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Polymers with photolabile groups absorbing in the mid UV (around 300 nm) were irradiated with excimer-lasers (248 and 308 nm). Irradiation with 248 nm (KrF laser) corresponds to an excitation of the photostable phenyl system whereas the XeCl laser (308 nm) excites the labile triazeno groups (–NN–N). Thin polymer films (0.1–3 μm) were coated onto quartz or glass and irradiated below and above the threshold of ablation. The films were subsequently analyzed with various surface analysis techniques. Below the threshold of ablation the main feature at both irradiation wavelengths was the reduction of the absorption maximum at about 330 nm and an increase of the surface oxygen content (X-ray photoelectron spectroscopy) and therefore the surface polarity (contact angle). The surface remained smooth with no detectable micro-structures (scanning electron microscopy). Above the ablation threshold the absorbance at 330 nm decreased dramatically and the color of the film changed. For 248 nm irradiation the surface was darkened and a carbonization (XPS) with microstructures (SEM) was detected. The surface became non-polar in agreement with surface carbonization. In the case of 308 nm irradiation the surface remained smooth and no change of the chemical composition or surface polarity was detected, suggesting a photochemically induced layer by layer ablation process.

We studied the method to fabricate microstructures in PDMS sheet using laser-generated EUV light. In the high power density EUV light irradiation region, PDMS can be machined without chemical modification.

Laser cutting of carbon fiber reinforced plastics (CFRP) with a cw IR fiber laser (λ= 1090 nm, average power: 1kW). A well-defined cutting of CFRP which was free of debris and thermal-damages around the grooves, was performed by the laser irradiation with a fast beam galvanometer scanning on a multiple-scan-pass method.

We have investigated responses of polymers to EUV radiation from laser-produced plasmas beyond ablation thresholds and micromachining. We concentrated on fabricate precise 3D micro-structures of PDMS, PMMA, acrylic block copolymers (BCP), and silica. The micromachining technique can be applied to three-dimensional micro-fluidic and bio-medical devices. The EUV processing is a promising to realize a practical micromachining technique. In the present work, we used two EUV radiation sources; (a) Wide band EUV light in a range of 10{300 eV was generated by irradiation of Ta targets with Nd:YAG laser light at 500 mJ/pulse. (b) Narrow band EUV light at 11 and 13 nm was generated by irradiation of solid Xe and Sn targets, respectively, with pulsed TEA CO2 laser light. The generated EUV light was condensed onto the materials at high power density beyond the ablation thresholds, using ellipsoidal mirrors. We found that through-holes with a diameter of one micrometer an be fabricated in PMMA and PDMS sheets with thicknesses of 4-10 micrometers, at 250 and 230 nm/shot, respectively. The effective ablation of PMMA sheets can be applied to a LIGA-like process for fabricating micro-structures of metals for micro- and nano-molds. PDMS sheets are ablated if it is irradiated with EUV light beyond a distinct threshold power density, while PDMS surfaces were modified at lower power densities. Furthermore, BCP sheets were ablated to have 1-micrometer structures. Thus, we have developed a practical technique for micromachining of PMMA, PDMS and BCP sheets in a micrometer scale.

We report on the laser cutting of carbon fiber reinforced plastics (CFRP) with a cw IR fiber laser (average power: 1kW). CFRP is a high strength composite material with a lightweight, and is increasingly being used various applications. A well-defined cutting of CFRP which were free of debris and thermal-damages around the grooves, were performed by the laser irradiation with a fast beam galvanometer scanning on a multiple-scan-pass method.

The threshold fluence, F T) , of ablation of a triazeno-polymer was measured in the low fluence range for thin films using conventional UV-spectroscopy. It was found that there is a clearly defined F T) for 308 nm ir- radiation between 20 and 25 mJ cm~2. In the case of 248 nm irradiation, a ''threshold fluence range'' between 16 and 32 mJ cm~2 was found. The ablation rate for both irradiation wavelengths depends on film-thickness. For the XeCl excimer-laser, the point at which the rate be- comes independent of thickness was observed to lie at a value which did not correspond to the calculated laser penetration depth, whereas for the KrF laser the indepen- dence was not reached within the applied thickness range (up to 0.35 lm). Additional transmission measurements have been performed showing that the target transmission at 248 nm increases only slightly, whereas for 308 nm the transmission increases by a factor of approximately 4. This result shows that dynamic target absorption proper- ties are very important for describing the ablation process. The results derived from the transmission studies and etch rates were analyzed theoretically with a two-level model of chromophore absorption. For 248 nm irradiation this model can describe the transmission behavior and the ablation rate. In the case of 308 nm irradiation, it was only possible to match one data set. A good agreement with the experimental transmission ratio does not match the abla- tion rate and vice versa.

Surface of poly(tetrafluoroethylene) [PTFE] film was modified chemically by an ArF excimer laser-induced reaction in a hydrazine gas atmosphere. The polymer surface modified upon the irradiation of 1000 pulses at 27 mJ cm −2 , which was a fairly lower fluence than the ablation threshold for usual polymer films, showed hydrophilicity (contact angle for water: 30°) enough to be metallized by chemical plating. The mechanism for chemical surface modification was investigated by FTIR, XPS, and SIMS analyses. The laser-treated PTFE film was metallized by a chemical plating process. These processes will be used to fabricate printed wiring boards for high frequency electronics.

The threshold fluenceFTh of a triazeno-polymer was measured in the low fluence range for thin films using conventional UV-spectroscopy. It was found that there is a clearly definedFTh for 308 nm irradiation between 20 and 25 mJ cm−2. In the case of 248 nm irradiation, a ‘threshold fluence range’ between 16 and 32 mJ cm−2 was determined. Additional transmission measurements have been performed showing that the target transmission at 248 nm increases only slightly, whereas for 308 nm the transmission increases by a factor of ≈ 4. This result shows that dynamic target absorption properties are very important for describing the ablation process.

The surface of poly(ethylene terephthalate) film was chemically modified with the fragments produced by ablation of pentafluorophenylazide at 90 K upon KrF excimer laser radiation. When the surface was exposed to the fragments in a vacuum, the photolyzed phenylazide was immobilized onto the surface through the chemical bond.

Standard spectroscopic and surface analysis techniques were used to study a triazeno polymer after laser treatment. Two different excimer lasers, KrF at 248 nm and XeCl at 308 nm, were applied as irradiation sources. For both excimer lasers fluences below and above the threshold of ablation were used. In the case of fluences below the threshold of ablation the irradiation led to a decrease of the absorption of the triazeno chromophore. From XPS spectrum and contact angle measurements a surface oxidation of the polymer is identified. After irradiation with fluences above the threshold of ablation for both irradiation wavelengths a different behavior is observed. Irradiation with the XeCl laser led to a less pronounced surface roughening as compared to KrF laser treatment. With the XPS and contact angle measurements, only slight changes could be detected. A totally different behavior was found for irradiation with the KrF excimer laser. The surface of the polymer turned black after the irradiation, and the ...

Initial stage of F2 laser ablation of LiCaAlF6 single crystal was investigated for clarifying the possibility of applying this wide bandgap fluoride crystal to vacuum ultraviolet (VUV) optical components. The ablation threshold, determined by the appearance of line emission from ablated species, was approximately 2 J cm-2pulse-1, similar to that of VUV grade CaF2 single crystal. The laser-induced damage on the front surface of LiCaAlF6 was faint, though adhesion of aggregated particulates of several microns was observed.

To clarify the initial stage of laser-induced backside wet etching, we directly measured transient pressure upon laser ablation of toluene under KrF excimer laser irradiation by using a fast-response pressure gauge. The propagation time of the pressure peak to the gauge agreed well with the time for the shock wave to reach the gauge on time-resolved images. The peak pressure P decreased slowly with increasing distance d: P=30.4 MPa for d=100 μm to P=11.1 MPa for d=1000 μm at a fluence F=1.0 J cm-2 pulse-1. The initial pressure, estimated to be of the order of 10–200 MPa, impinges on a transparent plate and contributes to the etching.

Laser irradiation of solid nitrogen containing cyanuric triazide (C3N12) could generate highly reactive carbon nitride species, NCN and dicyanocarbodiimide. These species were generated in the solid nitrogen at 20 K. After laser photolysis, generated reactive species were concentrated by removal of nitrogen, and converted into a film-like product. Thus, the obtained product was characterized by means of FTIR, SEM, and XPS measurements. The product was assigned to amorphous carbon nitride with relatively high nitrogen content (N/C=0.9∼1.3).

The chemical surface modification of poly(tetrafluoroethylene) (PTFE) film was carried out in hydrazine gas photolyzed with ArF excimer laser irradiation. Hydrophilic surface appeared on PTFE film after the laser treatment. The surface was analyzed with a measurement of water contact angle, X-ray photoelectron spectroscopy, and FTIR spectroscopy (attenuated total reflection). In addition, on the basis of the hydrophilic behavior, we succeeded in the area-selective electroless plating of nickel and copper metal on the chemically modified surface.

For crack-free marking of glass materials, a beam-scanning laser-induced backside wet etching (LIBWE) process by a beam spot with a fine periodic structure was examined. The fine periodic structure was produced within a beam spot by means of a Mach–Zehnder interferometer incorporated to the optical setup for the beam-scanning LIBWE. A fine structure with a period of 9 µm was observed within the microstructures with a diameter of ca. 40 µm fabricated by a laser shot under double-beam irradiation, and they could be homogeneously fabricated within an area of 800 × 800 µm. The area filled with the microstructures, including fine periodic structures, could be observed in high contrast under a diffuse, on-axis illumination that was used in commercial QR code readers.

Excimer laser photolysis of concentrated solutions of diazidobiphenyls (4,4′-diazido-3,3′-dimethoxybiphenyl ( 1a ) and disodium 4,4′-diazidobiphenyl-2,2′-disulphonate ( 1b )) gave polymers containing azo bonds in the main chain. Although the polymers formed contained a certain amount of insoluble component, the highest degrees of polymerization detected by gel permeation chromatography were 5-mer (photoproduct from 1a ) and 32-mer (photoproduct from 1b ). The intermolecular reaction of concentrated intermediates containing two reactive sites, which were generated efficiently on irradiation with pulsed excimer lasers, led to a polymer with a higher molecular weight in good yield. The degree of polymerization of the polymers obtained was dependent on the light intensity and concentration of precursors. From a comparison of the degree of polymerization of the polymers obtained by excimer laser photolysis and conventional light photolysis, it is concluded that excimer laser photolysis provides a novel method of polymerization.

We have investigated the photochemical reaction in the external photon field induced with KrF excimer laser (λ=248nm) for the bis(ethynylstyryl)benzene (BESB) films deposited by a molecular beam deposition technique. The cis-cis isomer crystalline films have grown on the KBr (001) substrate without laser irradiation. The laser irradiation to the film surface after and during deposition at the substrate temperature of 25°C caused the cis-to-trans photoisomerization and gave amorphous films due to disordering of the molecular arrangement. On the contrary, the photoisomerized trans-trans isomer crystals were found to be grown upon the irradiation during deposition at the substrate temperature of 60°C. These results indicate that the applied photon field to the molecular beam and the substrate temperatures during deposition play a significant role in thefilm structures.

The formation of radicals on the surface of poly(ethylene naphthalate) (PEN) and poly(ethylene terephthalate) (PET) films after KrF excimer laser ablation was investigated by measurements of electron spin resonance (ESR) and by analyses of surface reaction with a vinyl monomer at a cryogenic temperature. The ESR spectrum of the ablated films in a sealed tube showed a broad peak. Acrylic acid ester and styrene derivatives were immobilized on the ablated and fragment-deposited surfaces through chemical bonds.

We have fabricated β-FeSi2 microprecipitates at room temperature using KrF excimer laser ablation of an α-FeSi2 alloy target. Raman spectra with a spatial resolution of 1 μm confirmed that the micron-sized droplets generated by laser ablation precipitate as the β-FeSi2 crystalline phase on a silicon substrate maintained at RT, whereas the rest of the deposited film is amorphous. It was also found that films containing a high density of β-FeSi2 precipitates exhibited 1.55 μm photoluminescence at low temperature (up to 200 K) after annealing at 800 °C for 6 h in an argon atmosphere.

The resistance of LiCaAlF6 single crystals against F2 laser irradiation was studied to examine the possible use of LiCaAlF6 as optical components for F2 laser lithography. After the initial increase by F2 laser cleaning, transmittance of LiCaAlF6 at 157 nm remains relatively unchanged even after irradiation with an F2 laser beam up to 105 pulses at a fluence of approximately 160 mJcm-2pulse-1, indicating good tolerance against the cumulative irradiation. We also discuss the mechanism of the initial increase in transmittance with the results of X-ray photoelectron spectroscopy (XPS). The threshold fluence for the onset of optical damage of LiCaAlF6 is approximately 2 Jcm-2pulse-1, similar to that of vacuum ultraviolet (VUV) grade CaF2.

Sapphire plates were etched with the approach of laser-induced backside wet etching (LIBWE) using neat toluene or saturated pyrene/acetone solutions as the etching medium. Using this approach, flexible patterns on the scale of 4-µm can be fabricated on the surface of the plates. The etching process was observed in situ by a CCD camera, which revealed the deposition of black particles and the formation thereafter of a laser-absorbing film in the etched area. By Raman spectroscopic analysis, the film was characterized to be amorphous carbon resulting from the decomposition of toluene or pyrene upon laser irradiation, which is an essential factor contributing to the etching process.

Carbon fiber reinforced plastics (CFRP) composite material, which is expected to reduce the weight of automotive, airplane and etc., was cut by laser irradiation with a pulsed-CO 2 laser (TRUMPF TFL5000; P=800W, 20kHz, W=8 s, O =10.6 m, V=1m/min) and single-mode fiber lasers (IPG YLR-300-SM; P=300W, O =1.07 m, V=1m/min)(IPG YLR-2000-SM; P=2kW, O =1.07 m, V=7m/min). To detect thermal damage at the laser cutting of CFRP materials consisting of thermoset resin matrix and PAN or PI TCH-based carbon fiber, the cut quality was observed by X-ray CT. The effect of laser cutting process on the mechanical strength for CFRP tested at the tensile test. Acoustic emission (AE) monitoring, high-speed camera and scanning electron microscopy were used for the failure process analysis. AE signals and fractographic features ch aracteristic of each laser-cu t CFRP were identified. Keywords: CFRP, Laser process, Fiber laser, CO 2 laser, Water-jet, Machining, Tensile test, X-ray CT, Acoustic emission

This paper is discussed about Japanese-style of research structures and funding systems; technology transfer from research institutions (academic sites) to Industry in Japan.This paper is discussed about Japanese-style of research structures and funding systems; technology transfer from research institutions (academic sites) to Industry in Japan.

The formation of radicals on the surface of poly(ethylene naphthalate) (PEN) and poly(ethylene terephthalate) (PET) films after KrF excimer laser ablation was investigated by electron spin resonance (ESR) measurement and by surface immobilization reaction with an acrylic acid ester and a styrene derivative at a cryogenic temperature. The ESR spectrum of ablated PEN film in a sealed quartz tube shows a broad singlet-like peak.

紫外レーザーであるエキシマレーザーを使用して,高分子材料の超精密エッチングや新たな表面改質技術が生まれている.フッ素樹脂の親水化による微細なパターンの無電解めっき法も見い出された.ここでは,高分子の爆発的な分解反応であるアブレーションの利用や高分子膜表面での光化学反応の活用による高分子材料の高機能化を紹介する.

We have investigated ablation process of silica glass induced by X-ray irradiation. X-rays around 100 eV were generated by irradiation of Ta targets with Nd:YAG laser light. The laser plasma soft X-rays have a pulse duration of 10 ns. The soft X-rays were focused on silica surfaces at up to 10 8 W/cm 2 . We found that silica glass can be ablated by X-ray irradiation. Typically, the ablated surface have a roughness of 1 nm after ablation by 500 nm in depth. Further, trenches with a width of 50 nm can be clearly fabricated on silica surface. Thus, high quality, practical micromachining can be achieved by the X-ray technique. It is remarkable that more precise features can be fabricated on silica surface than the thermal diffusion length. The results implies non-thermal ablation process. We observed ions ejected from silica surfaces during the irradiation and found that ions are almost atomic species such as Si + , O + , Si 2 + , O 2 + , SiO + . The results revealed that silica surfaces are broken into atomic species by X-ray irradiation. Among X-ray ablated species, 0.5-15 % are estimated to be ionized. Even though 0.5 % atoms are ionized in silica surface, the energy density of Coulomb repulsive force is higher than the energy density of binding energy of silica glass. Therefore, we can conclude that Coulomb repulsion between X-ray generated ions are essential for X-ray ablation of silica glass.

Polydimethylsiloxane (PDMS) is fundamental materials in the field of biotechnology. Because of its biocompatibility, microfabricated PDMS sheets are applied to micro-reactors and microchips for cell culture. Conventionally, the microstructures were fabricated by means of cast or imprint using molds, however it is difficult to fabricate the structures at high aspect ratios such as through-holes/vertical channels. The fabrication of the high-aspect structures would enable us to stack sheets to realize 3D fluidic circuits. In order to achieve the micromachining, direct photo-ablation by short wavelength light is promising. In the previous works, we investigated ablation of transparent materials such as silica glass and poly(methyl methacrylate) induced by irradiation with laser plasma EUV light. We achieved smooth and fine nanomachining. In this work, we applied our technique to PDMS micromachining. We condensed the EUV light onto PDMS surfaces at high power density up to 108 W/cm2 using a Au coated ellipsoidal mirror. We found that PDMS sheet was ablated at a rate up to 440 nm/shot. It should be emphasized that through hole with a diameter of 1 μm was fabricated in a PDMS sheet with a thickness of 4 μm. Thus we demonstrated the micromachining of PDMS sheets using laser plasma EUV light.

We have investigated responses of PDMS, PMMA and acrylic block copolymers (BCP) to EUV light from laserproduced plasma beyond ablation thresholds and micromachining. We generated wide band EUV light around 100 eV by irradiation of Ta targets with Nd:YAG laser light. In addition, narrow band EUV light at 11 and 13 nm were generated by irradiation of solid Xe and Sn targets, respectively, with pulsed CO2 laser light. The generated EUV light was condensed onto samples, using an ellipsoidal mirror. The EUV light was incident through windows of contact masks on the samples. We found that through-holes with a diameter of 1 μm can be fabricated in PDMS sheets with thicknesses of 10 μm. PDMS sheets are ablated if they are irradiated with EUV light beyond a threshold power density, while PDMS surfaces were modified by irradiation with the narrow band EUV light at lower power densities. Effective ablation of PMMA sheets can be applied to a LIGA-like process for fabricating micro-structures of metals using the practical apparatus. Furthermore, BCP sheets were ablated to have micro-structures. Thus, we have developed a practical technique for microma chining of PMMA, PDMS and BCP sheets in a micrometer scale.

In this paper, we report on a micro-cutting of carbon fiber reinforced plastics (CFRP) by nanosecond-pulsed laser ablation with a diode-pumped solid state UV laser (DPSS UV laser, λ= 355nm). A well-defined cutting of CFRP which were free of debris and thermal-damages around the grooves, were performed by the laser ablation with a multiple-scanpass irradiation method. CFRP is a high strength composite material with a lightweight, and is increasingly being used various applications. UV pulsed laser ablation is suitable for laser cutting process of CFRP materials, which drastically reduces a thermal damage at cut regions.

Excimer laser ablation of poly(ethylene terephthalate), polyimide, and polyethersulfone films has been investigated by measuring the surface potential on the films and the velocity distribution in ionic fragments. Upon the irradiation with XeCl or KrF excimer laser in air, the surface potential of the films charged from neutral to positive. By the measurement of velocity distribution in ionic fragments with a Faraday cup assembly, it turned out that the change into a positive potential on the films was mainly caused by the redeposition of cationic fragments onto the surface of the ablated area. The change in surface potential was applied into the area-selective electroless plating (chemical plating) of copper or nickel on the ablated surface of the films.

Ablative photodecomposition of two polymers, poly(ethylene 2,6-naphthalate)(PEN) and polyether-sulfone (PES), has been investigated for the surface modification. Regular granular microstructures appeared on the surface of PEN film after irradiation with excimer lasers (ArF, KrF, XeCl, and XeF). The microstructure formation of PEN film is explained by the growth of debris originated from the different etching rate between crystalline and amorphous region. In the case of PES, when irradiation with XeCl excimer laser was performed at a fluence of 750 mJ cm−2, periodic wavy microstructures were formed. These surfaces modified by excimer laser ablation have potential application into alignment of liquid crystals and selective-area electroless plating.

We investigated a simple and productive micromachining method of silica glass by the ablation using a 10.6 μm TEA CO2 laser with a spatial resolution down to sub-wavelength scale. Copper grid mask with square apertures of 20×20 μm was attached to the silica glass surface, and the silica glass was irradiated by the TEA CO2 laser light through the mask. As a result, circular holes were formed on the silica glass surface at the center of the apertures due to the\ Fresnel diffraction effect, and a minimum diameter of the hole was less than 3 μm. The mechanism of the micromachining was discussed based on the electric field distribution of the CO2 laser light under the mask, by a 3D full-wave electromagnetic field simulation.

Benzdiynes, which are more unsaturated than benzyne, were proposed as reactive intermediates in the pyrolyses of aromatic dianhydrides in 1966. The generation and direct observation of these highly unsaturated species has been an experimental challenge. More than 30 years later, the first direct observation of a benzdiyne, 1,4-bis(trifluoromethyl)-2,3,5,6-tetradehydrobenzene, was reported. We outline the progress in the generation and observation of benzdiynes as well as theoretical studies on the background of benzyne chemistry. Spectroscopic observation of the benzdiynes, in particular detection of an IR band due to the asymmetric stretching of the two triple bonds, in conjunction with quantum chemical computations reveals their multireference character. In connection with the studies for generating benzdiynes, the studies for generating bisarynes with extended π-systems and the most highly unsaturated cyclic C6 are briefly reviewed.

By laser-induced backside wet etching (LIBWE), we can fabricate deep microstructures with high aspect ratios. To fabricate such deep microstructures by means of a mask-projection system, appropriate optimization of the sample positions is indispensable to maintain the imaging conditions of the mask-projection system at the etch front. By applying the appropriate optimization, the trenches with homogeneous widths and high aspect ratios could be fabricated. At present, a trench with an aspect ratio of 102 (width: 9.7 μm, depth: 986 μm) was successfully prepared. When the irradiated area was gradually shifted in a direction perpendicular to the incidence of the laser beam, inclined features could be fabricated in the deep microtrenches. The tilting angles of the features could be can be flexibly controlled between -30° and +30° by changing the shifting speed. Moreover, the angles could be varied within a single deep microtrench. Fabrication of deep microhole array was also demonstrated. Fabricated microholes were converted into through holes on grinding.

We have investigated a one-step method to fabricate a microstructure on a silica glass plate by using laser- induced backside wet etching (LIBWE) that consists of excimer laser mask projection system and diode- pumped solid state (DPSS) laser beam scanning system. Well-defined deep microtrenches without crack formations on a fused silica glass plate were fabricated by LIBWE method with the UV lasers. We have demonstrated the micro- fabrication of pits-array and patterned grating on the surface of silica glass plates by LIBWE method at 248 nm and 266 nm with dye solutions. The two new systems allow us to use rapid prototyping of high precision surface microfabrication of silica glass as laser direct-write processing.We have investigated a one-step method to fabricate a microstructure on a silica glass plate by using laser- induced backside wet etching (LIBWE) that consists of excimer laser mask projection system and diode- pumped solid state (DPSS) laser beam scanning system. Well-defined deep microtrenches without crack formations on a fused silica glass plate were fabricated by LIBWE method with the UV lasers. We have demonstrated the micro- fabrication of pits-array and patterned grating on the surface of silica glass plates by LIBWE method at 248 nm and 266 nm with dye solutions. The two new systems allow us to use rapid prototyping of high precision surface microfabrication of silica glass as laser direct-write processing.

The following chapter is an overview of processing fused silica and other transparent materials by pulsed-laser irradiation: (1) Direct excitation of materials with multi-wavelength excitation processes, and (2) Media-assisted process with a conventional pulsed laser. A method to etch transparent materials by using laserinduced plasma-assisted ablation (LIPAA), or laser-induced backside wet etching (LIBWE), has been described in detail.

The ablation of three polyethersulfone derivatives by excimer laser radiation at 308 nm and 248 nm was studied to determine the morphological modification of the polymer surface. Highly periodic micropatterns appeared on the surface of polyethersulfone and polyarylsulfone films ablated with a single laser beam at 308 nm in ambient air and in a vacuum, but a smooth surface remained in the case of polysulfone. The selection of radiative conditions, such as the fluence and the polarization of the ablating beam, allows the spacing and pattern of the microstructures to be modified. Topographical observation by scanning electron microscopy and analysis using a time-resolved light scattering technique were carried out to investigate the formation of the microstructure. These results indicate that the penetration depth of the ablating beam into the polymer film and the thermal processes of the surface during and after laser radiation play a significant role in the formation of the microstructures. The different micro-modifications of the three polymers can be explained in terms of the penetration of the beam and the rigidity of the polymers.

The photochemical dehydrochlorination of a chlorinated poly(vinyl chloride) film was investigated with respect to the preparation of a π-electron-conjugated polymer. The dehydrocholorination proceeds more effectively upon irradiation with a KrF excimer laser than with a low-pressure mercury lamp, showing the formation of new absorption bands in the range 300–800 nm. The most effective condition provided KrF excimer laser irradiation of 25− 30 mJ/cm2 at 1 Hz in a vacuum chamber of 10−6 Torr at 90°C. The surface of the irradiated film was analyzed by IR (attenuated total reflection method), X-ray photoelectron and Raman spectroscopy. The characteristic peaks (1 112, 1 488 and 2 188 cm−1) in the Raman spectrum were ascribed to a structure having eight conjugated CC bonds and twenty conjugated CC bonds.

Laser plasma soft X-rays were applied to fabricate nano- and microstructures on surfaces of transparent materials. The optimized X-ray optics and nano-ablation process of silica glass will be emphasized as key device and process.

Deep trenches with inclined parts were fabricated with laser-induced backside wet etching by gradual shifting the irradiation area. Inclined parts with tilting angle of up to 30° could be fabricated.