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US 6,319,355 B1Granted
Plasma processor with coil responsive to variable amplitude rf envelope
AssigneeLam Research Corporation
InventorJohn Patrick Holland
Life of this patent
Estimating the term…
Abstract
A vacuum plasma processor includes a coil for reactively exciting a plasma so plasma incident on a workpiece has substantially uniformity. The coil and a window which reactively couples fields from the coil to the plasma have approximately the same diameter. An r.f. source supplies a pulse amplitude modulated envelope including an r.f. carrier to the coil.
Claims39
A vacuum plasma processor for processing workpieces comprising
- a vacuum chamber for processing the workpieces with a plasma,
- a holder in the chamber for the workpieces,
- a coil for exciting gas in the chamber into the plasma,
- an r.f. source for supplying to the coil an r.f. carrier having a variable amplitude envelope;
- the variable amplitude, pressure within the chamber, and the arrangement of (a) the coil, (b) the chamber and (c) the holder being such as to cause the plasma to have a substantially constant flux across the workpiece while the workpiece is on the holder.
2 more elements
A method of plasma processing a workpiece on a holder in a vacuum plasma processor chamber comprising
- exciting gas in the chamber to a plasma by applying an r.f. carrier having envelope amplitude variations to a coil, the coil responding to the r.f. carrier to couple magnetic and electric plasma excitation fields to the plasma;
- the variations of the envelope amplitude and the coil, chamber, workpiece and holder parameters being such that the density of the plasma across the workpiece has substantially lower standard deviation than when the plasma envelope has a constant amplitude.
A method of plasma processing a workpiece on a holder in a vacuum plasma processor chamber comprising
- exciting gas in the chamber to a plasma by applying an r.f. carrier having envelope amplitude variations to a coil, the coil responding to the r.f. carrier to couple magnetic and electric plasma excitation fields to the plasma;
- maintaining the density of the plasma across the workpiece substantially constant by controlling the variations of the envelope amplitude so the plasma density across the workpiece has a substantially lower standard deviation while the plasma envelope has the amplitude variations than when the plasma envelope has a constant amplitude.
A vacuum plasma processor for processing workpieces comprising
- a vacuum chamber for processing the workpieces with a plasma,
- a holder in the chamber for the workpieces,
- a coil for exciting gas in the chamber into the plasma,
- an r.f. source for supplying to the coil an r.f. carrier having a variable amplitude envelope;
- the variable amplitude, pressure within the chamber, and the arrangement of (a) the coil, (b) the chamber and (c) the holder being such as to cause the plasma to have a higher flux on a portion of the workpiece aligned with a center portion of the coil than on a portion of the workpiece aligned with a portion of the coil removed from the center portion of the coil when a constant amplitude r.f. envelope is applied to the coil, the variable amplitude envelope being such as to cause the plasma flux across the workpiece to be such as to cause the plasma flux in a portion of the workpiece removed from the portion of the workpiece aligned with the center portion of the coil to be at least equal to the plasma flux in the portion of the workpiece aligned with the center portion of the coil.
2 more elements
A vacuum plasma processor for processing workpieces comprising
- a vacuum chamber for processing the workpieces with a plasma,
- a holder in the chamber for the workpieces,
- a coil for exciting gas in the chamber into the plasma,
- an r.f. source for supplying to the coil an r.f. carrier having a variable amplitude envelope;
- the source being arranged so the envelope includes variable amplitude, high amplitude segments spaced from each other by low amplitude segments, the source being arranged so the envelope includes segments with controllable high amplitudes and segments with controllable duration low amplitude segments, the high amplitude segments being spaced from each other by the low peak amplitude segments, the source being arranged so that the amplitude of the high amplitude segments increases with increases in the spacing of the high amplitude segments from each other.
2 more elements
A method of plasma processing a workpiece on a holder in a vacuum plasma processor chamber comprising
- exciting gas in the chamber to a plasma by applying an r.f. carrier having envelope amplitude variations to a coil, the coil responding to the r.f. carrier to couple magnetic and electric plasma excitation fields to the plasma, the pressure within the chamber, and the arrangement of (a) the coil, (b) the chamber and (c) the holder being such as to cause the plasma to have a higher flux on a portion of the workpiece aligned with the center of the coil than on a portion of the workpiece aligned with a portion of the coil removed from the center of the coil when a constant amplitude r.f. envelope is applied to the coil;
- and controlling the variable amplitude envelope so that the plasma flux on a portion of the workpiece removed from the portion of the workpiece aligned with the center of the coil is at least equal to the plasma flux at the portion of the workpiece aligned with the center of the coil.
Dependencies are inferred from the claim text.