CENTROTHERM E1200 HT 260-3, Operating Instructions Manual

Page: 224 / 233

E1200 HT 260-3
9BPreventive Maintenance
23.04.07
10-44
00401010_41087
10.14.4 Cleaning Graphite Process Boats
The process boat must be etched back when the deposition thicknesses stated in the
table have been reached. We recommend a wet chemical process for every second
etchback process to maintain an optimum surface structure of the process boat. At
least every fifth etchback process must be a wet chemical process if the necessary
wetbench capacity is not available.
Process boat material Process Etchback process according to
deposition thickness
PECVD-nitride 8 µm
PECVD-TEOS-
oxide 10 µm
graphite
PECVD-oxide 10 µm
The plasma process boat is chemically etched during the etchback process with the
dry/in-situ method. C
2
F
6
/O
2
or NF
3
/Air is used for this method. The process boat
surface is attacked and slightly roughened.
The process boat is etched in hydrofluoric acid (HF) during an etchback process with
the wet chemical/ex-situ method.
All piece parts of the process boat are dismantled. All piece parts must be rinsed and
dried after etching. The piece parts must be dried in a drying oven at a temperature
below 100 °C. Once dry, the piece parts are assembled.
10.14.5 Checking the Dry-Running Vacuum Pump (Option)
Further information on preventively maintaining the dry-running vacuum pump, please
refer to chapter 12.10 Suppliers' Documents, page 12-4.