Patent ID: 6750140
Filing Date: 2004-06-15
Classification: H01L

Abstract:
A process for producing contact holes on a metallization structure, which comprises:providing the metallization structure with at least one interconnect having a surface covered with a section of a hard-mask layer and configuring the metallization structure on a substrate surface; applying a dielectric layer including a material with carbon so that at least a surface of the section of the hard-mask layer is surrounded by the dielectric layer; etching contact holes through the dielectric layer in a first etch step using an etching-gas mixture including C4F8 and oxygen having a first oxygen concentration; making a determination that the hard-mask layer has been reached; in dependence on the determination, ending the first etch step and starting a second etch step using an etching-gas mixture including C4F8 and oxygen having a second oxygen concentration; and while performing the second etch step, selectively etching the hard-mask layer with respect to the dielectric layer and selecting the second oxygen concentration to increase a selectivity at which the hard-mask layer is being etched with respect to the dielectric layer.