Papers by jean-louis Stehlé
MRS Proceedings, 1999
Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize th... more Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize thin films and multilayers. It is now intensively used in microelectronics and especially for the microlithographic applications. Instrumentation for the next generation of UV lithography at 157nm requires special optical setup since oxygen and water are extremely absorbing below 190nm. The ellipsometer discussed in this paper works into a purged glove box to reduce the oxygen and water contamination in the part per million ranges. The optical setup has been especially studied for microlithographic applications. It includes for example a premonochromator in the polariser arm to avoid resist photobleaching. Technical details of the system and some first measurement results on substrates and thin films are reported hereafter.
Emerging Lithographic Technologies V, 2001
ABSTRACT Spectroscopic ellipsometry has long been recognized as the technique of choice to charac... more ABSTRACT Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize thin films and multilayers. In 1983, SOPRA has developed the first commercial spectroscopic ellipsometers for research and development. Since this date, the wavelength range has been extended from visible to near infrared (2micrometers ) and far infrared up to 18micrometers . For 193nm micro-lithography, deep UV option down to 190nm has also been developed and delivered more recently. Instrumentation for the next generation of VUV lithography at 157nm requires special optical setup since O2 and H2O are extremely absorbing below 190nm. A new system has been developed which works into a purged glove box to reduce the oxygen and water contamination in the part per million range. The optical setup includes a premonochromator in the polarizer arm to avoid photobleaching. The wavelength range of the instrument is 140-700nm. The system works in rotating analyzer configuration to minimize the parasitic residual polarization. Ellipsometric and photometric measurements versus wavelength and angle of incidence can be performed. Scatterometric measurements can also be made. In this wavelength range, the samples are extremely sensitive to any surface contamination and surface roughness. It is why a grazing x-ray option has been added on the same instrument to provide a better picture of the analyzed samples. This paper presents in details the new system with its two measurement methods, and including experimental results on resist, antireflective coatings and gate dielectrics for use in the field of micro-lithography.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
Thin Solid Films, 1992
ABSTRACT High resolution Raman spectroscopy and spectroscopic ellipsometry have been used to char... more ABSTRACT High resolution Raman spectroscopy and spectroscopic ellipsometry have been used to characterize SiGe superlattices and single strained epitaxial layers. The results are interpreted to give information on material quality, composition, layer thicknesses and state of strain. The complementary nature of the techniques is discussed.
Proceedings of SPIE, Aug 23, 2000
This paper reports progress on the integration of spectroscopic ellipsometry (SE) in the cool-dow... more This paper reports progress on the integration of spectroscopic ellipsometry (SE) in the cool-down chamber of an applied materials Epi Centura Cluster System. It has been shown that new spectroscopic ellipsometer can measure wafers through a window with non-normal incidence. Correction procedures have been established and tested with measurements on standard oxide samples. Strained SiGe layers can be characterized in
Proceedings of SPIE, Jun 2, 2000
Spectroscopic ellipsometry is one of the more important tools for thin film metrology. It is now ... more Spectroscopic ellipsometry is one of the more important tools for thin film metrology. It is now intensively used in microelectronics and especially for the microlithographic applications. Instrumentation for the next generation of UV lithography at 157 nm requires special optical setup since oxygen and water are extremely absorbing below 190 nm. The ellipsometer discussed in this paper works into a purged glove box to reduce the oxygen and water contamination in the part per million range. The optical setup has been especially studied for microlithographic applications with a premonochromator in the polarizer arm to avoid resist photobleaching. Technical details of the system and measurements results on substrates and thin films are reported hereafter. Results are compared to those obtained with more standard ellipsometers and correlated to other results obtained with grazing x-ray reflectance technique.
Thin Solid Films, 1992
ABSTRACT High resolution Raman spectroscopy and spectroscopic ellipsometry have been used to char... more ABSTRACT High resolution Raman spectroscopy and spectroscopic ellipsometry have been used to characterize SiGe superlattices and single strained epitaxial layers. The results are interpreted to give information on material quality, composition, layer thicknesses and state of strain. The complementary nature of the techniques is discussed.
MRS Proceedings, 1989
ABSTRACTUse of a Fourier—transform interferometer integrated with a variable incidence angle elli... more ABSTRACTUse of a Fourier—transform interferometer integrated with a variable incidence angle ellipsometer extends the spectral range and the capabilities of spectroscopic ellipsometry into the infrared. With a spectral range of 600 to 6600 cm—1, thick layers, such as epitaxial doped layers and polymers can be analysed.A full description of this novel instrument will be given. Incidence angle can be variedautomatically to enhance signal/noise and the ellipsometric data can be obtained together with vibrational absorption bands information to give a characteristic “fingerprint ” of the layers.Examples of spectra of HCN polymer on nickel, DMHS on aluminium and PMMA on silicon willbe presented for various incidence angles and layer thickness.
MRS Proceedings, 1989
ABSTRACTUse of a Fourier—transform interferometer integrated with a variable incidence angle elli... more ABSTRACTUse of a Fourier—transform interferometer integrated with a variable incidence angle ellipsometer extends the spectral range and the capabilities of spectroscopic ellipsometry into the infrared. With a spectral range of 600 to 6600 cm—1, thick layers, such as epitaxial doped layers and polymers can be analysed.A full description of this novel instrument will be given. Incidence angle can be variedautomatically to enhance signal/noise and the ellipsometric data can be obtained together with vibrational absorption bands information to give a characteristic “fingerprint ” of the layers.Examples of spectra of HCN polymer on nickel, DMHS on aluminium and PMMA on silicon willbe presented for various incidence angles and layer thickness.
MRS Proceedings, 1999
Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize th... more Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize thin films and multilayers. It is now intensively used in microelectronics and especially for the microlithographic applications. Instrumentation for the next generation of UV lithography at 157nm requires special optical setup since oxygen and water are extremely absorbing below 190nm. The ellipsometer discussed in this paper works into a purged glove box to reduce the oxygen and water contamination in the part per million ranges. The optical setup has been especially studied for microlithographic applications. It includes for example a premonochromator in the polariser arm to avoid resist photobleaching. Technical details of the system and some first measurement results on substrates and thin films are reported hereafter.
Proceedings of SPIE, Aug 20, 2001
ABSTRACT Precise characterization of high k gate dielectrics becomes a challenging task due to th... more ABSTRACT Precise characterization of high k gate dielectrics becomes a challenging task due to the very thin thickness (&amp;lt;3-4nm), which will be needed in the next generation integrated circuits. Conventional techniques such as spectroscopic ellipsometry in the visible range becomes difficult to use alone because of the great correlation between thickness and optical indices. To overcome this problem a new versatile instrument integrating spectroscopic ellipsometry (SE) and grazing x-ray reflectance (GXR) has been developed recently by SOPRA. Both kind of measurements can be made on the same position on the sample and at the same time. The analysis is made with the same optical model adjusting the layer thickness on the GXR data and the other parameters like surface or interface roughness or inter-diffusion on the SE data. The paper presents some experimental results on ZrO2 films.
MRS Proceedings, 2003
ABSTRACTAt present, new high-k dielectric materials are being intensively investigated to replace... more ABSTRACTAt present, new high-k dielectric materials are being intensively investigated to replace the silicon dioxide as gate dielectric for the next generation of electronic devices. Several candidate materials (such as ZrO2, HfO2, Al2O3) and deposition processes are currently under investigation. Because the layer thickness which is required in the next generations of devices is of the order of few nanometers, a precise determination and control of layer thickness will be mandatory. Although spectroscopic ellipsometry (SE) is well established non-contact, non-destructive and precise technique for determining thickness and optical properties of thin films, it becomes more difficult to obtain this information unambiguously and simultaneously for ultra-thin films with traditional SE alone because of possible high correlations between film structure and optical properties. The grazing x-ray reflectometry (XRR) is a complementary nondestructive optical technique and can be used to unam...
Thin Solid Films, 1993
ABSTRACT The principle and limitations of real time spectroscopic ellipsometry (RTSE) are demonst... more ABSTRACT The principle and limitations of real time spectroscopic ellipsometry (RTSE) are demonstrated. Several applications show the capability and accuracy of the instrument. The spectral range covers 260–1060 nm with 1024 pixels. The fastest spectra can be recorded at a rate of 40 spectra per second in groups of eight and with 128 spectral steps. The reproducibility of 10−3 is better than the accuracy by a factor of three. These features make RTSE an appropriate measurement tool for process control of diffusion and epitaxial growth processes as well as etching or cleaning.
Spectroscopic Ellipsometry (SE) and Grazing X-ray Reflectance (GXR) techniques are very complemen... more Spectroscopic Ellipsometry (SE) and Grazing X-ray Reflectance (GXR) techniques are very complementary techniques for accurate determination of structural parameters of complex multilayer structures rapidly and non-destructively. In this paper the two techniques are applied to different kinds of samples, and the advantages of coupling them are pointed out. Antireflection coatings (ARCs) for microlithography in the DUV range are analyzed first. When the layers are transparent in the infrared range one can take into account the optical index of the layers by a simple dispersion law. Thicknesses obtained by this method are checked by the GXR technique and the agreement is excellent. Extraction of the optical indices from the UV to IR is then performed from SE measurements at various angles of incidence. Another field of application is the characterization of complex epitaxial structures of semiconductor compounds. We show that GaAs/GaAlAs multilayer structures can be characterized more ...
MRS Proceedings, 1995
Spectroscopic Ellipsometry (SE) and Grazing X-ray Reflectance (GXR) techniques are applied on dif... more Spectroscopic Ellipsometry (SE) and Grazing X-ray Reflectance (GXR) techniques are applied on different III-V epitaxial structures in order to extract accurately their structural information. Thickness information are obtained directly from Fourier transformation of the GXR spectra and confirmed by simulation of the reflectance curve. Compositions are deduced from SE regression using GXR thickness as input values. Examples on monolayer and bilayer structures are first remembered. Then the potentiality of the method is demonstrated to more complex systems (multilayer mirrors and HEMT structures).
Proceedings of Semiconducting and Semi-Insulating Materials Conference
ABSTRACT Spectroscopic Ellipsometry (SE) and Grazing X-ray Reflectance (GXR) techniques are appli... more ABSTRACT Spectroscopic Ellipsometry (SE) and Grazing X-ray Reflectance (GXR) techniques are applied on a III-V periodic epitaxial structures in order to extract accurately structural informations. Thickness informations are obtained directly from Fourier transformation of the GXR spectra and confirmed by simulation of the reflectance curve. Compositions are deduced from SE regression using GXR thickness as input values. Using this method it was possible to detect g reduction of the density of the top layers. This layer imperfection is important to deduce accurate reflectance properties for the same structure
電子情報通信学会技術研究報告 Sdm シリコン材料 デバイス, Jun 23, 2000
Thin Solid Films, 1993
ABSTRACT Reference dielectric function spectra have been obtained for Al0.48In0.53As, In0.53Ga0.4... more ABSTRACT Reference dielectric function spectra have been obtained for Al0.48In0.53As, In0.53Ga0.47As and strained InxGa1−xAs (x = 0.1, 0.2). Spectroscopic ellipsometry (SE) data of three- and four-layer lattice-matched and pseudomorphic structures incorporating these materials and InP, GaAs and Al0.2Ga0.8As have been characterized, layer thicknesses in excellent agreement with direct techniques being obtained. Doublets due to transitions in single In0.1Ga0.9As quantum wells have been observed by SE and photoreflectance.
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Papers by jean-louis Stehlé