372595885

JPRS-UMS-92-003 16 March 1992

COATINGS

23

printed board. The researchers succeeded in producing Cu-Ni-P-Au printed Circuit board contacts that meet the reąuirements established for contemporary Circuit board technology. Experiments examining the exposure time dependence of the area of Ni-P deposited on Si revealed that while the area of a deposit does not initially depend on exposure time, it becomes very much dependent on exposure time further on into the process. Scanning the laser radiation along the substrate surface was found to result in the deposition of Ni-P pathways. Expcriments related to direct laser metallization of epoxy-resin glass-base textolites resulted in the formation of paths that are little suited to use in actual practice because of their resistance (tens to hundreds of ohms). This problem was remedied by completing the growth of the deposited paths. After this was done, the path resistance decreased to 1 Q. The researchers also succeeded in demonstrating the possibility of metallizing 100-pm-diameter holes in polycorundum wafers 500 pm thick by laser-stimulated deposition of Ni-P coatings onto the hole walls. Figures 6; references 12: 9 Russian, 3 Western.

The Porosity and Electrical Strength of Thin Alumina and Zirconia Films Produced by High-Frequency Magnetron Sputtering

927D0049F Moscow FIZIKA IKHIM1YA OBRABOTKIMATERIALOV in Russian No 3,

May-Jun 91 (manuscript received 2 Apr 90) pp 81-84

[Article by V.G. Padalka, I.V. Lunev, and V.I. Agafonov, Kharkov]

UDC 621.315.61

[Abstract] The authors of the study examined the porosity and electrical strength of thin alumina and zirconia films produced by high-frequency magnetron sputtering. Polycrystalline A1₂0₃ and Zr0₂ films were produced by high-frequency magnetron sputtering in argon under a pressure of 1 to 2 Pa. Pure powders of the respective compounds that had first been annealed at 1,000°C in a vacuum of about 10*⁴ Pa were used as targets. The films were deposited onto standard pyro-ceram substrates that had been precoated with a layer of chromium 0.5 pm thick by thermal vaporization. The dependcnces of porę density, porę size distribution, and electrical strength of the films on the respective film-formation parameters were recorded at fixed values of the said parameters. In the case of the A1₂0₃ films these parameters were as follows: film thickness, 200 nm; deposition ratę, 17 nm/min; deposition temperaturę, 270°C; and substrate grid bias, -50 V. For the ZrC>₂, these same parameters were as follows: film thickness, 200 nm; deposition ratę, 40 nm/min; deposition temperaturę, 300°C; and substrate grid bias, -40 V. The through porosity of the films was studied by the electrochemical method, and the films’ electrical strength was deter-mined by their volt-ampere characteristic. A sublayer of chromium and an extemal mercury contact served as electrodes. As the thickness of both types of films increased, the density of the through pores tended to decrease. At thicknesses greater than 200 nm, this trend wcakencd noticcably, thus indicating the end of the process of build-up of aggregates of film nucleation centers. Through porę density was found to behave analogously as the deposition ratę was increased. Increasing the speed at which the coating layer was deposited was found to result in a decrease in the ratio of the ratę at which the condensation of argon and residual gases reached the surface to the ratę at which particles of the deposited materiał reached it. This decrease in tum increased the mobility of the adatoms on the condensate surface and facilitated improved healing of the film defects that had formed. The density of the through micropores of both the alumina and zirconia films was found to decrease as the mobility of the adatoms increased. The porę size distribution functions of both the alumina and zirconia films studied had a normal distribution with a maximum in the rangę from 150 to 600 nm. As the deposition temperaturę was increased within the interval from 300 to 600°C, the electrical strength of both the alumina and zirconia films increased. Electrical strength decreased as film thickness increased, however. Increasing deposition speed also reduced electrical strength. The migration capability of the adatoms increased as the magnitude of the negative grid bias fed to the substrate during the film condensation process was increased. This increase in migration capability in tum resulted in the growth of a morę perfect crystalline structure and in an increase in the films’ electrical strength. Figures 2; references 5: 3 Russian, 2 Western.

The Formation Mechanism of Crystal Lattice Defects in Electrodeposited Nickel Films

927D0067H Moscow POYERKHNOST: FIZIKA, KHIMIYA, MEKHANIKA in Russian No 12, Dec 91 (manuscript received 13 Aug 90; after remion 5 Dec 90) pp 119-123

[Article by T.A. Tochitskiy and A.V. Bolutshkin, Solid-State Physics and Semiconductors Institute, BSSR Academy of Sciences, Mińsk]

UDC 539.216.2.548

[Abstract] The authors of the study reported herein examined the mechanism of lattice defect formation in nickel films 20 nm to 10 pm thick that were precipitated from a sulfuric acid electrolyte onto copper substrates. Specifically, the films were precipitated from an electrolyte containing 280 g/1 NiSÓ₄ x 7H₂0, 120 g/1 MgS0₄ x 7H₂0, and 30 g/1 H₃B0₃. The films were deposited at room temperaturę, a pH of 2 to 6, and a deposition current density of 5 to 70 mA/cm². Saccharin in a concentration of 0 to 5 g/1 was used as a surfactant. An EMV-100LM electron microscope and DRON-3 diffrac-tometer were used to study specimens of the films. Specifically, the specimens subjected to x-ray crystallo-graphic analysis consisted of 30 to 40 epitaxial layers