Process of making dual damascene structures using a sacrificial polymer

A method making dual damascene structures comprising the steps of:

• a) forming a sacrificial layer comprising a sacrificial polymer over an oxide layer;
• b) depositing a first hard mask at a temperature below 400 degrees Celsius over the sacrificial layer;
• c) depositing as a second hard mask at a temperature below 400 degrees Celsius over the first hard mask;
• d) depositing and patterning a photoresist via pattern;
• e) etching the second hard mask to form a via in the second hard mask;
• f) etching the first hard mask to extend the via through the first hard mask;
• g) depositing and patterning a photoresist line pattern;
• h) etching the second hard mask to form a line in the second hard mask;
• i) etching the sacrificial layer using the first hard mask as a via mask, whereby the via extends through the sacrificial layer;
• j) etching the first hard mask using the second hard mask as a line mask, whereby the line extends through the first hard mask;
• and
• k) etching off the second hard mask and etching into the oxide layer.
• 2., The method of claim 1, wherein the step of forming the sacrificial layer further comprises spin coating.