System and method for calibrating charge-regulating module
This invention provides a system and a method for calibrating charge-regulation module in vacuum environment. Means for mounting the charge-regulation module provides motions to the charge-regulation module such that a beam spot, illuminated by the charge-regulation module, on a sample surface can be moved to a pre-determined position which is irradiated by a charged particle beam.
1. A system for calibrating a charge-regulating module, comprising:
means for mounting a Laser and providing motions to move the Laser, wherein the Laser illuminates a beam on a surface of a sample with a beam spot thereon, and regulates charges on the sample surface;
a detector for receiving a reflected beam from the beam spot on the sample surface;
a controller, coupled to the detector, for receiving signals from the detector, calculating a position of the beam spot, and controlling the beam spot to a pre-determined location; and
a transmission, coupled to the controller, and driving the mounting means such that the beam spot is moved to the pre-determined location.
2. The system of claim 1 , wherein the mounting means is fastened to an objective lens of a charged particle beam tool, and the pre-determined location is irradiated by a charged particle beam of the charged particle beam tool.
3. The system of claim 2 , wherein the charged particle beam tool is an ebeam inspection tool.
4. The system of claim 3 , wherein the sample is a wafer or a mask.
5. The system of claim 4 , wherein the mounting means includes a first motor for driving the Laser with a rotational motion, and a second motor for driving the Laser with a vertical motion.
6. The system of claim 5 , wherein the transmission is a hollow rod within wires for providing powers and instructions to the first and second motors.
7. The system of claim 4 , wherein the mounting means is a C-shape mount and the Laser is fastened thereto.
8. The system of claim 7 , wherein the transmission includes a rotation-to-translation means.
9. The system of claim 8 , wherein the transmission includes a carved body fastened to the rotation-to-translation means and engaged to the C-shape mount.
10. The system of claim 9 , wherein a portion of the C-shape mount is engaged with the carved body.
11. The system of claim 10 , wherein the portion of the C-shape mount is forced to distort in vertical motion and the portion of the C-shape mount is forced to expand with horizontal motion.
12. An ebeam inspection tool, comprising:
an electron tip for providing an electron source;
an anode for extracting the electron source as a primary electron beam;
a condenser lens for condensing the primary electron beam;
a magnetic objective lens for focusing the primary electron beam on a surface of a sample;
a charge-regulation module, fastened to the magnetic objective lens, for regulating charges on the sample surface; and
a system for calibrating the charge-regulation module, includes:
means for mounting the charge-regulation module and providing motions to move the charge-regulation module, wherein the charge-regulation module illuminates a beam on a surface of a sample with a beam spot thereon;
a detector for receiving a reflected beam from the beam spot on the sample surface;
a controller, coupled to the detector, for receiving signals from the detector, calculating a position of the beam spot, and controlling the beam spot to a pre-determined location; and
a transmission, coupled to the controller, and driving the mounting means such that the beam spot is moved to the pre-determined location.
13. The ebeam inspection tool of claim 12 , wherein the sample is a wafer or a mask.
14. The ebeam inspection tool of claim 13 , wherein the mounting means includes a first motor for driving the charge-regulation module with a rotational motion, and a second motor for driving the charge-regulation module with a vertical motion.
15. The ebeam inspection tool of claim 14 , wherein the transmission is a hollow rod within wires for providing powers and instructions to the first and second motors.
16. The ebeam inspection tool of claim 13 , wherein the mounting means is a C-shape mount and the charge-regulation module is fastened thereto.
17. The ebeam inspection tool of claim 16 , wherein the transmission includes a rotation-to-translation means.
18. The ebeam inspection tool of claim 17 , wherein the transmission includes a carved body fastened to the rotation-to-translation means and engaged to the C-shape mount.
19. The ebeam inspection tool of claim 18 , wherein a portion of the C-shape mount is engaged with the carved body.
20. The ebeam inspection tool of claim 19 , wherein the portion of the C-shape mount is forced to distort in vertical motion and the portion of the C-shape mount is forced to expand with horizontal motion.
21. A method for calibrating a charge-regulation module under vacuum environment, comprising:
providing a beam on a surface of a sample by the charge-regulation module to form a beam spot on the surface, wherein the beam spot regulates charges on the sample surface;
detecting a location of the beam spot according to a reflection of the beam from the sample surface;
calculating a pre-determined position of a charged particle beam on the surface; and
driving the charge-regulation module such that the beam spot moves to the pre-determined position.