Method and apparatus for cleaning by-products from plasma chamber surfaces

• US 5,756,400 A
• Filed: 12/08/1995
• Issued: 05/26/1998
• Est. Priority Date: 12/08/1995
• Status: Expired due to Term

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Martinez, Paul, Siegel, Mark, Lu, Danny Chien, Ye, Yan, Papanu, James S., Ma, Diana Xiaobing, Mak, Steve S. Y., Yin, Gerald Zheyao, Prasad, Keshav
• Primary Examiner(s): DANG, THI D
• Application Number:
  US08/568,064
• Time in Patent Office: 900 Days
• Field of Search: 134/1.1, 134/22.1, 134/22.11, 216/67, 216/68, 156/643.1, 156/646.1, 156/345, 438/710, 438/905
• US Class Current: 438/710
• CPC Class Codes: B08B 7/0042 by laser
• CPC Class Codes: Y10S 438/905 Cleaning of reaction chamber

Abstract

The present invention provides an apparatus and process for plasma cleaning the interior surfaces of semiconductor processing chambers. The method is directed to the dry etching of accumulated contaminant residues attached to the inner surfaces of the plasma processing chamber and includes introducing a cleaning gas mixture of a halogen-containing gas; activating a plasma in an environment substantially free of oxygen species; contacting the contaminant residues with the activated cleaning gas to volatilize the residues; and removing the gaseous by-products from the chamber. The etchant gaseous mixture comprises an even or greater amount of at least one fluorine-containing gas and an even or lesser amount of at least one chlorine-containing gas. The instant invention enables the intermittent use of the cleaning steps in an ongoing plasma processing of semiconductor wafers without chamber downtime and significant loss of wafer production.

Claims

1. A method for cleaning the interior surfaces of a plasma treatment chamber comprising:

a) introducing an inorganic halogen containing plasma reactant gas mixture comprising an echant gaseous mixture of at least one fluorine-containing gas and an equal or lesser amount by volume of at least one chlorine-containing gas into a plasma treatment chamber;

b) generating a plasma by exiting the reactant gas mixture in an environment substantially free of any oxygen containing species; and

c) contacting the interior surfaces of the chamber with the volatile reactive species of the plasma whereby at least a portion of the organic and metallic plasma processing residue byproducts are volatilized into gaseous species which are removed from the gas flow exit port of the chamber.

2. The method of claim 1 wherein the fluorine-containing gas is selected from the group consisting of SF₆, NF₃, ClF₃, CF₄, CHF₃, C₄ F₈ and mixtures thereof and the chlorine-containing gas is selected from the group consisting of Cl₂, HCl, BCl₃, CCl₄, SiCl₄, and mixtures thereof.

3. The method of claim 2 wherein the fluorine-containing gases are selected from the group of inorganic gases consisting essentially of SF₆, NF₃, ClF₃ and mixtures thereof.

4. The method of claim 2 wherein the amount of fluorine-containing gas is in an amount of from about 50 to 90 volume percent of the total gas mixture.

5. The method of claim 4 wherein the amount of fluorine-containing gas is in an amount of from about 52% to 88% volume percent of the total gas mixture.

6. The method of claim 2 wherein the inorganic halogen-containing gas mixture is SF₆ /Cl₂.

7. A method of plasma processing to remove residue following the plasma processing of a workpiece comprising:

a) providing a plasma processing apparatus comprised of a chamber and a pair of electrodes disposed opposite to one another;

b) supplying electrical energy between the electrodes in the chamber sufficient to generate plasma glow discharge conditions, one of which electrodes supports a semiconductor workpiece;

c) communicating into the chamber a reactive gas capable of forming a plasma under the electrical energy applied to the electrodes;

d) plasma processing the workpiece wherein etch byproducts are generated and attach to the interior walls of the chamber as contaminant residue deposits;

e) removing the workpiece from the chamber; and

f) conducting a dry cleaning step comprised of;

(I) introducing a plasma reactive etchant gas mixture of at least one fluorine-containing gas and an equal or lesser amount by volume of a chlorine-containing gas into the internal space of the chamber;

(II) generating a plasma of the reactant gas mixture in an environment substantially free of any atomic oxygen species; and

(III) impinging said plasma on the accumulated contaminant deposits attached to the interior surfaces of the chamber whereby the plasma volatilizes the residues into gaseous species which are removed from the chamber.

8. The method of claim 7 wherein the fluorine-containing gas is selected from the group consisting of SF₆, NF₃, ClF₃, CF₄, CHF₃, C₄ F₈ and mixtures thereof, and the chlorine-containing gas is selected from the group consisting of Cl₂, HCl, BCl₃, CCl₄, SiCl₄, and mixtures thereof.

9. The method of claim 8 wherein the fluorine-containing gases are selected from the group of inorganic gases consisting essentially of SF₆, NF₃, ClF₃ and mixtures thereof.

10. The method of claim 7 wherein the amount of fluorine-containing gas is in an amount of from about 50 to 90 volume percent of the total gas mixture.

11. The method of claim 10 wherein the amount of fluorine-containing gas is in an amount of from about 52% to 88% volume percent of the total gas mixture.

12. The method of claim 9 wherein the inorganic halogen containing gas mixture is SF₆ /Cl₂.

13. A method of residue controlled plasma processing of a workpiece in a plasma reactor comprising conducting a dry clean etch of the interior surfaces of the reactor chamber said etch being intermittent to an ongoing plasma processing of semiconductor workpieces and comprised of the steps:

(a) introducing a halogen containing reactant gas mixture comprised of at least one fluorine containing gas and at least one of an even or lesser amount by volume of a chlorine-containing gas into the vacuum plasma processing chamber;

(b) generating a plasma of said reactant gas in an environment substantially free of oxygen species; and

(c) impinging the accumulated residues attached to the interior surfaces of the chamber with reactive species of the plasma whereby the residues are volatilized into gaseous species which are removed from the chamber.