Capacitively coupled plasma reactor with uniform radial distribution of plasma

A plasma reactor comprising:

• a side wall and an overhead ceiling defining a chamber, said overhead ceiling comprising an overhead electrode;
• a workpiece support cathode within said chamber having a working surface facing said ceiling for supporting a semiconductor workpiece;
• process gas inlets for introducing a process gas into said chamber;
• an RF bias power generator having a bias power frequency;
• a bias power feed point at said working surface;
• an RF conductor connected between said RF bias power generator and said bias power feed point and a dielectric sleeve surrounding a section of length of said conductor;
• a source power generator having a source frequency;
• an impedance match element connected between said source power generator and said overhead electrode;
• said feed point having an impedance at said source power frequency;
• wherein the reactance of said sleeve reduces the impedance of said feed point at said source frequency to at least nearly zero Ohms.

A plasma reactor comprising:

• a vacuum enclosure including a side wall and a ceiling defining a vacuum chamber, and a workpiece support within said chamber having a working surface facing said ceiling for supporting a planar workpiece, said workpiece support and said ceiling together defining a processing region between said workpiece support and said ceiling;
• process gas inlets for furnishing process gas into said chamber;
• an RF bias power generator having a bias frequency;
• at least a first overhead solenoidal electromagnet adjacent said ceiling, said overhead solenoidal electromagnet, said ceiling, said sidewall and said workpiece support being located along a common axis of symmetry;
• and
• a current source connected to said first solenoidal electromagnet and furnishing a first electric current in said first solenoidal electromagnet whereby to generate within said chamber a magnetic field which is a function of said first electric current, said first electric current having a value such that said magnetic field increases uniformity of plasma ion density radial distribution about said axis of symmetry near said working surface;
• a bias power feed point at said working surface;
• an RF conductor connected between said RF bias power generator and said bias power feed point at said working surface;
• and
• a dielectric sleeve surrounding a portion of said RF conductor, said sleeve having an axial length along said RF conductor, a dielectric constant and an axial location along said RF conductor, said length, dielectric constant and location of said sleeve being such that said sleeve provides a reactance that enhances plasma ion density uniformity over said working surface.