Plasma reactor apparatus

• US 4,209,357 A
• Filed: 05/18/1979
• Issued: 06/24/1980
• Est. Priority Date: 05/18/1979
• Status: Expired due to Term

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Tegal Corp. (Rennova Health, Inc.)
• Inventors: Gorin, Georges J., Hoog, Josef T.
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US06/040,604
• Time in Patent Office: 403 Days
• Field of Search: 204/164, 204/192 E, 204/298, 156/345, 156/643, 250/531
• US Class Current: 438/710
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence

Abstract

A plasma reactor apparatus providing improved uniformity of etching and having a totally active reaction volume. The reactor apparatus is comprised of two electrically separated electrodes which bound a reaction volume. The topmost electrode functions as both a gas distribution manifold for uniformly injecting reactant gases into the reaction volume and as an exhaust manifold for uniformly withdrawing reaction products from the reaction volume. The two electrodes are so configured that the plasma reaction takes place only between the electrodes; there is no inactive space surrounding the electrodes to fill with plasma. The configuration is thus conservative of both reactants and energy. The bottommost plate which serves as a workpiece holder is movable with respect to the upper plate to permit loading and unloading of workpieces. The uppermost plate is the active RF electrode while the workpiece holder is maintained at a RF ground potential. The uppermost plate has a larger electrode area which effectively imposes a dc offset to the RF field which enhances the uniformity of the etching and decreases the undesirable spread of undercut etching.

Claims

1. A gas plasma reactor apparatus which comprises:

first and second electrodes configured to bound a reaction volume which is adapted to be evacuated, said first electrode having a first array of orifices for the ingress of gaseous reactants to said reaction volume and a second array of orifices for the egress of gaseous reaction products from said reaction volume.

2. The reactor apparatus of claim 1 wherein one of said first and second electrodes is of greater area than the other of said first and second electrodes.

3. The reactor apparatus of claim 1 further comprising means for supplying radio frequency power to said first and second electrodes.

4. The reactor apparatus of claim 3 wherein said second electrode is adapted to be maintained at radio frequency ground potential.

5. The reactor apparatus of claim 4 wherein said first electrode has a greater area than said second electrode.

6. The reactor apparatus of claim 1 wherein said second electrode is moveable with respect to said first electrode to facilitate the loading and unloading of a workpiece into said reaction volume.

7. The reactor apparatus of claim 6 wherein said first electrode is capable of further serving as a workpiece holder.

8. The reactor apparatus of claim 1 wherein substantial portions of said first and second electrodes are parallel.

9. The reactor apparatus of claim 1 further comprising temperature control means.

10. The reactor apparatus of claim 1 further comprising means for automatically loading a workpiece into said reaction volume.

11. The reactor apparatus of claim 10 further comprising means for automatically unloading a workpiece from said reaction volume at the conclusion of a plasma process.

12. The reactor apparatus of claim 1 further comprising means for detecting the end point of a plasma reaction.

13. A gas plasma reactor apparatus which comprises:

a first metal electrode; and

a second metal electrode of smaller area than said first electrode, said second electrode movable with respect to said first electrode from a closed position to an open position, said first and second electrodes bounding a reaction volume which is adapted to be evacuated when in said closed position and permitting loading of a workpiece into said reaction volume when in said open position;

a source of radio frequency energy connected to said first and said second electrodes and capable of establishing an electrical field therebetween;

a gas distribution manifold integral with said first electrode for providing introduction dispersal and exhaust of gaseous reactants in said reaction volume.

14. The plasma reactor apparatus of claim 13 further comprising:

means for automatically loading a workpiece into and unloading a workpiece from said reaction volume.

15. A gas plasma reactor apparatus comprises:

a first plate portion, capable of supporting a workpiece;

a second cover portion;

an insulator positioned between and electrically separating said plate portion and said cover portion, said plate portion, insulator and cover portion bounding a reaction volume which is adapted to be evacuated;

a manifold electrically common with said cover portion, said manifold having a first set of orifices for dispensing reactant gas into said reaction volume and a second set of orifices for removing gaseous reactant products from said reaction volume.

16. The reactor apparatus of claim 15 further comprising means connected to said first plate portion and said second cover portion for establishing an RF electric field between said manifold and said plate portion.

17. The reactor apparatus of claim 15 wherein said plate portion and said cover portion are metal and said cover portion has a greater area than said plate portion.

18. A combined electrode and gas distribution manifold for maintaining a uniform distribution of reactants in a gas plasma reactor apparatus, comprising:

a first cavity bounded by a first piece and a second piece;

a second cavity bounded by said second piece and a third piece;

an inlet for conveying reactants to said first cavity;

a first array of orifices in said first piece for dispersing gaseous reactants from said first cavity into said reactor apparatus; and

a second array of orifices in said first piece for exhausting gaseous reaction products from said reactor apparatus to said second cavity.

19. The apparatus of claim 18 further comprising conduit means integral with said second piece for conveying said reaction products from said second array of orifices to said second cavity.

20. The apparatus of claim 18 wherein said first piece is fabricated from metal and is electrically common with said third piece.

21. A process for the gas plasma etching of a workpiece which comprises the step of:

positioning the workpiece between substantially parallel electrodes bounding a reaction volume;

injecting gaseous reactants from a manifold integral with one of said electrodes into said reaction volume;

applying radio frequency power to said electrodes to establish a field therebetween and to form a plasma of said reactants for etching said workpiece;

exhausting gaseous reaction products of said etching through said manifold.

22. The process of claim 21 further comprising the steps of automatically loading said workpiece into said reactor;

and automatically unloading said workpiece from said reactor after said etching is completed.

23. The process of claim 21 wherein said workpiece is a semiconductor wafer.

24. The process of claim 21 further comprising the step of controlling the temperature of said workpiece.

25. The process of claim 21 further comprising the step of controlling the pressure within said reaction volume.