Patent ID: 7838436
Filing Date: 2010-11-23
Classification: G11C,H01L

Abstract:
1. A process for forming multiple electrodes on a silicon nitride substrate having a top surface, comprising: cleaning said top surface through sputter cleaning; depositing a layer of NiCr on said top surface depositing a layer of ruthenium on said NiCr layer; depositing a first layer of alpha tantalum on said ruthenium layer; depositing a first layer of tantalum nitride on said first layer of alpha tantalum; forming on said top surface a photoresist mask that defines said multiple electrodes; then performing first reactive ion etching by means of an etchant selected from the group consisting of gaseous compounds of carbon and fluorine whereby all unprotected areas of alpha tantalum and tantalum nitride are etched at an etch rate that is reduced by a factor of about 10 when said ruthenium layer becomes exposed, at which point terminating first reactive ion etching; then removing all remaining photoresist; and then performing second reactive ion etching by means of an etchant selected from the group consisting of gaseous compounds of carbon, oxygen, and hydrogen whereby all exposed material is etched at an etch rate that is reduced by a factor of terminating second reactive ion etching with minimal penetration of said silicon nitride substrate.