Advanced load port for photolithography mask inspection tool

Patent metadata

Field	Value
Publication number	US-11592754-B2
Application number	US-202117478300-A
Country	US
Kind code	B2
Filing date	Sep 17, 2021
Priority date	Apr 22, 2021
Publication date	Feb 28, 2023
Grant date	Feb 28, 2023

Abstract

A method and a system for inspecting an extreme ultra violet mask and a mask pod for such masks is provided. An EUV mask inspection tool inspects a mask retrieved from a mask pod placed on the load port positioned exterior of the mask inspection tool. The inspection process is performed during a selected period of time. After the inspection process is initiated, a robotic handling mechanism such as a robotic arm or an AMHS picks up the mask pod and inspects the mask pod for foreign particles. A mask pod inspection tool determines whether the mask pod needs cleaning or replacing based on a selected swap criteria. The mask pod is retrieved from the mask pod inspection tool and placed on the load port before the selected period of time lapses. This method and system promotes a reduction in the overall time required for inspecting the mask and the mask pod.

First claim

What is claimed is:

1. A method comprising:
placing a mask pod including a photolithography mask on a load port of a mask inspection tool, the load port coupled to an exterior of the mask inspection tool;
removing the mask from inside the mask pod;
providing the removed mask to the mask inspection tool;
inspecting the mask within the mask inspection tool for a selected period of time;
retrieving the mask pod during the selected period of time;
inspecting the mask pod during the selected period of time;
determining whether the mask pod meets a selected swap criteria during the selected period of time;
in response to determining that the mask pod fails to meet the selected swap criteria, swapping the mask pod with a new mask pod that meets the selected swap criteria before the selected period of time lapses;
placing the new mask pod on the load port of the mask inspection tool;
removing the mask from the mask inspection tool; and
placing the mask inside the new mask pod.

2. The method of claim 1 , wherein determining whether the mask pod meets a selected swap criteria includes:
determining an accumulated operation time period of the mask pod; and
comparing the accumulated operation time period of the mask pod with a swap threshold time period of the mask pod.

3. The method of claim 2 , wherein in response to determining that the mask pod fails to meet the selected swap criteria, swapping the mask pod with a new mask pod that meets the selected swap criteria before the selected period of time lapses includes:
determining the swap threshold time period is less than the accumulated operation time period of the mask pod.

4. The method of claim 1 , wherein determining whether the mask pod meets a selected swap criteria includes:
determining an accumulated operation number of the mask pod; and
comparing the accumulated operation number of the mask pod with a swap threshold operation number of the mask pod.

5. The method of claim 4 , wherein in response to determining that the mask pod fails to meet the selected swap criteria, swapping the mask pod with a new mask pod that meets the selected swap criteria before the selected period of time lapses includes:
determining the swap threshold operation number being less than the accumulated operation number of the mask pod.

6. The method of claim 1 , wherein determining whether the mask pod meets a selected swap criteria includes:
determining a concentration rate of particles on a surface of the mask pod; and
comparing the concentration rate of particles on a surface of the mask pod with a swap threshold concentration rate of the mask pod.

7. The method of claim 6 , wherein in response to determining that the mask pod fails to meet the selected swap criteria, swapping the mask pod with a new mask pod that meets the selected swap criteria before the selected period of time lapses includes:
determining the swap threshold concentration rate being less than the concentration rate of particles on the surface of the mask pod.

8. The method of claim 7 , wherein the mask pod includes an inner pod and an outer pod housing the inner pod, the inner pod configured to house the mask, and
wherein the surface of the mask pod includes surfaces of the inner pod and the outer pod of the mask pod.

9. A method comprising:
placing a mask pod including a photolithography mask on a load port of a mask inspection tool, the load port coupled to an exterior of the mask inspection tool;
removing the mask from inside the mask pod;
providing the removed mask to the mask inspection tool;
inspecting the mask within the mask inspection tool for a selected period of time;
retrieving the mask pod during the selected period of time;
inspecting the mask pod during the selected period of time;
determining whether the mask pod meets a selected swap criteria during the selected period of time;
in response to determining that the mask pod meets the selected swap criteria, placing the inspected mask pod on the load port of the mask inspection tool before the selected period of time lapses;
removing the mask from the mask inspection tool; and
placing the mask inside the mask pod.

10. The method of claim 9 , wherein determining whether the mask pod meets a selected swap criteria includes:
determining an accumulated operation time period of the mask pod; and
comparing the accumulated operation time period of the mask pod with a swap threshold time period of the mask pod.

11. The method of claim 10 , wherein in response to determining that the mask pod meets the selected swap criteria, placing the inspected mask pod on the load port of the mask inspection tool before the selected period of time lapses includes:
determining the swap threshold time period is greater than the accumulated operation time period of the mask pod.

12. The method of claim 9 , wherein determining whether the mask pod meets a selected swap criteria includes:
determining an accumulated operation number of the mask pod; and
comparing the accumulated operation number of the mask pod with a swap threshold operation number of the mask pod.

13. The method of claim 12 , wherein in response to determining that the mask pod meets the selected swap criteria, placing the inspected mask pod on the load port of the mask inspection tool before the selected period of time lapses includes:
determining the swap threshold operation number being greater than the accumulated operation number of the mask pod.

14. The method of claim 9 , wherein determining whether the mask pod meets a selected swap criteria includes:
determining a concentration rate of particles on a surface of the mask pod; and
comparing the concentration rate of particles on a surface of the mask pod with a swap threshold concentration rate of the mask pod.

15. The method of claim 14 , wherein in response to determining that the mask pod meets the selected swap criteria, placing the inspected mask pod on the load port of the mask inspection tool before the selected period of time lapses includes:
determining the swap threshold concentration rate being greater than the concentration rate of particles on the surface of the mask pod.

16. The method of claim 15 , wherein the mask pod includes an inner pod and an outer pod housing the inner pod, the inner pod configured to house the mask, and
wherein the surface of the mask pod includes surfaces of the inner pod and the outer pod of the mask pod.

17. A system comprising:
a photolithography mask inspection tool configured to inspect one or more surfaces of a photolithography mask during a selected period of time;
a load port coupled to an exterior of the mask inspection tool;
a mask pod including an inner pod and an outer pod housing the inner pod, the inner pod configured to house the photolithography mask;
a mask pod inspection tool;
an automatic transport tool;
a processor configured to control a swap operation of the mask pod, the processor being operatively coupled to the photolithography mask inspection tool, the mask pod inspection tool, and the automatic transport tool, the processor further configured to:
provide a signal which causes the automatic transport tool to place the mask pod including the mask on the load port of the photolithography mask inspection tool;
provide a signal which causes the automatic transport tool to obtain the mask from inside the mask pod resulting in an empty mask pod;
provide a signal which causes the automatic transport tool to place the obtained mask inside the photolithography mask inspection tool;

Assignees

• Taiwan Semiconductor Mfg Co Ltd
• Taiwan Semiconductor Mfg Co Ltd

Inventors

• Chang Tung-Jung
• Chung Jen-Yang
• Chang Han-Lung

Classifications

• H10P72/0604 Primary

  Process monitoring, e.g. flow or thickness monitoring · CPC title

• G03F1/84 Primary

  Inspecting · CPC title

• G03F7/70741

  Handling masks outside exposure position, e.g. reticle libraries · CPC title

• G03F1/66

  Containers specially adapted for masks, mask blanks or pellicles; Preparation thereof · CPC title

• G03F7/70608 Primary

  Monitoring the unpatterned workpiece, e.g. measuring thickness, reflectivity or effects of immersion liquid on resist · CPC title