Patrick Evrard

Characterization of ultrathin gate dielectrics by grazing X-ray reflectance and VUV spectroscopic ellipsometry on the same instrument

Precise characterization of high k gate dielectrics becomes a challenging task due to the very thin thickness (<3 4 nm), which will be needed in the next generation of integrated circuits. Conventional techniques such as spectroscopic ellipsometry (SE) in the UV-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 SE in the VUV spectral range and grazing X-ray reflectance (GXR) has been developed recently by SOPRA. Both kinds of measurements can be made at the same location on the sample and at the same time. The analysis is made with a common optical model adjusting the layer thickness and the surface and interface roughness on the GXR data and the optical indices and other parameters like surface or interface roughness or inter-diffusion on the SE data. The paper describes some experimental results obtained with this system on ZrO 2 , HfO 2 and La 2 O 3 films. Results are correlated with other experimental techniques in some cases.

New purged UV spectroscopic ellipsometer to characterize thin films and multilayers at 157 nm

Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize thin films and multi layers. Instrumentation for the next generation of UV lithography at 157nm requires special optical set-up since O2 and H2O are extremely absorbing below 190nm. The new system works into a purged glove box to reduce the oxygen and water contamination in the part per million range. The optical set-up includes a premonochromator in the polarizer arm to avoid photo bleaching. The system works in rotating analyzer configuration to minimize the parasitic polarizations. Ellipsometric and photometric measurement versus wavelength from 145 up to 630 nm and angle of incidence can be performed. The proposed paper will present in details the new system with some first experimental results in the field of micro lithography. Results are compared to those obtained with more standard UV ellipsometers and correlated to other measurements obtained with grazing x-ray reflectance technique.

Combined metrology including VUV spectroscopic ellipsometer and grazing x-ray reflectance for precise characterization of thin films and multilayers at 157 nm

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 ellipsometer for research and development. Since this date, the wavelength range has been extended from visible to near infrared (2 micrometers ), and far infrared up to 18 micrometers . For 193-nm microlithography, deep UV option down to 190 nm has also been developed and delivered more recently. Instrumentation for the next generation of VUV lithography at 157 nm requires special optical setup since O2 and H2O are extremely absorbing below 190 nm. 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 polariser arm to avoid photobleaching. The wavelength range of the instrument is 140-700 nm. The system works in rotating analyser configuration to minimize the parasitic residual polarisation. 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 detail 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 microlithography.

New versatile system for characterization of antireflective coatings using combined spectroscopic ellipsometry and grazing x-ray reflectance

Spectroscopic ellipsometry has long been recognized as a powerful technique for nondestructive characterization of thin films and multilayer structures. In the case of photolithography it has been intensively used for layer thickness and optical index determinations. Nevertheless, the main drawback of this technique is that it is not direct. The data analysis must be made adjusting a prior optical models on the experimental data. For photolithographic films, it is sometimes difficult to find accurate structural model and the analysis becomes difficult when the film is absorbent in the entire wavelength range. It is why SOPRA has developed recently a new versatile instrument that integrates different experimental techniques. The base is the SOPRA GESP5 instrument which offers already the possibility to perform spectroscopic ellipsometry, spectroscopic photometry and scatterometry. We have added a grazing x-ray reflectometer option, which allows measurements on the same spot at the same time, and combine analysis of the different data. The source is a compact ceramic Cu fine focus x-ray tube. the x-ray beam is defined by Soller Slits and a parallel interchangeable slits. After reflection on the sample surface, the beam is monochromatized using a curve graphite crystal and focused on the detector. This new system is discussed in details hereafter and characterization of antireflective for microlithography is presented.

New instrument to characterize materials and optics for 157-nm lithography

Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize thin films and multilayers. In 1983, SOPRA developed the first commercial spectroscopic ellipsometer for research and development. Since this date, the wavelength range has been extended from visible to near IR, and far IR 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 in to a purged glove box to reduce the oxygen and water contamination in the part per million range. The optical setup includes a pre monochromator in the polarizer arm to avoid photo bleaching. 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 detail 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.

A new purged UV spectroscopic ellipsometer to characterize thin films and multilayers at 157 nm

Spectroscopic ellipsometry has long been recognized as the technique of choice to characterize thin films and multilayers. Instrumentation for the next generation of UV lithography at 157 nm requires special optical set-up since O2 and H2O are extremely absorbing below 190 nm. The new system works in a purged glove box to reduce the oxygen and water contamination in the part per million range. The optical set-up includes a premonochromator in the polarizer arm to avoid photo bleaching. The system works in rotating analyzer configuration to minimize the parasitic polarizations. Ellipsometric and photometric measurements versus wavelength from 145 up to 650 nm and versus angle of incidence can be performed. The paper presents details of the new system with some first experimental results in the field of microlithography. Results are compared to those obtained with more standard UV ellipsometer.

Combined metrology including VUV spectroscopic ellipsometry and grazing x-ray reflectance for precise characterization of thin films and multilayers at 157 nm

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.

Feasibility and applicability of integrated metrology using spectroscopic ellipsometry in a cluster tool

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 terms of Ge content and layer thickness indicating the feasibility of the integrate metrology technique. Further measurements are in progress with the system installed in a fully operating cluster tool. Future work will focus on improving the throughput by, for instance, rapid spectral data acquisition and application of novel algorithms to extract layer parameters during the automatic cool-down sequence.