CVD Temperature Research Articles

Effect of CVD Temperature on Orientation, Roughness, and Chemical Mechanical Polish Removal Rate of W Thin Films

The deposition temperature for tungsten films used as interconnects on Si integrated circuits is found to strongly influence the subsequent chemical mechanical polishing (CMP) removal rate. Careful analysis of the films by orientation imaging microscopy showed a direct correlation between the chemical vapor deposition temperature and the area fraction of (114) vs. (110) oriented tungsten grains. The CMP removal rate decreased as the fraction of (114) oriented grains in the film increased. © 2002 The Electrochemical Society. All rights reserved.

Effect of WC grain growth inhibitors on the adhesion of chemical vapor deposition diamond films on WC–Co cemented carbide

Two sets of Co-cemented tungsten carbide (WC–Co) cutting inserts were sintered using WC powders having different average sized particles (1 and 6 μm). Fine grained WC–Co inserts contained 5.8 wt.% Co and were doped by 0.2 wt.% VC and 0.2 wt.% TaC, which acted as grain growth inhibitors in the liquid-phase sintering. Coarse grained substrates contained 6 wt.% Co and no dopants. Prior to deposition, the inserts were etched using Murakami reagent and then with an acid solution of hydrogen peroxide. The substrates were coated by 31–33-μm diamond films using hot filament chemical vapor deposition (HFCVD) in an atmosphere of 1.5% methane in hydrogen for 14 h, at a substrate temperature of 950 °C. Upon cooling from CVD temperature, only films deposited onto coarse grained inserts were adherent, while films grown on fine grained substrates underwent spontaneous delamination. This fact was due to the presence of a layer of graphitic carbon at the interface between the diamond film and fine grained substrates only. The formation of this sp 2-carbon layer correlated well with the observed huge segregation of grain growth inhibitors at the interface between diamond and fine grained substrates.

Influence of deposition temperature on the hardness and dimensions of steels with hard coatings produced by chemical vapour deposition

CVD hard coatings are applied to steel parts at high and at medium reaction temperatures. The paper presents an introduction to the effect of CVD temperature on hardness and on the dimensions of the CVD-coated steel parts. In combined high temperature CVD and hardening processes, the coatings are deposited at temperatures which are equal to the austenitizing temperature of the steel base; the coated pieces are then quenched in the CVD reactor. Hence the hardness and dimensions of the steel bases depend on the CVD reaction temperature. The required hardness values of the base may be adjusted by tempering according to the hardness-austenitizing temperature-tempering temperature diagram. If the dimensions of the steel parts exceed about 20 mm, the dimensional changes due to heat treatment are larger than those involved in coatings of the usual thickness of 5–10 μm. Dimensional corrections may be made by means of cold treatment and tempering. In medium temperature CVD processes good dimensional stability of the treated steel parts may be achieved by pretempering the prehardened steel parts at temperatures that are equal to or very near to those which are applied in CVD, and by working the pretempered parts to dimensions which will change to within the allowed tolerances during deposition of the coatings. In these processes, high hardness values in D-type steel bases may be reached by the application of hardening temperatures higher than the usual ones. The anisotropic behavior of D-type tool steels may cause some problems in dimensional stability and in the distribution of internal stresses in the hard coatings; the stresses will be compressive in most kinds of CVD hard coatings.