Simplified pitch doubling process flow

A method for fabricating a semiconductor device, the method comprising:

• patterning a layer of photoresist material to form a plurality of photoresist mandrels over a hard mask layer, the photoresist mandrels having a pitch of about 150 nm or less;
• using an atomic layer deposition technique to blanket deposit an oxide material onto the plurality of mandrels;
• depositing another layer of photoresist material on the blanket deposited oxide material;
• patterning the other layer of photoresist material;
• anisotropically etching the oxide material to form spacers on sidewalls of mandrels and to pattern oxide under the patterned other layer of photoresist material;
• etching the photoresist material of the layer of photoresist material and the other layer of photoresist material selectively with respect to the oxide material, thereby forming a plurality of free-standing oxide spacers over the hard mask layer;
• transferring a pattern defined by the spacers and the patterned oxide to the hard mask layer;
• and
• transferring the pattern to a substrate underlying the hard mask layer.