Abstract: A method (1) creates charge carriers in a concentration that changes in a periodic manner (also called “modulation”) only with respect to time, and (2) determines the number of charge carriers created in the carrier creation region by measuring an interference signal obtained by interference between a reference beam and a portion of a probe beam that is reflected by charge carriers at various depths of the semiconductor material, and comparing the measurement with corresponding values obtained by simulation (e.g. in graphs of such measurements for different junction depths). Various properties of the reflected portion of the probe beam (such as power and phase) are functions of the depth at which the reflection occurs, and can be measured to determine the depth of the junction, and the profile of active dopants.

Abstract: A method (1) creates charge carriers in a concentration that changes in a periodic manner (also called “modulation”) only with respect to time, and (2) determines the number of charge carriers created in the carrier creation region by measuring an interference signal obtained by interference between a reference beam and a portion of a probe beam that is reflected by charge carriers at various depths of the semiconductor material, and comparing the measurement with corresponding values obtained by simulation (e.g. in graphs of such measurements for different junction depths). Various properties of the reflected portion of the probe beam (such as power and phase) are functions of the depth at which the reflection occurs, and can be measured to determine the depth of the junction, and the profile of active dopants.

Abstract: A method (1) creates charge carriers in a concentration that changes in a periodic manner (also called “modulation”) only with respect to time, and (2) determines the number of charge carriers created in the carrier creation region by measuring an interference signal obtained by interference between a reference beam and a portion of a probe beam that is reflected by charge carriers at various depths of the semiconductor material, and comparing the measurement with corresponding values obtained by simulation (e.g. in graphs of such measurements for different junction depths). Various properties of the reflected portion of the probe beam (such as power and phase) are functions of the depth at which the reflection occurs, and can be measured to determine the depth of the junction, and the profile of active dopants.

Abstract: A system for measuring an amount of microroughness of a surface of a substrate, wherein a first beam of electromagnetic radiation and a second beam of electromagnetic radiation are generated, the first and second beams being substantially parallel and spaced apart from each other so that the first and second beams are substantially non-overlapping, and the first and second beams are focused onto the substrate so that the beams impinge upon a selected area of the surface of the substrate having a surface contour, the surface contour of the substrate causing a scattering of both beams. The scattering of the first and second beams is detected, the amount of scattering corresponding to a microroughness value of the selected area of the substrate, and the microroughness value of the selected area of the substrate is determined from the amount of scattering of the first and second beams. The microroughness measuring system may also be used for controlling a fabrication process.

Abstract: A dark-field particle monitor and a method for reducing errors due to stray light in the particle monitor provides a particle monitor having (i) an optical element focussed on the laser beam for detecting particles and (ii) a filter for preferentially selecting light incident on said filter in a preferential direction. In one embodiments the filter is implemented by a narrow band filter having maximum transmission for light having a wavelength of the laser beam.

Abstract: An apparatus measures a property of a layer (such as the sheet resistance of a conductive layer or thermal conductivity of a dielectric layer that is located underneath the conductive layer) by performing the following method: (1) focusing the heating beam on the heated a region (also called "heated region") of the conductive layer (2) modulating the power of the heating beam at a predetermined frequency that is selected to be sufficiently low to ensure that at least a majority (preferably all) of the generated heat transfers out of the heated region by diffusion, and (3) measuring the power of another beam that is (a) reflected by the heated region, and (b) modulated in phase with modulation of the heating beam. The measurement in act (3) can be used directly as a measure of the resistance (per unit length) of a conductive line formed by patterning the conductive layer.

Abstract: An apparatus and method uses diffusive modulation (without generating a wave of carriers) for measuring a material property (such as any one or more of: mobility, doping, and lifetime) that is used in evaluating a semiconductor wafer. The measurements are carried out in a small area, for use on wafers having patterns for integrated circuit dice. The measurements are based on measurement of reflectance, for example as a function of carrier concentration. In one implementation, the semiconductor wafer is illuminated with two beams, one with photon energy above the bandgap energy of the semiconductor, and another with photon energy near or below the bandgap. The diameters of the two beams relative to one another are varied to extract additional information about the semiconductor material, for use in measuring, e.g. lifetime.

Abstract: A system for measuring a property of a semiconductor substrate, wherein an analyzer beam is generated and transmitted to the substrate, and a generation beam, superposed on top of the analyzer beam, is also generated and transmitted to the substrate. A response generated by the generation beam, in the substrate, causes a change in a predetermined characteristic of the analyzer beam that is measured by a detector. The property of the substrate is then determined from the change in a predetermined characteristic. The property measuring system may be used in a semiconductor fabrication process.

Abstract: A system for measuring the doping levels of a doped region in a semiconductor substrate, wherein an analyzer beam and a reference beam are generated, the analyzer and reference beams being substantially parallel and spaced apart from each other so that the analyzer and reference beams are non-overlapping. The analyzer beam is focused on a preselected doped region of the substrate and the reference beam is focused on an undoped region of the substrate, the doped region generating a phase shift of the analyzer beam relative to the reference beam corresponding to a level of doping of the doped region of the substrate. A detector detects the phase shift of the analyzer beam relative to the reference beam, and the doping level of the substrate in the preselected doped region is determined from the phase shift. The doping level measuring system may be used to control a semiconductor fabrication process.

Abstract: A system for measuring an amount of microroughness of a surface of a substrate, wherein a first beam of electromagnetic radiation and a second beam of electromagnetic radiation are generated, the first and second beams being substantially parallel and spaced apart from each other so that the first and second beams are substantially non-overlapping, and the first and second beams are focused onto the substrate so that the beams impinge upon a selected area of the surface of the substrate having a surface contour, the surface contour of the substrate causing a scattering of both beams. The scattering of the first and second beams is detected, the amount of scattering corresponding to a microroughness value of the selected area of the substrate, and the microroughness value of the selected area of the substrate is determined from the amount of scattering of the first and second beams. The microroughness measuring system may also be used for controlling a fabrication process.

Abstract: A structure and a method provide a quasi bright field particle sensor, using a laser beam of predetermined polarization. A phase shift caused by a particle passing through a laser beam is utilized to detect the presence of a particle. In one embodiment, the laser beam is split into two components of laser beams of orthogonal polarization separated by a predetermined distance, so as to allow detection of both spherical and non-spherical particles. In another embodiment, where only non-spherical particles are detected, a single laser beam is used.

Abstract: A method for accomplishing particle monitoring above the throttle valve of a turbo pump provides a particle sensor which is built into the throttle valve in such a way that it is insensitive to local plasma glows. Furthermore, the particle sensor is placed such that a particle monitoring laser beam of the particle sensor is offset from the centerline of the pipe, so as to maximize exposure to process gas flow which is diverted to the periphery of the pipe by the position of a butterfly valve plate.

Abstract: An apparatus and a method provide a modular design for a particle monitor of external design used in a vacuum process equipment. In one embodiment, the key elements, i.e. laser assembly, the detection module, the beam stop and a darkened surface opposite the detection module, can be independently mounted on a pump line. The particle monitors of the present invention can be mounted on both straight sections and bends of the pump line. Each key element can be accessed independently of other key elements for repair and service.

Abstract: A method and an apparatus allow dynamic tuning of a particle sensor. The particle sensor provides output signals indicating particle detection to a controller, which includes an amplifier whose bandwidth and gain can be adjusted. The bandwidth and the gain of the amplifier are adjusted in accordance with predetermined optimal performance levels under the varying process conditions in which the particle sensor is placed. The optimal signal-to-noise ratio is maintained by adjusting the bandwidth and the gain according to both expected particle velocities and whether a plasma glow is present in the exhaust line for carrying gasses out of a process chamber.

Abstract: An apparatus and a method provide a particle monitor mounted in an exhaust line of a loadlock chamber. The apparatus of the present invention comprises a particle monitor and a particle filter mounted down stream from the particle monitor away from the loadlock chamber. In one embodiment, the particle filter can be implemented by a wire-mesh screen, or a perforated stainless steel screen. The particle filter can be mounted in a centering ring of a standard vacuum connection which comprises two flanges, a centering ring, and an O-ring held together by a clamp.

Abstract: A structure and an apparatus are provided for use in particle sensor installed to monitor particle level of a process chamber. The process chamber receives process gas from a supply line and removes gas through an exhaust line. The particle sensor's optical components are prevented from contamination by corrosive or coating species in the effluent from the process, by a gas purge line installed in the particle sensor. The gas purge line allows a flow of gas to purge the optical components at a flux not less than the flux of gas being removed from the process chamber in the exhaust line. The flux out of the particle sensor prevents the undesired species from reaching the optical components of the particle sensor from the sampling area where the particle sensor detects the particle level.

Abstract: A structure and a method use a non-invasive particle monitor to detect particles in a process chamber for a "down sputtering" metal deposition process. In one embodiment, only non-spherical particles are detected using a single laser beam of a predetermined polarization is used, and the phase shift in the polarization due to the passing of a particle through the laser beam is measured. In another embodiment, two closely spaced orthogonally polarized laser beams are used, and the differential intensity of the laser beams is measured when a particle passes through one of the laser beams. In another embodiment, shield tubes for housing optical components are used to prevent coating of the optical components and to prevent deposition to take place outside the shielded area. Internal electric and magnetic fields are used to drive particles through the laser beams for particle detection.

Abstract: A converging funnel is placed in an exhaust line to direct substantially all the gas flow in the exhaust line to the sensing laser beam of a particle sensor, thereby preventing deposition of species carried by the gas from depositing on the particle sensor. By concentrating substantially all gas flow through the laser beam, the particle count rate is increased because substantially all particles carried by the exhaust gas is channeled through the laser beam. Further, the particle sensor is also prevented from adverse heating effects of the exhaust gas. In one embodiment, the converging funnel is mounted to the interior wall of the exhaust line by a centering ring.

Abstract: A method and an apparatus for synchronizing particle counts to process events provide a trigger signal related to the process events in lieu of a time-based trigger signal. In one embodiment, the controller to a particle counter further subdivides a process event into sub-intervals to allow profiling of particle counts during the process event. In one embodiment, the controller of the particle counter receives multiple trigger signals corresponding to multiple trigger signal sources, each trigger signal source being identified by a source tag. Particle counts and time-stamps are maintained for each source of the trigger signals.

Abstract: A raster scan apparatus provides a scanning assembly capable of moving in a sinusoidal motion along a first direction and stepping in fine steps in a second direction perpendicular to the first direction. In one embodiment, a piezoelectric bimorph sets in scanning motion a scanning assembly formed by a wafer holder and leaf springs. The amplitude of the scanning motion is controlled by a voltage applied across the piezoelectric bimorph. A Hall effect sensor provides an output signal indicating the instantaneous location of the scanning assembly in motion. The output signal of the Hall effect sensor is compared against a predetermined threshold to provide a trigger signal for synchronization. The output signal of the Hall effect sensor is also fed back to the source of sinusoidal voltage to adaptively adjust the sinusoidal voltage so as to achieve a predetermined amplitude for the scanning motion.