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US 7,125,809 B1Granted
Method and material for removing etch residue from high aspect ratio contact surfaces
AssigneeMicron Technology, Inc.
InventorsLarry Hillyer, Steve Byrne, Kelly Williamson, Doug Hahn
Life of this patent
Estimating the term…
Abstract
Contact openings in semiconductor substrates are formed through insulative layers using an etchant material. The etchant typically leaves behind a layer of etch residue which interferes with the subsequent deposition of conductive material in the opening, as well as the conductive performance of the resulting contact. A method of etch removal from semiconductor contact openings utilizes ammonia to clean the surfaces thereof of any etch residue.
Claims84
A method for removing polymer etch residue from an etched opening in a silicon wafer device comprising:
- forming an opening in an insulating layer, wherein a polymer etch residue remains within said opening after the opening forming step;
- contacting said opening with a first plasma to remove a portion of said polymer etch residue;
- stopping said contacting with said first plasma;
- contacting said opening with a second plasma to remove the polymer etch residue not removed by said first plasma, said second plasma generated from a gas consisting of ammonia and said first plasma being generated from a different gas, said second plasma forming a nitride deposit;
- and
- removing any nitride deposits formed by said second plasma in said opening.
3 more elements
A method for removing polymer etch residue from an etched opening in a silicon wafer device, comprising the steps of:
- contacting said opening with a plasma consisting of oxygen to remove a portion of said etch residue, stopping said oxygen plasma contacting before said polymer etch residue is completely removed and thereafter removing any remaining said residue by contacting said opening with a second plasma, said second plasma consisting of a hydrogen containing gas, and treating said opening with at least one of ammonium chloride or phosphoric acid to remove a nitride deposit formed by said second plasma.
A method of forming a contact opening in a semiconductor device, comprising:
- a) etching a contact opening in an insulative layer in said device down to a polysilicon element of said device;
- b) contacting said opening with an oxygen plasma to remove a portion of said etch residue;
- c) removing any remaining etch residue from said etched opening by contacting said opening with a plasma consisting of a hydrogen containing gas in the absence of added oxygen;
- and
- d) treating said contact opening with one of ammonium chloride and phosphoric acid after step (c).
2 more elements
A method of forming an integrated circuit structure comprising:
- forming an insulating layer over a polysilicon region;
- using a fluorine containing gas to form a high aspect ratio contact opening in said insulating layer to expose said polysilicon region;
- removing polymer residue from said contact opening by first contacting said opening with a first plasma, stopping said first contacting, and subsequently contacting said opening with a second plasma, said first plasma consisting of a gas other than ammonia gas and said second plasma consisting of ammonia gas, said first and second plasma treatments being configured to prevent the formation of silicon oxide on a bottom of said contact opening;
- treating said bottom of said contact opening to remove any nitride formed by said second plasma;
- forming a silicide layer at the bottom of said opening in contact with said polysilicon layer;
- forming a conductor in said opening in electrical contact with said silicide layer.
3 more elements
A method for removing polymer etch residue from an etched opening in a silicon wafer device comprising:
- forming an opening in an insulating layer, wherein a polymer etch residue remains within said opening after the opening forming step;
- first contacting said opening with a first plasma to remove a portion of said polymer etch residue;
- stopping said first contacting;
- and
- subsequently contacting said opening with a second plasma to remove the remainder of said polymer etch residue, said first plasma being generated from a gas other than a hydrogen-containing gas and said second plasma being generated from a gas consisting of hydrogen gas, wherein said first and said subsequent contacting with said first and second plasmas are configured so as not to leave silicon oxide in said opening after said subsequent contacting.
2 more elements
A method for removing polymer etch residue from an etched opening in a silicon wafer device comprising:
- forming an opening in an insulating layer, wherein a polymer etch residue remains within said opening after the opening forming step;
- and
- removing said polymer etch residue by contacting it with a first plasma and a second plasma, said first plasma being used to remove only a portion of said residue, said second plasma being used to remove the remainder of said polymer etch residue, said first plasma generated from a gas not containing hydrogen and said second plasma generated from a gas consisting of methane gas, wherein said removal of said polymer etch residue produces no silicon rich oxide in said opening.
A method of forming an integrated circuit structure comprising:
- forming an insulating layer over a polysilicon region;
- using a fluorine containing gas to form a high aspect ratio contact opening in said insulating layer and expose said polysilicon region;
- removing polymer residue from said contact opening by first contacting said opening with a first plasma, stopping said first contacting, and second contacting said opening with a second plasma, said first plasma comprising a gas not containing hydrogen and said second plasma consisting of hydrogen gas and said first and second plasmas being configured to not leave silicon oxide in said opening after said first and second contacting, wherein said second contacting provides an oxide free bottom of said contact opening and does not oxidize sidewalls or said bottom of said opening;
- forming a silicide layer at the bottom of said opening in contact with said polysilicon layer;
- forming a conductor in said opening in electrical contact with silicide layer.
2 more elements
A method of forming an integrated circuit structure comprising:
- forming an insulating layer over a polysilicon region;
- using a fluorine containing gas to form a high aspect ratio contact opening in said insulating layer to expose a portion of said polysilicon region;
- removing polymer residue from said contact opening by first contacting said opening with an oxygen plasma, stopping said first contacting, and second contacting said opening with a methane-comprising plasma, said removing preventing the formation of silicon rich oxide at the bottom of said contact opening;
- forming a silicide layer at the bottom of said opening in contact with said polysilicon layer;
- forming a conductor in said opening in electrical contact with silicide layer.
2 more elements
Dependencies are inferred from the claim text.