Controlling ion energy distribution in plasma processing systems

Patent metadata

Field	Value
Publication number	US-9887069-B2
Application number	US-63495909-A
Country	US
Kind code	B2
Filing date	Dec 10, 2009
Priority date	Dec 19, 2008
Publication date	Feb 6, 2018
Grant date	Feb 6, 2018

Abstract

A plasma processing system for processing at least a substrate with plasma. The plasma processing chamber is capable of controlling ion energy distribution. The plasma processing system may include a first electrode. The plasma processing system also includes a second electrode that is different from the first electrode and is configured for bearing the substrate. The plasma processing system may also include a signal source coupled with the first electrode. The signal source may provide a non-sinusoidal signal through the first electrode to control ion energy distribution at the substrate when the substrate is processed in the plasma processing system, wherein the non-sinusoidal signal is periodic.

First claim

What is claimed is:

1. A plasma processing system for processing a substrate with plasma, said plasma processing system comprising:
a first electrode, wherein said first electrode is a non-substrate bearing electrode;
a first ground plate configured to surround the first electrode, such that the first ground plate extends away from a center of the first electrode, and the first ground plate disposed at a physical separation from the first electrode;
a second electrode, said second electrode being different from said first electrode, said second electrode being configured for bearing said substrate;
a second ground plate configured to surround the second electrode, such that the second ground plate extends away from a center of the second electrode, the second ground plate disposed at a physical separation from the second electrode, the plasma during processing is defined between the first electrode and the second electrode and the center of the first electrode and the center of the second electrode are substantially aligned with one another, and wherein an interior diameter area of the first ground plate is disposed over the second electrode, wherein the first electrode has a diameter that is smaller than a diameter of the second electrode;
a first signal source coupled with said first electrode and configured to provide a non-sinusoidal signal to said first electrode for controlling ion energy distribution at said substrate when said substrate is disposed on said second electrode in said plasma processing system, said first signal source produces the non-sinusoidal signal that is periodic, wherein each period of the non-sinusoidal signal includes positive ramped portions of a first voltage magnitude and negatively ramped portions of a second voltage magnitude, the negatively ramped portions immediately following the positive ramped portions, the first voltage magnitude is higher than the second voltage magnitude, and the positive ramped portions are separated from the negative ramped portions by a vertical voltage offset;
a second signal source coupled to the second electrode, the second signal source configured to output a sinusoidal signal; and
a blocking capacitor, said blocking capacitor being a direct current (DC) blocking capacitor and is positioned between said first electrode and said first signal source, wherein said DC blocking capacitor is separate from said first electrode, the DC blocking capacitor reduces parasitic and series capacitance, which increases efficiency in controlling the ion energy distribution at said substrate.

2. The plasma processing system of claim 1 further comprising:
a dielectric layer disposed between said first ground plate and at least a portion of said first electrode for electrically isolating said first electrode from said first ground plate.

3. The plasma processing system of claim 1 wherein said second electrode is disposed opposite to said first electrode such that said substrate is disposed between said second electrode and said first electrode.

4. The plasma processing system of claim 1 wherein each said period defines a pulse.

5. The plasma processing system of claim 1 wherein each of said negatively ramped portions is configured to attract positive ions in said plasma processing system.

6. A plasma processing system comprising:
a first electrode, wherein said first electrode is a non-substrate bearing electrode;
a first ground plate configured to surround the first electrode, such that the first ground plate extends away from a center of the first electrode, and the first ground plate disposed at a physical separation from the first electrode;
a second electrode, said second electrode being different from said first electrode, said second electrode being configured for bearing a substrate;
a second ground plate configured to surround the second electrode, such that the second ground plate extends away from a center of the second electrode, the second ground plate disposed at a physical separation from the second electrode, and
wherein the first electrode has a surface area that faces toward second electrode that is less than each of a surface area of the first ground plate that faces the second ground plate, and a surface area of the second ground plate that faces the first ground plate; and
a first radio frequency (RF) signal source coupled with said first electrode and configured to provide a non-sinusoidal signal to said first electrode for controlling ion energy distribution at said substrate when said substrate is processed on said second electrode in said plasma processing system, said first RF signal source produces the non-sinusoidal signal that is periodic, wherein each period of the non-sinusoidal signal that is periodic includes pulses that have positive ramped portions of a first voltage magnitude and negatively ramped portions of a second voltage magnitude, the negatively ramped portions immediately following the positive ramped portions, the first voltage magnitude is higher than the second voltage magnitude, and a vertical voltage offset is defined between the positive ramped portions and negative ramped portions;
a second RF signal source coupled to the second electrode, the second RF signal source configured to output a sinusoidal signal;
a blocking capacitor, said blocking capacitor being a direct current (DC) blocking capacitor and is positioned between said first electrode and said first RF signal source, wherein said DC blocking capacitor is separate from said first electrode.

7. The plasma processing system of claim 6 further comprising:
a dielectric layer disposed between said first ground plate and at least a portion of said first electrode for electrically isolating said first electrode from said first ground plate.

8. The plasma processing system of claim 6 wherein said second electrode is disposed opposite to said first electrode such that said substrate is disposed between said second electrode and said first electrode.

9. The plasma processing system of claim 6 , wherein each said period defines a pulse.

10. The plasma processing system of claim 6 , wherein each of said negatively ramped portions is configured to attract positive ions in said plasma processing system.

Assignees

• Fischer Andreas
• Hudson Eric
• Lam Res Corp

Inventors

• Fischer Andreas
• Hudson Eric

Classifications

• H01J37/32091

  the radio frequency energy being capacitively coupled to the plasma · CPC title

• H01J37/32623 Primary

  Mechanical discharge control means · CPC title

• H10P50/242

  of Group IV materials · CPC title

• H10P50/00

  Etching of wafers, substrates or parts of devices · CPC title

• H05H1/46

  using applied electromagnetic fields, e.g. high frequency or microwave energy (H05H1/26 takes precedence) · CPC title