Abstract

We present a novel optical characterization technique called localized surface plasmon resonance (LSPR) spectroscopy [Fig. 1(a)]. LSPR spectroscopy exploits light excited surface plasmons, which are collective coherent electron oscillations at a metal/dielectric interface. The LSPR can be observed in a transmission spectrum [Fig. 1(b)] and it is very sensitive to the constituent materials as well as both lateral and vertical dimensions of the structures [1,2]. This makes LSPR spectroscopy interesting for a number of applications including nanometrology [3]. Like scatterometry, LSPR spectroscopy requires test structures and computer simulations [Fig. 1(c)] to establish the correlation between spectra and physical dimensions. Instead of measuring on individual structures like CD-SEM and AFM, LSPR spectroscopy measures on an array of test structures with an arbitrary array size. This makes LSPR spectroscopy particularly interesting for dense device layers where the vacant space for test structures is limited.

© 2013 IEEE