Test surfaces useful for calibration of surface profilometers
AssigneesThe Regents of the University of California, Brookhaven Science Associates, LLC
InventorsValeriy V. Yashchuk, Wayne R. McKinney, Peter Z. Takacs
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Abstract
The present invention provides for test surfaces and methods for calibration of surface profilometers, including interferometric and atomic force microscopes. Calibration is performed using a specially designed test surface, or the Binary Pseudo-random (BPR) grating (array). Utilizing the BPR grating (array) to measure the power spectral density (PSD) spectrum, the profilometer is calibrated by determining the instrumental modulation transfer function (IMTF).
Claims17
A test surface comprising:
- (a) a substrate;
- and
- (b) a plurality of grooves, wherein the plurality of grooves are distributed in a pseudo-random pattern on the substrate and have an essentially uniform depth, and wherein each groove is essentially parallel to each other groove and has a depth of about 1 nm to 100 μm;
- whereby the test surface is configured for calibration of a surface profilometer.
A method of calibrating surface profilometers using a test surface comprising:
- (a) providing a test surface comprising
- (i) a substrate, and
- (ii) a plurality of grooves, wherein the plurality of grooves are distributed in a pseudo-random pattern on the substrate and have an essentially uniform depth, and wherein each groove is essentially parallel to each other groove;
- and
- (b) experimentally measuring a power spectral density distribution using the test surface;
- (c) theoretically simulating an ideal power spectral density distribution of the test surface;
- and
- (d) taking the square root of the ratio of the experimentally measured power spectral density to the theoretically simulated power spectral density to find an instrumental modular transfer function (IMTF).
A method of determining instrumental modular transfer function (IMTF) of surface profilometers comprising:
- (a) providing a test surface comprising
- (i) a substrate, and
- (ii) a plurality of grooves, wherein the plurality of grooves are distributed in a pseudo-random pattern on the substrate and have an essentially uniform depth, and wherein each groove is essentially parallel to each other groove;
- (b) experimentally measuring a power spectral density distribution using the test surface;
- (c) theoretically simulating an ideal power spectral density distribution of the test surface;
- and
- (d) taking the square root of the ratio of the experimentally measured power spectral density to the theoretically simulated power spectral density to find an IMTF.
A test surface comprising:
- (a) a substrate,
- (b) a plurality of indentations, wherein the plurality of indentations are distributed in a pseudo-random pattern on the substrate and have an essentially uniform depth and each indentation has a depth of about 1 nm to 100 μm;
- whereby the test surface is configured for calibration of a surface profilometer.
Dependencies are inferred from the claim text.