METHOD OF FORMING A BARRIER LAYER IN A CONTACT STRUCTURE

摘要

The aluminum <111> crystal orientation content of an aluminum interconnect layer or the copper <111> crystal orientation content of a copper interconnect can be maintained at a consistently high value during the processing of an entire series of semiconductor substrates in a given process chamber. To provide the stable and consistent aluminum <111> content, or the stable and consistent copper <111> content, it is necessary that the barrier layer structure underlying the aluminum or the copper have a consistent crystal orientation throughout the processing of the entire series of substrates, as well. We have determined that to ensure the consistent crystal orientation content of the barrier layer structure, it is necessary to form the first layer of the barrier layer structure to have a minimal thickness of at least about 150 ANGSTROM , to compensate for irregularities in the crystal orientation which may by present during the initial deposition of this layer. As an alternative to increasing the thickness of the first layer of the barrier layer structure, this first layer can be deposited a low process chamber pressure, so that harmful irregularities in the crystal orientation are eliminated.