The UF is explained here:
http://en.wikipedia.org/wiki/Unidad_de_FomentoNormally, big cost items, such as real estate, is priced in UF instead of pesos. As a consequence to this you also have mortgages and time deposits in UF. Right now it seems the uncertainty of the future inflation (possible spike?) makes the banks afraid to accept time deposits in UF.
As fas as I know a time deposit in UF is the same as a CD, however, a time deposit in a chilean bank does not have any depositor insurance (similar to FDIC insurance).