Lithographic apparatus and device manufacturing method utilizing dynamic correction for magnification and position in maskless lithography

• US 20060215142A1
• Filed: 03/25/2005
• Published: 09/28/2006
• Est. Priority Date: 03/25/2005
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: De Jager, Pieter Willem Herman, Venema, Willem Jurrianus, Mulckhuyse, Wouter Frans Willem, Van Den Akker, Theodorus Leonardus, Kessels, Lambertus Gerardus Maria
• Granted Patent: US 7,209,216 B2
• Time in Patent Office: Days
• US Class Current: 355/69
• CPC Class Codes: G03F 7/70291 Addressable masks, e.g. spatial light modulators [SLMs], digital micro-mirror devices [DMDs] or liquid crystal display [LCD] patterning devices
• CPC Class Codes: G03F 7/70508 Data handling in all parts of the microlithographic apparatus, e.g. handling pattern data for addressable masks or data transfer to or from different components within the exposure apparatus

Abstract

A lithographic apparatus in which a size and/or a position of features formed on a substrate are adjusted by adjusting an intensity of radiation at boundaries of pattern features.

Claims

1. A lithographic apparatus, comprising:

an illumination system that conditions a radiation beam;

an array of individually controllable elements that modulate the radiation beam;

a projection system that projects the modulated beam onto a target portion of a substrate; and

a pattern controller that provides control signals to the array of individually controllable elements, such that the radiation beam is modulated to generate a desired pattern and dose profile on the substrate, wherein the pattern controller comprises a pattern adjuster that adjusts at least one of a size and a position, relative to the substrate, of at least a part of the pattern generated on the substrate by adjusting radiation intensity of at least a part of the modulated beam.

2. The lithographic apparatus of claim 1, wherein the pattern adjuster adjusts the magnification of at least one feature in the part of the pattern without adjusting the position of the at least one feature.

3. The lithographic apparatus of claim 1, wherein the pattern adjuster adjusts the radiation intensity of the portion of the modulated beam at a boundary between regions in the desired pattern of relatively high radiation intensely and adjacent regions of relatively low radiation intensity in order to adjust the position of the boundary.

4. The lithographic apparatus of claim 1, wherein:

the pattern adjuster determines a required adjustment of the position of boundaries of features of the desired pattern that are defined by regions of relatively high required radiation intensity in order to produce the required adjustment of at least one of the size and the position of the at least part of the pattern generated on the substrate, such that,

when the boundary is moved towards the region of relatively low required radiation intensity, the pattern adjuster increases the intensity of the modulated beam at the boundary; and

when the boundary is moved towards the region of relatively high required radiation intensity, the pattern adjuster decreases the intensity of the modulated beam at the boundary.

5. The lithographic apparatus of claim 1, wherein:

the pattern controller determines a radiation intensity for a plurality of virtual points on the substrate that collectively generate the desired pattern;

a number of the virtual points in a given region of the pattern is greater than a number of individually controllable elements used to generate the region of the pattern; and

the pattern controller determines radiation intensity in the part of the radiation beam corresponding to each of the individually controllable elements based on the radiation intensity for a plurality of the virtual points.

6. The lithographic apparatus of claim 5, wherein four of the virtual points are used to determine the radiation intensity of the part of the radiation beam corresponding to each of the individually controllable elements.

7. The lithographic apparatus of claim 5, wherein:

the pattern controller determines a nominal radiation intensity of the portion of the modulated beam associated with each of the virtual points to generate the desired pattern prior to adjusting at least one of the size and the position of the at least part of the pattern;

the pattern adjuster determines the adjustment of the position of the boundaries of features of the desired pattern that are defined by regions of relatively high required radiation intensity in order to produce the required adjustment of at least one of the size and the position of the at least part of the pattern generated on the substrate;

the pattern adjusted adjusts the pattern feature boundary through determining an adjusted radiation intensity for each of the virtual points using a bilinear interpolation of the nominal radiation intensity values for a plurality of the virtual points; and

the pattern adjusted uses the adjusted radiation intensity values for the virtual points to determine the radiation intensity for each part of the radiation beam corresponding to each of the individually controllable elements.

8. The lithographic apparatus of claim 1, wherein:

the pattern controller determines a nominal intensity of the portion of the modulated beam associated with each of the individually controllable elements to generate the desired pattern prior to adjusting at least one of the size and the position of the at least part of the pattern;

the pattern adjuster determines the required adjustment of the position of the boundaries of features of the desired pattern that are defined by regions of relatively high required radiation intensity in order to produce the adjustment of at least one of the size and the position of the at least part of the pattern generated on the substrate; and

the adjustment of the position of the pattern feature boundary is performed by setting each of the individually controllable elements such that the intensity of the corresponding portion of the modulated beam is a weighted average of the nominal intensity for the individually controllable element and the nominal intensity of at least one other individually controllable element located, relative to the individually controllable elements being set, in a direction parallel to the direction of the adjustment of the boundary, wherein the weight of the average is determined by the size of the adjustment of the boundary that is required.

9. The lithographic apparatus of claim 8, wherein each individually controllable elements is set according to the equation:

p1′

=p1+0.5*d 2*(p0+p2−

2*p1)+0.5*d*(p2−

p0)

where;

p1 is the nominal intensity of the portion of the modulated beam associated with the individually controllable element being set;

p1′

is the intensity of the portion of the modulated beam associated with the individually controllable element necessary to be set to include the adjustment of the position of the boundaries of the features;

d is the size of a local shift of the boundary of the feature as a proportion of the separation of the portions of the modulated beam associated with adjacent individually controllable elements;

p0 is the nominal intensity of the modulated beam associated with the individually controllable element adjacent to the individually controllable element being set in the direction of the shift of the boundary feature; and

p2 is the nominal intensity of the modulated beam associated with the individually controllable element adjacent the individually controllable element being set in a direction opposite that of the shift of the boundary feature.

10. The lithographic apparatus of claim 9, wherein the pattern controller evaluates the equation in order to set the individually controllable elements as through use of one or more look-up tables.

11. The lithographic apparatus of claim 1, wherein:

the pattern to be generated on the substrate is arranged such that the portion of the desired pattern associated with each individually controllable element is one of a plurality of predetermined pattern characters;

each pattern character is associated with a corresponding intensity of the portion of the modulated beam of the individually controllable element; and

the pattern controller sets each of the individually controllable elements to provide the intensity in each corresponding portion of the modulated beam according to the pattern character assigned to the individually controllable elements.

12. The lithographic apparatus of claim 11, wherein:

the pattern adjuster determines an adjustment of a position of boundaries of pattern features of the desired pattern that are defined by regions of relatively high radiation intensity in order to produce the adjustment of at least one of the size and the position of at least part of the pattern generated on substrate;

the pattern adjuster determines a corresponding position adjustment for the pattern characters associated with each of the individually controllable elements; and

the pattern controller sets each of the individually controllable elements to provide a predetermined radiation intensity in the corresponding portion of the modulated beam for each of the pattern characters for a given position adjustment.

13. The lithographic apparatus of claim 12, wherein the pattern controller includes look up tables containing settings for each of the individually controllable elements for each possible one of the position adjustments for each of the pattern characters.

14. The lithographic apparatus of claim 12, wherein:

the pattern adjuster uses the position adjustment for each of the pattern characters to determine which pattern character is associated with each of the individually controllable elements after the position adjustment is made; and

the pattern controller includes look up tables containing settings for each of the individually controllable elements for each of the pattern characters.

15. The lithographic apparatus of claim 11, wherein:

the pattern controller limits the pattern to be generated on the substrate such that, for each of the possible pattern characters at a given location, the pattern characters at each adjacent location is limited to a subset of all the pattern characters; and

the pattern controller determines the settings for a plurality of adjacent individually controllable elements jointly.

16. The lithographic apparatus of claim 15, wherein a size of the pattern feature generated by the plurality of adjacent individually controllable elements jointly set by the pattern controller is a minimum feature size of the pattern to be generated.

17. A device manufacturing method, comprising:

projecting a beam of radiation that is modulated by an array of individually controllable elements onto a substrate;

providing control signals to the array of individually controllable elements, such that the radiation beam is modulated to generate a desired pattern and dose profile on the substrate; and

adjusting at least one of a size and a position, relative to the substrate, of at least a part of the pattern generated on the substrate by adjusting an intensity of at least a part of the modulated beam.

18. A flat panel display manufactured by the method of claim 17.

19. An integrated circuit device manufactured by the method of claim 17.