Measurement system, lithographic apparatus and device manufacturing method

Patent metadata

Field	Value
Publication number	US-11009800-B2
Application number	US-201716071380-A
Country	US
Kind code	B2
Filing date	Jan 26, 2017
Priority date	Mar 10, 2016
Publication date	May 18, 2021
Grant date	May 18, 2021

Abstract

A measurement system to determine a deformation of an object having a front surface, a back surface and a pattern. The measurement system includes a processor system and an interferometer system. The interferometer system has a radiation source and a detector system. The source is configured to emit, to each of a plurality of locations on the object, measurement beams in order to generate, at each of the respective plurality of locations, reflected measurement beams off the front and back surfaces of the object respectively. The detector system is configured to receive the respective reflected measurement beams and output signals representative of the received reflected measurement beams to the processor system. The processor system is configured to receive the signals; determine, based on the signals as received, a characteristic of the object; and determine a deformation of the pattern based on the characteristic.

First claim

What is claimed is:

1. A measurement system configured to determine a deformation of an object having a front surface, a back surface and a pattern, the measurement system comprising:
a processing system; and
an interferometer system comprising a radiation output and a detector system, the radiation output configured to emit, to each of a plurality of locations on the object, one or more measurement beams in order to generate, at each of the respective plurality of locations, a reflected measurement beam off the front surface of object and a reflected measurement beam off the back surface of the object and the detector system configured to receive, for each of the plurality of locations, the respective reflected measurement beams and output one or more signals representative of the received reflected measurement beams to the processing system;
wherein the processing system is configured to:
receive, for each of the plurality of locations, the one or more signals;
determine, based on the plurality of one or more signals as received, a physical characteristic of the object, the physical characteristic being representative of a deformation of the object; and
determine, based on the physical characteristic of the object and a mathematical model of the object, a deformation of the pattern, wherein the physical characteristic comprises a temperature or a temperature offset at the plurality of locations.

2. The measurement system according to claim 1 , wherein the deformation comprises a local deformation of the object at the plurality of locations.

3. The measurement system according to claim 1 , wherein the interferometer system is configured to project a measurement beam to the front surface of the object, a first portion of the measurement beam being reflected off the front surface, so as to form the reflected measurement beam off the front surface and a second portion of the measurement beam propagating through the object and at least partially reflecting off the back surface, propagating towards the front surface and at least partially propagates outside the object, so as to form the reflected measurement beam off the back surface.

4. The measurement system according to claim 3 , wherein the measurement beam comprises a first component having a first frequency and a second component having a second frequency, the detector system being configured to determine a phase of a beat component of the measurement beam and a phase of a beat component of the reflected measurement beams.

5. The measurement system according to claim 4 , wherein the interferometer system comprises a beam sampler configured to deflect a sample portion of the measurement beam to a first detector of the detector system to determine the phase of the beat component of the measurement beam.

6. The measurement system according to claim 5 , wherein the first component is left-hand circularly polarized and the second component is right-hand circularly polarized and the interferometer system further comprises a first analyzer through which the sample portion propagates prior to the first detector.

7. The measurement system according to claim 5 , wherein the first component is right-hand circularly polarized and the second component is left-hand circularly polarized and the interferometer system further comprises a first analyzer through which the sample portion propagates prior to the first detector.

8. The measurement system according to claim 4 , wherein the interferometer system is configured to provide a reflected measurement beam off the front surface having the first frequency and a reflected measurement beam off the back surface having the second frequency to a detector of the detector system and prohibit a reflected measurement beam off the front surface having the second frequency and a reflected measurement beam off the back surface having the first frequency, to reach the detector.

9. The measurement system according to claim 8 , wherein the interferometer system is configured to spatially displace the first component relative to the second component prior to impacting the object.

10. The measurement system according to claim 1 , further comprising one or more temperature sensors configured to determine a surface temperature profile of the front surface or the back surface or both.

11. The measurement system according to claim 10 , wherein the processing system is configured to determine a temperature gradient of the object based on the temperature or the temperature offset at the plurality of locations and the surface temperature profile.

12. The measurement system according to claim 11 , wherein the processing system is configured to determine an out-of-plane deformation of the pattern based on the temperature gradient of the object and the mathematical model of the object.

13. A lithographic apparatus comprising:
an illumination system configured to condition a radiation beam;
a support constructed 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 constructed to hold a substrate; and
a projection system configured to project the patterned radiation beam onto a target portion of the substrate,
wherein the apparatus further comprises the measurement system according to claim 1 .

14. A device manufacturing method comprising transferring a pattern from a patterning device onto a substrate using the lithographic apparatus according to claim 13 .

15. The device manufacturing method according to claim 14 , wherein transferring the pattern is preceded by:
determining a deformation of the pattern by means of the measurement system of the lithographic apparatus, and
adjusting a setting of the illumination system or projection system of the lithographic apparatus based on the deformation of the pattern.

16. A method comprising:
emitting, to each of a plurality of locations on an object, one or more measurement beams in order to generate, at each of the respective plurality of locations, a reflected measurement beam off a front surface of object and a reflected measurement beam off a back surface of the object;
by a detector system, receiving, for each of the plurality of locations, the respective reflected measurement beams and generating one or more signals representative of the received reflected measurement beams;
determining, based on the plurality of one or more signals, a physical characteristic of the object, the physical characteristic being representative of a deformation of the object; and
determining, based on the physical characteristic of the object and a mathematical model of the object, a deformation of a pattern of the object,
wherein the physical characteristic comprises a temperature or a temperature offset at the plurality of locations.

17. The method according to claim 16 , wherein the deformation comprises a local deformation of the object at the plurality of locations.

18. The method according to claim 16 , wherein the emitting comprises projecting a measurement beam to the front surface of the object, a first portion of the measurement beam being reflected off the front surface, so as to form the reflected measurement beam off the front surface and a second portion of the measurement beam propagating through the object and at least partially reflecting off the back surface, propagating towards the front surface and at least partially propagates outside the object, so as to form the reflected measurement beam off the back sur

Assignees

• Asml Netherlands Bv

Inventors

• Nienhuys Han-Kwang
• Nakiboğlu Güneş
• Petit Rita Marguerite Albin Lambertine
• Pen Hermen Folken
• Van De Moesdijk Remco Yuri
• Van Boxtel Frank Johannes Jacobus
• Kruizinga Borgert

Classifications

• G03F1/84

  Inspecting · CPC title

• G03F7/70875

  Temperature, e.g. temperature control of masks or workpieces via control of stage temperature · CPC title

• G03F7/70783 Primary

  Handling stress or warp of chucks, masks or workpieces, e.g. to compensate for imaging errors or considerations related to warpage of masks or workpieces due to their own weight · CPC title

• G03F7/7085

  Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load · CPC title