Active damper for semiconductor metrology and inspection systems

Patent metadata

Field	Value
Publication number	US-11280381-B2
Application number	US-201916422511-A
Country	US
Kind code	B2
Filing date	May 24, 2019
Priority date	May 24, 2019
Publication date	Mar 22, 2022
Grant date	Mar 22, 2022

Abstract

A damper for a semiconductor metrology or inspection system includes a pair of parallel plates with a fluid with a variable viscosity retained between plates. At least one wire is disposed between the plates, which may include one or more sets of lands and grooves. In some implementations, both plates include intermeshed lands and grooves. A controller is configured to provide a current to the at least one wire in order to adjust an electromagnetic field or a current through the fluid. The fluid may be a magnetorheological fluid or an electrorheological fluid in which the viscosity of the fluid is variable based on the electromagnetic field or current through the fluid. The controller varies the current applied to the wire to adjust the viscosity of the fluid to alter the damping of the semiconductor metrology or inspection system based on movement of the stage.

First claim

What is claimed is:

1. A damper for a semiconductor metrology or inspection system, the damper comprising
a first plate having a first surface that extends along a first plane;
a second plate having a second surface that extends along a second plane that is parallel with the first plane, wherein one of the first plate and the second plate is configured to be mounted to the semiconductor metrology or inspection system;
at least one wire disposed between the first plate and the second plate;
a fluid with a viscosity that is variable and is retained between the first plate and the second plate, wherein the at least one wire is disposed between the fluid and at least one of the first plate and the second plate; and
a controller coupled to the at least one wire and configured to provide a current to the at least one wire between the fluid and the at least one of the first plate and the second plate to alter the viscosity of the fluid to adjust an amount of damping provided to the semiconductor metrology or inspection system.

2. The damper of claim 1 , further comprising:
a passive isolation mount configured to be mounted to the semiconductor metrology or inspection system.

3. The damper of claim 2 , wherein the passive isolation mount and the one of the first plate and the second plate are configured to be both mounted between the semiconductor metrology or inspection system and a frame or ground, and wherein the passive isolation mount supports the semiconductor metrology or inspection system.

4. The damper of claim 2 , wherein the passive isolation mount comprises a spring mount, an elastomer mount, or an air isolator.

5. The damper of claim 1 , wherein the controller is configured to increase the amount of damping while a stage in the semiconductor metrology or inspection system is moving and to decrease the amount of damping while the stage is not moving.

6. The damper of claim 1 , further comprising a sidewall around the first plate and the second plate and retaining the fluid.

7. The damper of claim 6 , wherein the sidewall is flexible and is connected between the first plate and the second plate.

8. The damper of claim 1 , wherein the fluid comprises an electrorheological fluid or a magnetorheological fluid.

9. The damper of claim 1 , wherein the first plate includes a first set of lands and grooves in the second surface.

10. The damper of claim 9 , wherein the at least one wire is disposed in the grooves of the first set of lands and grooves.

11. The damper of claim 9 , wherein the second plate includes a second set of lands and grooves in the second surface.

12. The damper of claim 11 , wherein the lands from the first set of lands and grooves fit within the grooves of the second set of lands and grooves and the lands from the second set of lands and grooves fit within the grooves of the first set of lands and grooves.

13. The damper of claim 9 , wherein the first set of lands and grooves in the first surface extend in one of a spiral shape, a plurality of concentric circles or lines across the first surface.

14. The damper of claim 1 , wherein the damper provides damping to the semiconductor metrology or inspection system with six-degrees-of-freedom.

15. A method of controlling damping vibration of a semiconductor metrology or inspection system, the method comprising:
providing a first plate having a first surface that extends along a first plane, and a second plate having a second surface that extends along a second plane that is parallel with the first plane, wherein one of the first plate and the second plate is mounted to the semiconductor metrology or inspection system, with at least one wire disposed between the first plate and the second plate and a fluid with a viscosity that is variable retained between the first plate and the second plate, wherein the at least one wire is disposed between the fluid and at least one of the first plate and the second plate;
increasing a current in the at least one wire between the fluid and the at least one of the first plate and the second plate to increase the viscosity of the fluid between the first plate and the second plate to increase an amount of damping provided to the semiconductor metrology or inspection system; and
decreasing the current in the at least one wire between the fluid and the at least one of the first plate and the second plate to decrease the viscosity of the fluid between the first plate and the second plate to decrease the amount of damping provided to the semiconductor metrology or inspection system.

16. The method of claim 15 , wherein the first plate includes a first set of lands and grooves in the first surface.

17. The method of claim 16 , wherein the at least one wire is disposed in the grooves of the first set of lands and grooves.

18. The method of claim 16 , wherein the second plate includes a second set of lands and grooves in the second surface.

19. The method of claim 18 , wherein the lands from the first set of lands and grooves fit within the grooves of the second set lands and grooves and the lands from the second set of lands and grooves fit within the grooves of the first set of lands and grooves.

20. The method of claim 16 , wherein the first set of lands and grooves in the first surface extend in one of a spiral shape, a plurality of concentric circles or lines across the first surface.

21. The method of claim 15 , wherein damping in the semiconductor metrology or inspection system has six-degrees-of-freedom.

22. The method of claim 15 , wherein decreasing the current in the at least one wire comprises providing no current to the at least one wire.

23. The method of claim 15 , wherein the current in the at least one wire produces a magnetic field and the fluid comprises a magnetorheological fluid.

24. The method of claim 15 , wherein the current in the at least one wire produces a current through the fluid and the fluid comprises an electrorheological fluid.

25. The method of claim 15 , supporting the semiconductor metrology or inspection system with a passive isolation mount mounted between the semiconductor metrology or inspection system and a frame or ground.

26. The method of claim 15 , wherein the semiconductor metrology or inspection system comprises a stage that moves, wherein increasing the current in the at least one wire to increase the viscosity of the fluid between the first plate and the second plate to increase the amount of damping provided to the semiconductor metrology or inspection system is performed during movement of the stage in the semiconductor metrology or inspection system;
and wherein decreasing the current in the at least one wire to decrease the viscosity of the fluid between the first plate and the second plate to decrease the amount of damping provided to the semiconductor metrology or inspection system is performed when there is no movement of the stage.

27. The method of claim 26 , wherein the movement of the stage produces relative movement between a sample and an optical system of the semiconductor metrology or inspection system.

28. The method of claim 26 , wherein the movement of the stage is to move a sample to an unload position, the method further comprising:
unloading the sample from the stage of the semiconductor metrology or inspection system;
loading a new sample onto the stage of the semiconductor metrology or inspecti

Assignees

• Onto Innovation Inc

Inventors

• Doyle Paul A
• Franceschi Mark James
• Crouch Morgan A
• James Kenneth E

Classifications

• F16F9/535

  Magnetorheological [MR] fluid dampers (springs comprising magnetorheological [MR] elastomers F16F1/361) · CPC title

• F16F15/027 Primary

  comprising control arrangements {(F16F15/0237 takes precedence)} · CPC title

• G01N21/9501

  Semiconductor wafers (manufacturing processes per se of semiconductor devices implementing a measuring step H10P74/20) · CPC title

• F16F9/532 Primary

  Electrorheological [ER] fluid dampers · CPC title

• G01R31/2865

  Holding devices, e.g. chucks; Handlers or transport devices (having contacts G01R31/2863) · CPC title