Growth and resistivity behavior of copper film by chemical vapor deposition

The film growth of copper from Cu(hfac)VTMS by chemical vapor deposition is shown to be limited by the amount of the source transported to the substrate. The maximum possible growth rate under this transport-limited condition is derived. An explanation is forwarded for a sudden increase in the growth rate between 175 and 200 degrees C based on the deposition mechanism. Selective deposition is shown to take place between TiN and SiO2 surfaces at temperatures below 175 degrees C. The origin of the selectivity is attributed to a prohibitively high activation step on the SiO, surface. The resistivity of deposited copper is lower for higher temperature and is practically constant in the temperature range of 200 to 250 degrees C. The resistivity is almost unaffected by the carrier gas flow rate. The effect of the type of carrier gas is such that a gas of a lower molecular weight gives a higher growth rate.