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US 5,403,433 AGranted
Method and apparatus for monitoring layer processing
AssigneeOn-Line Technologies, Inc.
InventorsPhilip W. Morrison, Peter R. Solomon, Robert M. Carangelo, David G. Hamblen
Life of this patent
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Abstract
The method and apparatus of the invention permit in situ determinations to be made of the temperature and optical constants of a substrate surface that is being treated, by measurements of radiance, reflectance and transmittance. These determinations in turn provide, at any given instant during processing, compositional and other information, thereby affording highly effective feedback control of the processing conditions. The apparatus comprises an integrated, small and relatively inexpensive instrument for process monitoring.
Claims27
A method for the treatment and in situ analysis of an article during processing, comprising the steps:
- (a) providing a substrate having a surface;
- (b) treating at least a portion of said surface for a certain period of time to effect modification thereof, optionally by developing a film of material thereon, and carrying out the following steps in connection with said surface portion, as so modified;
- (c) substantially continuously throughout said period causing electromagnetic radiation of frequencies v throughout a selected spectral range to impinge upon said surface portion at a selected angle of incidence;
- (d) substantially continuously throughout said period measuring, at substantially the specular angle, spectral reflectance of said radiation from said surface portion, as a function of frequency;
- (e) substantially continuously throughout said period measuring the radiance of said surface portion at least at one selected wavelength;
- (f) determining, from the reflectance and radiance data obtained in said steps (d) and (e), the temperature T of said surface portion at selected instants during said period of time;
- and
- (g) determining optical constants for said surface portion at said instants by (1) selecting values for said optical constants utilizing a selection scheme in which the imaginary component of the optical constant expression is represented by a selected number s of oscillators spaced across at least a portion of said selected spectral range, s having a value of at least two;
- (2) calculating reflectance based upon said angle of incidence, said selected values for said optical constants, and the thickness of any film of material that may be developed upon said substrate surface in said step (b);
- (3) comparing said calculated reflectance to the value of said reflectance measured in said step (d);
- and (4) iteratively adjusting said selected values of optical constants and comparing said calculated reflectance and measured reflectance value until said calculated reflectance substantially equals said measured value.
8 more elements
A method for fabricating an article, comprising the steps:
- (a) providing a substrate having a surface;
- (b) treating at least a portion of said surface for a certain period of time to effect modification thereof, accompanied by the formation of ambient gases and optionally by developing a film of material thereon, and carrying out the following steps in connection with said surface portion, as so modified;
- (c) substantially continuously throughout said period causing electromagnetic radiation of frequencies v throughout a selected spectral range to impinge upon said surface portion at a selected angle of incidence;
- (d) substantially continuously throughout said period measuring, at substantially the specular angle, spectral reflectance of said radiation from said surface portion, as a function of frequency;
- (e) substantially continuously throughout said period measuring the radiance of said surface portion at least at one selected wavelength;
- (f) determining, from the reflectance and radiance data obtained in said steps (d) and (e), the temperature T of said surface portion at selected instants during said period of time;
- (g) determining optical constants for said surface portion at said instants by (1) selecting values for said optical constants utilizing a selection scheme in which the imaginary component of the optical constant expression is represented by a selected number of oscillators spaced across at least a portion of said selected spectral range, s having a value of at least two;
- (2) calculating reflectance based upon said angle of incidence, said selected values for said optical constants, and the thickness of any film of material that may be developed upon said substrate surface in said step (b);
- (3) comparing said calculated reflectance to the value of said reflectance measured in said step (d);
- and (4) iteratively adjusting said selected values of optical constants and comparing said calculated reflectance and measured reflectance value until said calculated reflectance substantially equals said measured value;
- (h) identifying features of said reflectance measured in said step (d) that are attributable to absorbance of radiation by said ambient gases, and subtracting said features from said measured reflectance;
- and
- (i) controlling said treating step (b) based upon said determined temperature and optical constants.
10 more elements
Apparatus for the in situ analysis of an article during processing, comprising:
- (a) means for producing electromagnetic radiation of frequencies v throughout a selected spectral range, and for causing such radiation to impinge at a selected angle of incidence upon the surface of a substrate supported in a position proximate said apparatus;
- (b) means for continuously measuring, as a function of frequency, specular reflectance of such impinging radiation from the surface of the substrate so supported, and for storing data so obtained;
- (c) means for continuously measuring, at least at one selected wavelength, the radiance of the surface of the substrate so supported, and for storing data so obtained;
- and
- (d) electronic data processing means programmed and operatively connected for processing reflectance and radiance data obtained by said means for measuring to determine, at any instant, the temperature of and the optical constants for the substrate surface, said optical constants being determined by (1) selecting values for said optical constants utilizing a selection scheme in which the imaginary component of the optical constant expression is represented by a selected number s of oscillators spaced across said selected spectral range, s having a value of at least two;
- (2) calculating reflectance based upon said angle of incidence, said selected values for said optical constants, and the thickness of any film of material that may be developed upon said substrate surface;
- (3) comparing said calculated reflectance to the value of said reflectance measured in said step (b), and (4) iteratively adjusting said selected values of optical constants and comparing said calculated reflectance and measured reflectance value until said calculated reflectance substantially equals said measured value.
4 more elements
Dependencies are inferred from the claim text.