Changes in filling characteristics when adding oxygen to sputtering gas (1 at.% N-2-Ar) were investigated using high-vacuum planar magnetron sputtering equipment having little residual gas effects. It was found that copper filling accelerates for oxygen partial pressure in sputtering gas of P-O2 = 5 x 10(-5) to 1 x 10(-4) Pa and a substrate temperature of 300-320 degrees C. Under these conditions, 70% copper filling in fine holes of diameter phi = 100 nm (AR = 4.5) was obtained. (C) 2009 Elsevier B. V. All rights reserved.