Patent ID: 6461529
Filing Date: 2002-10-08
Classification: H01L

Abstract:
A composition for etching a trench in a silicon nitride layer of a multilayer structure in a damascene etch scheme, said composition consisting essentially of:polymerizing agent selected from the group consisting of at least one of CF4, C2F6, and C3F8 in an amount of about 0.1-25% by volume; a hydrogen source selected from the group consisting of at least one of CHF3, CH2F2, CH3F, and H2 in an amount of about 5-30% by volume; a noble gas diluent selected from the group consisting of at least one of He, Ar, and Ne in an amount of about 0.1-50% by volume; an oxidant comprising a carbon-containing oxidant component and an oxidant-noble gas component, wherein said carbon-containing component is selected from the group consisting of at least one of CO2 and and CO and is added in an amount of about 1-25% by volume and said oxidant-noble gas component is O2 in He and is added in an amount of about 0.1-20% by volume in a relative concentration of about 30% oxidant in said noble gas; wherein said polymerizing agent, said hydrogen source, said noble gas diluent, and said oxidant are added in relative amounts to achieve a nitride selectivity to silicon oxide of at least about 4:1 and a nitride selectivity to photoresist of at least about 3:1.