AVS 53rd International Symposium
    Manufacturing Science and Technology Thursday Sessions
       Session MS-ThA

Paper MS-ThA6
Characterizing Copper Lines for Advanced Interconnect Using Normal Incidence Scatterometry

Thursday, November 16, 2006, 3:40 pm, Room 2018

Session: Sensors, Metrology, and Control
Presenter: Z. Liu, Nanometrics Inc.
Authors: Z. Liu, Nanometrics Inc.
Y. Hao, Nanometrics Inc.
Correspondent: Click to Email
With the continuous evolution of smaller device dimensions and denser circuit integration, copper interconnect with low-k dielectrics have been the most popular solution for future technology generations. In copper interconnect, one of the major challenges is the dimensional control of the interconnect features, which is critical to achieve necessary circuit performance of the device. To achieve best device performance, there is limited tolerance of the profile variation in interconnect structures. This dimensional control requirement demands metrology solutions to characterize the interconnect structures in all metal levels. In this paper we propose to use normal incidence scatterometry to characterize the copper lines (line width and height) at various metal levels. Normal incidence scatterometry uses a polarized broadband light source to measure the reflectance spectrum of the grating line structure. Using the modeling technique, profile information including line width and height can be determined. In this work we measure copper grating line structures at different metal levels (M1, M3 and M7) after each chemical mechanical polishing. These structures correspond to different copper line-widths ranging from 0.09 to 0.8 um. Structures with copper lines either parallel or perpendicular to each other between adjacent metal levels are studied. Advanced modeling techniques are used to decouple spectral contributions between the top metal level and the metal levels below. The measurement results are compared with results from other reference techniques, e.g. X-SEM and a very good agreement is demonstrated.