Nonlinearity corrections for amplitude measurement from Hadamard sums application to a rotating polarizer ellipsometer

Zalczer, G.

doi:10.1063/1.1139910

Cited by 3 publications

(2 citation statements)

References 1 publication

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“…. u and v can be found quite simply from the data, either by performing a least squares fit [15], a Fourier analysis [16] or by the use of a Hadamard transform [17], so that tan ψ and cos can be determined. There are several areas of possible systematic error:…”

Section: Instrumentationmentioning

confidence: 99%

Multiple-angle-of-incidence ellipsometry

Jenkins

1999

J. Phys. D: Appl. Phys.

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When plane-polarized light is reflected from the surface of a material at some oblique angle of incidence, the reflected light is, in general, elliptically polarized. The degree of ellipticity is determined by the optical parameters (refractive index and absorption coefficient) of the reflecting medium. Thus, using an ellipsometer to determine the degree of ellipticity enables a measurement of material parameters. In this review, we will concentrate on ellipsometers in which the angle of incidence of light on the material is varied. The review will look at both the theoretical and practical problems associated with this form of ellipsometry and will present some examples of its use from the literature.

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Section: Instrumentationmentioning

confidence: 99%

Multiple-angle-of-incidence ellipsometry

Jenkins

1999

J. Phys. D: Appl. Phys.

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“…Both null and rotating analyzer ellipsometer types have their advantages and disadvantages in comparison to each other. The null type, because of the nature of nulling operation, does not involve errors connected with nonlinearity and drift of the electronic part 1,6,7 and the optical element imperfections can be more easily accounted for by using two or four zone measurements. 1 Rotating element type is faster; thus it is more suitable for kinetic measurements, and can operate without a wavelength dependent compensator, which is important for spectroscopic applications.…”

Section: Introductionmentioning

confidence: 99%

Rotating analyzer–fixed analyzer ellipsometer based on null type ellipsometer

Russev

Arguirov

1999

Review of Scientific Instruments

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The theory and design of an inexpensive rotating analyzer unit is presented, which allows a conventional null type ellipsometer to work as rotating analyzer-fixed analyzer automatic ellipsometer, without sacrificing the possibility to work in null mode. The mode switching is performed simply by adding or removing the rotating analyzer from its holder. It is shown that the rotating analyzer phase shift in rotating analyzer-fixed analyzer mode can be run-time determined from the measured Fourier coefficients. This avoids any need of recalibration procedure after mode switching and makes unnecessary plane of incidence synchronization, which further simplifies the needed hardware and reduces the errors connected with the phase shift instability of the output signal. The run-time phase shift calibration procedure and subsequent ellipsometric angles determination do not involve normalization of the output signal Fourier coefficients to the zeroth harmonic, eliminating in this way the influence of the dc component time drift.

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Compensation for transient chamber wall condition using real-time plasma density feedback control in an inductively coupled plasma etcher

Klimecky

Grizzle

Terry

2003

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Articles you may be interested inSurface loss rates of H and Cl radicals in an inductively coupled plasma etcher derived from time-resolved electron density and optical emission measurements J. Vac. Sci. Technol. A 28, 360 (2010); 10.1116/1.3330766Feedback control of plasma electron density and ion energy in an inductively coupled plasma etcher Real-time control of ion density and ion energy in chlorine inductively coupled plasma etch processing Reactive ion etch processing is known to exhibit significant variability in final etch performance due to wall condition. Previous studies have shown that neutral species transients depend strongly upon chamber seasoning. In this article, we show simultaneous measurements of wall-state-induced changes in plasma density and poly-Si etch rate, and demonstrate a real-time feedback control system that corrects for the plasma density variation. We demonstrate that controlling the plasma density to constant value eliminates the classic ''first wafer effect'' in Cl 2 etching of poly-Si in a Lam 9400 transformer coupled plasma ͑TCP͒. Chamber conditions studied include fluorination/ cleaning by C 2 F 6 plasmas compared to chlorination/deposition from Cl 2 plasmas. Transient density changes due to wall condition were measured using a microwave resonance cavity technique called broadband rf. Following chamber fluorination, broadband data show a significant drop in electron density ͑ϳ39%͒ from nominal levels. This is followed by subsequent partial recovery of the nominal density during a 60 s Cl 2 etch. Independent measurements correlate strongly with the broadband signals; particularly real-time poly-Si etch rate and SiCl 4 etch product concentration. Observed real-time variations in all signals were then compensated using a single input/single output proportional-integral ͑PI͒ feedback control algorithm, in which the broadband peak frequency is the system output variable and TCP power is the system actuator. Such PI control not only stabilizes broadband peak frequencies, but also steadies poly-Si real-time etch rate and SiCl 4 etch product concentration. This compensation scheme is then applied over multiple runs to reduce etch depth variability due to chamber condition. Results of this control system are shown to attenuate first wafer effects by a factor of 3 and reduce overall etch depth variation from run to run by an additional 33% compared to standard manufacturing practice. When applied to patterned wafer etches, feedback control of plasma density with an oxide hardmask is found not to alter critical dimensions or profile in any observable way. Only total etch depth appears to be affected using density control, as the real-time etch rate is in general increased in comparison to open-loop etching.

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Nonlinearity corrections for amplitude measurement from Hadamard sums application to a rotating polarizer ellipsometer

Cited by 3 publications

References 1 publication

Multiple-angle-of-incidence ellipsometry

Multiple-angle-of-incidence ellipsometry

Rotating analyzer–fixed analyzer ellipsometer based on null type ellipsometer

Compensation for transient chamber wall condition using real-time plasma density feedback control in an inductively coupled plasma etcher

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