Laser oxide removal for plating (LORP) is a plating preparation system that uses laser irradiation to remove the native oxide film from the substrate immersed in an electrolyte solution. While LORP reduces the pre-processing required to plate metals and allows for simultaneous plating and oxide removal, it also suffers from drawbacks such as high cost and time consumption as well as the use of environmentally harmful chemicals. This technology presents several improvements over previously developed LORP techniques that serve to reduce cost and minimize optical attenuation, thus increasing the efficiency of the system. These improvements include the use of a thin electrolyte layer and the removal of the electrolytic cell window through which the laser beam passes. The improved LORP system functions by wetting a porous material in contact with the substrate to cause immersion plating. The substrate is then passed into a second tank for plate-up via electroplating.
An electrolyte layer that is only several microns thick serves to reduce optical attenuation and minimize waste of electrolyte. In previous LORP configurations, a long focal length lens was required to prevent damage to the electrolytic cell window through which the laser beam passed. This increased the travel distance of the laser resulting in substantial optical attenuation. In the improved system, the removal of the cell window turns the long focal length lens into an advantage. The distance between the focal lens and laser can be made arbitrarily large, preventing the lens from being splashed by electrolyte. These improvements enhance the LORP process by reducing laser damage to the electrolytes, decreasing electrolyte waste, and increasing the efficiency of the laser for oxide removal. A number of oxide metals will be tested at 532 and 266 nm using Q-tips to wet the sample just prior to laser impingement.
Patent Pending (US20110104396)
Tech Ventures Reference: IR M10-023