Variable mode plasma chamber utilizing tunable plasma potential

Patent metadata

Field	Value
Publication number	US-2022084792-A1
Application number	US-202117536733-A
Country	US
Kind code	A1
Filing date	Nov 29, 2021
Priority date	Jul 17, 2019
Publication date	Mar 17, 2022
Grant date	—

Abstract

Plasma processing apparatus and associated methods are provided. In one example, a plasma processing apparatus can include a plasma chamber configured to be able to hold a plasma. The plasma processing apparatus can include a dielectric window forming at least a portion of a wall of the plasma chamber. The plasma processing apparatus can include an inductive coupling element located proximate the dielectric window. The inductive coupling element can be configured to generate a plasma from the process gas in the plasma chamber when energized with radio frequency (RF) energy. The plasma processing apparatus can include a processing chamber having a workpiece support configured to support a workpiece. The plasma processing apparatus can include an electrostatic shield located between the inductive coupling element and the dielectric window. The electrostatic shield can be grounded via a tunable reactive impedance circuit to a ground reference.

First claim

1 .- 7 . (canceled)

8 . A plasma processing apparatus, comprising:
a plasma chamber configured to be able to hold a plasma; a dielectric window forming at least a portion of a wall of the plasma chamber; a gas supply configured supply a process gas to the plasma chamber; an inductive coupling element located proximate the dielectric window, the inductive coupling element configured to generate a plasma from the process gas in the plasma chamber when energized with radio frequency (RF) energy; a processing chamber having a workpiece support configured to support a workpiece, the processing chamber being in fluid communication with the plasma chamber; an electrostatic shield located between the inductive coupling element and the dielectric window, the electrostatic shield having a stray capacitance to the inductive coupling element; and a tunable reactive impedance circuit coupled between the inductive coupling element and the electrostatic shield, the tunable reactive impedance circuit configured to adjust a reactance between the inductive coupling element and the electrostatic shield between a condition of capacitive reactance and a condition of inductive reactance at a frequency of RF energy supplied to the inductive coupling element; wherein the tunable reactive impedance circuit is operable to achieve an inductive reactance at least approximately equal to the capacitive reactance of the stay capacitance.

9 . The plasma processing apparatus of claim 8 , wherein the tunable reactive impedance circuit comprises an inductor and a variable capacitor, wherein an inductor has an inductance of about b/(ω 2 *C A ) where ω is the frequency of RF energy supplied to the inductive coupling element, C A is a stray capacitance between the inductive coupling element and the electrostatic shield, and b is a constant greater than about 1.01.

10 . The plasma processing apparatus of claim 9 , wherein the variable capacitor has a range such that the tunable reactive impedance circuit can achieve a series resonance condition between inductive coupling element and the electrostatic shield.

11 . The plasma processing apparatus of claim 8 , further comprising a baffle structure configured to absorb one or more charged species from the plasma.

12 . The plasma processing apparatus of claim 8 , further comprising a plurality of dielectric restricting elements, wherein at least two of the plurality of dielectric restricting elements are separated by a gap, wherein the gap is less than about 1 cm in width.

13 . The plasma processing apparatus of claim 12 , wherein the plurality of dielectric restricting elements comprise a plurality of dielectric chamber liners mounted generally parallel to a grounded side wall of the processing chamber.

14 . The plasma processing apparatus of claim 11 , where the baffle structure is located between the plasma chamber and the processing chamber, wherein the baffle structure has a diameter in a range of about 10% to about 70% of a diameter of the plasma chamber.

15 . The plasma processing apparatus of claim 14 , wherein a center of the baffle structure is located above an approximate center of the workpiece support.

16 . A plasma processing apparatus, comprising:
a plasma chamber configured to be able to hold a plasma;
a dielectric window forming at least a portion of a wall of the plasma chamber;
a gas supply configured supply a process gas to the plasma chamber;
an inductive coupling element located proximate the dielectric window, the inductive coupling element configured to generate a plasma from the process gas in the plasma chamber when energized with radio frequency (RF) energy;
a processing chamber having a workpiece support configured to support a workpiece, the processing chamber being in fluid communication with the plasma chamber;
an electrostatic shield located between the inductive coupling element and the dielectric window, the electrostatic shield grounded via a first tunable reactive impedance circuit, the first tunable reactive impedance circuit configured to have a reactance that can be adjusted in a range from an inductive reactance to a capacitive reactance; and
a second tunable reactive impedance circuit coupled between the inductive coupling element and the electrostatic shield, the second tunable reactive impedance circuit configured to have a reactance that can be adjusted in a range from an inductive reactance to a capacitive reactance.

17 . The plasma processing apparatus of claim 16 , wherein the first tunable reactive impedance circuit is operable to achieve a parallel resonance condition with a stray capacitance between the electrostatic shield and the ground reference.

18 . The plasma processing apparatus of claim 17 , wherein the first tunable reactive impedance circuit comprises an inductor and a variable capacitor coupled in series, wherein the variable capacitor has a range operable to achieve a series resonance condition with the inductor in the first tunable impedance circuit at the frequency of the RF energy supplied to the inductive coupling element.

19 . The plasma processing apparatus of claim 16 , wherein the second tunable reactive impedance circuit is operable to achieve a parallel resonance condition with a stray capacitance between the inductive coupling element to the electrostatic shield at the frequency of the RF energy supplied to the inductive coupling element.

20 . The plasma processing apparatus of claim 16 , wherein the second tunable reactive impedance circuit is operable to achieve a net capacitive reactance of less than about 50 ohms between the inductive coupling element and the electrostatic shield at the frequency of the RF energy supplied to the inductive coupling element.

Assignees

• Mattson Tech Inc
• Beijing E Town Semiconductor Tech Co Ltd

Inventors

• Savas Stephen E
• Ma Shawming

Classifications

• H01J37/32697 Primary

  Electrostatic control · CPC title

• H01J2237/334

  Etching · CPC title

• H01J37/32119

  Windows · CPC title

• H01J37/32715

  Workpiece holder · CPC title

• H01J2237/3321

  CVD [Chemical Vapor Deposition] · CPC title