Stress engineering related to the LSI process is required. With shallow trench isolation (STI) structures, a high stress field causes a variation in electrical characteristics. Although stress fields in a Si substrate can be detected by Raman spectroscopy, no effective technique has been reported for the measurement of nanoscale stress fields in a dielectric material used for STI filling. Recently, we have reported that ''cathodoluminescence (CL) spectroscopy'' enables us to detect nanometer-scale stress fields in LSI structures. In this study, we performed the first estimation of the stress fields with a STI structure by CL and Raman spectroscopy, as well as finite element method (FEM) calculation. We were able to repeatedly acquire clear stress distributions by CL and Raman spectroscopy. Moreover, CL, Raman, and FEM results showed excellent agreement with one another, revealing that a large variation in stresses along the AA/STI boundary was induced by the intrinsic tensile stress of the SiO 2 film.

This paper describes evaluation of surface stress distribution in single-crystal silicon (SCS) microstructure using laser Raman spectroscope. An in-house uniaxial tensile tester was employed to apply the uniaxial tensile stresses to SCS (001)[100] and (001) [110] film specimens with a number of microscale convex structures. A linear relationship between the applied tensile stress and Raman peak shift increment was obtained from Raman spectroscopy at a flat section of the specimen. Raman spectroscopy was also conducted to observe nonuniform stress distribution around the convex structures under uniaxial tensile loading. In observations around a convex structure, ''twocurve fitting'' was adopted for the asymmetric spectrum, which had been observed clearly under the tensile stresses of over 1000 MPa. The two-curve fitting was able to separate information of the top corner from that of the bottom one at the edge. The stress distribution estimated by the two peak positions was much closer to finite element analysis (FEA) results than that obtained by the one peak position.

No abstract

This paper describes Raman spectroscopic stress analysis of single crystal silicon (SCS) microstructures for development of reliability evaluation technique utilized for silicon-based microelectromechanical systems (MEMS). An inhouse tensile tester was employed to apply a uniaxial tensile stress to the SCS specimen with a 270 nm-height, 4 m-square SCS boss in the gauge section. Raman spectra on the boss were obtained under a constant tensile stress applied. The stress distribution obtained from two-curve fitting of Raman spectrum was in good agreement with that estimated by finite element analysis (FEA). The Raman spectroscopic stress evaluation method would be effective for nondestructive reliability testing for silicon-MEMS.

No abstract