Patent ID: 6153528
Filing Date: 2000-11-28
Classification: H01L

Abstract:
A method for fabricating dual damascene structure on a substrate, having a patterned metal layer, the comprising:forming a first liner oxide layer over the substrate;forming a first seed layer over the first liner oxide layer;patterning the first seed layer to form a first opening above the patterned metal layer to expose a portion of the first liner oxide layer;forming a first dielectric layer over the substrate, wherein the dielectric layer includes a first normal dielectric layer formed on the exposed portion of the first liner oxide layer, and a first porous dielectric layer formed on the first seed layer;forming a first cap layer over the first dielectric layer;forming an etching stop layer on the first cap layer with a second opening above the first opening, wherein the second opening is narrower than the first opening;forming a second liner oxide layer over the substrate;forming a second seed layer on the second liner oxide layer with a third opening above the second opening to expose a portion of the second liner oxide layer, wherein the third opening is wider than the second opening of the etching stop layer;forming a second dielectric layer over the substrate, wherein the dielectric layer includes a second normal dielectric layer formed on the exposed portion of the second liner oxide layer, and a second porous dielectric layer formed on the second seed layer;forming a second cap layer over the second dielectric layer;forming a mask layer on the second cap layer;forming a dual damascene opening in the second normal dielectric layer and the first normal dielectric layer to expose the patterned metal layer, wherein the dual damascene opening comprises an upper wider opening formed in the second normal dielectric layer to expose the etching stop layer and its second opening, and a lower narrower opening formed in the first normal dielectric layer to exposed a portion of the patterned metal layer, according to a dimension of the second opening;forming a conductive layer over the substrate; andperforming a planarization process, using the mask layer as a planarization stop point, to remove the conductive layer so that a remaining portion of the conductive layer fills the dual damascene opening to form the dual damascene structure.