Back to results
US 6,184,488 B2Granted
Low inductance large area coil for an inductively coupled plasma source
AssigneeLam Research Corporation
InventorDuane Charles Gates
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeLam Research Corporation
InventorDuane Charles Gates
Estimating the term…
A low inductance large area coil (LILAC) is provided as a source for generating a large area plasma. The LILAC comprises at least two windings which, when connected to an RF source via impedance matching circuitry, produce a circulating flow of electrons to cause a magnetic field in the plasma. Because the LILAC employs multiple windings, few turns of winding are required to obtain a large area coil, so that the inductance of the LILAC is low. The low inductance of the LILAC ensures that the self-resonating frequency of the LILAC is kept at a level far above the RF driving frequency, allowing a broad frequency range for impedance matching. Thus, there is no difficulty in impedance matching, and power transfer can be maximized, permitting efficient generation of a large area plasma.
A vacuum plasma processor comprising a vacuum plasma processing chamber arranged to be responsive to a source of ionizable gas and including a workpiece holder, a coil responsive to an r.f. source for exciting the gas to a plasma capable of processing workpieces on the holder, the coil including plural windings, each of the windings including inner and outer terminals and plural turns extending radially and circumferentially between the inner and outer terminals, the r.f. source including a matching network having first and second output terminals, the matching network first output terminal being connected to the inner terminals, the matching network second output terminal being connected to the outer terminals, the connections between the matching network first and second output terminals and the inner and outer terminals of the plural windings being such that current flowing through the matching network output terminals drives the plural windings in parallel.
An excitation source for use in a vacuum processing chamber responsive to a source of ionizable gas and including a workpiece holder, the source comprising a coil having plural windings connected to be responsive to an r.f. source including a matching network having first and second output terminals, the coil being connected so it is adapted to respond to current from the source to excite the gas to a plasma capable of processing workpieces on the holder, each of the windings including inner and outer terminals and plural turns extending radially and circumferentially between the inner and outer terminals, the matching network first output terminal being connected to the inner terminals, the matching network second output terminal being connected to the outer terminals, the connections between the matching network first and second output terminals and the inner and outer terminals of the plural windings being such that current flowing through the matching network output terminals drives the plural windings in parallel.
Dependencies are inferred from the claim text.