Patent ID: 7888269

Claim:
A method, comprising: forming a first layer directly on a layer of material, the first layer being formed to a thickness ranging from about 50 Å to about 250 Å, where the first layer comprises a layer of silicon oxynitride (SiON); forming a second layer directly on the first layer, the second layer being formed to thickness ranging from about 200 Å to about 600 Å, where the second layer comprises a layer of silicon nitride (Si 3 N 4 ) and has an extinction coefficient ranging from about 0.9 to about 1.3; forming a third layer directly on the second layer, the third layer being formed to a thickness ranging from about 200 Å to about 400 Å, where the third layer comprises Si 3 N 4 and has an extinction coefficient ranging from about 0.2 to about 0.5; and etching a pattern in the layer of material using the first layer, the second layer, and the third layer as a mask.