Assessment and optimization for metrology instrument
AssigneeInternational Business Machines Corporation
InventorsCharles N. Archie, G. William Banke, Jr.
Life of this patent
Estimating the term…
Abstract
Methods and related program product for assessing and optimizing metrology instruments by determining a total measurement uncertainty (TMU) based on precision and accuracy. The TMU is calculated based on a linear regression analysis and removing a reference measuring system uncertainty (URMS) from a net residual error. The TMU provides an objective and more accurate representation of whether a measurement system under test has an ability to sense true product variation.
Claims18
A method for assessing a measurement system under test (MSUT), the method comprising the steps of:
- (a) providing a substrate having a plurality of structures;
- (b) measuring a dimension of the plurality of structures using a reference measurement system (RMS) to generate a first data set, and calculating an RMS uncertainty (URMS) from the first data set, where the RMS uncertainty (URMS) is defined as one of an RMS precision and an independently determined RMS total measurement uncertainty (TMURMS);
- (c) measuring the dimension of the plurality of structures using the MSUT to generate a second data set, and calculating a precision of the MSUT from the second data set;
- (d) conducting a linear regression analysis of the first and second data sets to determine a corrected precision of the MSUT and a net residual error;
- (e) determining a total measurement uncertainty (TMU) for the MSUT by removing the RMS uncertainty (URMS) from the net residual error;
- and
- (f) outputting the TMU to a system capable of optimizing the MSUT.
A method for optimizing a measurement system under test (MSUT), the method comprising the steps of:
- (a) providing a plurality of structures;
- (b) measuring a dimension of the plurality of structures according to a measurement parameter using a reference measurement system (RMS) to generate a first data set, and calculating an RMS uncertainty (URMS) from the first data set, where the RMS uncertainty (URMS) is defined as one of an RMS precision and an independently determined RMS total measurement uncertainty (TMURMS);
- (c) measuring the dimension of the plurality of structures according to the measurement parameter using the MSUT to generate a second data set, and calculating a precision of the MSUT from the second data set;
- (d) conducting a linear regression analysis of the first and second data sets to determine a corrected precision of the MSUT and a net residual error;
- (e) determining a total measurement uncertainty (TMU) for the MSUT by removing the RMS uncertainty (URMS) from the net residual error;
- (f) repeating steps (c) to (e) for at least one other measurement parameter;
- (g) outputting the TMU to a system capable of optimizing the MSUT;
- and
- (h) optimizing the MSUT by determining an optimal measurement parameter based on a minimal total measurement uncertainty.
Dependencies are inferred from the claim text.