Abstract: Systems and methods for controlling deposition of a charge on a wafer for measurement of one or more electrical properties of the wafer are provided. One system includes a corona source configured to deposit the charge on the wafer and a sensor configured to measure one or more conditions within the corona source. This system also includes a control subsystem configured to alter one or more parameters of the corona source based on the one or more conditions. Another system includes a corona source configured to deposit the charge on the wafer and a mixture of gases disposed within a discharge chamber of the corona source during the deposition of the charge. The mixture of gases alters one or more parameters of the charge deposited on the wafer.

Abstract: Various methods and systems for determining one or more properties of a specimen are provided. One system for determining a property of a specimen is configured to illuminate a specimen with different wavelengths of light substantially simultaneously. The different wavelengths of light are modulated at substantially the same frequency. The system is also configured to perform at least two measurements on the specimen. A minority carrier diffusion length of the specimen may be determined from the measurements and absorption coefficients of the specimen at the different wavelengths. Another system for detecting defects on a specimen is configured to deposit a charge at multiple locations on an upper surface of the specimen. This system is also configured to measure a vibration of a probe at the multiple locations. Defects may be detected on the specimen using a two-dimensional map of the specimen generated from the measured surface voltages.

Abstract: Test pads, methods, and systems for measuring properties of a wafer are provided. One test pad formed on a wafer includes a test structure configured such that one or more electrical properties of the test structure can be measured. The test pad also includes a conductive layer formed between the test structure and the wafer. The conductive layer prevents structures located under the test structure between the conductive layer and the wafer from affecting the one or more electrical properties of the test structure during measurement. One method for assessing plasma damage of a wafer includes measuring one or more electrical properties of a test structure formed on the wafer and determining an index characterizing the plasma damage of the test structure using the one or more electrical properties.

Abstract: Systems and methods for controlling deposition of a charge on a wafer for measurement of one or more electrical properties of the wafer are provided. One system includes a corona source configured to deposit the charge on the wafer and a sensor configured to measure one or more conditions within the corona source. This system also includes a control subsystem configured to alter one or more parameters of the corona source based on the one or more conditions. Another system includes a corona source configured to deposit the charge on the wafer and a mixture of gases disposed within a discharge chamber of the corona source during the deposition of the charge. The mixture of gases alters one or more parameters of the charge deposited on the wafer.

Abstract: Various methods and systems for determining one or more properties of a specimen are provided. One system for determining a property of a specimen is configured to illuminate a specimen with different wavelengths of light substantially simultaneously. The different wavelengths of light are modulated at substantially the same frequency. The system is also configured to perform at least two measurements on the specimen. A minority carrier diffusion length of the specimen may be determined from the measurements and absorption coefficients of the specimen at the different wavelengths. Another system for detecting defects on a specimen is configured to deposit a charge at multiple locations on an upper surface of the specimen. This system is also configured to measure a vibration of a probe at the multiple locations. Defects may be detected on the specimen using a two-dimensional map of the specimen generated from the measured surface voltages.

Abstract: A method and a system for calibrating the work function of a non-contact voltage sensor are provided. The method includes preparing a reference sample to have a stable work function, measuring a voltage of the sample using a non-contact voltage sensor, and determining a work function correction factor of the sensor from the measured voltage. In turn, the calibrated work function may be used to adjust voltages of substrates measured by the sensor. A corona gun which includes a first electrode and one or more conductive rods is provided. In some embodiments, the conductive rods may be angled between 0 and 90 degrees with respect to a first electrode sidewall and/or be concentrically arranged less than 90 degrees from each other. In addition or alternatively, the corona gun may be adapted to alter its length and/or include a second electrode partially inset within a space surrounded by the first electrode.

Abstract: Various methods and systems for determining one or more properties of a specimen are provided. One system for determining a property of a specimen is configured to illuminate a specimen with different wavelengths of light substantially simultaneously. The different wavelengths of light are modulated at substantially the same frequency. The system is also configured to perform at least two measurements on the specimen. A minority carrier diffusion length of the specimen may be determined from the measurements and absorption coefficients of the specimen at the different wavelengths. Another system for detecting defects on a specimen is configured to deposit a charge at multiple locations on an upper surface of the specimen. This system is also configured to measure a vibration of a probe at the multiple locations. Defects may be detected on the specimen using a two-dimensional map of the specimen generated from the measured surface voltages.

Abstract: A method and a system for calibrating the work function of a non-contact voltage sensor are provided. The method includes preparing a reference sample to have a stable work function, measuring a voltage of the sample using a non-contact voltage sensor, and determining a work function correction factor of the sensor from the measured voltage. In turn, the calibrated work function may be used to adjust voltages of substrates measured by the sensor. A corona gun which includes a first electrode and one or more conductive rods is provided. In some embodiments, the conductive rods may be angled between 0 and 90 degrees with respect to a first electrode sidewall and/or be concentrically arranged less than 90 degrees from each other. In addition or alternatively, the corona gun may be adapted to alter its length and/or include a second electrode partially inset within a space surrounded by the first electrode.

Abstract: Scattered radiation from a sample surface is collected by means of a collector that collects radiation substantially symmetrically about a line normal to the surface. The collected radiation is directed to channels at different azimuthal angles so- that information related to relative azimuthal positions of the collected scattered radiation about the line is preserved. The collected radiation is converted into respective signals representative of radiation scattered at different azimuthal angles about the line. The presence and/or characteristics of anomalies are determined from the signals. Alternatively, the radiation collected by the collector may be filtered by means of a spatial filter having an annular gap of an angle related to the angular separation of expected pattern scattering. Signals obtained from the narrow and wide collection channels may be compared to distinguish between micro-scratches and particles.