Structure and method of forming vias

A contact structure between two conducting portions of an integrated circuit device, comprising:

• a first interconnect;
• a first insulating layer over the first interconnect;
• a planarizing layer over at least a portion of the first insulating layer, wherein the planarizing layer is formed from a material having an etch rate approximately equal to an etch rate of the first insulating layer for an etchant;
• a second insulating layer over the planarizing layer and the first insulating layer, wherein the second insulating layer is formed from a material having an etch rate different from an etch rate of the first insulating layer for an etchant;
• an opening extending through the second insulating layer, at least partially through a portion of the planarizing layer, and partially through the first insulating layer to expose a portion of the first interconnect, the opening having a bottom defining a contact surface comprising the exposed portion of the first interconnect and an exposed portion of first insulating layer;
• and
• a second interconnect which overlays the second insulating layer and contacts the contact surface through the bottom of the opening.

A structure consisting of a portion of a semiconductor integrated circuit, comprising:

• a first conductive region disposed over a portion of an underlying region;
• a substantially planar insulating layer comprising first and second insulating materials having a substantially uniform etch rate for an etchant, the planar insulating layer disposed over the underlying region and a portion of the first conductive region so that a remaining portion of the first conductive region is exposed;
• a second insulating layer disposed over the planar insulating layer, the second insulating layer having an etch rate differing from the etch rate of the planar insulating layer for the etchant, the second insulating layer having an opening extending through the second insulating layer and at least a Portion of the first insulating layer with a bottom that defines a contact surface formed from the exposed remaining portion of the first conductive region and an exposed portion of the planar insulating layer overlying the underlying region;
• and
• a second conductive layer disposed over the second insulating layer, the second conductive layer contacting the contact surface at the bottom of the opening.