RF antenna assembly for treatment of inner surfaces of tubes with inductively coupled plasma

摘要

An antenna assembly for forming a barrier coating on the inner surface of a tube by means of a sealed annular chemical-plasma-reaction chamber defined by the inner wall of the tube, two spaced elements slidingly and sealingly moveable inside the tube, and a quartz tube that interconnects the cylindrical elements. The coating is formed by a PE CVD process generated inside the chamber by a transversal RF antenna unit which creates a plasma column that participates in rotation simultaneously with linear motion thus providing uniform coating of the inner surface of the tube. The method of the invention consists of depositing a layer of silicon dioxide onto the inner surface of a plastic tube by means of the aforementioned antenna assembly. The plasma column is rotated by the RF magnetic field which is rotated by using two RF generators of different frequencies that energize two groups of specifically interconnected coils.