Patent ID: 7189636

Claim:
A fabrication method of a semiconductor integrated circuit device, comprising: a first step of depositing a cobalt film over the main surface of a silicon substrate, the cobalt film being deposited on a bare silicon surface of the main surface of the silicon substrate; and a second step of heat treating the silicon substrate to form a silicide layer on the interface between the silicon substrate and the cobalt film, wherein in the first step, the cobalt film is deposited at a temperature lower than a temperature at which a reaction layer of silicon and cobalt is formed on the interface between the bare silicon substrate surface and the cobalt film, said temperature, lower than the temperature at which said reaction layer is formed, being maintained until the end of depositing the cobalt film, and wherein the heat treatment of the silicon substrate in the second step comprises the steps of: (a) a first-stage heat treatment for forming a disilicide layer having, as a main component, dicobalt silicide (Co 2 Si) on the interface between the silicon substrate and the cobalt film; (b) a second-stage heat treatment for forming the main component of the monosilicide layer from dicobalt silicide into cobalt monosilicide (CoSi); and (c) removing an unreacted portion of the cobalt film from the main surface of the silicon substrate after the second-stage heat treatment, and a third-stage heat treatment for forming a main component of a cobalt disilicide layer by converting from cobalt monosilicide to cobalt disilicide (CoSi 2 ).