Process for forming a via in an integrated circuit structure by etching through an insulation layer while inhibiting sputtering of underlying metal

A process for forming a via by etching through an insulation layer over a metal layer on a semiconductor wafer in an etch chamber without depositing sputtered metal residues on the sidewall of the via which comprises:

• a) flowing into said etch chamber an etch gas mixture which includes:
• i) from about 10 to about 100 volume % of one or more 3-6 carbon fluorinated hydrocarbons having the formula C.sub.x H.sub.y F.sub.z, wherein x is 3 to 6, y is 0 to 3, and z is 2x-y when said fluorinated hydrocarbon is cyclic and 2x-y+2 when said fluorinated hydrocarbon is non-cyclic;
• and
• ii) optionally from 0 to about 90 volume % of one or more inert gases;
• and
• b) maintaining a plasma within said etch chamber during said etch within a power range of from about 300 to about 2500 watts.

A process for forming a via by etching through an insulation layer over a metal layer on a semiconductor wafer in an etch chamber without depositing sputtered metal or other etch residues on the sidewall of the via which comprises:

• a) flowing into said etch chamber a gaseous mixture which includes:
• i) one or more fluorine-containing gases comprising from about 10 to about 100 volume % of one or more 3-6 carbon fluorinated hydrocarbons having the formula C.sub.x H.sub.y F.sub.z, wherein x is 3 to 6, y is 0 to 3, and z is 2x-y when said fluorinated hydrocarbon is cyclic and 2x-y+2 when said fluorinated hydrocarbon is non-cyclic;
• ii) from 0 to about 90 volume % of one or more other fluorine-containing gases;
• and
• iii) one or more inert gases wherein the amount of said inert gases comprise from 0 to about 90 volume % of the total volume of said gaseous mixture of fluorine-containing gases and inert gases;
• b) maintaining a plasma within said etch chamber during said etch within a power range of from about 300 to about 2500 watts;
• and
• c) immersing said wafer in a magnetic field having a magnetic strength parallel to the plane of said wafer ranging from 1 to about 150 gauss.

A method for forming one or more vias by etching through an insulation layer over a metal layer on a semiconductor wafer in an etch chamber without depositing sputtered metal residues on the sidewall of the via which comprises:

• a) flowing into said etch chamber containing said semiconductor wafer an etch gas mixture which includes:
• i) one or more fluorine-containing etchant gases;
• and
• ii) one or more nitrogen-containing gases selected from the group consisting of N.sub.2 and N.sub.2 O;
• in a ratio ranging from about 1 volume part of said one or more nitrogen-containing gases per 15 volume parts of said one or more fluorine-containing gases to about 1 volume part of said one or more nitrogen-containing gases per 2 volume parts of said fluorine-containing gases;
• and
• b) maintaining a plasma within said etch chamber during said etch within a power range of from about 300 to about 2500 watts.

A method for forming one or more vias by etching through an insulation layer over a metal layer on a semiconductor wafer in an etch chamber without depositing sputtered metal residues on the sidewall of the via which comprises:

• a) flowing into said etch chamber containing said semiconductor wafer an etch gas mixture which includes:
• i) one or more fluorine-containing etchant gases selected from the group consisting of CHF.sub.3, CF.sub.4, C.sub.2 F.sub.6, NF.sub.3, SF.sub.6, and mixtures of same;
• ii) N.sub.2 gas;
• and
• iii) optionally from 0 to about 94 volume % of an inert gas;
• in an N.sub.2 to fluorine-containing gas ratio ranging from about 1 volume part N.sub.2 gas per 15 volume parts fluorine-containing gas to about 1 volume part N.sub.2 gas per 2 volume parts fluorine-containing gas;
• b) maintaining said etch chamber at a pressure ranging from about 5 milliTorr to about 200 milliTorr during said etch;
• c) maintaining the temperature of a wafer support in said etch chamber on which said wafer is mounted within a range of from about -120.degree. C. to about 50.degree. C. during said etch;
• d) immersing said wafer in a magnetic field having a magnetic strength parallel to the plane of said wafer ranging from 0 to about 150 gauss during said etch;
• and
• e) maintaining a plasma within said etch chamber during said etch within a power range of from about 300 to about 2500 watts.