To obtain a slurry for polishing a metal film, capable of polishing a metal film even under low-load conditions at a high speed and controlling occurrence of defects of a face to be polished such as scratch, dishing, erosion, etc. in a process for flattening a metal film on a semiconductor substrate.

This slurry for polishing a metal film is characterized by comprising colloidal titanium oxide and an iron (III) compound as essential components. Etching properties of the slurry itself are reduced by an interaction between colloidal titanium oxide and iron (III) ion produced from the iron (III) compound and occurrence of defects such as dishing, erosion, etc. can be controlled. Since the slurry has excellent polishing performances such as high-speed polishing properties, low scratch properties, etc., the slurry can be expected to have an application to a mass production process and a process using a porous type low-dielectric-constant insulating film.