Method and system for high speed height control of a substrate surface within a wafer inspection system
First Claim
1. A system for high speed height control of a surface of the substrate within a wafer inspection system comprising:
- a dynamically actuatable substrate stage assembly including a substrate stage for securing a substrate;
an actuator configured to actuate the substrate along a direction substantially perpendicular to the surface of the substrate;
a height error detection system configured to measure height error of a surface of the substrate at a position of inspection of the surface;
a displacement sensor operably coupled to the substrate stage assembly and configured to measure a displacement substantially perpendicular to the surface of the substrate at the location of the substrate stage assembly;
a feedback control system communicatively coupled to the height error detection system and the actuator, wherein the feedback control system is configured to;
receive one or more height error measurements from the height error detection system; and
responsive to the measured one or more height error measurements, adjust an actuation state of the actuator in order to maintain the substrate surface substantially at an imaging plane of a detector of the inspection system or a focus of illumination of the inspection system; and
a feed forward control system communicatively coupled to the height error detection system and the actuator, wherein the feed forward control system is configured to;
receive one or more displacement measurements from the displacement sensor;
responsive to one or more displacement values from the one or more displacements measurements with the one or more height error values from the one or more height error measurements, generate one or more displacement targets; and
actuate the actuator using at least one of the one or more displacement targets in order to maintain the substrate surface substantially at an imaging plane of a detector of the inspection system or a focus of illumination of the inspection system.
1 Assignment
0 Petitions
Accused Products
Abstract
High speed height control of a surface of a substrate within a wafer inspection system includes positioning a substrate on a substrate stage of a dynamically adjustable substrate stage assembly, actuating the substrate perpendicular to the surface of the substrate, measuring a height error value of the surface of the substrate at a position of inspection of the surface, measuring a displacement value perpendicular to the surface of the substrate at the location of the substrate stage assembly, generating a displacement target from the height error value and the displacement value, and adjusting an actuation state of the actuator using the measured height error value and the generated displacement target in order to maintain the substrate surface at an imaging plane of a detector of the inspection system or a focus of illumination of the inspection system.
-
Citations
27 Claims
-
1. A system for high speed height control of a surface of the substrate within a wafer inspection system comprising:
-
a dynamically actuatable substrate stage assembly including a substrate stage for securing a substrate; an actuator configured to actuate the substrate along a direction substantially perpendicular to the surface of the substrate; a height error detection system configured to measure height error of a surface of the substrate at a position of inspection of the surface; a displacement sensor operably coupled to the substrate stage assembly and configured to measure a displacement substantially perpendicular to the surface of the substrate at the location of the substrate stage assembly; a feedback control system communicatively coupled to the height error detection system and the actuator, wherein the feedback control system is configured to; receive one or more height error measurements from the height error detection system; and responsive to the measured one or more height error measurements, adjust an actuation state of the actuator in order to maintain the substrate surface substantially at an imaging plane of a detector of the inspection system or a focus of illumination of the inspection system; and a feed forward control system communicatively coupled to the height error detection system and the actuator, wherein the feed forward control system is configured to; receive one or more displacement measurements from the displacement sensor; responsive to one or more displacement values from the one or more displacements measurements with the one or more height error values from the one or more height error measurements, generate one or more displacement targets; and actuate the actuator using at least one of the one or more displacement targets in order to maintain the substrate surface substantially at an imaging plane of a detector of the inspection system or a focus of illumination of the inspection system. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A method for high speed height control of a surface of the substrate within a wafer inspection system comprising:
-
positioning a substrate on a substrate stage of a dynamically adjustable substrate stage assembly; actuating the substrate along a direction substantially perpendicular to the surface of the substrate; measuring one or more height error values of the surface of the substrate at a position of inspection of the surface using a height error detection system; measuring one or more displacement values substantially perpendicular to the surface of the substrate at the location of the substrate stage assembly using a displacement sensor; generating one or more displacement targets from the one or more height error values and one or more displacement values; adjusting an actuation state of the actuator using the measured one or more height error values in order to maintain the substrate surface substantially at an imaging plane of a detector of the inspection system or a focus of illumination of the inspection system; and adjusting an actuation state of the actuator using the generated one or more displacement targets in order to maintain the substrate surface substantially at an imaging plane of a detector of the inspection system or a focus of illumination of the inspection system.
-
-
14. A system for high speed height control of a surface of the substrate within a wafer inspection system comprising:
-
a dynamically actuatable substrate stage assembly including a substrate stage for securing a substrate; an actuator configured to actuate the substrate along a direction substantially perpendicular to the surface of the substrate; a height error detection system configured to measure height error of a surface of the substrate at a position of inspection of the surface; a displacement sensor operably coupled to the substrate stage assembly and configured to measure a displacement substantially perpendicular to the surface of the substrate at the location of the substrate stage assembly; a feedback control system communicatively coupled to the height error detection system and the actuator, wherein the feedback control system is configured to; receive one or more height error measurements from the height error detection system; and responsive to the measured one or more height error measurements, adjust an actuation state of the actuator in order to maintain the substrate surface substantially at an imaging plane of a detector of the inspection system or a focus of illumination of the inspection system; a feed forward control system communicatively coupled to the height error detection system and the actuator, wherein the feed forward control system is configured to; receive one or more displacement measurements from the displacement sensor; responsive to one or more displacement values from the one or more displacements measurements with the one or more height error values from the one or more height error measurements, generate one or more displacement targets; and actuate the actuator using at least one of the one or more displacement targets in order to maintain the substrate surface substantially at an imaging plane of a detector of the inspection system or a focus of illumination of the inspection system; and a track unit communicatively coupled to the feed forward system and configured to acquire a displacement target from one or more previous displacement target measurements, wherein the acquired displacement target is used as the feed forward target in order to reduce an effective phase delay of the feed forward control system. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
-
-
27. A method for high speed height control of a surface of the substrate within a wafer inspection system comprising:
-
positioning a substrate on a substrate stage of a dynamically adjustable substrate stage assembly; actuating the substrate along a direction substantially perpendicular to the surface of the substrate; measuring one or more height error values of the surface of the substrate at a position of inspection of the surface using a height error detection system; measuring one or more displacement values substantially perpendicular to the surface of the substrate at the location of the substrate stage assembly using a displacement sensor; generating one or more displacement targets from the one or more displacement targets of the one or more previous tracks; adjusting an actuation state of the actuator using the measured one or more height error values in order to maintain the substrate surface substantially at an imaging plane of a detector of the inspection system or a focus of illumination of the inspection system; and adjusting an actuation state of the actuator using the generated one or more displacement targets in order to maintain the substrate surface substantially at an imaging plane of a detector of the inspection system or a focus of illumination of the inspection system.
-
Specification