RF Multi-Feed Structure To Improve Plasma Uniformity

A plasma source assembly comprising:

• a housing having an inner edge, an outer edge and side walls, the housing including an electrically grounded front face, the inner edge and outer edge defining a length and the side walls defining a width, the electrically grounded front face including holes to allow a gas to pass therethrough;
• an RF hot electrode within the housing spaced from the electrically grounded front face and defining a gap, the RF hot electrode including a plurality of holes to allow a gas to pass therethrough;
• a first coaxial RF feed line including an outer conductor and an inner conductor separated by an insulator, the outer conductor in electrical communication with electrical ground and the inner conductor in electrical communication with the RF hot electrode, the first coaxial RF feed line connecting to the RF hot electrode at a first distance from the inner edge of the housing;
• and
• a second coaxial RF feed line including an outer conductor and an inner conductor separated by an insulator, the outer conductor in electrical communication with electrical ground and the inner conductor in electrical communication with the RF hot electrode, the second coaxial RF feed line connecting to the RF hot electrode at a second distance from the inner edge of the housing, the second distance being greater than the first distance.