Abstract A method for forming a film of refractory metal used for interconnection in a semiconductor integrated circuit and, above all, to a method for forming a tungsten film (Blk-W film) by a blanket CVD method. A blanket tungsten (Blk-W) film 10 is formed with good adherence and coverage on an SiO X based interlayer insulating film 3 having a minute-sized contact hole 4 for improving reliability in an interconnection. Before proceeding to Blk-W-CVD, a substrate having a Ti-based adherent layer 7 on its uppermost surface is heated and exposed to a silane-based gas atmosphere for forming Si-nuclei on its surface. A W-nucleus 9 is formed by reducing the WF 6 gas with H 2 and a Blk-W film 10 is also formed by reducing the WF 6 with SiH 4 under a rate determined by the rate of the surface reaction. If the substrate is preliminarily heated before forming the Si nuclei, formation of the Si nuclei proceeds with improved uniformity. The W-nuclei may be carried out uniformly in a temperature range of 450° C. or higher. If the substrate heating temperature during high speed growth is lowered to a temperature lower than that during W-nucleus formation, the thermal stress in the substrate may be released for further improving adherence between the Blk-W film 10 and the substrate.
A method for forming a refractory metal film comprising: a pre-processing step of exposing a substrate to an atmosphere containing a silane-based gas while heating said substrate resulting in Si nuclei formation on the surface of said substrate; and a film-forming step of forming a refractory metal film on said substrate by CVD.
Claim 2
Independent Claim
53 words
A method for forming a refractory metal film comprising: a pre-processing step of exposing a substrate to an atmosphere containing a silane-based gas while heating said substrate resulting in Si nuclei formation on the surface of said substrate; and a film-forming step of forming a refractory metal film on said substrate by CVD.
Claim 3
Dependent Claim
20 words
The method as claimed in claim 1 wherein an inert gas is added to said atmosphere during said pre-processing step.
Claim 4
Dependent Claim
25 words
The method as claimed in claim 1 further comprising a preliminary heating step of heating said substrate for a pre-set time before said pre-processing step.
Claim 5
Dependent Claim
62 words
The method as claimed in claim 1 wherein formation of nuclei of the refractory metal and rapid growth of the refractory metal film are sequentially carried out during the film-forming step and wherein the formation of nuclei of the refractory metal and rapid growth of the refractory metal film are allowed to proceed at a rate mainly determined by surface reaction rate.
Claim 6
Dependent Claim
29 words
The method as claimed in claim 4 wherein rapid growth of the refractory metal film is carried out at a substrate heating temperature lower than that during nucleus formation.
Claim 7
Dependent Claim
16 words
The method as claimed in claim 1 wherein the refractory metal film is a tungsten film.
Claim 8
Dependent Claim
26 words
The method as claimed in claim 1 wherein the nuclei of the refractory metal film are formed in a temperature range not lower than 450° C.
Claim 9
Dependent Claim
18 words
The method as claimed in claim 1 wherein said substrate has a titanium-based adherent layer on its surface.
Claim 10
Dependent Claim
25 words
The method as claimed in claim 4, wherein said nuclei of the refractory metal are formed by reducing WF 6 gas with H 2 .
Claim 11
Dependent Claim
32 words
The method as claimed in claim 4, wherein said refractory metal film is formed by reducing WF 6 with SiH 4 under a rate determined by the rate of the surface reaction.