Automatic Filling Up Container for Toxic Doping Agents
Original Publication Date: 1988-Sep-01
Included in the Prior Art Database: 2005-Feb-15
Most of the doping agents currently used in the processing of semiconductor wafers are toxic products which need careful handling. As an example, oxide deposition in Low Pressure Chemical Vapor Deposition (LPCVD) equipment uses TEOS (TetraEthlylOrthoSilicate) as a deposition source to produce doped nitrogen. This product is liquid and is commercially available in a 500 cm3 bubbler made of quartz or boronsilicate glass. The bubbler is installed in a heating pot, and its temperature is maintained at about 40-50oC. During each deposition, the liquid level goes down so that it is required to fill up the bubbler after about 10 operations. The present proposal consists of providing an automatic filling-up system which would prevent the need for any manual handling from the operator.