A method for forming contact holes having different depths in an insulating layer which covers a semiconductor substrate. A first step selectively etches the upper parts of the insulating layer which correspond to contact holes having a greater depth than the shallowest contact hole, using a first mask pattern. A second etch step selectively etches the remainder of the insulating layer for all of the contact holes at the same time using a second mask pattern. Thus, contact hole misalignment is kept to a minimum.