and back to solid through controlled laser heating. This phase change mechanism efficiently creates surface variations with relatively low energy input, as the latent heat of fusion provides a natural energy sink that limits excessive heating and reduces total energy consumption.
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 laser method increases surface area and promotes better plating adhesion, providing a uniform matte finish suitable for immersion plating solutions like silver or tin, reducing processing time and operator intervention.
Implementation Method 1
applying a laser beam to the surface of the copper substrate. The method also includes moving the laser beam across the surface of the copper substrate. The method also includes modifying the surface of the copper substrate to vary the surface up to one micron
Implementation Method 2
modifying the surface of the copper substrate with the laser beam to vary the surface up to one micron
Implementation Method 3
cleaning a copper substrate having a surface using a chemical solution to increase reflectivity of the surface
Implementation Method 4
The method also includes wet-etching the surface of the copper substrate
Data Source
AI summary
A laser system emits a laser beam at a surface of a substrate to modify the surface. The substrate is cleaned to increase reflectivity of the surface. The laser beam is applied to the surface. The laser beam moves across the surface of the substrate. The surface is modified by the laser beam to vary the surface up to one micron, or 1 μm. A surface area of the surface is increased by the variations. The laser beam is stopped after modification of the surface of the substrate is complete.