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This paper presents a detailed three-dimensional analysis for the modelling of the photoreflectance effect, in particular the response of layered samples is considered. The dependence of t h e photoreflectance signal on various parameters such as lifetime, surface recombination velocity and carrier diffusion coefficient is discussed. It is shown that the carrier diffusion coefficient and the thermal diffusivity play an important role in determining the signal level from the photoreflectance system. The effects of the wavelength of the pump and probe beams are also discussed. Furthermore, a fast numerical algorithm, allowing for a rapid computational evaluation, has been applied.

This paper presents lithographic performance results obtained from the newest member of ASML's TWINSCAN TM platform-based step & scan systems, the TWINSCAN TM XT:1400. The system has been designed to meet the semiconductor industry's aggressive requirements on CD control, overlay and productivity at and below the 65 nm node. This dual stage 193 nm lithographic system combines the worlds highest NA, with excellent overlay and CD control at high throughput on both 200 and 300 mm wafers and is intended for use in volume production environments. Advances in stage technology have enabled further extension of stage scan speeds and an associated increase in tool productivity. However, maximizing the number of yielding die per day also requires stringent overlay and Critical Dimension (CD) control. Tight CD control at improved resolution is supported by the Starlith TM 1400 projection lens and the extended sigma capabilities of the new AERIAL TM -E illumination system. Focus control is improved in line with the stringent requirements posed by low-k 1 imaging applications, taking full advantage of the unique dual-stage TWINSCAN TM system architecture.

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A dual beam thermal wave probe has been used to measure the thickness of opaque thin films in a noncontact, nondestructive manner. The method relies on the measurement of the differential phase of two interferometrically determined photodisplacement signals. The technique does not require calibration against standard samples and can be used to determine film thicknesses from a few tens of nanometers up to several micrometers. Alternatively, if the film thickness is known, thermal material properties like diffusivity or conductivity can be determined. The conditions under which the system is expected to give the most accurate results are analyzed.