Gas mixing method to enhance plasma

A gas mixing method to enhance plasma comprising:

• providing a reaction chamber;
• wherein the reaction chamber includes an accommodating space and the reaction chamber includes a top opening connected to the accommodating space;
• providing an adapter plate, and fixing the adapter plate to the reaction chamber to be arranged corresponding to the top opening;
• wherein the adapter plate further includes a window area communicating both sides of the adapter plate and an air intake channel connecting an outer side surface of the adapter plate and the window area;
• providing a target disposed on top of the adapter plate to seal the top opening,
• premixing a plasma gas and an auxiliary gas into a gas mixture, and introducing the gas mixture into the accommodating space;
• providing a biasing field to the accommodating space wherein disposing a holder plate in the accommodating space, providing a biasing power source electrically connected to the holder plate, and providing a biasing signal to the holder plate with the biasing power source, so as to generate the biasing field;
• providing a shielding ring disposed within the accommodating space;
• wherein the shielding ring is a circular structure and comprises a first side wall, a second side wall and a bottom;
• the first side wall is a circular wall, facing the adapter plate, and connected to an inner side surface of the adapter plate;
• the second side wall is the circular wall in parallel to the first side wall, and extends toward the target, and an inner side of the second side wall defines a shielding ring opening;
• the bottom connects the first side wall and the second side wall;
• and
• providing a cover ring disposed above the shielding ring, wherein the cover ring comprises a horizontal extension portion and a vertical extension portion;
• the horizontal extension portion is directly or indirectly connected to the adapter plate and extends toward the bottom without contacting the bottom;
• the inner side of the adapter plate, the shielding ring and the first side wall define an auxiliary intake channel connecting to the air intake channel.