Method of cleaning and conditioning plasma reaction chamber

• US 6,350,697 B1
• Filed: 12/22/1999
• Issued: 02/26/2002
• Est. Priority Date: 12/22/1999
• Status: Expired due to Term

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Outka, Duane, Richardson, Brett C.
• Primary Examiner(s): Utech, Benjamin L.
• Assistant Examiner(s): CHEN, KIN CHAN
• Application Number:
  US09/469,286
• Time in Patent Office: 797 Days
• Field of Search: 438/695, 438/696, 438/706, 438/710, 438/733, 438/720, 438/725, 134/1.1, 134/21, 134/22
• US Class Current: 438/710
• CPC Class Codes: C23C 16/4404 Coatings or surface treatment on the inside of the reaction chamber or on parts thereof
• CPC Class Codes: H01J 37/32477 characterised by the means for protecting vessels or internal parts, e.g. coatings
• CPC Class Codes: H01J 37/32862 In situ cleaning of vessels and/or internal parts

Abstract

A method for cleaning and conditioning interior surfaces of a plasma chamber in which substrates such as silicon wafers are processed. The method includes cleaning the chamber such as by a wet clean or in-situ plasma clean, introducing a conditioning gas into the chamber, energizing the conditioning gas into a plasma state, depositing a polymer coating on the interior surfaces and processing a substrate. The conditioning step can be performed without a substrate such as a wafer in the chamber and the processing step can be carried out without running conditioning wafers through the chamber prior to processing production wafers. In the case of a plasma chamber used for etching aluminum, the conditioning gas can include a fluorine-containing gas, a carbon-containing gas and a chlorine-containing gas.

Claims

1. A method of cleaning and conditioning a plasma reaction chamber in which substrates are processed, comprising the steps of:

cleaning the plasma reaction chamber so as to remove deposits built up on surfaces within the chamber;

conditioning the chamber by introducing a conditioning gas comprising a fluorine-containing gas and a carbon-containing gas into the chamber, energizing the conditioning gas into a plasma and, depositing a polymer coating formed by the plasma on interior surfaces of the chamber, the conditioning step being carried out while the chamber does not contain a substrate therein; and

processing a substrate in the chamber after the conditioning step.

2. The method of claim 1, wherein the energizing step is carried out by exposing the conditioning gas to an inductive field generated by resonating a radio frequency current in an RF antenna coil, the RF antenna coil being disposed external to the chamber, proximate to a dielectric shield which forms a part of an enclosure of the chamber.

3. The method of claim 2, wherein the RF antenna is supplied 200 to 1000 Watts during the conditioning step.

4. The method of claim 1, wherein the conditioning gas further comprises a chlorine-containing gas and the polymer deposited in the depositing step includes chlorine therein.

5. The method of claim 1, wherein the cleaning step is carried out by opening the chamber and performing a wet clean.

6. The method of claim 1, wherein the cleaning step is carried out by introducing a cleaning gas into the chamber, energizing the cleaning gas into a plasma state, and contacting the interior surfaces with the plasma to remove the deposits.

7. The method of claim 5, wherein the plasma cleaning gas converts the deposits on the interior surfaces to gas by-products.

8. The method of claim 1, wherein the substrate comprises a production wafer and the processing step is carried out without processing conditioning wafers in the chamber prior to processing the production wafer.

9. The method of claim 1, wherein the processing step comprises etching an aluminum film stack on the production wafer.

10. The method of claim 1, wherein the conditioning step is carried out without applying power to an RF biasing electrode of a substrate support on which the substrate is supported during the processing step.

11. The method of claim 1, wherein the conditioning gas includes Cl₂, BCl₃, CCl₄, SiCl₄ or mixture thereof.

12. The method of claim 1, wherein the conditioning gas includes CHF₃ and BCl₃ and/or Cl₂.

13. The method of claim 1, wherein the chamber pressure during the conditioning step is in the range of from about 5 to 80 mTorr.

14. The method of claim 1, wherein the chamber is a plasma etch chamber.

15. The method of claim 14, further comprising a step of etching aluminum on one or more semiconductor substrates in the chamber prior to the cleaning step, the etching step producing the deposits on the interior surfaces of the chamber.

16. The method of claim 14, wherein the conditioning step is followed by introducing one or more semiconductor substrates into the chamber and etching aluminum on the one or more substrates.

17. The method of claim 1, wherein the conditioning step is performed until an endpoint determined by optical emission or interferometry is reached.

18. The method of claim 1, wherein the conditioning step is carried out in first and second steps, the conditioning gas further including a chlorine-containing gas in the first step and the conditioning gas being fluorine-free in the second step.

19. The method of claim 18, wherein the conditioning gas comprises 1-30 sccm BCl₃ and 10-60 sccm CHF₃ in the first step and the conditioning gas comprises 20-60 sccm BCl₃ and 20-60 sccm Cl₂ in the second step.

20. The method of claim 1, wherein residual oxygen in the plasma reaction chamber is scavenged by the plasma formed from the conditioning gas.

21. The method of claim 1, wherein an etch rate of a first substrate processed according to an etch recipe in the plasma reaction chamber prior to the cleaning step and an etch rate of a second substrate processed according to the etch recipe in the plasma reaction chamber after the depositing step are substantially equal etch rates.