Coupling of microwave energy through reactor wall - uses prim. and sec. aerial which are connected via coaxial feed-through inserted in vessel wall

摘要

Microwave energy coupler transferring energy from one chamber into another comprises a prim. antenna (2) in the first chamber, a sec. antenna (3) in the second chamber, pref. the plasma-reactor, and a separator wall (20) inside which the connector (11) is fitted. The connector (11) has a dark room cap (12) on the inside of the reactor, the cap is pan shaped and has the open end towards the wall (20). Both antennae pref. have the form of an open loop, with one end connected to the connector (11) and the other end to a socket (4) which is fitted inside the separator wall. The socket (4) pref. has a small opening at the reactor end and a large opening on the generator end. The socket has essentially a U-shaped cross section with the upper part displaced with respect to the lower part. The separator wall (20) pref. has a hole corresp. with the shape of the socket in which a shelf (32) is provided to seat the socket and a seal is provided with an elastomer ring. The inner core of the connector (11) pref. is rod shaped and has a ring shaped collar (24), and a length of lambda/2 whereby lambda is the microwave length. The collar is compressed between 2 ceramic discs (25,26) pref. made of AlSin 99.7, providing good thermal contact, and the lower collar (26) presses down on a metal sealing ring (27). USE/ADVANTAGE - The coupler provides an efficient means of transmitting high levels of microwave energy into the chamber without the effect in the plasma chamber being as restricted in area as in conventional quartz window couplers. The heating up effect is very small and there is very little contamination. There is no plasma discharge forming inside the vacuum feedthrough of the coupler.