US 5,350,454 A · Plasma processing apparatus for controlling plasma constituents using neutral and plasma sound waves

Abstract

A neutral or plasma sound wave is launched into a plasma used within a plasma processing chamber in order to selectively control the location and concentration of plasma constituents, including (1) contaminants; (2) reactants, including ions or molecules; and/or (3) reaction products. The plasma sound wave comprises a periodic waveform controlled to include at least a second harmonic component. Oseen or Oseen-like forces associated with a neutral or plasma sound wave impart a drift velocity to contaminant particles, e.g., micron-sized dust particles, that moves such particles in a desired direction, e.g., away from a wafer or other work surface being processed by the plasma. An analogous Oseen or Oseen-like force associated with a plasma sound wave imparts a drift velocity to the reactants or reaction products in the plasma so as to move such atomic-sized reactants or products in a desired direction, e.g., proximate the workpiece in the case of the reactants, or removed from the workpiece in the case of the products. The drift velocity, including its direction, is controlled by controlling the harmonic content, intensity and/or phase of the neutral or plasma sound wave.

Claims23

Dependent claims

Plasma processing apparatus comprising:

a plasma processing chamber;
means for introducing a prescribed gas into said plasma processing chamber;
means for establishing and maintaining a plasma from said gas within said plasma processing chambers, said plasma processing chamber including a workpiece to be processed by said plasma;
launching means for launching a periodic sound wave into said plasma, said sound wave being characterized by an intensity and fundamental frequency and harmonic content that includes at least a second harmonic, said sound wave interacting with a constituent within said plasma so as to impart a drift velocity thereto;
control means for controlling the characteristics of said sound wave so as to cause said constituent to move within said plasma as a result of said drift velocity in a desired direction within said plasma processing chamber;
whereby the location and flow of said constituent within said plasma may be controlled by controlling said sound wave.

3 more elements

Dependencies are inferred from the claim text.

Plasma processing apparatus for controlling plasma constituents using neutral and plasma sound waves

Life of this patent

Plasma processing apparatus for controlling plasma constituents using neutral and plasma sound waves

Life of this patent

Abstract

Claims23