Manufacturing method of semiconductor device

A manufacturing method of a semiconductor device, comprising the steps of:

• (a) preparing a semiconductor substrate;
• (b) forming a semiconductor region in the semiconductor substrate;
• (c) forming a metal film over the semiconductor substrate including over the semiconductor region;
• (d) forming a metal silicide layer at the upper part of the semiconductor region by applying a first heat treatment having a first heat treatment temperature, and selectively reacting the metal film with the semiconductor region;
• (e) after the process (d), removing the unreacted part of the metal film and keeping the metal silicide layer over the semiconductor region;
• (f) after the process (e), applying a second heat treatment, the heat treatment temperature of which is higher than that of the first heat treatment;
• and
• (g) after the process (f), forming an insulation film over the semiconductor substrate including over the metal silicide layer,
• wherein the time taken for the temperature of the semiconductor substrate in the process (d) to reach the first heat treatment temperature for reacting the metal film with the semiconductor region from a temperature of the semiconductor substrate immediately before commencement of the first heat treatment is less than one second, and
• wherein crystal grain sizes in the metal silicide layer formed through the first heat treatment in the process (d) are not more than one third of crystal grain sizes in the metal silicide layer after the second heat treatment in the process (f).