Production CMOS technology node shallow trench isolation (STI) etching process control has been discussed in the present paper. It has been shown that optical scatterometry can be adopted for that in order to increase throughput and informativity of the control. In addition, it has been shown that scatterometry can replace a number of currently used techniques. The process of model suitable for the STI application creation has been discussed. A number of cross-control techniques is used to enable scatterometry for the discussed application. The application limits of the optical scatterometry are developed and techniques for control of the nodes beyond these limits have been discussed. In particular, process of CD control beyond 20 nm node has been discussed. The model created enables the control of not only the width of the trench but also its depth and sidewall angle. Those additional parameters were not controlled in-line previously and it helped to reduce production cost and increase the IC reliability. The control process has been tested on the CMOS 180 nm technology node, but its adoption to smaller nodes has been discussed.
Литература
1. Liou F.-T., Chen F.E. Method for forming planarized shallow trench isolation in an inte-grated circuit and a structure formed thereby // Patent US N 5130268 A. 1992.
2. Review of CD measurement and scatterometry / P. Thony, D. Herisson, D. Henry et al. // Proceedings of the Characterization and Metrology for VLSI Technology. –2003. – P. 381–388.
3. Tompkins H.G., Irene E.A. Handbook of ellipsometry. – William Andrew Publishing, NY and Springer-Verlag GmbH, Heidelberg. – 2005. – 891 p.
4. Broadband spectral operation of a rotating-compensator ellipsometer / J. Opsal, J. Fanton, J. Chen et al. // Thin Solid Films. – 1998. – Vol. 313–314. – P. 58–61.
5. Opsal J., Chu H. Fundamental solutions for real-time optical CD metrology // Proceedings of SPIE. – 2002. – Vol. 4689. – P. 163–176.
6. Through Pitch monitoring by optical scatterometry/ R. Melzer, C. Hartig, G. Grasshoff et al. // Proceedings of SPIE. – 2015. – Vol. 9424. – P. 942429-1 – 942429-9.
7. Fast and accurate scatterometry metrology method for STI CMP stepheight process eval-uation / C.-H. Lina, C. Huang, C.-L. Hsu et al. // Proceedings of SPIE. – 2012. – Vol. 8324. – P. 832421-1 – 832421-8.
8. Nondestructive analysis of lithographic patterns with natural lineedge roughness from Mueller matrix ellipsometric data / X. Chen, Y. Shi, H. Jiang et al. // Applied Surface Science. – 2016. – Vol. 388. – P. 524–530.
9. Problems in measurements of parameters of elements and structures in modern micro- and nanoelectronics considering TiN/Ti diffusion barrier structures as an example / D.I. Smirnov, R.M. Giniyatyllin, I.Yu. Zyul’kov et al. // Technical Physics Letters. – 2013. – Vol. 39. – No 7. – P. 34–42.
10. Sullivan N., Dixson R., Bunday B. Electron beam metrology of 193 nm resists at ultra-low voltage // Proceedings of SPIE. – 2003. – Vol. 5038. – P. 483–492.
11. Modeling of line roughness and its impact on the diffraction intensities and the recon-structed critical dimensions in scatterometry / H. Gross, M.-A. Henn, S. Heidenreich et al. // Applied Optics. – 2012. – Vol. 51. – No 30. – P. 7384 – 7394.
12. Palik E.D. Handbook of optical constants of solids // Academic Press. – 1998. – 999 p.
13. Comparison of algorithms used for evaluation of ellipsometric measurements Random search, genetic algorithms, simulated annealing and hill climbing graph-searches / O. Polgár, M. Fried, T. Lohner et al. // Surface Science. – 2000. – Vol. 457. – P. 157–177.
14. Accurate and reliable optical CD of MuGFET down to 10nm / P. Leray, G.F. Lorusso, S. Cheng et al. // Proceedings of SPIE. –2003. – Vol. 6518. – P. 65183B-1–65183В-10.
15. Ito Y., Higuchi A., Omote K. Characterization of cross-sectional profile of resist L/S and holepattern using CD-SAXS // Proceedings of SPIE. – 2016. – Vol. 9778. – P. 97780L-1–97780L-8.