LPCVD of aluminium in a batch-type load-locked multi-chamber processing system

A reliable aluminium CVD technique for the filling of submicron contacts and vias providing good step coverage has been developed in a load-locked, batch-type, multichamber system. Because of the low resistivity of aluminium the subsequent metallization layer can be realized in the same process sequence. The Al CVD system configured consists of a reactor module, an I/O port, a bake-out annex activation module, a sputter deposition module, and an etch module, all grouped around an evacuated central wafer handling system which transfers wafers, on a single-wafer basis, in a vacuum of 2×10^-5 Pa. The sputter deposition module provides the option to either deposit a sputtered diffusion barrier prior to the CVD film or to cap the CVD film with a Cu-doped sputtered Al layer to further enhance electromigration resistance. For a film thickness of 1 μm, reflectivities of 55±5% are achieved at uniformities of ±5%. Films exhibit resistivities of 2.8±0.2 μΩ-cm and show good adhesion to most of the commonly used substrates. With a load of 30 wafers for each Al batch reactor, a throughput of 40 wafers per hour can be realized when two Al reactor modules are configured in one system