Patent ID: 8829442
Filing Date: 2014-09-09
Classification: G01N,H01L

Abstract:
1. A non-contacting system for measuring the dopant content of semiconductor material, comprising: a) an infrared radiation source configured to focus infrared radiation on a point on the material; b) a modulator for modulating the radiation from the source before the radiation strikes the material; c) a first lens is positioned to collect the radiation reflected from the material and focus the radiation; d) a first band pass filter positioned to receive the radiation from the first lens, the first filter configured to pass a narrow wavelength band of the radiation through the filter and reflect the balance of the radiation, the first filter passing a narrow hand of infrared radiation centered at a selected wavelength of the infrared radiation source; e) a second band pass filter positioned to receive the radiation that reflects off the first filter, the second filter configured to pass a narrow wavelength band of the radiation through the second filter and configured so that the narrow wavelength band that is passed by the second filter is different as compared to the narrow wavelength band passed by the first filter, the second filter passing a narrow wavelength, of infrared radiation centered at a selected wavelength of the infrared radiation source; f) a first radiation detector positioned to receive the radiation that passes the first band pass filter and configured to determine a first level of energy; g) a second radiation detector positioned to receive the radiation that passes the second filter and configured to determine a second level of energy; and h) a calculator configured to compare the first and second levels and return a dopant content value using a correlation curve, the correlation curve relating the dopant content of the semiconductor material based on a comparison of the level of energy reaching the two detectors for a series of the same semiconductor material of known different levels of dopant content.