Lithographic apparatus, radiation supply and device manufacturing method

• US 20070222961A1
• Filed: 03/21/2006
• Published: 09/27/2007
• Est. Priority Date: 03/21/2006
• Status: Active Grant

• Current Assignee: ASML Netherlands BV (ASML Holding NV)
• Original Assignee: ASML Netherlands BV (ASML Holding NV)
• Inventors: Schmidt, Robert-Han
• Granted Patent: US 7,728,955 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 7/7055 Exposure light control in all parts of the microlithographic apparatus, e.g. pulse length control or light interruption
• CPC Class Codes: G03F 7/70558 Dose control, i.e. achievement of a desired dose
• CPC Class Codes: G03F 7/70791 Large workpieces, e.g. glass substrates for flat panel displays or solar panels

Abstract

A system for controlling the radiation dose in a pulse of radiation having a relatively large dose, in which a pulsed beam of radiation is divided into a plurality of pulsed sub-beams of radiation and the radiation dose of the pulses is adjusted after the radiation beam has been divided.

Claims

1. A lithographic projection apparatus, comprising:

an illumination system configured to condition a pulsed beam of radiation;

a radiation beam divider configured to divide the pulsed beam of radiation into at least first and second pulsed sub-beams of radiation;

at least one sensor, configured to determine a radiation dose of a pulse of radiation in the pulsed beam of radiation or the pulsed first and second sub-beams of radiation;

an optical delay line, configured to delay a pulse of radiation after the radiation dose of the pulse of radiation has been determined by said at least one sensor;

a first radiation pulse modulator, configured to adjust a radiation dose of a pulse of radiation in said first pulsed sub-beam of radiation based on the radiation dose determined by the at least one sensor; and

a second radiation pulse modulator, configured to adjust a radiation dose of a pulse of;

radiation in said second pulsed sub-beam of radiation based on the radiation dose determined by said at least one sensor.

2. A lithographic projection apparatus according to claim 1, wherein said radiation beam divider divides the pulsed beam of radiation into at least three pulsed sub-beams of radiation;

and the lithographic apparatus comprises a plurality of radiation pulse modulators, each associated with one of said pulsed sub-beams of radiation and configured to adjust the radiation dose of a pulse of radiation in the respective pulsed sub-beam of radiation based on the radiation dose of said pulse determined by said at least one sensor.

3. A lithographic projection apparatus according to claim 1, wherein the lithographic apparatus comprises a sensor configured to determine a radiation dose within a pulse of radiation in said pulsed beam of radiation conditioned by the illumination system before said pulsed beam is divided by the radiation beam divider;

and wherein

the first and second radiation pulse modulators adjust radiation doses of first and second pulses of radiation in the first and second pulsed sub-beams of radiation, respectively, based on determination by said sensor of a radiation dose of a corresponding pulse of radiation in the pulsed beam of radiation before said pulsed beam is divided into said first and second pulses of radiation by the radiation beam divider.

4. A lithographic projection apparatus according to claim 1, wherein the lithographic apparatus comprises first and second sensors, configured to determine radiation doses of the first and second pulses of radiation within respective first and second sub-beams of radiation;

and wherein

the first and second radiation pulse modulators adjust the radiation dose of said first and second pulses, respectively, based on determining the respective radiation doses of said first and second pulses by the first and second sensors.

5. A lithographic projection apparatus according to claim 1, wherein the optical delay line is configured to delay a pulse of radiation of said pulsed beam of radiation before said pulsed beam is divided into said first and second pulsed sub-beams of radiation by the radiation beam divider.

6. A lithographic projection apparatus according to claim 1, wherein the lithographic projection apparatus comprises first and second optical delay lines, configured to delay pulses of radiation in said first and second pulsed sub-beams of radiation, respectively.

7. A lithographic projection apparatus according to claim 1, wherein said optical delay line is configured to delay a pulse of radiation in said first pulsed sub-beam of radiation and a pulse of radiation in said second pulsed sub-beam of radiation.

8. A lithographic projection apparatus according to claim 1, further comprising a first array of individually controllable elements, configured to modulate pulses of radiation in said first pulsed sub-beam of radiation;

and a second array of individually controllable elements, configured to modulate pulses of radiation in said second pulsed sub-beam of radiation.

9. A lithographic projection apparatus according to claim 1, further comprising:

at least one additional radiation beam divider, configured to divide at least one of said first and second pulsed sub-beams of radiation after a respective radiation pulse modulator adjusts a radiation dose of pulses of said first or said second pulsed sub-beams of radiation; and

a plurality of arrays of individually controllable elements, configured such that each array of the plurality of arrays modulates pulses of radiation from one of the first and second pulsed sub-beams of radiation and the further divided pulsed sub-beams of radiation.

10. A lithographic projection apparatus according to claim 1, wherein at least one of said first and second radiation pulse modulators comprises:

a pockels cell configured to rotate an orientation of linearly polarized radiation input into the pockels cell to an extent dependent on a control voltage applied to it; and

a polarizing filter, configured to transmit radiation to an extent dependent on the orientation of the linearly polarized radiation.

11. A lithographic projection apparatus according to claim 10, wherein the polarizing filter is a polarizing beam splitter that reflects radiation linearly polarized in a first orientation and transmits radiation linearly polarized in a second orientation, orthogonal to the first orientation;

and wherein one of the radiation reflected by the polarizing beam splitter and the radiation transmitted by the polarizing beam splitter is directed to a next component in the beam path of an associated first or second pulsed sub-beam of radiation.

12. A lithographic projection apparatus according to claim 11, wherein the one of the radiation reflected by the polarizing beam splitter and the radiation transmitted by the polarizing beam splitter not directed to the next component, is directed to a radiation sink, configured to absorb the radiation.

13. A lithographic projection apparatus according to claim 12, wherein said first and second radiation pulse modulators share a common radiation sink.

14. A lithographic projection apparatus according to claim 1, wherein at least one of the first and second radiation pulse modulators is configured to adjust the radiation dose of a pulse of radiation by transmitting the pulse of radiation at substantially full intensity for a first period of time and substantially no radiation for a second period of time.

15. A lithographic projection apparatus according to claim 1, wherein at least one of the first and second radiation pulse modulators is configured to adjust the radiation dose of a pulse of radiation by reducing an intensity of the radiation of the pulse by a substantially constant factor for the duration of said pulse.

16. A lithographic projection apparatus according to claim 1, configured such that the adjusted dose of a pulse of radiation adjusted by said first radiation pulse modulator is substantially the same as the adjusted dose of a pulse of radiation adjusted by said second radiation pulse modulator.

17. A lithographic projection apparatus according to claim 1, further comprising a dose controller that determines first and second required radiation doses for pulses of radiation in the first and second pulsed sub-beams of radiation, respectively;

and controls the first and second radiation pulse modulators to adjust doses of pulses of radiation in the first and second pulsed sub-beams of radiation to said first and second required radiation doses, respectively.

18. A device manufacturing method, comprising

conditioning a pulsed beam of radiation;

dividing the pulsed beam of radiation into at least first and second pulsed sub-beams of radiation;

determining a radiation dose of at least one pulse of radiation of said pulsed beam of radiation or pulsed sub-beams of radiation;

delaying said pulse of radiation in an optical delay line after the radiation dose of the pulse has been determined;

adjusting a radiation dose of a pulse of radiation in said first pulsed sub-beam of radiation based on said determined radiation dose of said at least one pulse; and

adjusting a radiation dose of a pulse of radiation in said second pulsed sub-beam of radiation based on said determined radiation dose of said at least one pulse.

19. A device manufacturing method according to claim 18, further comprising projecting the respective adjusted radiation doses of the first and second pulsed sub-beams onto a substrate.

20. A device manufacturing method according to claim 19, wherein the substrate is one of a flat panel display and an integrated circuit device.

21. A radiation supply system suitable for use with a pulsed source of radiation, comprising:

a radiation beam divider configured to divide a pulsed beam of radiation into at least first and second pulsed sub-beams of radiation;

at least one sensor, configured to determine a radiation dose within a pulse of radiation in the pulsed beam of radiation or the pulsed sub-beams of radiation;

an optical delay line, configured to delay a pulse of radiation after the radiation dose of the pulse has been determined by the sensor;

a first radiation modulator, configured to adjust a radiation dose of a pulse of radiation in said first pulsed sub-beam of radiation based on the radiation dose of said pulse determined by said at least one sensor;

a second radiation modulator, configured to adjust the radiation dose of a pulse of radiation in said second pulsed sub-beam of radiation based on the radiation dose of said pulse determined by said at least one sensor.