Laser-enhanced Plating Research Articles

Electrochemical microfabrication by laser-enhanced photothermal processes

Laser-enhanced processes have found an increasingly important role as the interest in microfabrication continues to grow. An especially attractive feature of laser processing in liquids is the ability to obtain maskless patterning in the form of material deposition or dissolution, dictated by the path of the focused laser on the sample. In the present discussion we review theoretical and experimental aspects of laser-enhanced plating and etching for a variety of materials. Some of the substrates readily etched with the help of the laser are extremely difficult to process by conventional methods. Even though the laser processes can handle materials only in a serial manner, the plating and etching rates in certain instances are sufficiently rapid to make them competitive with batch processing methods. This is particularly interesting as it pertains to laser-enhanced jet plating of copper and gold, where rates as high as 50 and 20 µm/s have respectively been obtained.

Laser-enhanced patterning using photothermal effects: maskless plating and etching

We review our work on laser-enhanced plating and etching with emphasis on the chemical, electrochemical, and thermal mechanisms giving rise to the experimental observations. The metallurgical properties of the deposits and their applications, particularly in the field of microelectronics, are also discussed. The work on laser-enhanced electroplating and electrodeless plating includes high-speed deposition of copper, gold, and nickel by using the argon-ion laser as the source of localized energy. Deposition rates up to 3 orders of magnitude higher have been observed for laser-irradiated regions compared with nonirradiated ones. Mechanisms responsible for the plating enhancement are (1) enhanced chemical and electrochemical kinetics with increased temperature, (2) shifts in the local rest potential with temperature, and (3) local agitation of the solution as a result of large temperature gradients. Applications of these techniques to circuit design and repair as well as to high-speed plating of precious metals onto electrical contact areas of microelectronic circuits are considered. Experiments on high-speed laser-enhanced etching of several dielectrics are also reviewed. Volume removal rates as high as 106μm3/sec for an alumina/TiC ceramic and 105μm3/sec for 〈111〉 silicon using KOH as the etchant have been obtained.

Laser-enhanced plating and etching for microelectronic applications : Robert J. Von Gutfeld. IEEE Circuits Devices Mag., 57 (January 1986)

Laser-enhanced plating and etching for microelectronic applications : Robert J. Von Gutfeld. IEEE Circuits Devices Mag., 57 (January 1986)

Laser-enhanced plating and etching for microelectronic applications

The author describes the use of lasers to obtain patterns using plating and etching techniques. The enhanced rates result from accelerated electrochemistry and mass transport of the electrolytic solutions resulting from local heating produced by laser absorption at the workpiece-electrolyte interface. Examples of laser electroplating include results for nickel, copper, and gold with rates as high as ~1-5 μm/s. This is ~3 orders of magnitude higher than conventional electroplating rates. Similarly, high rates of electro-etching have been observed, particularly for such metals as stainless steel. Several applications of this technique are described, particularly as they pertain to VLSI circuit boards and connectors. A recent modification of the laser plating technique combines a laser with a high-velocity jet of electrolyte to obtain still higher rates of deposition. This scheme is described in some detail for gold and copper plating with observed rates as high as 20 and 50 μm/s, respectively, for the two metals.

Recent Advances in Laser-Enhanced Plating

ABSTRACTA summary of the recent work on laser-enhanced gold plating is presented. The purpose of the study has been to obtain rapid maskless plating on thick metal samples. Results will be described on the plating rates for a variety of laser and electrical parameters. The most recent work on a laser-jet plating system will be discussed. With this system, rates of up to 30 μm/s have been achieved on 8 mil thick Be-Cu samples.

Laser-enhanced plating: A review of its mechanisms and applications

Laser-enhanced plating: A review of its mechanisms and applications

Laser-Enhanced Plating and Etching: Mechanisms and Applications

We have developed experimental electroplating, electrodeless plating, and etching techniques that use a focused laser beam to define the localized plating or etching region. Enhancements in plating (etching) rates up to ≅1O3 to 1O4, compared to background rates, have been observed in the region of laser irradiation. A thermal model has been developed to describe the observed effects over the entire overpotential (polarization) curve. In the low overpotential region the enhancement is dominated by the increase in the local charge-transfer kinetics due to the local increase in temperature produced by absorption of the laser energy by the cathode (anode). At higher overpotentials, in the mass-transport-limited region, the main enhancement occurs due to hydrodynamic stirring caused by the the large local temperature gradients. Examples of gold, nickel, and copper electroplating are described to illustrate the value of this technique for micron-sized circuit personalization and repair. Additional examples of electroless laser-enhanced plating and exchange plating are also described.