Tung & Associates
Apparatus and method for preventing chamber contamination
 An apparatus and a method for preventing contamination to a low pressure chemical vapor deposition chamber (LPCVD) are provided. The apparatus includes an exhaust-vent device which is connected to a vent outlet and a vacuum pump on a process chamber in parallel with and bypassing a gate valve such that the exhaust-vent remains open during a continuous pumping of the process chamber for wafer loading and unloading. The exhaust-vent device is constructed by two end conduits that have a larger diameter connected by a middle conduit that has a smaller diameter such that during vacuum evacuation, the fluid flow rate in the smaller diameter conduit is at least four times that in the large conduit to effectively prevent the deposition in the small conduit of reaction by-products. The present invention apparatus may further be enhanced by mounting heating tapes on the vacuum conduits and heating the conduits to a temperature of between about 100.degree. C. and about 180.degree. C. to further prevent the deposition of contaminating particles on the interior walls of the conduits. 
Taiwan Semincondutor Manufacturing Company, Ltd
C C
C23C C23C
inventional inventional
Kun-lin Wei-jen Jin-lang
Guan Liu Wu