COPPER FILM GROWTH BY CHEMICAL VAPOR-DEPOSITION - ELECTRICAL AND OPTICAL MEASUREMENTS IN REAL-TIME, AND STUDIES OF MORPHOLOGY

The deposition of copper by low pressure chemical vapor deposition (CVD) from copper bis-hexafluoroacetylacetonate is monitored in real time and in situ by the measurement of the optical reflectivity and electrical resistance of the growing metal film. Changes of the deposit morphology during growth were analyzed by interrupting the CVD process at different stages and observing the samples by transmission electron microscopy. Pure copper is deposited at a temperature of 400-degrees-C and 1 mbar total reactor pressure of helium, precursor, and water vapor. Two successive regimes are distinguished in the deposition: island formation and continuous film growth. The transition between these two regimes is visible in the real time specular reflectance measurement. The copper deposition rate is twice higher during the island growth than during the continuous film growth at the applied conditions. The influence of a metal seeding layer (from 0.001 monolayer to 1 monolayer) on the copper deposition is shown both in the real time measurements and in the ex situ analysis of films.