Method using a thin resist mask for dual damascene stop layer etch

A dual damascene method comprising:

• providing a substrate having a first low k material layer;
• forming a first hard mask layer over the first low k material layer;
• patterning a first opening having a first width in the first hard mask layer using a first ultra-thin photoresist having a thickness of about 1,500 Å or less thereby exposing a portion of the first low k material layer;
• removing the first ultra-thin photoresist;
• depositing a second low k material layer over the patterned first hard mask layer and the exposed portion of the first low k material layer;
• forming a second hard mask layer over the second low k material layer;
• patterning a second opening having a width larger than the first width in the second hard mask layer using a second ultra-thin photoresist having a thickness of about 1,500 Å or less thereby exposing a portion of the second low k material layer;
• anisotropically etching the exposed portions of the first and second low k material layers to form a dual damascene opening;
• removing the second ultra-thin photoresist;
• and
• filling the dual damascene opening with a conductive material.

A dual damascene method comprising:

• providing a substrate having a first low k material layer;
• forming a first hard mask layer over the first low k material layer;
• patterning a first opening having a first width in the first hard mask layer using a first photoresist having a thickness of about 1,250 Å or less thereby exposing a portion of the first low k material layer;
• removing the first photoresist;
• depositing a second low k material layer over the patterned first hard mask layer and the exposed portion of the first low k material layer;
• forming a second hard mask layer over the second low k material layer;
• patterning a second opening having a width larger than the first width in the second hard mask layer using a second photoresist having a thickness of about 1,250 Å or less thereby exposing a portion of the second low k material layer;
• anisotropically etching the exposed portions of the first and second low k material layers to form a dual damascene opening;
• removing the second photoresist;
• and
• filling the dual damascene opening with a conductive material.