Lithographic Apparatus and Device Manufacturing Method
First Claim
1. A lithographic apparatus comprising:
- an illumination system configured to condition a radiation beam;
a support configured to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam;
a substrate table configured to hold a substrate;
a projection system configured to project the patterned radiation beam onto a target portion of the substrate,an alignment apparatus configured to align the substrate according to an alignment strategy, prior to the projection of the patterned radiation beam onto a target portion of the substrate; and
a scanning control module configured to control at least one of the support, substrate table, and projection system by periodically retrieving measurements that define baseline control parameters from one or more monitor wafers to determine a parameter drift from the baseline control, the one or more wafers having been initially exposed using a first alignment strategy;
wherein the apparatus is configured to, when exposing a production substrate using a second alignment strategy different from the first alignment strategy, adjust a correction made for the parameter drift, thereby being substantially closer to the correction that would have been made had the second alignment strategy been used in exposure of the one or more monitor wafers.
1 Assignment
0 Petitions
Accused Products
Abstract
A method controls a scanning function of a lithographic apparatus. A first alignment strategy is used. A monitor wafer is exposed to determine baseline control parameters pertaining to the scanning function. The baseline control parameters are periodically retrieved from the monitor wafer. Parameter drift is determined from the baseline control parameters. Corrective action is taken based on the determination. A production wafer is exposed using a second alignment strategy, different to the first alignment strategy. The corrective action is modified so as to be substantially closer to the correction that would have been made had the second alignment strategy been used in exposing the monitor wafer.
-
Citations
28 Claims
-
1. A lithographic apparatus comprising:
-
an illumination system configured to condition a radiation beam; a support configured to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table configured to hold a substrate; a projection system configured to project the patterned radiation beam onto a target portion of the substrate, an alignment apparatus configured to align the substrate according to an alignment strategy, prior to the projection of the patterned radiation beam onto a target portion of the substrate; and a scanning control module configured to control at least one of the support, substrate table, and projection system by periodically retrieving measurements that define baseline control parameters from one or more monitor wafers to determine a parameter drift from the baseline control, the one or more wafers having been initially exposed using a first alignment strategy; wherein the apparatus is configured to, when exposing a production substrate using a second alignment strategy different from the first alignment strategy, adjust a correction made for the parameter drift, thereby being substantially closer to the correction that would have been made had the second alignment strategy been used in exposure of the one or more monitor wafers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
-
-
15. A method comprising:
-
exposing at least one monitor wafer so as to determine baseline control parameters pertaining to a scanning function, the exposure being performed using a first alignment strategy; periodically retrieving the baseline control parameters from the at least one monitor wafer; determining parameter drift from the baseline control parameters and making a correction based on the determination; exposing a production substrate using a second alignment strategy, wherein the alignment strategy is different from the first alignment strategy; and modifying the correction so as to be substantially closer to an anticipated correction that would have been made had the second alignment strategy been used in exposing the at least one monitor wafer. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
-
Specification