Method for forming a high aspect ratio borderless contact hole

An etching environment for performing an etching process on a silicon oxide layer while a silicon nitride layer is used as an etching end point, wherein the etching process is performed within an etcher containing a roof, a ring, a chiller and a chamber with an etchant, and the etchant includes of gaseous C4F8/C2F6/Ar/CO, the etching environment comprising conditions of:

• a C4F8 flow controlled at about 10 to 20 sccm;
• an Ar flow controlled at about 100 to 500 sccm;
• a CO flow controlled at about 1 to 100 sccm;
• a C2F6 flow that is about 0.5 to 1.5 times that of C4F8;
• a roof temperature controlled at about 150 to 300° C.;
• a wall temperature of the chamber controlled at about 150 to 400° C.;
• a ring temperature controlled at about 150 to 400° C.;
• a chiller temperature controlled at about −20 to 20° C.;
• a pressure within the chamber controlled at about 4 to 50 mtorr;
• and
• an etcher bias controlled at about 2000 to 2000 watts;
• an etcher power controlled at about 1500 to 3000 watts.

A method for forming a via hole to expose a portion of a substrate in a silicon oxide layer by performing an etching process on an etcher containing a roof, a ring, a chiller and a chamber, the method comprising the steps of:

• forming a silicon nitride layer on the substrate, wherein the silicon nitride layer serves as an etching end point;
• forming a silicon oxide layer on the silicon nitride layer;
• performing a plasma etching process in the chamber to form an opening in the silicon oxide layer to expose a portion of the silicon nitride layer underneath by using an etchant, wherein the etchant consists of gaseous C4F8/C2F6/Ar/CO, and wherein the etchant works under conditions of:
• a C4F8 flow controlled at about 10 to 20 sccm;
• an Ar flow controlled at about 100 to 500 sccm;
• a CO flow controlled at about 1 to 100 sccm;
• a C2F6 flow that is about 0.5 to 1.5 times that of C4F8;
• a roof temperature controlled at about 150 to 300° C.;
• a wall temperature of the chamber controlled at about 150 to 400° C.;
• a ring temperature controlled at about 150 to 400° C.;
• a chiller temperature controlled at about −20 to 20° C.;
• a chamber pressure within the chamber controlled at about 4 to 50 mtorr;
• an etcher bias controlled at about 1000 to 2000 watts;
• and
• an etcher power controlled at about 1500 to 3000 watts;
• and
• removing the exposed portion of the silicon nitride layer to expose a portion of the substrate underneath the exposed portion of the silicon nitride layer.

A method for forming a HAR (>4:1)contact hole to expose a portion of a substrate in a silicon oxide layer by performing an etching process on an etcher containing a roof, a ring, a chiller and a chamber, the method comprising the steps of:

• forming a silicon nitride layer on the substrate, wherein the silicon nitride layer serves as an etching end point;
• forming a silicon oxide layer on the silicon nitride layer;
• performing a plasma etching process in the chamber to form an opening in the silicon oxide layer to expose a portion of the silicon nitride layer underneath by using an etchant, wherein the etchant consists of gaseous C4F8/Ar/CO, and wherein the etchant works under conditions of:
• a C4F8 flow controlled at about 10 to 20 sccm;
• an Ar flow controlled at about 100 to 500 sccm;
• a CO flow controlled at about 1 to 100 sccm;
• a roof temperature controlled at about 150 to 300° C.;
• a wall temperature of the chamber controlled at about 150 to 400° C.;
• a ring temperature controlled at about 150 to 400° C.;
• a chiller temperature controlled at about −20 to 20° C.;
• a pressure within the chamber controlled at about 4 to 50 mtorr;
• an etcher bias controlled at about 1000 to 2000 watts;
• and
• an etcher power controlled at about 1500 to 3000 watts;
• and
• removing the exposed portion of the silicon nitride layer to expose a portion of the substrate underneath the exposed portion of the silicon nitride layer.

An etching environment for performing an etching process on a silicon oxide layer while a silicon nitride layer is used as an etching end point, wherein the etching process is performed within an etcher containing a roof, a ring, a chiller and a chamber with an etchant, and the etchant includes of gaseous C4F8/Ar/CO, the etching environment comprising conditions of:

• a C4F8 flow controlled at about 10 to 20 sccm;
• an Ar flow controlled at about 100 to 500 sccm;
• a CO flow controlled at about 1 to 100 sccm;
• a roof temperature controlled at about 150 to 300° C.;
• a wall temperature of the chamber controlled at about 150 to 400° C.;
• a ring temperature controlled at about 150 to 400° C.;
• a chiller temperature controlled at about −20 to 20° C.;
• a pressure within the chamber controlled at about 4 to 50 mtorr;
• and
• an etcher bias controlled at about 1000 to 2000 watts;
• an etcher power controlled at about 1500 to 3000 watts.

A method for forming a via hole to expose a portion of a substrate in a silicon oxide layer by performing an etching process on an etcher containing a roof, a ring, a chiller and a chamber, the method comprising the steps of:

• forming a silicon nitride layer on the substrate, wherein the silicon nitride layer serves as an etching end point;
• forming a silicon oxide layer on the silicon nitride layer;
• performing a plasma etching process in the chamber to form an opening in the silicon oxide layer to expose a portion of the silicon nitride layer underneath by using an etchant, wherein the etchant consists of gaseous C4F8/Ar/CO, and wherein the etchant works under conditions of:
• C4F8 flow controlled at about 10 to 20 sccm;
• an Ar flow controlled at about 100 to 500 sccm;
• a CO flow controlled at about 1 to 100 sccm;
• a roof temperature controlled at about 150 to 300° C.;
• a wall temperature of the chamber controlled at about 150 to 400° C.;
• a ring temperature controlled at about 150 to 400° C.;
• a chiller temperature controlled at about −20 to 20° C.;
• a chamber pressure within the chamber controlled at about 4 to 50 mtorr;
• an etcher bias controlled at about 1000 to 2000 watts;
• and an etcher power controlled at about 1500 to 3000 watts;
• and
• removing the exposed portion of the silicon nitride layer to expose a portion of the substrate underneath the exposed portion of the silicon nitride layer.