REAL-TIME LATENT IMAGE MONITORING DURING HOLOGRAPHIC FABRICATION OF SUBMICRON DIFFRACTION GRATINGS

Citation
Ja. Gregus et al., REAL-TIME LATENT IMAGE MONITORING DURING HOLOGRAPHIC FABRICATION OF SUBMICRON DIFFRACTION GRATINGS, Journal of vacuum science & technology. B, Microelectronics and nanometer structures processing, measurement and phenomena, 11(6), 1993, pp. 2468-2472
Citations number
11
Categorie Soggetti
Physics, Applied
ISSN journal
10711023
Volume
11
Issue
6
Year of publication
1993
Pages
2468 - 2472
Database
ISI
SICI code
1071-1023(1993)11:6<2468:RLIMDH>2.0.ZU;2-L
Abstract
Real-time monitoring of latent images in photoresist during the hologr aphic exposure of submicron period diffraction gratings is reported. T he first-order diffraction efficiency is recorded as a function of tim e for different resist thicknesses and polarizations. By monitoring th e diffraction efficiency in real time, the process can be controlled t o compensate for variations in exposure dose, resist thickness, and th e optical properties of underlying materials. It is demonstrated that latent image monitoring (LIM) can be performed in real time and that t he diffraction efficiency correlates well with the linewidth. To inter pret diffraction efficiencies with changes in resist thickness and pol arization, rigorous coupled wave analysis combined with a commercial s oftware package to simulate the real-time data was used. However, the data show evidence for slow changes in the composition of the resist d uring exposure that are consistent with chemical intermediates reactin g with water in the film. The commercial exposure simulation tool cann ot account for these phenomena, which complicate the application of LI M to real-time exposure control.