| abstract |
Reliable contacts/vias are formed by sputter etching to flare exposed edges of an opening formed in a dielectric layer, depositing a composite barrier layer and then filling the opening with tungsten at a low deposition rate. The resulting contact/via exhibits significantly reduced porosity and contact resistance. Embodiments include sputter etching to incline the edges of an opening formed in an oxide dielectric layer, e.g., a silicon oxide derived from TEOS or BPSG, at an angle of about 83° to about 86°, depositing a thin layer of Ti, e.g., at a thickness of about 250 Å to about 350 Å, depositing at least one layer of titanium nitride, e.g., three layers of titanium nitride, at a total thickness of about 130 Å to about 170 Å, and then depositing tungsten at a deposition rate of about 1,900 to about 2,300 Å/min to fill the opening. |