Non-contact nanoparticle removal with laser induced plasma pulses

Abstract

Nanoscale substrate cleanliness is an essential requirement in a variety of nanotechnologyapplications. The proposed particle removal technique based on pressure shock wavesdue to laser induced plasma is of interest in various nano/micro-manufacturingapplications in which the minimum feature size is reducing rapidly. Any removalmethod adopted in a manufacturing process must be on the same shrinking featurereduction curve since, for device reliability, the minimum tolerable foreign particle sizeon a substrate depends on the minimum feature size on a nano/microsystem ordevice. In the current study, the transient pressure fields exerted on a surfacewith nanosecond pulse laser generated plasma shock waves are measured using apolyvinylidene difluoride film (PVDF)-based line transducer that was designedand tested for this particular measurement task. Using the pressure data, thecorresponding diameters of latex particles that can be removed at these pressure levelsare then calculated. It has been shown that latex particles as small as 60 nm indiameter can be removed from silicon surfaces using the nanosecond pulsed laser.Experimental removal data supporting these predictions are also included and discussed.