Patent ID: 7137866

Claim:
A polishing apparatus which imparts relative motion between a layer with a concave portion and a convex portion on a semiconductor wafer, comprising: a polishing tool comprising a grindstone and having a plane polishing surface to polish the surface of said semiconductor wafer by said plane polishing surface of said grindstone; a dressing tool having a plane dressing surface for forming a surface roughness on the plane polishing surface of said grindstone; a first moving means for imparting relative motion in a direction horizontal to the plane polishing surface of said grindstone between said dressing tool and said polishing tool; a second moving means for moving said dressing tool in a direction vertical to the plane polishing surface of said grindstone; and a control means for permitting to execute movement caused by said first moving means while controlling a position of said second moving means; wherein said control means comprises a detection means for detecting contact of said grindstone with said dressing tool and controls to stop said second moving means on the basis of the detection of contact between said grindstone and said dressing tool by said detection means.