Patent ID: 8308898

Claim:
A tuner, provided in a microwave transmission path for transmitting a microwave from a microwave power source to a chamber for performing a microwave plasma process, for matching an impedance of a load in the chamber to a characteristic impedance of the microwave power source, the tuner comprising: a body having a tubular outer conductor and a tubular inner conductor coaxially provided in the outer conductor, the body forming a part of the microwave transmission path; an annular dielectric slug provided between the outer conductor and the inner conductor, the slug being movable along a longitudinal direction of the inner conductor; and a drive mechanism for moving the slug, wherein the drive mechanism comprises: a drive part for applying a driving force; a drive transmission part for transmitting the driving force from the drive part to the slug; a drive guide part for guiding movement of the slug; and a holding part for holding the slug at the drive transmission part, wherein the drive transmission part, the drive guide part and the holding part are accommodated in the inner conductor.