Laser enhanced electroplating and maskless pattern generation

Abstract

Maskless plating has been achieved through a new technique that utilizes a cw or pulsed laser, focused onto an electrode in an electroplating bath. In the region of optical absorption on the cathode, plating enhancement rates on the order of 103 occur for optical power densities on the order of 104 W/cm2. Laser scanning produces a plating pattern along the scanning path. A qualitative theory based on convective mass transport is used to explain the results.

Photoinduced Thermal Copper Reduction onto Gold Nanocrystals under Potentiostatic Control

“…A thermal effect in the Butler-Volmer equation is consistent with the interpretation of early laser-induced copper deposition studies by von Gutfeld and colleagues. [4][5][6][7] Our study shows how significant the heating photocurrent can be for small temperature rises in underpotential deposition. It is possible there is some additional two-photon tunneling photocurrent.…”

“…The Au array-ITO working electrode was used as a bottom window in a photoelectrochemical cell containing 200 mM aqueous CuSO 4 . A gold wire served as the pseudoreference electrode.…”

“…4 Electrode laser heating processes have been systematically explored by these workers and others subsequently. [5][6][7][8][9][10] Recently, Lowe et al studied the photocurrent response of 10 nm gold nanoparticles attached to ITO by organic molecule linkers.…”

Laser-induced copper deposition with weak reducing agents

“…Von Gutfeld [5][6][7] and Kordas et al [2] explain this effect by exclusively a thermal factor (increase the reaction rate of metal reduction with heat), as well as mixing the solution. In the experiments of von Gutfeld the laser beam was focused at the interface of copper electrode-copper sulfate solution.…”

Direct-write techniques for maskless production of microelectronics: A review of current state-of-the-art technologies

“…The popularity of lasers in direct writing results mainly from a subtractive process called laser micromachining, however there are many other types of laser based methods such as laser chemical vapour deposition (LCVD) [17], electro-less plating or electroplating with laser assistance [18,19], matrix assisted pulsed laser evaporation direct write (MAPLE-DW) [20], etc.. Some laser based patterning methods are subtractive methods, but are still sometimes considered direct writing, however this paper only introduces additive methods of depositing materials, in line with definition given at the beginning as their being an additive technique without etching.…”