Semiconductor structure and method of fabrication including forming aluminum columns

摘要

High aspect ratio vias formed in a first insulating layer covering a semiconductor substrate (body) are filled with conductors in a manner that both reduces the number of processing steps and allows an alignment tool (stepper) to align to alignment and overlay marks. Sidewalls and a bottom of each via are coated with a composite layer of titanium, titanium nitride, and a chemical vapor deposited seed layer of aluminum. A physical vapor deposited layer of aluminum is then formed while the structure is heated to about 400 degrees C. to completly fill the vias and to overfill same to form a blanket layer of aluminum above the first insulating layer (34). The blanket layer of aluminum is then patterned and portions not covered by the pattern are removed to result in columns of aluminum. A second insulating layer is then formed around the columns of aluminum. The ends of the columns at a top of the second insulating layer lie in a relatively common plane to which steppers can relatively easily align patterns.