GAS DISTRIBUTION SYSTEM HAVING FAST GAS SWITCHING CAPABILITIES

• US 20100159707A1
• Filed: 03/03/2010
• Published: 06/24/2010
• Est. Priority Date: 04/30/2004
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Sam, Jose Tong, Sadjadi, Reza, Lenz, Eric H., Dhindsa, Rajinder, Huang, Zhisong
• Granted Patent: US 8,673,785 B2
• Time in Patent Office: Days
• US Class Current: 438/714
• CPC Class Codes: C23C 16/45561 Gas plumbing upstream of the reaction chamber
• CPC Class Codes: C23C 16/45565 Shower nozzles
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H01J 37/32449 Gas control, e.g. control of the gas flow

Abstract

A gas distribution system for supplying different gas compositions to a chamber, such as a plasma processing chamber of a plasma processing apparatus is provided. The gas distribution system can include a gas supply section, a flow control section and a switching section. The gas supply section provides first and second gases, typically gas mixtures, to the flow control section, which controls the flows of the first and second gases to the chamber. The chamber can include multiple zones, and the flow control section can supply the first and second gases to the multiple zones at desired flow ratios of the gases. The gas distribution system can continuously supply the first and second gases to the switching section and the switching section is operable to switch the flows of the first and second gases, such that one of the first and second process gases is supplied to the chamber while the other of the first and second gases is supplied to a by-pass line, and then to switch the gas flows. The switching section preferably includes fast switching valves operable to quickly open and close to allow fast switching of the first and second gases, preferably without the occurrence of undesirable pressure surges or flow instabilities in the flow of either gas.

Claims

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23. A method of processing a semiconductor structure in a plasma processing chamber, comprising:

a) supplying a first process gas into the plasma processing chamber while diverting a second process gas to a bypass-line, the plasma processing chamber containing a semiconductor substrate including at least one layer and a patterned resist mask overlying the layer;

b) energizing the first process gas to produce a first plasma and (i) etching at least one feature in the layer or (ii) forming a polymer deposit on the mask;

c) switching the flows of the first and second process gases so that the second process gas is supplied into the plasma processing chamber while diverting the first process gas to the by-pass line, the first process gas being substantially replaced in a plasma confinement zone of the plasma processing chamber by the second process gas within a period of less than about 1 s, or less than about 200 ms;

d) energizing the second process gas to produce a second plasma and (iii) etching the at least one feature in the layer or (iv) forming a polymer deposit on the layer and the mask;

e) switching the flows of the first and second process gases so that the first process gas is supplied into the plasma processing chamber while diverting the second process gas to the by-pass line, the second process gas being substantially replaced in the plasma confinement zone of the plasma processing chamber by the first process gas within a period of less than about 1 s, or less than about 200 ms;

and f) repeating a)-e) a plurality of times with the substrate.

24. The method of claim 23, wherein the polymer deposit is formed to a maximum thickness of less than about 100 angstroms after repeating a)-e) a plurality of times with the substrate.

25. The method of claim 23, wherein the first plasma etches the at least one feature in the layer, and the second plasma forms the deposit on the layer and the mask, the deposit repairing striations in the mask.

26. The method of claim 23, wherein the plasma confinement zone has a volume of about ½

liter to about 4 liters.

27. The method of claim 23, wherein:

the first layer is of SiO₂;

the mask is a UV-resist mask;

the first process gas comprises a mixture of C₄F₈, O₂ and argon and the first plasma etches the layer; and

the second process gas comprises a mixture of CH₃F, argon and optionally O₂ and the second plasma forms the polymer deposit on the feature and the mask.

28. The method of claim 27, wherein the first process gas is supplied into the plasma processing chamber for a period of about 5 seconds to about 20 seconds, and the second process gas is supplied into the plasma processing chamber for a period of about 1 second to about 3 seconds, each time that the first and second process gases, respectively, are supplied into the plasma processing chamber.

29. The method of claim 23, wherein the plasma processing chamber comprises a showerhead electrode assembly including an inner zone and an outer zone, the first process gas being supplied to the inner zone and the outer zone while the second process gas is diverted to the by-pass line, and the second process gas being supplied to the inner zone and the outer zone while the first process gas is diverted to the by-pass line.

30. The method of claim 29, wherein the first process gas and/or the second process gas is/are supplied to the inner zone and the outer zone at different flow rates.