Characterization in Silicon Processing

in

depth, depending

upon

the application. The main problem which CVD tung-

sten solves is one of step coverage, or the coverage of the metallization

layer

as it

deposits

onto

the

wall

and

bottom

of the contact holes. Since sputtering and evapo-

ration techniques are performed at low substrate temperatures, they suffer from

poor

step coverage due to the low surface mobility of the deposited species. Al-

though modern sputtering techniques such as wafer heating and resputtering offer

improvements, the conformality of such films in extremely small contacts is insuf-

ficient to meet the demands of manufacturing ICs with submicron features.

Chemica