Interaction of laser-generated surface acoustic pulses with fine particles: Surface cleaning and adhesion studies

Kolomenskii, A.A.; Schuessler, H. A.; Mikhalevich, V. G.; Maznev, A. A.

doi:10.1063/1.368367

Cited by 66 publications

(39 citation statements)

References 19 publications

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“…Depending on the parameters (e.g. with longer pulses), the force balance may be more relevant than the energetic consideration [27]. Expansion of the substrate may lead to the compression of the particle and an increase in its elastic energy [28].…”

Section: Pmma Substratesmentioning

confidence: 99%

Laser cleaning of polymer surfaces

et al. 2001

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Abstract.We have investigated the removal of small spherical particles from polymer surfaces by means of 193-nm ArF and 248-nm KrF laser light. Polystyrene (PS) particles with diameters in the range of 110 nm to 1700 nm and silica particles (SiO 2 ) with sizes of 400 nm and 800 nm are successfully removed from two different substrates, polyimide (PI) and polymethylmethacrylate (PMMA). Experiments were performed in air (23• C, relative humidity 24%-28%) and in an environment with a relative humidity (RH) of about 90%. PACS: 42.62.CfLaser cleaning of surfaces from particles with diameters in the range from 100 nm to several microns has become increasingly important in lithography [1], semiconductor device fabrication [2-6], micromechanics, optics, telecommunications, etc.Conventional techniques such as ultrasonic and megasonic cleaning, wiping and scrubbing, high-pressure jet spraying, etching, plasma cleaning, etc., are often inadequate for the removal of particulate contaminants of micron and submicron size. The problems with these techniques include ineffectiveness, addition of contaminants, damage of prefabricated parts, etc. It has been demonstrated that laser cleaning can be used to efficiently remove micron and submicron particles from solid surfaces. Such particulates adhere with relatively strong forces [7] that are difficult to overcome with the traditional cleaning techniques. Laser cleaning based on the absorption of pulsed-laser radiation by the substrate and/or the particulates is denoted as dry laser cleaning (DLC) [6,8]. If the removal of particulates is related to the superheating and explosive evaporation of an auxiliary thin liquid film, the technique is denoted as steam laser cleaning (SLC) [4,5].Since 1991 of the particles from the surface and their spatial distribution after leaving the substrate in relation to the surface roughness [9]. In recent publications there has been a significant increase in the use of polymer science in the fields of microelectronics and sensor technology [10]. From polymers used in packaging to polymers used as electrets, polymers will soon be facing the same cleaning difficulties as conventional semiconductor materials. Only a few existing papers [11,12] describe the removal of residues of polymers from polymers. Nonetheless, to the authors' knowledge, no papers have dealt with laser-induced removal of particles from polymer substrates.In this paper we investigate laser cleaning of PI (polyimide) and PMMA (polymethylmethacrylate) from PS (polystyrol) and SiO 2 (silica) microspheres of different sizes. Experimental procedureThe experimental setup consists of a KrF excimer laser (Lambda Physik LPX 205), which provides at λ = 248 nm a maximum pulse energy of E ≈ 470 mJ (at a ν r = 1 Hz repetition rate). Its pulse length is τ (FWHM) ≈ 31 ns and its repetition rate is between 1 Hz and 30 Hz. The pulse energy is computer-controlled by an external adjustable tunable dielectric attenuator.The output from a circular aperture was imaged using a lens onto the polymer target...

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Section: Pmma Substratesmentioning

confidence: 99%

Laser cleaning of polymer surfaces

et al. 2001

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“…Most of the models do not consider temporal profile of the laser pulse, which assumes infinite acceleration/deceleration. Though energy criterion was mentioned 12 , its region of applicability was not clearly stated.…”

Section: Introductionmentioning

confidence: 99%

Dynamic particle removal by nanosecond dry laser cleaning: theory

et al. 2002

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A model for ns dry laser cleaning that treats the substrate and particle expansion on a unified basis is suggested. Formulas for the time-dependent thermal expansion of the substrate, valid for temperaturedependent parameters are derived. Van der Waals adhesion, the elasticity of the substrate and particle, as well as particle inertia is taken into account for an arbitrary temporal profile of the laser pulse. Time scale related to the size of the particles and the adhesion/elastic constants is revealed. Cleaning proceeds in different regimes if the duration of the laser pulse is much shorter/longer than this characteristic time. Expressions for cleaning thresholds are provided and compared with experiments on the cleaning of Si surfaces from spherical SiO 2 particles with radii between 200 and 2585 nm in vacuum with 248 nm KrF excimer laser and 532 nm frequency doubled Nd-YAG laser. Large discrepancies between the experimental data and theoretical results for KrF laser suggest that ns dry laser cleaning cannot be explained on the basis of thermal expansion mechanism alone.

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“…5,6 As a result, substrate atom displacements of 1nm and larger have been recorded by pulsed laser induced SAWs. 7 This phenomenon has been used to detach/desorb micro/nano size particles 8 where the driving physical force is more mechanical in nature (i.e. particles are accelerated off).…”

Section: Introductionmentioning

confidence: 99%

Demonstration of enhanced surface mobility of adsorbate cluster species by surface acoustic wave excitation induced by a pulsed laser

Manzo

Helvajian

2014

SPIE Proceedings

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Fluorescence microscopy is used to explore the efficacy of surface acoustic waves (SAWs), as generated by a pulsed laser "tapping" a surface, to enhance the surface mobility of molecular adsorbates. The candidate adsorbate system under investigation comprises a series of gold clusters that are directly prepared on a silicon (111) surface by laser ablation of nanoparticles. Within the debris field the gold cluster Au 8 is tracked because the fluorescence spectrum is known. The gold cluster is distinguished by using band-pass filters and tracked by fluorescence. The SAW source is a pulsed UV (355nm) laser operating at a repetition rate of 100Hz, where the laser fluence is set below the damage threshold of silicon. The experiment measures the location of the emitted light for a particular cluster through a high magnification (100X) imaging microscope that is integrated with a water-cooled (512x512 pixel) EMCCD camera. Image processing algorithms are used to track the light emission. Initial results show that the cluster Au 8 moves approximately 0.5 Angstroms/s (when the excitation source is approximately 0.65 cm away). Diffusion and displacement data of adsorbed atoms and molecules on surfaces is sparse, though this value is similar for displacements of gold clusters on polymer films at 440 K 1 , some metal-on-metal adatoms at room temperatures 2 , and other nonmetalmetal interactions 3 . The experiment also includes a laser heterodyne probe which measures the frequency distribution of the surface displacement induced by the pulsed SAWs. Results show that even at a source-to-probe distance of 1.8cm, frequency components up to 120MHz are present. These results suggest that "growing"/synthesizing thin films via surface aggregation of cluster compounds may be feasible.

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Interaction of laser-generated surface acoustic pulses with fine particles: Surface cleaning and adhesion studies

Cited by 66 publications

References 19 publications

Laser cleaning of polymer surfaces

Laser cleaning of polymer surfaces

Dynamic particle removal by nanosecond dry laser cleaning: theory

Demonstration of enhanced surface mobility of adsorbate cluster species by surface acoustic wave excitation induced by a pulsed laser

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