Laser removal of copper particles from silicon wafers using UV, visible and IR radiation

Acoustic emission monitoring during laser shock cleaning of silicon wafers

“…For example, the speed of laser cleaning is relatively slow due to small laser spot size, and direct interactions between the laser beam and the substrate surface cause severe surface damage easily on the delicate wafer surfaces. In addition, this conventional laser cleaning employing mostly ultraviolet radiation is expensive process and inorganic particles smaller than the laser wavelength is difficult to remove due to the limitation of cleaning force, which should be larger than adhesion force of particles [3]. Therefore, a more effective laser cleaning technique is required not only to obtain high throughput by high speed cleaning but also to remove nano-scale particles successfully without causing any surface damages.…”

“…Recently, a laser cleaning technique has attracted considerable interest as a new alternative cleaning technique to replace conventional wet chemical wafer cleaning, since it is a dry cleaning process [2][3][4]. This is seen to be non-obtrusive in the production process since no vacuum or special protective atmospheres are required and the beam of the laser can be highly localized allowing specific areas of contamination to be targeted.…”

“…However, the strong chemicals could easily attack the sensitive semiconductor surfaces such as metal interconnect and low-k materials, and the application of 300 mm wafers causes the more consumption of chemicals inducing higher cost and environment impacts. In order to solve these problems, there have been many efforts to develop dry cleaning method [2][3][4].…”

Large-area laser printing of Ag thick film pattern with stepwise edge morphology

“…Silver thin films solution deposited on glass substrate were transferred onto diverse receiver substrates such as Si, glass, and plastics by a spatially modulated Nd:YAG pulsed laser beam (1064 nm, 6 ns pulse width) incident from the backside of the glass substrate. Our approach is fundamentally based on the laser-induced thermal desorption (LITD) of particles [15][16][17][18][19]. Particles adhered to the surface can be desorbed when the thermo-elastic force, caused by rapid thermal expansion of the particle and/or the surface resulting from a pulsed laser irradiation, exceeds the adhesive force (predominantly van der Waals force) between the particle and the surface [15,16].…”

“…Our approach is fundamentally based on the laser-induced thermal desorption (LITD) of particles [15][16][17][18][19]. Particles adhered to the surface can be desorbed when the thermo-elastic force, caused by rapid thermal expansion of the particle and/or the surface resulting from a pulsed laser irradiation, exceeds the adhesive force (predominantly van der Waals force) between the particle and the surface [15,16]. Metal thin film patterning is of technological significance because modern electronic devices commonly require electrodes, metallization or interconnect lines.…”