AVS 46th International Symposium
    Plasma Science and Technology Division Wednesday Sessions
       Session PS-WeA

Invited Paper PS-WeA1
Dielectric Etching : From Oxide to Low k Dielectrics

Wednesday, October 27, 1999, 2:00 pm, Room 609

Session: Dielectric Etching
Presenter: P. Berruyer, LETI (CEA-Grenoble), France
Authors: P. Berruyer, LETI (CEA-Grenoble), France
O. Joubert, CNRS-LTM Grenoble, France
D. Fuard, CNRS-LTM Grenoble, France
C. Verove, ST-Microelectronics, France
M. Assous, LETI (CEA-Grenoble), France
R. Blanc, ST-Microelectronics, France
H. Feldis, ST-Microelectronics, France
E. Tabouret, LETI (CEA-Grenoble), France
Y. Morand, ST-Microelectronics, France
Correspondent: Click to Email
Dielectric etching for interconnection is one of the most critical processes of the ULSI technology. Up to now oxide has been used as inter-metal dielectric with an aluminum based metallisation. The well known issue of contact and vias etch process is the etch-stop phenomenon occurring in high aspect ratio structures, if highly selective process is required. The introduction of copper and thus dual damascene architectures, has increased the number of dielectric etch processes required in the fabrication of ICs. Moreover the level of difficulty of these processes has increased : aspect ratio can be higher than it is in contact and vias, holes but also lines can be etched and high selectivity to nitride is required. If the introduction of copper has led to a more critical oxide etch process, the introduction of low k material dielectrics will lead to a break off in dielectric etch processes. These low k materials can be either mineral or organic with various porosity. This paper deals with the different etching processes and plasma source required for these different dielectrics. First of all, process performances such as profile, selectivity, CD, trenching, µloading, etch stop, yield, plasma induced damage will be studied as a function of process parameters. We will point out that, if etch stop in high aspect ratio structures is the main issue in oxide etch, profile control is the main issue of the etching of low k polymer materials (SiLK). Mechanisms related with these 2 issues will be proposed. Process conditions required for the etching of aerogel materials will also be discussed. Then, taking into account the process performances and limitations obtained previously, different schemes of dual damascene structures with copper metallisation will be compared. @FootnoteText@ @footnote 1@ This work has been carried out in the frame of GRESSI consortium between CEA.G-LETI and FRANCE TELECOM-CNET