The silicon trench etching in BCl3/Cl2 reactive ion etching plasma leads to the intrinsic bonding damage, the permeations of etching species and impurities into silicon substrates, and the deposition of residue film on trench sidewall. The contaminations and the damages in trench were investigated by using high resolution transmission electron microscopy (HRTEM), secondary ion mass spectrometry (SIMS), and x-ray photoelectron spectroscopy (XPS). The microstructure of the rounded bottom surface showed that the surface region was distorted by 2 - 6 atomic layers and the trench etch was mainly limited by the physical sputtering-like mechanism. The damage in the silicon lattice consisted of prominent planar defects roughly confined to {110} and {111} planes. The thickness of sidewall residue film was 10 - 90 nm, which was thinner at deeper region of the trench, whereas that of residue film at the trench bottom was 1.5 - 3.5 nm. The SIMS results of no-patterned specimen presented that the permeation depths of boron and chlorine into the Si-substrate were about 40 and 20 nm, respectively. The presence of BxCly and Cl-related Si chemical states was identified from XPS analysis of the residue film.

In recent years the on-chip delay has gone down much more rapidly than the signal delay in packaged circuits. As a consequence of this the packaging delay times have had to be reduced drastically, which means that a greater packging density had to be implemented. A novel planar packaging technique, used in the new Siemens main frame computer 7500 H 90 has led to considerable progress in solving this problem. An essential part of this system is a multi-chip-module which can hold up to 144 bare chips. The carrier of these IC's is a 16-layer high density multilayer printed circuit board, which is fabricated in a sequential process. Interlayer contacts are formed by 80 µm wide blind via-holes, which are generated by excimer-laser ablation of the dielectric. The process desribed in this paper shows that it is possible to produce blind via-holes with an aspect ratio of about one in an extremely reliable and reproducible way. This process is already being successfully run on a production line. It is to our best knowledge the first time excimer lasers have been used on a large-scale in an industrial environment.

Superconducting films of Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O on (100) SrTiO3 and (100) MgO substrates have been fabricated by reactive excimer-laser sputtering from ceramic targets. Film patterning by laser-induced reduction/metallization, oxidation, and ablation has been investigated.

On polished sodium trisilicate glass surfaces, a fairly distinct threshold in laser fluence is observed to commence ablative etching. An incubation or induction effect is also seen where a series of laser pulses is required to induce etching. In this paper we examine features of the charged particle emission over a broader range of fluences (in particular, at lower fluences) to identify those factors which control the onset of etching. Laser--free electron heating is proposed as a dominant mechanism.

Ablation and etching of the surface of polymethyl methacrylate (=PMMA) by pulses of 248 nm laser radiation ∼20 ns full width at half maximum (FWHM) have been probed by pulses of visible laser radiation (596 nm; < 1 ns FWHM). The results were recorded photographically in real time with a set time delay between the 248 nm ablation pulse and the 596 nm probe pulse. Modification of the surface structure of the polymer at a fluence ∼ 3 J/cm2 is first visible at 12 ns and appears to be complete in ∼ 60 ns. The first manifestation of the ablation does not occur until the UV pulse is over and consists of a nearly transparent shock-wave that has an initial velocity of 6 ∼ 104 cm/sec. Solid material from the ablated zone begins to leave the surface at ∼150 - 200 ns and reaches a maximum in intensity at 6 µs, continuing for ∼ 20 µs. The average velocity of the solid material, which is probably a low molecular weight polymer of PMMA, is 1.5 ∼ 104 cm/sec. The conclusion to be drawn from the present work is that the signal measured by photoacoustic detectors does not coincide with the bulk of the material leaving the surface.

We have investigated the formation of various multilayer thin films by the laser physical vapor deposition technique. A multi stage target holder was constructed to perform all process steps in-situ; target/substrate cleaning, deposition, and annealing. The laser physical vapor deposition technique offers many advantages over conventional physical vapor techniques, such as, lower substrate temperature, microstructural control, and very low contamination levels. Film thickness can be controlled from near atomic to micron dimensions. A layer-by-layer (two dimensional) growth can be achieved, resulting in nonequilibrium structures. The films were analyzed using cross-section and high resolution transmission electron microscopy (TEM). The significant reduction in substrate temperature for the formation of high quality multilayer and epitaxial films opens up many new areas of applications requiring reduced thermal-budget processing.

0.6 µm-wide lines of high Tc Y-Ba-Cu-O have been fabricated by direct laser writing on mirror-like thin films which were grown by laser deposition without post annealing. Laser ablation etching had no effect on the Tc and Jc until the lines were < 1µm wide. The 0.6 µm-wide strip showed some degradation of Tc and Jc. The critical current densities for these patterned lines were measured to be ∼5×106 A/cm2 at 50 K.