JPH05126196A - Damper mechanism - Google Patents

Abstract

PURPOSE:To provide a damper mechanism in which rod volume inside a cylinder is not changed by advance/retraction of a rod. CONSTITUTION:A cylinder is formed by a first member 62 and a second member 64, a double-shaft piston is installed inside the cylinder, and working fluid is filled to provide a damper mechanism 6, where an outer diameter of a disc-like piston 66 is smaller than an inner diameter of the cylinder. The piston has a rod installed to be double shafts to be symmetric. A volume of the piston and the rod inside the cylinder is therefore kept constant regardless of advance/ retraction of the piston. Action of the piston is performed very smoothly, and vibration is absorbed regularly. Possibilities of leak of the working fluid, blowout of the cylinder, etc., are almost completely eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damper mechanism. More specifically, the present invention relates to a damper mechanism suitable for absorbing roll of an air mount system such as an optical surface inspection device.

[0002]

2. Description of the Related Art A damper mechanism is used when intentionally attenuating vibration or mitigating a shock. An example of such a conventionally used damper mechanism is shown in FIG. A piston 106 is provided in a cylinder 104 composed of a container 100 and a lid 102, and the piston is moved up and down (or moved back and forth) by a rod 108. The cylinder is filled with hydraulic oil 110. Due to the relative movement of the piston and the cylinder, the oil inside is configured to move between the upper and lower chambers through a small hole 112 provided in the piston. Container 100 and lid 102 and lid 1
An O-ring 112 is attached to the interface between 02 and the rod 108 in order to prevent leakage of hydraulic oil.

[0003]

In such a damper mechanism, as the rod 108 enters the cylinder, the volume of the rod in the cylinder increases. For this reason, the total volume in the cylinder also increases, and there is no escape area for the hydraulic oil. As a result, vibration absorption may be adversely affected, and in the worst case, a cylinder may burst or hydraulic oil may leak.

Therefore, it is an object of the present invention to provide a damper mechanism in which the rod volume occupied in the cylinder does not change as the rod advances and retracts.

[0005]

In order to achieve the above-mentioned object, in the present invention, a cylinder is formed by a first member and a second member, and a biaxial piston is mounted in the cylinder and an operation is performed. A damper mechanism consisting of being filled with oil is provided.

[0006]

As described above, in the damper mechanism of the present invention, the rods are biaxially attached so that the piston is symmetrical. Therefore, the volume occupied by the piston and the rod in the cylinder is always constant regardless of the advance / retreat of the piston. Therefore, the operation of the piston becomes extremely smooth, and the vibration is regularly absorbed. In addition, there is no risk of hydraulic fluid leakage or cylinder rupture.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the damper mechanism of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway sectional view of an example of the damper mechanism of the present invention. This damper mechanism 6
Is the first member 62 and the screws 63, 6 attached to the first member 62.
It has the 2nd member 64 screwed by 3. First member 6
A hydraulic oil (for example, silicon oil) filling cylinder 65 having a predetermined volume is formed between the second member 64 and the second member 64. The rod 61 is slidably inserted into the shaft holes of the first member 62 and the second member 64. This rod 61
Has a disc-shaped piston 66 in its substantially central portion. A leaf spring 67 is screwed on the tip of the base plate side of the rod with a screw 68. Each end of the leaf spring is fixed to the second member with screws 63, 63. The leaf spring 67 is provided to restore the rod 61 to the base board 4 side when the rod 61 moves to the gantry frame 3 side. In order to prevent leakage of the filled hydraulic oil in the cylinder, an O-ring 69 is provided on the boundary surface of each member.
Are arranged.

This damper mechanism can be fixed to the upper end surface 34 of the gantry frame via the first member 62 with the screw 9, for example. A suitable cushioning material 91 can be arranged between the first member and the gantry frame 3. FIG. 2 is a front view of the damper mechanism of FIG.

The characteristic of this damper mechanism is that the rod is of a double shaft type and there is a gap between the peripheral edge of the disk-shaped piston 66 and the circumference of the cylinder 65. In the case of the conventional uniaxial rod, when the rod enters the cylinder, the volume in the cylinder increases by the amount of the rod that has entered, there is no escape place for the filled hydraulic oil, and there is a risk of breaking the cylinder. Since the damper mechanism of the present invention has both axes, the volume occupied by the rod and the piston in the cylinder is always constant regardless of the direction in which the rod and the piston move. Therefore, there is no risk of cylinder breakage due to the filled hydraulic oil. Further, in the damper mechanism of the present invention,
As shown in FIG. 3, as the disc-shaped piston 66 moves left and right, the filled hydraulic oil can flow through the gap as shown by the dotted line. As a result, the rolling of the object to be buffered (for example, the base board 4) is quickly attenuated.

The damper mechanism of the present invention is suitable for absorbing the rolling of the base board in the air mount system in which the base board having the movable table arranged on the upper surface is supported by the air spring. More specifically, it is particularly suitable as a roll absorbing mechanism in an optical surface inspection apparatus having such an air mount system.

When inspecting a foreign substance or a defect on the surface of an object to be inspected (for example, a wafer), the wafer is adsorbed on a stage and the foreign substance or the defect is detected by the irregular reflection light of the laser while moving in the XY directions. In this case, the stage and the optical system are arranged on the base board, and the base board is supported by the air spring. Therefore, when the XY stage is moved, a low frequency vibration of 3 to 5 Hz is generated with a change in acceleration, which adversely affects the detection. The damper mechanism of the present invention is extremely suitable for absorbing this roll.

FIG. 4 is a schematic sectional view of a usage example of the damper mechanism of the present invention. The illustrated air mount system 1
Has a gantry frame 3. The damper 6 is disposed on the upper end surface 34 of the peripheral portion of the frame. The air spring 5 is fixed to a surface 35 that is recessed at a predetermined depth from the upper end surface 34 of the frame peripheral portion. The air spring 5 supports the base board 4. An X stage 7 and a Y stage 8 are arranged on the upper surface of the base board 4. The X stage 7 can be moved back and forth in the X direction by the drive motor 71. On the other hand, the Y stage 8 can be moved back and forth in the Y direction by the drive motor 81. The wafer 2 is placed on the upper surface of the X stage 7. The X stage can also have a suction mechanism. As a result, the wafer can be held by suction so as not to move. The rod 61 of the damper 6 is in contact with the side wall surface of the base board.

FIG. 5 is a plan view of the air mount system of FIG. The damper 6 is the upper end surface 34 of the peripheral edge of the gantry frame.
The front, rear, left, and right are arranged at approximately equal intervals. As a result, it is possible to eliminate the rolling motion caused by the advance / retreat of either the X stage or the Y stage.

Although an optical system is not shown in FIGS. 4 and 5, if a laser light irradiation system and a scattered light receiving system from an object to be inspected (for example, wafer 2) are added to this system,
An optical surface inspection device is constructed.

The damper mechanism of the present invention is not limited to the optical surface inspection device, but has all the measuring instruments (for example, the flatness measuring device, which has a horizontal moving table on the upper surface and has the possibility of rolling). Ellipsometer) or semiconductor manufacturing equipment (for example, ion implantation equipment, pattern generator, photo repeater, wafer exposure equipment, electron beam drawing equipment, etc.),
Can be used for test equipment.

[0016]

As described above, in the damper mechanism of the present invention, the rods are biaxially attached so that the piston is symmetrical. Therefore, the volume occupied by the piston and the rod in the cylinder is always constant regardless of the advance / retreat of the piston. Therefore, the operation of the piston becomes extremely smooth, and the vibration is regularly absorbed. In addition, there is no risk of hydraulic fluid leakage or cylinder rupture. The damper mechanism of the present invention is particularly useful for absorbing a low frequency vibration (rolling) of 3 to 5 Hz generated by the movement of the moving stage in an air mount system having a moving stage on a base board supported by an air spring. Are suitable.

[Brief description of drawings]

FIG. 1 is a partially cutaway sectional view of an example of a damper mechanism of the present invention.

2 is a front view of the damper mechanism of FIG. 1. FIG.

3 is a partially enlarged sectional view of a cylinder and a piston in the damper mechanism of FIG.

FIG. 4 is a schematic cross-sectional view of an air mount system in which the damper mechanism of the present invention is used.

5 is a plan view of the system of FIG.

FIG. 6 is a schematic sectional view of an example of a conventional damper mechanism.

[Explanation of symbols]

 3 Base Frame 4 Buffered Object (Base Board) 6 Damper Mechanism of the Present Invention 61 Rod 62 First Member 63 Screw 64 Second Member 65 Hydraulic Oil Filling Cylinder 66 Disc-Shaped Piston 67 Leaf Spring 68 Screw 69 O-ring

Claims (2)

[Claims] 1. A cylinder is formed by a first member and a second member, and a biaxial piston is mounted in the cylinder,
A damper mechanism that is filled with hydraulic oil. 2. The damper mechanism according to claim 1, wherein the piston is disk-shaped and has an outer diameter smaller than the inner diameter of the cylinder.