Patent ID: 6926800

Claim:
A plasma etching apparatus comprising: a reaction tube including an outer circumference and made of a dielectric material in the form of a cylinder; a high frequency coil antenna comprising first and second winding segments, located around the reaction tube and electrically connected to a power supply and a ground to generate a plasma inside the reaction tube, and a third segment, continuously formed with the first and the second winding segments and successively extending between the first and the second winding segments to produce a relatively large uniformly distributed capacitive coupling with the reaction tube, said third segment being closer to the outer circumference of the reaction tube than the first and second winding segments; a drive mechanism to move at least one of the high frequency coil antenna and the reaction tube relative to the other to perform plasma etching at a variable speed; and a controller connected to the drive mechanism to control a relative moving speed between the high frequency coil antenna and the reaction tube, wherein the uniformly distributed capacitive coupling between the high frequency coil antenna and the reaction tube reduces a depositing rate of etching products to extend a cleaning interval for cleaning inner walls of the reaction tube.