Optically monitoring the thickness of a depositing layer
First Claim
1. A method of optically monitoring the thickness of a layer of material being deposited on a substrate within a reaction chamber comprising the steps of:
- forming on a body a diffraction grating profile having an aspect groove width Ao and a periodicity d,exposing said diffraction grating profile to a beam of monochromatic light while depositing said material on both said substrate and said diffraction grating profile within said reaction chamber, whereby said diffraction grating profile, including the material deposited thereon, functions as a relief pattern, diffracting said beam of monochromatic light into diffracted beams of various orders, said relief pattern having a changing aspect groove width A,measuring the intensity of the first order beam (I
1) and the second order beam (I
2) to obtain a ratio signal (I 2/I1) comprising the second order beam intensity divided by the first order beam intensity,transmitting said ratio signal (I 2/I1) to processing means for determining said aspect groove width A, whereby the thickness T of said layer being deposited is determined from a pre-established relationship dependent upon the aspect groove width A.
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Abstract
A method of optically monitoring the thickness of a layer of material being deposited on a substrate within a reaction chamber comprises forming on a body a diffraction grating profile, exposing the grating profile to a beam of light while depositing the material on both the substrate and the grating profile, whereby the grating profile functions as a relief pattern diffracting the light beam into diffracted beams of various orders, measuring the intensity of the first order (I1) and second order (I2) beams to obtain a ratio signal (I2 /I1), and then transmitting the ratio signal to processing means for determining the aspect groove width of the relief pattern, whereby the thickness of the depositing layer is determined from a pre-established relationship dependent upon the aspect groove width.
75 Citations
8 Claims
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1. A method of optically monitoring the thickness of a layer of material being deposited on a substrate within a reaction chamber comprising the steps of:
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forming on a body a diffraction grating profile having an aspect groove width Ao and a periodicity d, exposing said diffraction grating profile to a beam of monochromatic light while depositing said material on both said substrate and said diffraction grating profile within said reaction chamber, whereby said diffraction grating profile, including the material deposited thereon, functions as a relief pattern, diffracting said beam of monochromatic light into diffracted beams of various orders, said relief pattern having a changing aspect groove width A, measuring the intensity of the first order beam (I
1) and the second order beam (I
2) to obtain a ratio signal (I 2/I1) comprising the second order beam intensity divided by the first order beam intensity,transmitting said ratio signal (I 2/I1) to processing means for determining said aspect groove width A, whereby the thickness T of said layer being deposited is determined from a pre-established relationship dependent upon the aspect groove width A. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification