Gas feed for reactive ion etch system

• US 4,496,423 A
• Filed: 11/14/1983
• Issued: 01/29/1985
• Est. Priority Date: 11/14/1983
• Status: Expired due to Fees

• Current Assignee: GCA Corp. (SPX Corporation)
• Original Assignee: GCA Corp. (SPX Corporation)
• Inventors: Walton, Frank J.
• Primary Examiner(s): Powell, William A.
• Application Number:
  US06/550,801
• Time in Patent Office: 442 Days
• Field of Search: 156/345, 156/643, 156/646, 204/298, 204/192 E
• US Class Current: 156/345.29
• CPC Class Codes: H01J 37/3244 Gas supply means
• CPC Class Codes: Y10S 438/935 Gas flow control

Abstract

The gas feed system disclosed herein is useful in a reactive ion etching system in which a gas plasma is energized by an electrode plate through which the gas is introduced. Propagation of the plasma discharge down the gas feed path is blocked by a feed system in which the space between a pair of porous metal plugs is filled with a porous insulating material having a pore size too small to support discharge, i.e. corresponding to the mean free electron path in the gas.

Claims

1. In a system for etching semi-conductor wafers by means of reactive ions in a gas plasma, the plasma being energized by an electrode which is adjacent the wafer and through which the gas is introduced, a gas feed comprising

a gas feed line which is electrically grounded;

a hollow insulating housing;

at one end of said housing, a porous metal plug which is in contact with said electrode;

at the other end of said housing;

a second porous metal plug through which gas is fed from said feed line;

filling the space between said plugs, a porous insulating material.

2. In a system for etching semi-conductor wafers by means of reactive ions in a gas plasma, the plasma being energized by an electrode which is adjacent the wafer and through which the gas is introduced, a gas feed comprising

a gas feed line which is electrically grounded;

a hollow insulating cylinder;

at one end of said cylinder, a porous metal plug which is in contact with said electrode;

at the other end of said cylinder;

a second porous metal plug through which gas is fed from said feed line;

filling the space between said plugs, a porous particulate insulating material in which the pore size between the particles corresponds to the mean free electron path in said gas.

3. A gas feed as set forth in claim 2 wherein said particulate insulating material comprises glass beads.

4. A gas feed as set forth in claim 3 wherein said glass beads have a diameter of about one millimeter.

5. A gas feed as set forth in claim 4 wherein said insulating cylinder is constructed of polyethylene.

6. In a system for etching semi-conductor wafers by means of reactive ions in a gas plasma, the plasma being energized by an electrode which is adjacent the wafer and through which the gas is introduced, a gas feed comprising

a gas feed line which is electrically grounded;

a hollow cylinder constructed of an insulating synthetic resin;

at one end of said cylinder, a porous metal plug which is in contact with said electrode;

at the other end of said cylinder;

a second porous metal plug through which gas is fed from said feed line;

filling the space between said plugs with a mass of glass beads.

7. A gas feed as set forth in claim 6 wherein said porous metal plugs are made of aluminum foam.

8. A gas feed as set forth in claim 7 wherein the diameter of said glass beads is about one millimeter.