The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 30, 1995
Filed:
Feb. 18, 1994
Gurvinder Jolly, Ontario, CA;
Northern Telecom Limited, Montreal, CA;
Abstract
A method of selectively etching a layer of a refractory metal nitride, with application to formation of TiN local interconnects for VLSI integrated circuits, and particularly a method of selectively etching TiN relative to a refractory metal silicide. The method comprises the step of heating surfaces of the substrate to a selected etch temperature between 50.degree. C. and 200.degree. C. in a non-reactive gas and then exposing the heated substrate to reactive halogen species of a plasma having ion energies substantially less than 100 eV, and preferably below 30 eV. The etch selectivity is controlled by selecting a relatively low ion energy to reduce ion bombardment and heating effects during etching, and independently controlling the etch temperature in the heating step. The reactive species of the plasma are preferably generated by electron cyclotron resonance (ECR) excitation of a halocarbon containing gas, and heating comprises ion bombardment with a non-reactive gas. For etching TiN, preferred halocarbon containing gases are CF4 and C2F6, and mixtures thereof, whereby optimum etch selectivity is obtained with reactive species having ion energies less than 30 eV, and at an etch temperature in the range 100.degree. to 120.degree. C.