Mechanical, geometrical, and electrical characterization of silicon membranes for open stencil masks

Abstract

Sossna, E.; Degen, A.; Rangelow, I. W.; Drzik, M.; Hudek, P.; Tiwald, T. E.; and Woollam, John A., "Mechanical, geometrical, and electrical characterization of silicon membranes for open stencil masks" (2001 Silicon membranes are used for stencil masks which are key to charged particle projection lithography, particularly for ion projection lithography, electron beam projection. Quantitative and qualitative determination of the mechanical properties of the true thickness, thickness variations ͑morphology͒, electrical conductivity and stress is critical to the development of next generation lithography. The metrology setup includes high accuracy thickness, refractive index and electrical conductivity measurement based on infrared variable angle spectroscopic ellipsometry, thickness variation characterization based on the Fizeau interferometric scheme and mechanical stress evaluation based on a novel double bulging technique.

Progress in spectroscopic ellipsometry: Applications from vacuum ultraviolet to infrared

“…It has been applied to doping implants 37 and silicon membranes. 38 In both cases, the doping concentration ͑and thus the optical properties͒ varied with depth through the material.…”

<title>Laser and optical measurement techniques for characterization of microelectronic components</title>

“…u1(-Mx,-My)(9) Performing this multiplying, an expression is obtained, where the different derivatives are present I(-Mx,-My)l+Kj '+K2[CJ(10) where the second derivative term has been taken as a last one. K1, K2, C1, C2 are the constants related to the value of 2/d, the last quadratic term can be omitted due to its negligible value.The influence of different terms on the resulting pattern is related to the ratio of2/d.…”