Design and operation of an automated, high-temperature ellipsometer

Meulen, Y. J. van der; Hien, N. C.

doi:10.1364/josa.64.000804

Cited by 93 publications

(29 citation statements)

References 12 publications

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“…The actual temperature of the sample surface has been checked using the measured value of refractive index at 633 nm. 5 We show in Fig. 1 the temperature dependence reported in Refs.…”

Section: Experimental Setup and Data Analysismentioning

confidence: 66%

Optical functions of silicon at high temperatures

Šik

Hora

Humlíček

1998

Journal of Applied Physics

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The optical spectra of silicon are studied ellipsometrically at temperatures between 300 and 1200 K in the spectral range from 2 to 4.3 eV. We present a database of optical constants for pure and heavily doped samples, with the highest concentration of free carriers of 4ϫ10 20 cm Ϫ3 . We cover the photon energy range between 0.2 and 2 eV by using an oscillator representation of the visible and ultraviolet ellipsometric data. We also report the results for the temperature dependence of the E 1 interband transition. The values of the energy shift and Lorentzian broadening of this spectral feature are obtained from analytical critical-point line shapes by fitting differentiated dielectric functions; alternatively, we apply the numerical convolution with Lorentzian contours to describe quantitatively the increased broadening with increasing temperature.

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“…The actual temperature of the sample surface has been checked using the measured value of refractive index at 633 nm. 5 We show in Fig. 1 the temperature dependence reported in Refs.…”

Section: Experimental Setup and Data Analysismentioning

confidence: 66%

Optical functions of silicon at high temperatures

Šik

Hora

Humlíček

1998

Journal of Applied Physics

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“…Measurement of the Sio film thickness is usually performed by ellipsometry, 2 an optical technique based on changes in the state of polarization of an incident monochromatic light beam upon reflection from the film covered Si surface. The advent of the use of in-situ ellipsometric studies where an oxidation furnace is mounted at the focus of an ellipsometer has been an important development in studying Si oxidation kinetics (39)(40)(41). This in-situ set up enables the collection of dense thickness versus 0' time data sets and therefore allows an accurate determination of the rate constants.…”

Section: Early Models Of the Oxidation Processmentioning

confidence: 99%

Models for the oxidation of silicon

Irene

1988

Critical Reviews in Solid State and Materials Sciences

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“…USL -LSL (5) A measurement equipment can be accepted for process control when its PTCC value is below 10%. To estimate the minimum precision required for an in situ ellipsometer for the control of thermal oxidation and nitride deposition, we analyzed process data published by different vertical furnace suppliers.…”

Section: Ptcc= 6gage 100%mentioning

confidence: 99%

<title>Advanced process control system for vertical furnaces</title>

Berger¹,

Schneider

Lehnert

et al. 1996

SPIE Proceedings

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For the first time, a layer thickness sensor has been integrated into a vertical furnace for in situ sensing ofthe layer growth as well as forpostprocess control ofthe batch. Because ofits high accuracy and versatility, an in situ spectroscopic ellipsometer (SE) was selected. The adaption ofthe SE to the vertical furnace was performed with only minor modifications to the furnace geometry. The ellipsometer light beam is guided through the base plate into the furnace tube and directed onto the wafer by quartz glass prisms operated in total internal reflection (TIR) mode. This arrangement introduces an additional phase shift in the polarization state of the light which can be determined and subtracted from the measured phase shift. The ellipsometer setup is mechanically fixed to the boat loader. SE measurements therefore can be performed with the wafer boat out ofthe furnace tube as well as during the process run with the wafer boat inserted. The SE thus can be used for in situ end-point detection during layer growth and also for postprocess measurements on selected wafers ofthe batch during the unloading sequence. A realtime controller and a run-by-run coniroller integrated into the furnace controller utilize the layer thickness data measured in the in situ and in the postprocess mode, respectively, for inimediate and automated correction of the parameter settings during the actual process run and for the following process run. The advantages ofthis novel furnace control system such as a reduction intime needed for process optimization, the avoidance of monitor wafers and a better control in integrated multilayer processing can be beneficial for future thermal batchlminibatch processing.Key words: Vertical furnace; in situ ellipsometry; end-point detection BACKGROUNDIn recent years, the prevailing attitude ofthe semiconductor industry towards the implementation of in situ measurement techniques has undergone a considerable change. Today, they are often regarded as the key not only to a better understanding ofthe process, but also to cost-effective manufacturing in the future. In spite of the increasing interest, the number of installations of in situ metrology (in situ in the sense ofmeasurements on the wafer itself) in manufacturing equipment is still very small because some prerequisits for a successful integration are not fulfilled in most cases.' Nearly no semiconductor manufacturing system provides the optical access for a ready-to-use integration of an in situ sensor and hardly any ofthe available in situ measurement tools has been sufficiently tested and qualified for use in a production environment. If, however, the manufacturing capability of the sensor cannot be demonstrated, the equipment supplier is not willing to integrate in situ sensors, because this could detrimentally affect the reliability ofthe system. A failure ofthe in situ sensor would cause a failure ofthe whole machine. In this work, an in situ spectroscopic ellipsometer was integrated into a vertical oxidation furnace. Oxidation and also CV...

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Design and operation of an automated, high-temperature ellipsometer

Cited by 93 publications

References 12 publications

Optical functions of silicon at high temperatures

Optical functions of silicon at high temperatures

Models for the oxidation of silicon

<title>Advanced process control system for vertical furnaces</title>

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