High-speed Deposition Research Articles

Using Simultaneous Deposition and Rapid Growth to Produce Nanostructured Composite Films of AIN/TiN by Chemical Vapor Deposition

Brittleness has been the major obstacle in using ceramics. Previous research has shown, however, that ceramic materials that have small grain size show plasticity. We therefore propose two methods to produce nanostructured ceramic films by chemical vapor deposition (CVD): (1) high‐speed deposition and (2) simultaneous deposition of insoluble materials (contained in a mixture of insoluble solids). These methods were successfully applied to aluminum nitride/ titanium nitride (AlN/TiN) films produced by CVD. The AlN/TiN nanostructured composite films were synthesized by atmospheric‐pressure CVD (APCVD), using aluminum chloride (AlC13), titanium chloride (TiCl4), and ammonia (NH3) as reactant gases at temperatures ranging from 923 to 1123 K in a horizontal tubular reactor. For the highspeed deposition strategy, we obtained growth rates as high as 1.2 mm/h. Using either method, we were able to attain AlN/TiN composite films that had a grain size of 8 nm (AlN crystals) and 6 nm (TIN crystals), showing that these methods are effective in producing nanostructured composite films by CVD. Measurements of the fracture toughness of the prepared materials indicated that these strategies can be used to improve the ductility of ceramics.

Vacuum deposited polymer/metal multilayer films for optical application

Vacuum-deposited polymer/silver/polymer reflectors and tantalum/polymer/aluminum Fabry-Perot interference filters were fabricated in a vacuum web coating operation on polyester substrates with a new, high-speed deposition process. Reflectivities were measured in the wavelength range from 0.3 μm to 0.8 μm. This new vacuum processing technique has been shown to be capable of deposition line speeds in excess of 500 linear m min −1 (D.G. Shaw and M.G. Langlois, Proc. 7th Int. Conf. Vacuum Web Coating, November 1993, p. 268). Central to this technique is a new vacuum deposition process for the high-rate deposition of polymer films. This polymer process involves the flash evaporation of an acrylic monomer onto a moving substrate. The monomer is subsequently cured by an electron beam or ultraviolet light. This high-speed polymer film deposition process has been named the polymer multi-layer process. Also, vacuum-deposited, index-matched, polymer/CaF 2 composites were fabricated from monomer slurries that were subsequently cured with ultraviolet light. This second technique is called the liquid multi-layer process. Each of these polymer processes is compatible with each other and with conventional vacuum deposition processes such as sputtering or evaporation.

High-speed laser chemical vapor deposition of copper: A search for optimum conditions

The photothermal laser-induced chemical vapor deposition of copper is studied as a function of the writing speed, the light intensity, and the diameter of the focal spot on the substrate, at three different pressures of the copperbishexafluoroacetylacetonate precursor. The height, the width, and the electrical conductivity of the deposited metal stripes are measured. The metalorganic vapor pressure is the key variable for attaining high writing speeds. Copper stripes have been obtained at 1 mm s−1 .

Laser Surface Modification for Copper Deposition on Polyimide

ABSTRACTSelective modification of surface reactivities with lasers, using either direct writing or projection method, is intrinsically a sensitive method to prepare a surface for highresolution and high-speed area selective thin film deposition. In this paper, we demonstrated the use of laser direct-writing and projection patterning techniques for selective modification of the electrochemical property of a polyimide surface. High quality and highresolution copper patterns on polyimide surfaces are produced when the surface-modified sample is subsequently placed in an electroless plating solution. These results demonstrated that the use of laser-selective-modification of surface properties in conjunction with other batch thin film deposition processes provides an attractive approach for area-selective metallization for a variety of applications in which high writing speed and high sensitivity are required.

High Quality P-Type A-SiC Film Doped with B(Ch3)3 and its Application to A-Si Solar Cells

High-quality p-type a-SiC films were prepared using a new doping gas, B(CH 3 ) 3 , instead of B 2 H 6 . a-SiC films deposited with B(CH 3 ) 1 show high photoluminescence intensity and low defect density. Doping efficiency was also improved by usiyg B(CH 3 ) 3 . A module efficiency of more than 9% was achieved for a 100 cm 2 a-Si solar cell whose p-layer was doped with B(CH 3 ) 3 . A new plasma CVD method, called controlled plasma magnetron (CPM) method was developed to realize high electron-density plasma with low damage to substrate. High conductive p-type μc(microcrystalline)- SiC films were prepared by CPM method with B(CH 3 ) 3 . CPM method was found to be suitable not only for preparation of μc films but for high-speed deposition.

High speed deposition of high-quality ferrite films from aqueous solution at low temperatures (≤90 °C)

We have plated polycrystalline CoxFe3−xO4 (x=0 and 0.43) films on PET and glass substrates at 80–90 °C in an aqueous solution by new three methods: (1) spraying, (2) spin coating, and (3) thin liquid-film methods. The reaction solution is (1) sprayed, (2) spin coated, and (3) flowed through a gap between the substrate and a glass plate, respectively, making a thin (5–400 μm) coating of the solution on the substrate. Since the solution flows off, the composition of the solution on the substrate does not significantly change during the plating, and the ferrite particles formed in the solution are washed away. This improves the film quality compared to previous methods. We have further improved the film quality by introducing CH3COO− buffer ions into the solution, and also by filtering the solution. By the thin liquid-film method, we have obtained maximum deposition rates of ∼160 and ∼300 Å/min by the spraying and the thin liquid-film methods, respectively. The films of Fe3O4 and CoxFe3–xO4 (x=0.43) plated by the thin liquid-film method exhibited a preferential texture of (100) and (111) planes, respectively, parallel to the surface. Both films had a columnar structure normal to the surface, but the magnetization lies in the surface plane.

Laser-enhanced patterning using photothermal effects: maskless plating and etching

We review our work on laser-enhanced plating and etching with emphasis on the chemical, electrochemical, and thermal mechanisms giving rise to the experimental observations. The metallurgical properties of the deposits and their applications, particularly in the field of microelectronics, are also discussed. The work on laser-enhanced electroplating and electrodeless plating includes high-speed deposition of copper, gold, and nickel by using the argon-ion laser as the source of localized energy. Deposition rates up to 3 orders of magnitude higher have been observed for laser-irradiated regions compared with nonirradiated ones. Mechanisms responsible for the plating enhancement are (1) enhanced chemical and electrochemical kinetics with increased temperature, (2) shifts in the local rest potential with temperature, and (3) local agitation of the solution as a result of large temperature gradients. Applications of these techniques to circuit design and repair as well as to high-speed plating of precious metals onto electrical contact areas of microelectronic circuits are considered. Experiments on high-speed laser-enhanced etching of several dielectrics are also reviewed. Volume removal rates as high as 106μm3/sec for an alumina/TiC ceramic and 105μm3/sec for 〈111〉 silicon using KOH as the etchant have been obtained.

Future trends in electroplating for the electronics industry

Electronic component miniaturisation is assessed in terms of its future requirements from plating processes. Improvements needed in electroless plating, high speed deposition, laser enhanced proces...

Stacking Structures of Multilayered Thin Films

Magnetostatic coupling between layers in multilayer films enables more complex domain structures than are possible in single-layer films. Both high-speed sputtering and vacuum deposition were used to form films in which magnetic (Fe, Ni) and nonmagnetic (Si, SiO, C) layers alternate. Due to interdiffusion at layer boundaries, sputtered Fe-Si multilayer films metamorphosed into films of alternating layers of ferromagnetic Fe-rich Fe-Si and nonmagnetic Si-rich Si-Fe, which layers are magnetostatically coupled.

High-speed electroplating of copper using the laser-jet technique

The laser-jet electroplating technique has been applied to the high-speed deposition of copper at rates up to 50 μm/s. The high plating efficiency of the Cu/Cu++ system makes the deposition rate independent of laser power (unlike that of gold). On the other hand, the morphology of the copper is greatly improved with increasing laser power. Four-point probe measurements for laser-jet copper depositions indicate a resistivity close to that of the published bulk value.

ＥＤＴＡ浴による高速度無電解銅めっきの反応機構

Mechanisms of high-speed electroless copper deposition from EDTA bath were investigated by means of analytical method, X-ray diffraction and electrochemical method. From the analysis of bath components and the reaction products such as copper and hydrogen gas during the electroless copper deposition at 70°C, it was confirmed that the following reactions were occurring in the bath.Cu deposition reaction: Cu(II)-EDTA+2HCHO+4OH-→Cu+2HCOO-+H2+2H2O+EDTA…(1)Cannizzaro reaction: 2HCHO+OH-→CH3OH+HCOO- …(2)The reaction (2) was remarkably promoted by the increase of bath temperature above 60°C and pH higher than 12.5. X-ray diffraction data of the powdery deposits which have been obtained by 1 hour mixing of CuO and Cu2O powders with the Cu-EDTA bath at 60°C showed that the reducing power of the solution containing both formaldehyde and EDTA was higher than that of the solution containing each component separately. In the former case, the added Cu2O was completely reduced to metallic copper. This fact suggests that the spontaneous decomposition of the EDTA bath does not occur through the formation of Cu2O contrary to the case of Rochelle salt bath, but spontaneous decomposition starts in the bath either by copper particles removed from the surface or by the reduction of metallic copper when the reducing power of the solution increases. The mixed potential theory of the reaction (1) was also studied by potential sweep method.

ＥＤＴＡ浴による高速度無電解銅めっきの延性に及ぼす添加剤の影響

Effects of various additives on the high-speed electroless copper deposition from EDTA bath were investigated. By electron-microscopic observation of the surface of copper deposit from the additive free EDTA bath, it was shown that the surface consisted of fine and easily fallen off particles that would cause spontaneous decomposition of the bath when they fell off into the solution. Single use of ferrocyanide, potassium nickel cyanide, or sodium nitroprusside as additive in EDTA bath improved the ductility of the copper deposits to some extent, and the deposits from these baths provided the surface consisting of small pyramidal crystals at 50°C, which grew to larger and more leveled grains at 70°C. As previously reported, the authors found that the ductility of copper deposit was remarkably improved when 2, 2'-dipyridyl and the other compound, e.g. potassium nickel cyanide, were added together into the EDTA bath. Electron-micrographs of copper deposits from these baths contaning two additives provided the surfaces apparently more leveled than those from the baths containing each additive individually. Thus the corelation between ductility and surface leveling was confirmed. Ductility of copper deposit and deposition rate increased with increasing bath temperature up to 80°C, beyond the temperature deposition rate decreased because of the predominance of Cannizzaro reaction. Further addition of some kinds of nonion type surface active agents into the plating bath was found to give favorable effects on the ductility of the deposit.