Uniform etch system

• US 7,371,332 B2
• Filed: 08/14/2003
• Issued: 05/13/2008
• Est. Priority Date: 12/13/2002
• Status: Expired due to Fees

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Wu, Di, Su, Xingcai, Loewenhardt, Peter, Kadkhodayan, Babak, Takeshita, Kenji, Larson, Dean J., Yen, Bi-Ming, Denty, William M. Jr.
• Primary Examiner(s): Olsen; Allan
• Application Number:
  US10/642,083
• Publication Number:
  US 20040112539A1
• Time in Patent Office: 1,734 Days
• Field of Search: 216/58
• US Class Current: 216/58
• CPC Class Codes: H01L 21/67017 Apparatus for fluid treatment H01L21/67126, H01L21/6715 take precedence

Abstract

Etching a layer over a substrate is provided. The substrate is placed in a plasma processing chamber. A first gas is provided to an inner zone within the plasma processing chamber. A second gas is provided to the outer zone within the plasma processing chamber, where the outer zone surrounds the inner zone and the first gas is different than the second gas. Plasmas are simultaneously generated from the first gas and second gas. The layer is etched, where the layer is etched by the plasmas from the first gas and second gas.

Claims

1. A method for etching a layer over a substrate, comprising:

placing the substrate in a plasma processing chamber, with a gas distribution system with an inner zone placed opposite an inner portion of the substrate and an outer zone surrounding the inner zone;

combining a first component gas with a second component gas;

splitting the combined first component gas and second component gas into a first gas and a second gas by passing the combined first component gas and second component gas through a first fixed orifice in a first leg connected to the inner zone and a second fixed orifice in a second leg connected to the outer zone;

adding additional first component gas to the second leg, wherein the first component gas has a lower molecular weight than the second gas component, wherein a ratio of the first component gas to the second component gas for the second gas is greater than a ratio of the first component gas to the second component gas for the first gas wherein the second component gas is provided to the first leg connected to the inner zone at a first flow rate greater than or equal to zero from a single tuning gas source, and wherein the adding includes operating a valve connecting the single tuning gas source and the first and second legs such that the first component gas is provided to the second leg connected to the outer zone at a second flow rate greater than or equal to zero from the single tuning gas source, and wherein the second flow rate is different than the first flow rate;

providing the first gas to the inner zone of the gas distribution system;

providing the second gas to the outer zone of the gas distribution system;

simultaneously generating plasmas from the first gas and second gas; and

etching the layer, wherein the layer is etched by the plasmas from the first gas and second gas.

2. The method, as recited in claim 1, wherein the first gas is different than the second gas in that the first gas has a first ratio of gases and the second gas has a second ratio of gases, wherein the first ratio is different than the second ratio.

3. The method, as recited in claim 1, wherein the outer zone is adjacent to an edge of the substrate and the inner zone is adjacent to an interior of the substrate surrounded by the edge of the substrate adjacent to the outer zone.

4. The method, as recited in claim 1, further comprising tuning the second gas to the first gas to provide a more uniform etch.

5. The method, as recited in claim 1, further comprising tuning the second gas to the first gas to provide a more uniform critical dimensions, a more uniform taper, a more uniform selectivity, and a more uniform profile.

6. The method, as recited in claim 1, further comprising tuning the second gas to the first gas to provide a more uniform etch.

7. The method, as recited in claim 1, wherein the tuning gas is provided to only one of the first leg and the second leg.

8. The method, as recited in claim 1, wherein the first leg includes a flow resistance device that alters the flow ratio between the first leg and the second leg.

9. The method, as recited in claim 8, wherein the first leg further includes a fixed plate orifice, which provides a specific resistance to gas flow.

10. The method, as recited in claim 8, wherein the first gas is different than the second gas, in that the first gas and the second gas are made of different component gases.

11. The method, as recited in claim 10, further comprising tuning the second gas to the first gas to provide a more uniform etch.