A semiconductor device including a dielectric layer having a opening form therein having a cross-sectional area of less than 1 μm 2 and a PVD aluminum base conductor filled in the opening.

Aluminum based conductor for via fill and interconnect

A method is described for improving the step coverage of tungsten interconnects and plugs when deposited at low temperatures into contact/via openings having high aspect ratios. The depositions are made at pressures between 4.5 and 100 Torr in a CVD tool. The method includes a first nucleation step, and a second step for filling the contact/via openings wherein deposition conditions favor good step coverage. For forming an interconnect and a third deposition step, providing moderate step coverage and low stress, is used to build up the interconnect. The high pressures permit deposition at practical rates at low temperatures. In addition the high pressures also permit application of backside gas pressure to the wafer during deposition, thereby improving the thermal contact between the wafer and the heated substrate holder. This contributes significantly to stress reduction and improved step coverage.

Method for reducing stress and improving step-coverage of tungsten interconnects and plugs

A method of making connection between an aluminum or aluminum based material and tungsten. The method includes providing an underlying region containing a layer of tungsten thereover. The underlying region is preferably a layer of titanium over which is a layer of titanium nitride. The layer of tungsten is etched back to the underlying region while exposed tungsten is retained over a portion of the underlying region. The underlying region also may contain a via therein which contains the exposed tungsten. An nitrogen-containing plasma, preferably elemental nitrogen, is then applied to the exposed tungsten and exposed underlying region and a layer of a barrier material is formed by reaction of the nitrogen in the plasma and the tungsten over the exposed tungsten. A further barrier layer, preferably titanium nitride, is optionally then applied followed by a layer of aluminum over the exposed surface, the barrier layer isolating the layer of aluminum from the tungsten. Plasma is preferably an argon/nitrogen plasma.

Aluminum based conductor for via fill and interconnect

References

Method for reducing stress and improving step-coverage of tungsten interconnects and plugs

Method of improving the texture of aluminum metallization for tungsten etch back processing