Chemical vapour deposition methods.

摘要

In a CVD method, a wafer (3) is retained on a wafer holder (2) in a reaction tank or chamber (1) to be put under reduced pressure. At least one through hole is made in an insulating film formed on a substrate of the wafer (3). A gas containing at least a metallic element is introduced into the reaction chamber (1) under reduced pressure so that a first metallic film of the metal element is formed on the substrate in the through hole of the insulating film of the wafer (3). This gas and a reduction gas are then introduced into the reaction chamber (1) under reduced pressure through inlets (4a, 4b) and radiation from a heating lamp (8) is directed on to the wafer (3) so that a temperature difference arises between the insulating film and the first metallic film, as a result of differences of absorption rates of the radiation between the insulating film, the substrate and the first metallic film. A chemical reaction is effected only on the first metallic film, and a second metallic film of the metal element is formed on the first metallic film. The metallic element containing gas may be introduced in a sheet-like manner substantially parallel to the surface of the wafer (3) by shaping the inlets (4a, 4b) so that their width is much less than their length. An inert gas or a gas containing mainly inert gas is introduced through a perforated plate (6a) towards the surface of the wafer (3) so that the reaction gases maintain laminar flow (R, R'). The metallic element containing gas and a reduction gas such as hydrogen are then introduced in a sheet-like manner substantially parallel to the surface of the wafer (3) into the reaction chamber (1) under reduced pressure, the at least substantially inert gas being introduced towards the surface of the wafer (3). The wafer (3) is heated so that a second metallic film of the metal element is formed on the first metallic film.