EP-4736211-A1 - IN-VACUUM, IN-SITU WAFER TEMPERATURE MEASURING METHOD AND APPARATUS

Abstract

An improved particle beam inspection apparatus, and more particularly, a particle beam inspection apparatus including a contactless temperature sensor for accurately measuring a temperature of a wafer without risk of contamination is disclosed. The charged particle beam apparatus may calibrate the contactless temperature sensor using a temperature adjustable calibration pad, and then use the calibrated contactless temperature sensor to determine a temperature of a sample with an accuracy of 0.01-0.1 °C. The charged particle beam apparatus may further optimize and adjust a thermal conditioning station based on the accurately measured sample temperature.

Inventors

• YU, Dongchi
• LIU, YU
• CHANG, Huan-yu
• KOLE, Maghiel, Jan

Assignees

• ASML Netherlands B.V.

Dates

Publication Date

20260506

Application Date

20240528

Claims (15)

1. 1. An in-vacuum temperature measurement system comprising: a vacuum chamber; a wafer holder located in the vacuum chamber and configured to hold a wafer; a temperature adjustable calibration pad coupled to an internal component of the vacuum chamber; a contactless temperature sensor configured to generate an output signal based on a temperature of the temperature adjustable calibration pad; a contact temperature sensor coupled to the temperature adjustable calibration pad, wherein the contact temperature sensor is configured to determine a temperature of the temperature adjustable calibration pad; and a controller configured to calibrate the contactless temperature sensor based on the output signal from the contactless temperature sensor and the temperature of the temperature adjustable calibration pad determined by the contact temperature sensor.
2. 2. The system of claim 1, wherein the temperature adjustable calibration pad is a same material as a wafer held by the wafer holder.
3. 3. The system of claim 1, wherein the temperature adjustable calibration pad is a same material of a component of the charged particle beam apparatus that is contacted to a sample to be inspected.
4. 4. The system of claim 1, further comprising a temperature adjusting element positioned between the temperature adjustable calibration pad and the component of the vacuum chamber.
5. 5. The system of claim 1, wherein the temperature adjustable calibration pad is coupled to a lower surface of the internal component of the vacuum chamber.
6. 6. The system of claim 1, wherein the temperature adjustable calibration pad is within a field of view of the contactless temperature sensor.
7. 7. The system of claim 6, wherein an upper surface of the temperature adjustable calibration pad is within a field of view of the contactless temperature sensor.
8. 8. The system of claim 1, wherein the contact temperature sensor is coupled to a lower surface of the temperature adjustable calibration pad.
9. 9. The system of claim 1, wherein the internal component of the vacuum chamber to which the temperature adjustable calibration pad is coupled is movable.
10. 10. The system of claim 9, wherein the internal component of the vacuum chamber is configured to move the temperature adjustable calibration pad within a field of view of the contactless temperature sensor.
11. 11. The system of claim 9, wherein the internal component of the vacuum chamber is configured to move the temperature adjustable calibration pad outside a field of view of the contactless temperature sensor.
12. 12. The system of claim 1, wherein the contactless temperature sensor is an infrared (IR) sensor.
13. 13. The system of claim 1, wherein the output signal of the contactless temperature sensor is an electrical signal.
14. 14. A charged particle beam apparatus, comprising: a vacuum chamber configured to provide a vacuum environment; a sample holder located in the vacuum chamber and configured to hold a sample; a calibration pad coupled to an internal component of the vacuum chamber; an IR sensor configured to generate an output signal based on a temperature of the calibration pad; a contact temperature sensor coupled to the calibration pad, wherein the contact temperature sensor is configured to measure a temperature of the calibration pad; and a controller configured to calibrate the IR sensor based on the output signal from the IR sensor and the temperature of the calibration pad determined by the contact temperature sensor.
15. 15. A non- transitory computer readable medium including a set of instructions that is executable by one or more processors of a controller to cause the controller to perform operations for measuring a temperature of a sample in vacuum using a charged particle beam apparatus, the operations comprising: adjusting a temperature of a temperature adjustable calibration pad to a first temperature; collecting a first set of measurements of the temperature adjustable calibration pad at the first temperature using a contact temperature sensor and a contactless temperature sensor; adjusting a temperature of the temperature adjustable calibration pad to a second temperature; collecting a second set of measurements of the temperature adjustable calibration pad at the second temperature using the contact temperature sensor and the contactless temperature sensor; calibrating the contactless temperature sensor; and measuring a temperature characteristic of a sample to be inspected using the calibrated contactless temperature sensor.

Description

IN- VACUUM, IN-SITU WAFER TEMPERATURE MEASURING METHOD AND APPARATUS CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority of US application 63/524,568 which was filed on June 30, 2023 and which is incorporated herein in its entirety by reference. FIELD [0002] The embodiments provided herein disclose a charged particle beam inspection apparatus, and more particularly, a charged particle beam inspection apparatus including a contactless temperature sensor for measuring a temperature of a wafer. BACKGROUND [0003] When manufacturing semiconductor integrated circuit (IC) chips, pattern defects or uninvited particles (residuals) inevitably appear on a wafer or a mask during fabrication processes, thereby reducing the yield. For example, uninvited particles may be troublesome for patterns with smaller critical feature dimensions, which have been adopted to meet the increasingly more advanced performance requirements of IC chips. [0004] Pattern inspection tools with a charged particle beam have been used to detect the defects or uninvited particles. These tools typically employ a scanning electron microscope (SEM). In a SEM, a beam of primary electrons having a relatively high energy is decelerated to land on a sample at a relatively low landing energy and is focused to form a probe spot thereon. Due to this focused probe spot of primary electrons, secondary electrons will be generated from the surface. The secondary electrons may comprise backscattered electrons, secondary electrons, or Auger electrons, resulting from the interactions of the primary electrons with the sample. By scanning the probe spot over the sample surface and collecting the secondary electrons, pattern inspection tools may obtain an image of the sample surface. [0005] During operation of an inspection tool, the wafer is typically held by a wafer stage. The inspection tool may comprise a wafer positioning device for positioning the wafer stage and wafer relative to the e-beam. This may be used to position a target area on the wafer, e.g., an area to be inspected, in an operating range of the e-beam. SUMMARY [0006] The embodiments provided herein disclose a charged particle beam inspection apparatus, and more particularly, a particle beam inspection apparatus including a contact-less temperature sensor for measuring a temperature of a wafer. [0007] Some embodiments provide an in-vacuum temperature measurement system. The in-vacuum temperature measurement system comprises a vacuum chamber, a wafer holder located in the vacuum chamber and configured to hold a wafer, a temperature adjustable calibration pad coupled to an internal component of the vacuum chamber, a contactless temperature sensor configured to generate an output signal based on a temperature of the temperature adjustable calibration pad, a contact temperature sensor coupled to the temperature adjustable calibration pad, wherein the contact temperature sensor is configured to determine a temperature of the temperature adjustable calibration pad, and a controller configured to calibrate the contactless temperature sensor based on the output signal from the contactless temperature sensor and the temperature of the temperature adjustable calibration pad determined by the contact temperature sensor. [0008] In some embodiments, a charged-particle beam apparatus is provided. The charged-particle beam apparatus comprises a vacuum chamber configured to provide a vacuum environment, a sample holder located in the vacuum chamber and configured to hold a sample, a calibration pad coupled to an internal component of the vacuum chamber, an IR sensor configured to generate an output signal based on a temperature of the calibration pad, a contact temperature sensor coupled to the calibration pad, wherein the contact temperature sensor is configured to measure a temperature of the calibration pad, and a controller configured to calibrate the IR sensor based on the output signal from the IR sensor and the temperature of the calibration pad determined by the temperature sensor. [0009] In some embodiments, a non-transitory computer readable medium including a set of instructions that is executable by one or more processors of a controller to cause the controller to perform operations for measuring a temperature of a sample in vacuum using a charged particle beam apparatus is provided. The operations comprise adjusting a temperature of a temperature adjustable calibration pad to a first temperature, collecting a first set of measurements of the temperature adjustable calibration pad at the first temperature using a contact temperature sensor and a contactless temperature sensor, adjusting a temperature of the temperature adjustable calibration pad to a second temperature, collecting a second set of measurements of the temperature adjustable calibration pad at the second temperature using the contact temperature sensor and the contactless temperature sensor, calibrating the co