Aluminum Metallization Using a Combination of Chemical Vapor Deposition and Sputtering.-A combination process meeting the requirements for ULSI (ultralarge scale integration) interconnections and being promising for the manufacturing of subhalf micron multilevel interconnections for ULSI comprises hole filling by CVD of Al from Me2AlH onto TiN followed by film thickening by Al alloy sputtering. Via holes with a diameter of 0. 3 µm and an aspect ratio of 2.7 are successfully filled at 130 . degree.C. Contact resistivities of p-and n-type Si of 1.0 · 10-7 and 2.9 · 10-8 Ω cm2, resp., and for via holes of 1.6 . times. 10-9 Ω cm2 are obtained by this process. -(SUGAI, K.; KISHIDA, S.; SHINZAWA, T.; OKABAYASHI, H.; YAKO, T.; KADOKURA, H.; ISEMURA, M.; KOBAYASHI, T.; HOSOKAWA, N.; J.

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An aluminum metallization process that combines blanket chemical vapor deposition and sputtering was developed for use in fabrication of future ultralarge scale integration interconnections. Blanket chemical vapor deposition of aluminum using dimethylaluminum hydride on titanium nitride, which provides superior step coverage and a smooth surface morphology for films of less than approximately 0.15 μm thickness, was only used for hole‐filling. Subsequent aluminum alloy sputtering, which has a high deposition rate and provides smooth surface films, was used for the thickening of the aluminum films. This combination process draws on the respective advantages of both chemical vapor deposition and sputtering, which mutually compensate for each other's drawbacks. As a result, via holes with a diameter of 0.3 μm and an aspect ratio of 2.7 were successfully filled. The resistance of contact holes fabricated by the combination process was slightly lower than that obtained in the conventional tungsten plug process due to low film resistivity of chemically vapor deposited aluminum. The contact resistivity for contacts to p‐ and n‐type Si were 1.0×10−7 and 2.9×10−8 normalΩ cm2 , respectively. Via hole resistance for 0.45 μm diameter holes was less than 1 Ω, which corresponds to a contact resistivity of less than 1.6×10−9 normalΩ cm2 between chemically vapor deposited aluminum and the underlayer titanium nitride.

A nondestructive, noncontact monitoring method has been developed for Al chemical vapor deposition (CVD). This monitoring method involves irradiating He-Ne laser light on the substrate surface and detecting the reflected light intensity. The intensity changes with deposition time corresponded to the following stage of Al island formation, island coalescence, continuous smooth film formation, and surface roughening. The effectiveness of this method was demonstrated by applying it to Al growth on both in situ sputtered Ti and SiO2 pretreated with tetrakisdimethylamino-titanium for nucleation enhancement.