Lithographic projection apparatus and a device manufacturing method using such lithographic projection apparatus

• US 20060008716A1
• Filed: 07/08/2004
• Published: 01/12/2006
• Est. Priority Date: 07/08/2004
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Baselmans, Johannes Jacobus Matheus, Jeunink, Andre Bernardus, De Groot, Simon, Akhssay, M'Hamed, Tel, Wim Tjibbo, Van De Stadt, Arnout, Commissaris, Franciscus Antonius Chrysogonus Marie, Van Dijk, Remco Marcel, Van Der Hoff, Alexander Hendrikus Martinus
• Granted Patent: US 7,403,264 B2
• Time in Patent Office: Days
• US Class Current: 430/30
• CPC Class Codes: G03F 7/70258 Projection system adjustments, e.g. adjustments during exposure or alignment during assembly of projection system
• CPC Class Codes: G03F 7/70491 Information management, e.g. software; Active and passive control, e.g. details of controlling exposure processes or exposure tool monitoring processes
• CPC Class Codes: G03F 7/705 Modelling or simulating from physical phenomena up to complete wafer processes or whole workflow in wafer productions
• CPC Class Codes: G03F 7/706 Aberration measurement
• CPC Class Codes: G03F 7/70891 Temperature
• CPC Class Codes: G03F 9/7046 Strategy, e.g. mark, sensor or wavelength selection

Abstract

A manufacturing method is utilized in lithographic projection apparatus in order to enable all aberrations to be compensated for but with those aberrations that are of most significance to the particular application (the particular pattern, illumination mode, etc.) being given precedence over aberrations that are of lesser significance in relation to that particular application. The method uses a substrate having a target portion for receiving an image, a mask for applying a pattern in accordance with a required patterning application, and a projection system to project a selected beam of radiation onto the mask to produce a specific required patterned beam providing an image of the pattern on the target portion. In order to compensate for the aberrations in a manner that gives precedence to those aberrations of particular significance to the required application, the method incorporates the steps of predicting projection system aberration changes with time, determining the application-specific effect on certain parameters of the image of such predicted projection system aberration changes with respect to certain measured aberration values, generating a control signal specific to the required patterned beam according to such predicted projection system aberration changes in the projection system aberrations with time and their application-specific effect on certain parameters of the image; and carrying out imaging adjustments in dependence on the control signal to compensate for the application-specific effect of the predicted changes in the aberrations on the image. The adjustments are therefore determined optimally for the given application.

Claims

1. Lithographic projection apparatus comprising:

a support structure for supporting a patterning device to impart a selected pattern to a beam of radiation;

a substrate table for holding a substrate;

a projection system for projecting the patterned beam onto a target portion of the substrate to form an image;

a predictive system for predicting changes in projection system aberrations with time with respect to measured aberration values;

a modelling system for determining an application-specific effect of said predicted projection system aberration changes on at least one parameter of the image for the selected pattern;

a control system for generating a control signal specific to the selected pattern according to said predicted projection system aberration changes and their application-specific effect on the at least one parameter of the image; and

an image adjusting system, responsive to the control signal, to compensate for the application-specific effect of said predicted projection system aberration changes on the image.

2. Lithographic projection apparatus according to claim 1, wherein the control signal preferentially compensates predicted changes in features of the image in one of two directions in the plane of the image in accordance with known sensitivities of the selected pattern to projection system aberrations in the two directions.

3. Lithographic projection apparatus according to claim 1, wherein the control system is arranged to generate a control signal which preferentially compensates predicted changes in features of the image in a direction normal to a plane of the image, in accordance with known sensitivities of the selected pattern to projection system aberrations in said direction.

4. Lithographic projection apparatus according to claim 1, wherein the control signal further depends on a defined merit function determining relative weightings to be given to the effects of projection system aberrations on the at least one parameter of the image.

5. Lithographic projection apparatus according to claim 1, wherein the predicted changes are predicted on the basis of a lens heating model that predicts changes in at least one aberration value with time as a result of lens heating or cooling.

6. Lithographic projection apparatus according to claim 1, wherein the modelling system is arranged to determine the application-specific effect of said projection system aberration changes on the basis of data indicative of the selected pattern and an illumination mode setting of the projection system.

7. Lithographic projection apparatus according to claim 1, wherein the control signal depends on known correspondence between changes in imaging adjustments of the adjustment system and the aberration changes.

8. Lithographic projection apparatus according to claim 1, further including an overlay metrology feedback system constructed and arranged to correct for a shift in a metrology overlay target for a current layer measured with respect to a metrology overlay target for a previous layer, said shift resulting from said predicted projection system aberration changes and the image adjusting system, on the basis of an optimization procedure providing for the changes in the aberrations to which the image is most sensitive to be compensated for according to a defined merit-function.

9. Lithographic projection apparatus according to claim 1, further including an alignment system constructed and arranged to compensate for effects of a shift in a respective wafer alignment mark provided for the alignment of each layer of successive layers of images to be applied to the target portion, said shift resulting from said predicted projection system aberration changes and said image adjusting system, on the basis of an optimisation procedure providing for the changes in the aberrations to which the image is most sensitive to be compensated for according to a defined merit-function.

10. Lithographic projection apparatus according to claim 1, including an alignment system constructed and arranged to compensate for effects of a shift in a respective mask alignment mark provided for the alignment of each layer of successive layers of images to be applied to the target portion, said shift resulting from said predicted projection system aberration changes and said image adjusting system, on the basis of an optimisation procedure providing for the changes in the aberrations to which the image is most sensitive to be compensated for according to a defined merit-function.

11. Lithographic projection apparatus according to claim 1, wherein the control system incorporates a measuring system constructed and arranged to re-measure at least one aberration value when the modelled effect on the at least one image parameter with time is greater than a corresponding threshold value.

12. Lithographic projection apparatus according to claim 1, wherein the image adjusting system is further arranged to carry out imaging adjustments over successive scan positions during scanning exposure of the substrate to allow for variations in the scanned image over the extent of the substrate in order to optimise the image as a function of scan position.

13. A device manufacturing method using lithographic projection apparatus, the method comprising:

selecting a patterning device in accordance with a required patterning application,

illuminating the patterning device with a beam of radiation to produce a patterned beam;

projecting the patterned beam onto the target portion to form an image thereon;

predicting changes in projection aberrations with time with respect to measured aberration values;

determining an application-specific effect of said predicted projection aberration changes on at least one parameter of the image;

generating a control signal specific to the required patterning application according to said predicted projection system aberration changes and their application-specific effect; and

adjusting the imaging based on the control signal.

14. The device manufacturing method according to claim 13, wherein the generating further comprises preferentially compensating predicted changes in features of the image in one of two directions in the plane of the image, in accordance with known sensitivities of the selected patterning device to projection system aberrations in the two directions.

15. The device manufacturing method according to claim 13, wherein the generating further comprises preferentially compensating changes in features of the image in a direction normal to the plane of the image, in accordance with known sensitivities of the selected patterning device to projection system aberrations in said direction.

16. The device manufacturing method according to claim 13, wherein the control signal further takes into account a defined merit function determining relative weightings to be given to selected effects of projection system aberrations on different parameters of the image.

17. The device manufacturing method according to claim 13, wherein said predicting is performed on the basis of a lens heating model that predicts changes in at least one aberration value with time as a result of lens heating or cooling.

18. The device manufacturing method according to claim 13, wherein the application-specific effect is determined on the basis of data indicative of the selected patterning device and an illumination mode used in the illuminating.

19. The device manufacturing method according to claim 13, wherein the generating is performed on the basis of known correspondence between changes in imaging adjustments of the adjustment system and the aberration changes being compensated for by such imaging adjustments.

20. The device manufacturing method according to claim 13, further comprising feeding back overlay metrology information to correct for a shift in a metrology overlay target for a current layer measured with respect to the metrology overlay target for a previous layer, as a result of said predicted changes and said adjusting, on the basis of an optimization procedure providing for changes in the aberrations to which the image is most sensitive to be compensated for according to a defined merit-function.

21. The device manufacturing method according to claim 13, further comprising, re-measuring at least one aberration value when the predicted effect on the at least one parameter is greater than a corresponding threshold value.

22. The device manufacturing method according to claim 13, wherein the adjusting is carried out over successive scan positions during scanning exposure of the substrate to allow for variations in the scanned image over the extent of the substrate, in order to optimize the image as a function of scan position.

23. A machine readable medium encoded with machine executable instructions for performing a method comprising:

predicting changes in projection aberrations with time with respect to measured aberration values for a required patterning application on a lithographic projection apparatus;

determining an application-specific effect of said predicted projection aberration changes on at least one parameter of an image;

generating a control signal specific to the required patterning application according to said predicted projection system aberration changes and their application-specific effect; and

adjusting the imaging based on the control signal.