Apparatus and method for real time measurement of substrate temperatures for use in semiconductor growth and wafer processing
First Claim
1. A method for determining the temperature of a semiconductor material via spectral analysis in an environment where there are light signals from wanted and unwanted sources, said method comprising the steps of:
- a) providing a semiconductor material;
b) interacting light signals with the semiconductor material to produce diffusely scattered light;
c) collecting light in a spectrometer to produce spectra data by resolving light signals into discrete wavelength components of particular light intensity, the light containing both diffusely scattered light from the semiconductor material along with a component of unwanted light signals;
d) identifying an absorption edge feature in the spectra data;
e) ignoring a predetermined level of light deemed noise based on experimental conditions;
f) obtaining a reference lamp spectrum from a lamp;
g) dividing a reference lamp spectrum from the collected light to remove any unwanted features introduced by a lamp; and
h) removing unwanted light from the spectra data to create preprocessed spectra.
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Abstract
The invention is an optical method and apparatus for measuring the temperature of semiconductor substrates in real-time, during thin film growth and wafer processing. Utilizing the nearly linear dependence of the interband optical absorption edge on temperature, the present method and apparatus result in highly accurate measurement of the absorption edge in diffuse reflectance and transmission geometry, in real time, with sufficient accuracy and sensitivity to enable closed loop temperature control of wafers during film growth and processing. The apparatus operates across a wide range of temperatures covering all of the required range for common semiconductor substrates.
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9 Claims
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1. A method for determining the temperature of a semiconductor material via spectral analysis in an environment where there are light signals from wanted and unwanted sources, said method comprising the steps of:
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a) providing a semiconductor material; b) interacting light signals with the semiconductor material to produce diffusely scattered light; c) collecting light in a spectrometer to produce spectra data by resolving light signals into discrete wavelength components of particular light intensity, the light containing both diffusely scattered light from the semiconductor material along with a component of unwanted light signals; d) identifying an absorption edge feature in the spectra data; e) ignoring a predetermined level of light deemed noise based on experimental conditions; f) obtaining a reference lamp spectrum from a lamp; g) dividing a reference lamp spectrum from the collected light to remove any unwanted features introduced by a lamp; and h) removing unwanted light from the spectra data to create preprocessed spectra. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification