Abstract: Thermal, optical, physical and chemical characteristics of a substrate (11) surface are determined with non-contact optical techniques that include illuminating (23) the surface with radiation having a ripple intensity characteristic (51), and then measuring the combined intensities (53) of that radiation after modification by the substrate surface and radiation emitted from the surface. Precise determinations of emissivity, reflectivity, temperature, changing surface composition, the existence of any layer formed on the surface and its thickness are all possible from this measurement. They may be made in situ and substantially in real time, thus allowing the measurement to control (39, 41) various processes of treating a substrate surface. This has significant applicability to semiconductor wafer processing and metal processing.

Abstract: An automatic gain control technique integrates samples of an incoming analog signal a controlled amount of time so that the magnitudes of the samples lie within the desired input window of an analog-to-digital converter or other signal processing device. The values of the samples are then determined from a combination of the output of the signal processing device and their integration time. This is utilized in a system for determining the temperature of a surface of an object, without contacting the surface, by measuring the level of its infra-red radiation emission. A particular application of the system is to measure the temperature of a semiconductor wafer within a processing chamber while forming integrated circuits on it. The measuring system is configured on a single printed circuit board with an extra height metal heat sink structure to which a cooling unit is mounted.

Abstract: In a process of selectively removing material from an exposed layer carried by a substrate, a technique for determining endpoint by monitoring the intensity of a radiation beam that is passed through the substrate and any intervening layers to be reflected off the layer being processed. This monitoring technique is used during photoresist developing, wet etching, and mechanical planarization and polishing during the manufacture of integrated circuits on semiconductor wafers, flat panel displays on glass substrates, and similar articles. Planarization and polishing processes are alternatively monitored by monitoring temperature.

Abstract: A single channel electronic system for measuring a parameter, such as temperature, by a single sensor or multiple sensors that each include luminescent material. A parameter dependent characteristic, such as decay time, of the sensor's luminescence radiation emitted in response to appropriate excitation, such as in the form of a pulse, is measured. Automatic gain control is provided by adjusting the duration of the excitation radiation pulses instead of their intensities. An undesired effect of excitation radiation directly striking the photodetector is minimized by subtracting a compensating signal from the photodetector output signal, that compensating signal being provided through a compensating photodetector connected in series with the luminescence receiving photodetector.

Abstract: In a process of selectively removing material from an exposed layer carried by a substrate, a technique for determining endpoint by monitoring the intensity of a radiation beam that is passed through the substrate and any intervening layers to be reflected off the layer being processed. This monitoring technique is used during photoresist developing, wet etching, and mechanical planarization and polishing during the manufacture of integrated circuits on semiconductor wafers, flat panel displays on glass substrates, and similar articles. Planarization and polishing processes are alternatively monitored by monitoring temperature.

Abstract: Thermal, optical, physical and chemical characteristics of a substrate (11) surface are determined with non-contact optical techniques that include illuminating (23) the surface with radiation having a ripple intensity characteristic (51), and then measuring the combined intensities (53) of that radiation after modification by the substrate surface and radiation emitted from the surface. Precise determinations of emissivity, reflectivity, temperature, changing surface composition, the existence of any layer formed on the surface and its thickness are all possible from this measurement. They may be made in situ and substantially in real time, thus allowing the measurement to control (39, 41) various processes of treating a substrate surface. This has significant applicability to semiconductor wafer processing and metal processing.

Abstract: A system for measuring a parameter, such as temperature, by multiple sensors that include luminescent material. A parameter dependent characteristic, such as decay time, of each sensor's luminescence radiation emitted in response to appropriate excitation, such as in the form of a pulse, is measured. Automatic gain control is provided by adjusting the duration of the excitation radiation pulses instead of their intensities. An undesired effect of excitation radiation directly striking the photodetector is minimized by subtracting a compensating signal from the photodetector output signal, that compensating signal being provided through a compensating photodetector connected in series with the luminescence receiving photodetector. Multiple sensors are handled by the electronic system through time division multiplexing, separate photodetectors provided for the sensors being connected in parallel while their associated sensors are excited to luminescence one at a time.

Abstract: A non-contact temperature measuring system and a dual-reference body structure employed therein is described, wherein a moving object whose temperature is to be determined, is passed by first and second reference bodies having a same form factor with respect to the moving object. Each of the reference bodies has a heat flow sensor embedded at the end of a cavity formed in the reference body such that the heat flow sensor primarily responds to radiation heat flow generated by a temperature differential between the moving object and its respective reference body.

Abstract: A system for measuring a parameter, such as temperature, includes a sensor of that parameter, such as a luminescent material based sensor at an end of an optical fiber, and an electro-optic module connected to the sensor, such as through the optical fiber, in order to measure changes in some sensor characteristic, such as luminescence decay time, that is related to the parameter to which the sensor is being subjected. The sensor is designed to have a relationship of such a characteristic to the parameter being measured that is matched to the ability of the module to measure the characteristic. In a temperature measurement system example, a luminescent material is chosen with decay time vs.

Abstract: A blackbody high temperature probe is formed by thermally fusing a coating of composite ceramic material on the tip of a high temperature lightpipe or fiber. The ceramic coating replaces conventional sputtered metallic thin films to form a blackbody optical cavity. The ingredients of the composite ceramic material include a mixture of refractory metal oxides forming the bulk of the material, various pigments and/or refractory metal powders, and binding agents. A firing process is used to thermally fuse the coating onto the lightpipe. Embodiments of the firing process include using a flame or furnace technique, or alternatively using various flame- or plasma- spraying techniques.

Abstract: A detector structure and technique for non-contact monitoring of a process being performed on a surface, such as in semiconductor wafer integrated circuit processing and flat panel display substrate processing, in order to determine when the process has reached endpoint. In one embodiment, multiple small area radiation sources, such as light emitting diodes, are symmetrically arranged around a large area photodetector, and each have similar radiation distribution patterns. In an alternative embodiment, multiple photodetectors are symmetrically arranged around a single light emitting diode with a symmetrical radiation distribution pattern. In either case, the amount of source radiation reflected onto the detector from the surface being processed is not significantly affected by any wobble or tilting of the surface that may occur during processing.

Abstract: A luminescence-based integrated optical and electronic system for measuring temperature or some other parameter from the decay time of a luminescent sensor is disclosed. A high bandwidth, low noise amplifier applies a detected decaying luminescent signal to a digital system that acquires that signal and processes it in order to determine its decay time characteristics that are related to temperature or another parameter being measured. The digital signal processing includes use of a digital curve-fitting technique. A preferred luminescent material for temperature measurement is a chromium-doped yttrium gallium garnet material. The entire optical and electronic portions of the measuring system can be accommodated on a small single circuit card.

Abstract: A non-contact pyrometric technique is provided for measuring the temperature and/or emissivity of an object that is being heated by electromagnetic radiation within the optical range. The measurement is made at short wavelengths for the best results. The measurement may be made at wavelengths within those of the heating optical radiation, and the resulting potential error from detecting heating radiation reflected from the object is avoided by one of two specific techniques. A first technique utilizes a mirror positioned between the heating lamps and the object, the mirror reflecting a narrow wavelength band of radiation in which the optical pyrometer detector operates. The second technique is to independently measure the a.c. ripple of the heating lamp radiation and subtract the background optical noise from the detected object signal in order to determine temperature and emissivity of the object. Both of these techniques can be combined, if desired.

Abstract: Thermal, optical, physical and chemical characteristics of a substrate (11) surface are determined with non-contact optical techniques that include illuminating (23) the surface with radiation having a ripple intensity characteristic (51), and then measuring the combined intensities (53) of that radiation after modification by the substrate surface and radiation emitted from the surface. Precise determinations of emissivity, reflectivity, temperature, changing surface composition, the existence of any layer formed on the surface and its thickness are all possible from this measurement. They may be made in situ and substantially in real time, thus allowing the measurement to control (39, 41) various processes of treating a substrate surface. This has significant applicability to semiconductor wafer processing and metal processing.

Abstract: Techniques of monitoring and controlling removal or forming of layers of material, such as employed in the manufacture of flat panel displays and integrated circuit wafers. Examples of material removal include the development of a photoresist layer and etching of layers of other material according to a pattern across the surface of the layer. The material removal process is terminated in response to detecting when breakthrough occurs in a preselected number of individual regions across the surface of the layer. A measure of uniformity of processing across the layer surface is obtained from monitoring removal of material in such individual surface regions, and can be used to control the process to improve such uniformity.

Abstract: A video camera of a type using an array of charge coupled devices (CCDs) is utilized to measure a condition, such as temperature, by imaging onto the camera a luminescent signal which contains information of the signal's decay time. The luminescent decay time is measured by comparing, such as by ratioing, the integrated signal values obtained in successive frames of operation of the CCD. One application includes use to measure a two-dimensional temperature distribution across a surface. The surface of interest is either coated with a layer of the luminescent material or emissions from the surface are imaged onto a separate luminescent screen. Another application is as a multiplexer and detector system for a large array of optical fiber sensors, a luminescent signal from each of the sensors being imaged through its respective fiber onto a unique one or more of CCD photosites.

Abstract: A device for measuring the temperature of an external moving filament is disclosed. The device includes dual thermal sinks or reference bodies; each reference body has two heat flow sensors that are matched in sensitivity and are connected in series. By utilizing dual thermal reference bodies, which are maintained at different temperatures, the device yields the absolute temperature of the filament by measuring the temperatures of the referenced bodies and the heat flow rates between each of the reference bodies and the filament. The device automatically calculates the proportionality constant between the heat flow rates and the temperature differences between the filament and the reference bodies and thus calculates the filament temperature. Each heat flow sensor has a row of sensitive elements or active junction lines that is not parallel to the path of the filament.

Abstract: A method and apparatus for measuring the temperature of an external body is disclosed. The apparatus comprises dual thermal sinks or reference bodies wherein heat flow sensors are mounted. By utilizing dual thermal reference bodies, which are at different temperatures, the method of the invention yields the absolute temperature of the external body by measuring the temperatures of the referenced bodies and the heat flow rates between each of the reference bodies and the external body. The apparatus automatically calculates the proportionality constant between the heat flow rates and the temperature differences between the external body and the reference bodies and thus calculates the external body temperature.

Abstract: Methods and apparatus for enhancing the accuracy for detecting the endpoint of certain operations (such as etching, photoresist development or chemical reaction) in the processing of materials which results in a change in the reflectivity or refractive index of the material are provided. The methods decrease the sensitivity of endpoint detection to high frequency noise and periodic oscillations. The methods also allow accurate calculation of overprocessing time and real-time viewing of data by the user.

Abstract: High temperature range black body techniques are combined with lower temperature range photoluminescent techniques to provide an optical method and apparatus for measuring temperature over a very wide range. Among the various optical probe configurations disclosed which combine the black body and photoluminescent technologies is an optical temperature measuring probe including an elongated transparent light pipe with a black body cavity and a photoluminescent material adjacent one end of the light pipe. Signal detection and processing can be combined, and temperature measurements made by the photoluminescent technique within an overlap of the two temperature ranges can be used to calibrate measurements made in the higher range by the black body technique.