SYSTEM AND METHOD FOR LITHOGRAPHY WITH LEVELING SENSOR

• US 20130201463A1
• Filed: 02/03/2012
• Published: 08/08/2013
• Est. Priority Date: 02/03/2012
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Chen, Li-Jui
• Granted Patent: US 9,389,520 B2
• Time in Patent Office: Days
• US Class Current: 355/55
• CPC Class Codes: G03F 7/7085 Detection arrangement, e.g. detectors of apparatus alignment possibly mounted on wafers, exposure dose, photo-cleaning flux, stray light, thermal load
• CPC Class Codes: G03F 9/7034 Leveling

Abstract

Disclosed is a lithography system. The lithography system includes a radiation source for providing radiation energy; a reticle stage configured to hold a reticle; an imaging lens module configured to direct the radiation energy onto a substrate to form an image of the reticle; and a leveling sensor configured to receive a leveling signal from an exposure field of the reticle secured on the reticle stage.

Claims

1. A lithography system, comprising:

a radiation source for providing radiation energy;

a reticle stage configured to hold a reticle;

an imaging lens module configured to direct the radiation energy onto a substrate to form an image of the reticle; and

a leveling sensor configured to receive a leveling signal from an exposure field of the reticle secured on the reticle stage.

2. The lithography system of claim 1, wherein the leveling sensor includes a plurality of sensing units configured in an array.

3. The lithography system of claim 1, further comprising a substrate stage configured to hold the substrate and operable to move relative to the reticle stage, wherein the leveling sensor is integrated with the substrate stage.

4. The lithography system of claim 3, further comprising a leveling signal source configured to direct and scan a leveling signal to the exposure field of the reticle secured on the reticle stage.

5. The lithography system of claim 4, wherein the leveling signal source is a laser source.

6. The lithography system of claim 3, wherein the leveling signal source is secured on the substrate stage.

7. The lithography system of claim 6, wherein the imaging lens module includes a projection lens module configured between the reticle stage and the substrate stage.

8. The lithography system of claim 7, wherein the leveling signal source and the leveling sensor are configured such that the leveling signal from the leveling signal source is directed to the leveling sensor through the projection lens module.

9. The lithography system of claim 6, wherein the leveling signal source and the leveling sensor are configured such that the leveling signal is directly reflected from the reticle to the leveling sensor.

10. The lithography system of claim 1, wherein the reticle is secured on the reticle stage by an e-chuck clamp.

11. The lithography system of claim 1, wherein the reticle is secured on the reticle stage by a vacuum clamp.

12. The lithography system of claim 1, further comprising

a leveling analysis module to analyze the leveling signal for reticle leveling;

and

a control module coupled to the leveling analysis module and configured to control the reticle stage for at least one of tilting and focusing according to a feedback from the leveling analysis module.

13. A lithography system, comprising:

a radiation source for providing radiation energy;

a reticle stage configured to hold a reticle having a circuit pattern within an exposure field;

a substrate stage configured to secure a substrate;

an optical module configured to direct the radiation energy onto the substrate to form an image of the circuit pattern;

a leveling signal source to provide a leveling signal to the reticle; and

leveling sensor to receive the leveling signal from the reticle, wherein the leveling signal source and the leveling sensor are configured to scan the leveling signal over the exposure field of the reticle.

14. The lithography system of claim 13, wherein the leveling signal source is a laser source and the leveling signal is a coherent light.

15. The lithography system of claim 14, further comprising

a leveling optical module to split the coherent light from the leveling signal source, generating a first beam and a second beam;

and

a leveling analysis module to extract leveling data of the reticle, wherein

the leveling optical module is operable to direct the first beam to the leveling sensor, and direct the second beam to reticle and then to the sensor such that an interference pattern is formed between the first and second beams, and

the leveling analysis module is operable to extract the leveling data of the reticle from the interference pattern.

16. The lithography system of claim 13, further comprising a control module operable to control the reticle stage for tilting and focusing according to the leveling data from the leveling analysis module.

17. The lithography system of claim 16, wherein the control module is operable to dynamically tilt the reticle stage during an exposure process.

18. A method for a lithography system, comprising:

securing a reticle on a reticle stage of the lithography system, wherein the reticle incudes a circuit pattern within an exposure field;

scanning the reticle using a leveling signal over the exposure field of the reticle for reticle leveling while the reticle is secured on the reticle stage; and

thereafter, applying radiation energy from a radiation source of the lithography system to form an image of the circuit pattern of the reticle within the exposure field on a substrate.

19. The method of claim 18, further comprising moving the reticle stage to tune at least one of tilting angle and focus length based on the reticle leveling after the scanning of the reticle.

20. The method of claim 19, wherein

the applying radiation energy from a radiation source includes scanning the radiation energy over the exposure field of the reticle;

and

the moving the reticle stage includes moving the reticle stage dynamically during the scanning radiation energy over the exposure field of the reticle.

21. The method of claim 18, further comprising receiving the leveling signal directed from the reticle by a leveling sensor.

22. The method of claim 18, wherein the scanning of the reticle using a leveling signal over the exposure field of the reticle is implemented while the reticle stage is positioned on one of reticle transfer path and reticle exposure location.