Abstract: The present invention relates to a process for etching a metal layer system. The metal layer system includes a first aluminum-containing layer, a second aluminum-containing layer, and an interlayer arranged between the two aluminum-containing layers. The interlayer consists of a material that is suitable for end-point detection. The etching process includes a first etching step, in which the upper aluminum-containing layer is etched using a first etching angle, and a second etching step, in which the lower aluminum-containing layer is etched using a second etching angle. The process switches between the first etching step and the second etching step as soon as the end-point detection has detected that the interlayer has been reached. Accordingly, the interlayer is arranged at a location at which it is intended for the process to switch from the first etching step to the second etching step.

Abstract: A method for reducing capacitative coupling between interconnects on a semiconductor structure includes producing a first insulating layer on a semiconductor substrate and etching trenches in the first insulating layer. Metallic interconnects are formed in the trenches by metallization. The semiconductor structure is polished to remove metal from the first insulating layer, leaving behind metal in the trenches. A portion of the first insulating layer between the first and second metallic interconnects is etched so that the first and second metallic interconnects project above the first insulating layer. A second insulating layer is applied on the substrate such that the metallic interconnects project into the second insulating layer. The second insulating layer has a relative permittivity that is lower than the relative permittivity of the first insulating layer.

Abstract: The present invention relates to a process for producing contact holes on a metallization structure, which can be used, for example, to produce electrical contacts between adjacent metallization levels. A dielectric layer is applied to interconnects which are covered with a hard-mask layer that is usually used for patterning the interconnects. Then, contact holes are etched through the dielectric layer, and this step is ended as soon as the hard-mask layer is reached. Then, the hard-mask layer is etched selectively with respect to the dielectric layer, so that the phenomenon where the contact holes break out into the space between adjacent interconnects is minimized. In this way the risk of short circuits is drastically reduced.