A semiconductor process endpoint detection system uses a relatively wide wavelength range of light to reflect off a semiconductor wafer being processed. Relatively narrow wavelength ranges can be monitored within this wide reflected wavelength range in order to produce an endpoint of the process. An indication can be produced which is a function of detected light intensities at multiple wavelength ranges. These indications aid in the determination of an endpoint of a process.
A working process end point real time determination method by which a working process end point can be determined accurately without an error even if a working process measurement signal has such a great variation that; the variation cannot be removed fully from and still remains in resulting smoothed data is disclosed. In the method, a working process end point is estimated by extrapolation from the variation of the average gradient of the averaged data in a predetermined period of the working process measurement signal to perform determination of the end point. Where the working process does not allow such extrapolation, it is first determined that the working process is near the working process end point based on the absolute value of the average gradient of the averaged data, and then the working process end point is determined using a short time gradient calculated from a value at the present measurement point of time and another value in the nearest past of the averaged data of the working process measurement signal.
A method and system are presented for optical measurements in multi-layer structures to determine the properties of at least some of the layers. The structure is patterned by removing layer materials within a measurement site of the structure from the top layer to the lowermost layer of interests. Optical measurements are sequentially applied to the layers, by illuminating a measurement area in the layer under measurements, when the layer material above said layer under measurements is removed, thereby obtaining measured data portions for the at least some of the layers, respectively. The properties of each of the at least some layers are calculated, by analyzing the measured data portion of the lowermost layer, and then sequentially interpreting the measured data portions of all the other layers towards the uppermost layer, while utilizing for each layer the calculation results of the one or more underlying layers.
A method and system are presented for optical measurements in multi-layer structures to determine the properties of at least some of the layers. The structure is patterned by removing layer materials within a measurement site of the structure from the top layer to the lowermost layer of interest. Optical measurements are sequentially applied to the layers, by illuminating a measurement area in the layer under measurements, when the layer material above said layer under measurements is removed, thereby obtaining measured data portions for the at least some of the layers, respectively. The properties of each of the at least some layers are calculated, by analyzing the measured data portion of the lowermost layer, and then sequentially interpreting the measured data portions of all the other layers towards the uppermost layer, while utilizing for each layer the calculation results of the one or more underlying layers.
In determining an endpoint of etching a substrate, light that is directed toward the substrate is reflected from the substrate. A wavelength of the light is selected to locally maximize the intensity of the reflected light at an initial time point of the etching process. The reflected light is detected to determine an endpoint of the substrate etching process.
A method of etching a substrate, includes measuring a reflectance signal from a reflective material deposited on the substrate as the substrate is being etched, correlating the substrate etch rate to the reflectance signal from the reflective material, and using the etch relation between the substrate and the reflective material to determine the etch target.
