Abstract: An in-situ gas flow measurement controller measures the temperature and rate of pressure drop upstream from a flow control device (FCD). The controller samples the pressure and temperature data and applies the equivalent of a decimating filter to the data to produce filtered data at a slower sampling rate. The controller derives timestamps by counting ticks from the sampling clock of the A/D converter that is sampling the pressure at regular intervals to ensure the timestamps associated with the pressure samples are accurate and do not contain jitter that is associated with software clocks. The controller additionally normalizes the temperature reading to account for power supply fluctuations, filters out noise from the pressure and temperature readings, and excludes data during periods of instability. It calculates the gas flow rate accounting for possible non-linearities in the pressure measurements, and provides the computed gas flow measurement via one of many possible interfaces.

Abstract: A method and apparatus for self-calibrating control of gas flow. The gas flow rate is initially set by controlling, to a high degree of precision, the amount of opening of a flow restriction, where the design of the apparatus containing the flow restriction lends itself to achieving high precision. The gas flow rate is then measured by a pressure rate-of-drop upstream of the flow restriction, and the amount of flow restriction opening is adjusted, if need be, to obtain exactly the desired flow.

Abstract: Embodiments of the present invention relate to the analysis of the components of one or more gases, for example a gas mixture sampled from a semiconductor manufacturing process such as plasma etching or plasma enhanced chemical vapor deposition (PECVD). Particular embodiments provide sufficient power to a plasma of the sample, to dissociate a large number of the molecules and molecular fragments into individual atoms. With sufficient power (typically a power density of between 3-40 W/cm3) delivered into the plasma, most of the emission peaks result from emission of individual atoms, thereby creating spectra conducive to simplifying the identification of the chemical composition of the gases under investigation. Such accurate identification of components of the gas may allow for the precise determination of the stage of the process being performed, and in particular for detection of process endpoint.

Abstract: Embodiments of the present invention relate to managing timestamps associated with received data. According to one embodiment, data is collected from a device that generates data at a specified rate, but which lacks a built-in clock. An accurate timestamp is assigned to the data by first taking an absolute timestamp from a reference clock, and then adding a calculated amount of time to each subsequent data point based on an estimate of the sampling frequency of the device. As the generated timestamp drifts from the actual reference clock time, the sampling frequency is re-estimated based on the amount of detected drift.

Abstract: Methods and apparatus utilize a rate of drop in pressure upstream of a gas flow controller (GFC) to accurately measure a rate of flow through the GFC. Measurement of the gas flow through the many gas flow controllers in production use today is enabled, without requiring any special or sophisticated pressure regulators or other special components. Various provisions ensure that none of the changes in pressure that occur during or after the measurement perturb the constant flow of gas through the GFC under test.

Abstract: A method for controlling the plasma etching of semiconductor wafers determines the impedance of a plasma chamber using values representing voltage, current, and the phase angle between them, as provided by a sensor. All or less than all of the data during a first time period may be used to calculate a model. During a second time period, real time data is used to calculate a version of the instant impedance of the chamber. This version of impendence is compared to a time-projected version of the model. The method determines that etching should be stopped when the received data deviates from the extrapolated model by a certain amount. In some embodiments a rolling average is used in the second time period, the rolling average compared to the model to determine the end point condition.

Abstract: Embodiments in accordance with the present invention allow a second end-point determination (EPD) system to actively control the end-pointing of a semiconductor process chamber, by leveraging a legacy EPD system that is already integrated with the chamber. In one embodiment, the second EPD system controls a shutter that regulates the amount of light transmitted between a plasma light source and an optical emission spectroscopy (OES) sensor of the legacy OES EPD system. In this embodiment, the legacy OES EPD system is pre-configured to call end-point when an artificial end-point condition occurs, i.e. the intensity of light falls below a pre-set threshold. When the second EPD system determines an actual end-point condition has been reached, it closes the shutter which, causes the light intensity being read by the OES sensor to fall below the pre-set threshold. This in turn triggers an end-point command to the chamber from the legacy OES EPD system.

Abstract: Methods and apparatus utilize a rate of drop in pressure upstream of a gas flow controller (GFC) to accurately measure a rate of flow through the GFC. Measurement of the gas flow through the many gas flow controllers in production use today is enabled, without requiring any special or sophisticated pressure regulators or other special components. Various provisions ensure that none of the changes in pressure that occur during or after the measurement perturb the constant flow of gas through the GFC under test.

Abstract: An embodiment of a method in accordance with the present invention to determine the flow rate of a second gas relative to a first gas, comprises, setting a flow of a first gas to a known level, taking a first measurement of the first gas with a measurement technique sensitive to a concentration of the first gas, and establishing a flow of a second gas mixed with the first gas. A second measurement of the first gas is taken with a measurement technique that is sensitive to the concentration of the first gas, and the flow of the second gas is determined by a calculation involving a difference between the first measurement and the second measurement. In alternative embodiments, the first measurement may be taken of a flow of two or more gases combined, with the second measurement taken with one of the gases removed from the mixture. Certain embodiments of methods of the present invention may be employed in sequence in order to determine flow rates of more than two gases.

Abstract: Method and system for detecting endpoint for a plasma etch process are provided. In accordance with one embodiment, the method provides a semiconductor substrate having a film to be processed thereon. The film is processed in a plasma environment during a time period to provide for device structures. Information associated with the plasma process is collected. The information is characterized by a first signal intensity. Information on a change in the first signal intensity is extracted. The change in the first signal intensity has a second signal intensity. The change in signal intensity at the second signal intensity is associated to an endpoint of processing the film in the plasma environment. The second signal intensity may be about 0.25% and less of the first signal intensity.

Abstract: Embodiments of the present invention employ measurement of argon as the means to detect the presence of an atmospheric leak in a processing chamber. Argon detected inside the process chamber is conclusive evidence of a leak. Furthermore, the amount of detected argon provides information on the rate of air entering through the leak. In one embodiment, leak detection takes place in the main plasma inside the processing chamber. In another embodiment, leak detection takes place in the self-contained plasma generated in a remote plasma sensor. Additional measurements can be performed, such as measuring the amount of oxygen, and/or the presence of moisture to help in detecting and quantifying outgassing from the processing chamber.

Abstract: Leaks in a processing chamber, including “virtual leaks” resulting from outgassing of material present within the chamber, may be detected utilizing an optical emission spectroscopy (OES) sensor configured to monitor light emitted from plasma of a sample from the chamber. According to certain embodiments, gas introduced into the chamber by the leak may be detected directly on the basis of its optical spectrum. Alternatively, gas introduced by the leak may be detected indirectly, based upon an optical spectrum of a material resulting from reaction of the gas attributable to the leak. According to one embodiment, data from the OES sensor is received by a processor that is configured to compute a leak detection index. The value of the leak detection index is compared against a threshold to determine if a leak is detected. If the value of the index crosses the threshold, a notification of the existence of a leak is sent.

Abstract: Methods and apparatus utilize a rate of drop in pressure upstream of a gas flow controller (GFC) to accurately measure a rate of flow through the GFC. Measurement of the gas flow through the many gas flow controllers in production use today is enabled, without requiring any special or sophisticated pressure regulators or other special components. Various provisions ensure that none of the changes in pressure that occur during or after the measurement perturb the constant flow of gas through the GFC under test.

Abstract: Methods and apparatus utilize a rate of drop in pressure upstream of a gas flow controller (GFC) to accurately measure a rate of flow through the GFC. Measurement of the gas flow through the many gas flow controllers in production use today is enabled, without requiring any special or sophisticated pressure regulators or other special components. Various provisions ensure that none of the changes in pressure that occur during or after the measurement perturb the constant flow of gas through the GFC under test.

Abstract: Embodiments of the present invention relate to the analysis of the components of one or more gases, for example a gas mixture sampled from a semiconductor manufacturing process such as plasma etching or plasma enhanced chemical vapor deposition (PECVD). Particular embodiments provide sufficient power to a plasma of the sample, to dissociate a large number of the molecules and molecular fragments into individual atoms. With sufficient power (typically a power density of between 3-40 W/cm3) delivered into the plasma, most of the emission peaks result from emission of individual atoms, thereby creating spectra conducive to simplifying the identification of the chemical composition of the gases under investigation. Such accurate identification of components of the gas may allow for the precise determination of the stage of the process being performed, and in particular for detection of process endpoint.

Abstract: Embodiments in accordance with the present invention allow a second end-point determination (EPD) system to actively control the end-pointing of a semiconductor process chamber, by leveraging a legacy EPD system that is already integrated with the chamber. In one embodiment, the second EPD system controls a shutter that regulates the amount of light transmitted between a plasma light source and an optical emission spectroscopy (OES) sensor of the legacy OES EPD system. In this embodiment, the legacy OES EPD system is pre-configured to call end-point when an artificial end-point condition occurs, i.e. the intensity of light falls below a pre-set threshold. When the second EPD system determines an actual end-point condition has been reached, it closes the shutter which, causes the light intensity being read by the OES sensor to fall below the pre-set threshold. This in turn triggers an end-point command to the chamber from the legacy OES EPD system.