Lithographic apparatus, method of determining a model parameter, device manufacturing method, and device manufactured thereby
First Claim
Patent Images
1. A lithographic apparatus comprising:
- a projection system configured to project a patterned beam of radiation onto a target portion of a substrate,a sensor;
a processing unit arranged to communicate with the sensor; and
a beam generator arranged to project an alignment beam to at least one of a plurality of alignment marks, of which desired positions are known,wherein the sensor is arranged to measure positional parameters for each of the plurality of alignment marks based on the projected alignment beam and to transfer the measured positional parameters to the processing unit, the positional parameters based on a plurality of diffraction orders generated by projecting the alignment beam to the at least one of a plurality of alignment marks, andwherein the processing unit is arranged to determine at least one parameter of a model providing information about a position of the substrate, based on the measured positional parameters, andwherein the measured positional parameters are weighted with variable weighing coefficients, the variable weighing coefficients based on the diffraction orders, andwherein the processing unit is arranged to determine a numerical value of at least one of the weighing coefficients and the at least one parameter of the model simultaneously.
1 Assignment
0 Petitions
Accused Products
Abstract
A method according to one embodiment of the invention relates to determining at least one parameter of a model that provides information about a position of an object. The object has a plurality of alignment marks of which desired positions are known. The method includes measuring a plurality of positional parameters for each alignment mark. Based on the measured plurality of positional parameters, which are weighted with weighing coefficients, at least one parameter of the model of the object is determined. The numerical value of each weighing coefficient is determined together with the at least one parameter of the model.
-
Citations
9 Claims
-
1. A lithographic apparatus comprising:
-
a projection system configured to project a patterned beam of radiation onto a target portion of a substrate, a sensor; a processing unit arranged to communicate with the sensor; and a beam generator arranged to project an alignment beam to at least one of a plurality of alignment marks, of which desired positions are known, wherein the sensor is arranged to measure positional parameters for each of the plurality of alignment marks based on the projected alignment beam and to transfer the measured positional parameters to the processing unit, the positional parameters based on a plurality of diffraction orders generated by projecting the alignment beam to the at least one of a plurality of alignment marks, and wherein the processing unit is arranged to determine at least one parameter of a model providing information about a position of the substrate, based on the measured positional parameters, and wherein the measured positional parameters are weighted with variable weighing coefficients, the variable weighing coefficients based on the diffraction orders, and wherein the processing unit is arranged to determine a numerical value of at least one of the weighing coefficients and the at least one parameter of the model simultaneously. - View Dependent Claims (2, 3, 4, 6, 7, 8, 9)
-
-
5. A lithographic apparatus comprising:
-
a projection system configured to project a patterned beam of radiation onto a target portion of a substrate, a sensor; a processing unit arranged to communicate with the sensor; and a beam generator arranged to project an alignment beam to at least one of a plurality of alignment marks, of which desired positions are known, wherein the sensor is arranged to measure positional parameters for each of the plurality of alignment marks based on the projected alignment beam and to transfer the measured positional parameters to the processing unit, and wherein the processing unit is arranged to determine at least one parameter of a model providing information about a position of the substrate, based on the measured positional parameters, and wherein the measured positional parameters are weighted with weighing coefficients, and wherein the processing unit is arranged to determine a numerical value of at least one of the weighing coefficients together with the at least one parameter of the model, and wherein the processing unit is arranged to set the value of a weighing coefficient to zero when the signal strength of a corresponding positional parameter is below a certain threshold.
-
Specification