Patent ID: 7799694

Claim:
A method of forming a semiconductor construction, comprising: providing a semiconductor substrate having a first opening extending therein; forming a carbon-containing liner within the first opening; punching through a bottom of the liner to expose the substrate along a bottom of the first opening, and to leave a remaining portion of the liner along sidewalls of the first opening; in a method step different from the punching through, etching into the exposed substrate along the bottom of the first opening to form a second opening which is narrower than the first opening and which joins to the first opening; forming electrically insulative material within the first and second openings; wherein the forming of the carbon-containing liner comprises three or more cycles of deposition/etch; with the deposition utilizing one or more of CH 3 F/N 2 , CH 3 F/CO, and CH 3 F/H 2 ; and with the etch utilizing one or more of CF 4 /Ar and CH 3 F/N 2 ; wherein the deposition is conducted at lower substrate bias than the etch; and wherein the deposition of each cycle is conducted for at least about 5 seconds, and wherein the etch of each cycle is conducted for at least one second less than the deposition of each cycle.