UV-excimer laser

The requirements of thin-film ferroelectrics are stoichiometry, phase formation, crystallization, and microstmctural development for the various device appHcations. As of this writing multimagnetron sputtering (MMS) (56), multiion beam-reactive sputter (MIBERS) deposition (57), uv-excimer laser ablation (58), and electron cyclotron resonance (ECR) plasma-assisted growth (59) are the latest ferroelectric thin-film growth processes to satisfy the requirements. 

Compaction has also been observed as a result of neutron irradiation and extended exposure to iatense uv (excimer) laser light (131,132). The compaction tends to relax over months at room temperature and can be reversed quickly by annealing at sufficiently high temperatures (133). 

Plastic materials have gained importance in microfabrication due to their ease of molding, inexpensiveness, and disposability. Some workers have used these substrates for fabrication of microchips. Pethig et al. [78] and Roberts et al. [79] used laser ablation as a direct method for creating microchannels in plastic chips without the need for fabrication. The methods used an UV excimer laser to bum the microchannels onto the polymer substrate, moving in a predefined,... 

Rossier et al. [80] used UV excimer laser photoablation for changing the surface properties of the plastics and drilling. The authors discussed the method for patterning biomolecules on a polymer along with surface coverage of active antibodies and equilibration time. Besides, a method of designing NCE comprising an on-chip injector, column and electrochemical detector was also discussed. Furthermore, the potential of this disposable device was discussed and compared to classical systems. 

An excimer laser was also used to machine a PC chip (6 mm thick) to create 160-pm-wide channels (60 pm deep), [811] or on a polyimide sheet [192,811]. Another UV excimer laser (248 nm) was used to ablate microstructures within PC channels (fabricated by imprinting) [193]. 

Bovine carotid artery endothelial cells UV excimer laser ablation to open polyacrylamide coating, protein backfill 2005 [102]... 

Iwanaga S, Akiyama Y, Kikuchi A et al (2005) Fabrication of a cell array on ultrathin hydrophilic polymer gels utilising electron beam irradiation and UV excimer laser ablation. Biomaterials 26(26) 5395-5404... 

Reactions of C2 (X1 2+) and (a3 nu) Produced by Multiphoton UV Excimer Laser Photolysis... 

Main Reactions of Chlorine- and Silicon-Containing Electron and Deep-UV (Excimer Laser) Negative Resists... 

In 1982, organic polymers were reported to be self-developable in an imagewise fashion by the use of high-flux light sources such as UV excimer lasers. Since these initial reports, the field has expanded rapidly (70, 71). 

The DR and AC intermediates of the photopolymerization reaction are stable only at low temperatures. At temperatures above about 100 K they react to form long macromolecules by subsequent addition of monomer molecules. The 10 K optical absorption spectra of Fig. 17 show the result of the thermal reaction as a function of the time at 100 K The initial spectrum showing only the dimer A absorption has been prepared at 10 K by only one UV-excimer laser pulse at 308 nm. Only pure thermal addition polymerization reactions are observed within the DR-series A, B, C,. .. No chain termination reactions are detectable in the optical spectra. The final product P is situated in the vicinity of the final polymer absorption. 

LFP/UV, Excimer laser photolysis, UV absorption detection of hydrocarbon. LFP/PIMS, Excimer laser photolysis, photoionization mass spectrometric monitoring of hydrocarbon. RR, Relative rate determination. DF/MS Discharge flow production of radicals, mass spectrometric monitoring of hydrocarbon radicals. PR/UV, Pulsed radiolysis in 760 Torr H2, UV absorption detection of ethyl and ethyl peroxy. 

Figure la shows the experimental set-up for measurement of outgassed species from fluoropolymers on exposure to 157 nm. The exposure source is a LAMBDA PHYSIK OPTex UV excimer laser (Wavelength 157 nm, Power 0.8 mJ/pulse, Rep. Rate 30 Hz, Pulse duration 5-10 ns FWHM, laser intensity 2 MW/cm2) where a vacuum chamber was connected via CaF2 lens. A PFEIRRER... 

The U.S. National Institutes of Standards and Technology provides absolute calibration of such detectors see, for example, R.W. Leonhardt and T.R. Scott, Deep UV excimer laser measurements at NIST, Proc. SPIE 2439, 448 459 (1995). 

Wong, W., Chan, K., Yeung, K.W., Tsang, Y.M., Lau, K.S., 2000a. Surface structuring of poly(ethylene terephthalate) fibers with a UV excimer laser and low temperature plasma. J. Mater. Process. Technol. 103, 225-229. 

The laser bums less material in thermoplastics than IR lasers resulting in a cleaner cut and runs more stable than UV excimer lasers... 

The work by Pireaux et al. (1995) on the so-called reactive (pol3detra-fluoroethylene) and even more stable (polypropylene and polyethylene) polymers based on the use of XPS valence band spectra, showed that irradiation can lead to superficial structural modification - lateral chain grafting, or cross-linking. This structural modification appears more pronounced for high fluence UV excimer laser irradiation in air, than for (more moderate) exposition to harder X-rays in vacuum. 

Yip,J.,Chan,K.,Sin,K.M.,Lau,K.S.(2004)Comprehensive study of polymer fiber surface modifications. Part 1 high-fluence UV-excimer-laser-induced structures. PoZym. Int., 53, 627-633. 

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