METHOD FOR IMPROVING EXPOSURE PERFORMANCE AND APPARATUS THEREOF

• US 20200133142A1
• Filed: 05/02/2019
• Published: 04/30/2020
• Est. Priority Date: 10/31/2018
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: LU, CHAO PEI, LEE, YUNG-YAO
• Granted Patent: US 11,221,564 B2
• Time in Patent Office: Days
• CPC Class Codes: G03F 7/70066 Size and form of the illuminated area in the mask plane, e.g. reticle masking blades or blinds
• 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 7/70858 Environment aspects, e.g. pressure of beam-path gas, temperature pollution aspects G03F7/70916
• CPC Class Codes: G03F 7/70891 Temperature

Abstract

A method of operating an illuminator and apparatus thereof are proposed. A method includes: directing a radiation beam to the illuminator comprising slit fingers; sensing a temperature value of each of the slit fingers; determining a shifting value of the respective slit finger based on the temperature value; causing the respective slit finger to move according to the shifting value to form a light slit from the radiation beam; and exposing a workpiece using the light slit.

Claims

1. A method of operating an illuminator, comprising:

directing a radiation beam to the illuminator comprising slit fingers;

sensing a temperature value of each of the slit fingers;

determining a shifting value of the respective slit finger based on the temperature value;

causing the respective slit finger to move according to the shifting value to form a light slit from the radiation beam; and

exposing a workpiece using the light slit.

2. The method according to claim 1, further comprising directing the radiation beam through a reticle comprising a pattern to thereby form an exposure pattern based on the pattern.

3. The method according to claim 2, further comprising projecting the exposure pattern onto the workpiece through a lens.

4. The method according to claim 1, wherein causing the respective slit finger to move by the shifting value comprises moving the respective slit finger into or out of intersection with the radiation beam.

5. The method according to claim 1, wherein determining a shifting value of the respective slit finger based on the temperature value comprises determining the shifting value related to a temperature difference.

6. The method according to claim 5, wherein the temperature difference is measured before and after an exposure operation.

7. The method according to claim 5, wherein the shifting value is proportional to the temperature difference.

8. The method according to claim 1, wherein determining a shifting value of the respective slit finger based on the temperature value further comprises determining the shifting value based on an intensity profile of the light slit.

9. The method according to claim 1, further comprising determining whether a uniformity of the light slit complies with a criterion prior to exposing the workpiece using the light slit.

10. The method according to claim 9, wherein determining whether a uniformity of the light slit complies with a criterion prior to exposing the workpiece using the light slit comprises determining whether temperatures of the slit fingers are balanced.

11. The method according to claim 1, wherein sensing a temperature value of each of the slit fingers comprises sensing the temperature value at a tip portion of the slit fingers.

12. The method according to claim 1, wherein sensing a temperature value of each of the slit fingers comprises taking multiple temperature measurements and averaging the multiple temperature measurements to obtain one representative temperature value.

13. A method of operating an illuminator, comprising:

directing a radiation beam to the illuminator comprising slit fingers;

sensing temperature values of the slit fingers;

determining shifting value of the respective slit fingers based on the temperature values;

causing the slit fingers to move according to the shifting values to form a light slit from the radiation beam; and

determining whether a profile of the light slit complies with a uniformity criterion.

14. The method according to claim 13, further comprising directing the light slit through a reticle comprising a circuit pattern to form an exposure pattern based on the circuit pattern in response to determining that the profile of the light slit complies with a uniformity criterion.

15. The method according to claim 13, wherein the shifting values of the respective slit fingers are determined based on temperature difference values of the respective slit finger and a shifting coefficient.

16. The method according to claim 13, further comprising obtaining positions of the slit fingers.

17. An apparatus, comprising:

a light source configured to emit light; and

an illuminator, comprising;

a plurality of slit fingers configured to allow the light to pass through and form a light slit;

a plurality of temperature sensors configured to sense temperature values of the slit fingers; and

a plurality of actuators configured to move the corresponding slit fingers in response to a sensing result of the temperature sensors.

20. The apparatus according to claim 17, wherein each of the slit fingers is configured to move in a direction to control an amount of the light passing through the slit.

18. The apparatus according to claim 18, further comprising a reticle stage configured to hold a reticle comprising a pattern thereon and allow the light slit received from the illuminator to pass through to thereby form an exposure pattern.

19. The apparatus according to claim 19, further comprising a lens configured to project the exposure pattern onto a workpiece.