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

Paper MS-ThA3
Critical Dimension Metrology: A Comprehensive Evaluation of Current Techniques in Spectroscopy-Based Scatterometry

Thursday, November 16, 2006, 2:40 pm, Room 2018

Session: Sensors, Metrology, and Control
Presenter: C. Saravanan, Nanometrics Inc
Authors: C. Saravanan, Nanometrics Inc
Z. Liu, Nanometrics Inc
Correspondent: Click to Email
In recent years scatterometry has evolved into a reliable, non-invasive and fast technique to characterize critical dimensions (CD) in semiconductor device fabrication. Both polarized-light Normal Incidence Spectroscopy (NIS) and Spectroscopic Ellipsometry (SE) have been successfully used as competing techniques in CD metrology. While several studies have been performed to evaluate these techniques, a thorough evaluation of the 'optimal space' of applicability for these individual techniques does not exist. Furthermore, very little is known about the combined NIS and SE approach as an alternate method for CD metrology. In this paper we first explore 'regions' of optimal applicability of these three techniques (NIS, SE and NIS+SE) by performing simulations on multiple structures with varying heights, sidewall angles, optical properties and pitch (360nm, 180nm, 90nm, 45nm, 32nm and 16nm). We show that regions of optimal applicability exist for all three techniques. We also perform experimental studies for some typical applications and demonstrate the benefit of using combined analysis of NIS and SE to limit parameter correlation and to enhance sensitivity. This is particularly important for scatterometry applications in future technology nodes with much smaller device dimensions.