JPH05126973A - Pneumatic mount system - Google Patents

Abstract

PURPOSE:To obtain an optical surface inspection device consisting of a pneumatic mount system which has an absorption mechanism of lateral vibration generated from movement of a traveling stage, and such a newly invented pnuematic mount system, in the pneumatic mount system having the traveling stage on a base table supported by pneumatic springs. CONSTITUTION:In a pneumatic mount system 1 that the base table 4 thereof on an upper surface of which traveling tables 7 and 8 are arranged, is supported by pnuematic springs 5, dumper mechanisms 6 are put tightly to each of at least two mutually facing side wall surfaces of the base table 4. A cylinder is formed by the first member and the second member, a double shaft piston is loaded into the cylinder and also a dumper mechanism of which dumper function comes from working oil filled therein, is used.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an air mount system. More particularly, the present invention relates to an air mount system having a base with greatly reduced roll and a surface inspection apparatus comprising the same.

[0002]

2. Description of the Related Art Printed circuit patterns, semiconductor wafers,
Micro-defects on precision-machined surfaces such as photomasks and magnetic disks (for example, foreign matter, pattern breaks, shorts, protrusions,
Visual inspections for cracks, other scratches, pinholes, etc.) have hitherto relied on visual inspection, but there is the problem that it is difficult to obtain stable standards for inspection results, as well as securing and training inspectors. Further, with the recent increase in the density of patterns and / or the higher density (higher integration) of electronic technology, the demand for quality has become more and more strict. In particular, foreign matter control in the semiconductor manufacturing process is important, and very strict control is required.

In order to solve this problem, an apparatus for automatically inspecting the surface with a laser beam is used instead of the conventional visual inspection. Such an optical surface inspection device is a precise structure, and vibration is strictly prohibited. Therefore, the entire apparatus is used by mounting it on a vibration isolation frame, for example, an air mount system.

FIG. 6 is a partially cutaway schematic perspective view showing an example of such an air mount system. FIG. 7 is a partially enlarged cross-sectional view showing how the air spring is attached. The air mount system 10 is configured by attaching a base board 4 to a rectangular frame 3 via four air springs 5, and supports an optical surface inspection device mounted on the base board by vibration isolation. To do. Explaining the structure of the air mount system in detail, each air spring is attached to the fixing plate 31 provided on the upper surface of the square pipe 32 that constitutes the frame, and the fixing bolt 3 is attached.
It is fixed using 3 and 4 of the mounting holes 41 at the 4 corners of the frame
The head is fixed to the base board by the fixing bolts 43 arranged at a certain position. The base board 4 is made of cast metal or marble, and reinforcing ribs are provided in parallel on the lower surface, and each air spring is interposed between the ribs. FIG. 8 is a perspective view of the air spring. The bottom plate 51 has mounting portions 52 in four symmetrical directions.
Further, bolt holes 53 are provided in the head respectively. Here, the vibration damping effect of the base board will be described. The base board is made of cast or marble to make it heavy, and an air spring is also used to provide the vibration damping effect.

[0005]

When inspecting foreign matters or defects on the surface of an object to be inspected (for example, a wafer), the wafer is adsorbed on a stage and moved in the XY directions by the irregular reflection light of the laser. Or detect a defect. 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. For this reason, when the XY stage is moved, it is 3 to 5 Hz due to a change in acceleration.
The low frequency vibration of the was generated and had a bad influence on the detection.

Therefore, it is an object of the present invention to provide an air mount system having a moving stage on a base plate supported by an air spring, and having a mechanism for absorbing a lateral vibration generated by the movement of the moving stage. Another object of the present invention is to provide an optical surface inspection apparatus including such a novel air mount system.

[0007]

In order to achieve the above object, the present invention provides an air mount system in which a base plate having a moving table disposed on its upper surface is supported by an air spring, and at least the base plate is provided. Provided is an air mount system, wherein damper mechanisms are respectively brought into contact with two opposing side wall surfaces. Further, the present invention is an optical surface inspection apparatus having a base board supported by an air spring fixed to a gantry frame, and an XY stage mounted on the base board,
The base board is provided with a surface inspection apparatus in which dampers are in contact with side wall surfaces of the base board from four directions of front, rear, left and right.

[0008]

As described above, in the surface inspection apparatus of the present invention, since the damper is in contact with the base board in the left-right direction, the X-
Low-frequency vibrations (horizontal vibrations) of 3 to 5 Hz that occur with the movement of the Y stage are absorbed by this damper and reduced or eliminated. As a result, the reliability of the inspection result can be improved.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the air mount system of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of an example of the air mount system of the present invention. In the air mounting system of the present invention, the same members as those in the conventional air mounting system use the same reference numerals. The air mount system 1 of the present invention has a gantry frame 3. The damper 6 is disposed on the upper end surface 34 of the peripheral portion of the frame. Frame peripheral edge upper end surface 34
The air spring 5 is fixed to the surface 35 that is recessed at a predetermined depth from. 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. 2 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. 1 and 2, 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 itself is a member known to those skilled in the art.
However, an air mount system and an optical surface inspection device having a damper as a roll preventing means for such a base board have not yet been known to those skilled in the art. A device has been proposed that absorbs lateral vibration by causing a reaction in the opposite direction with a piezo element or the like, but it is not easy to absorb lateral vibration because the device becomes large and electrical control is involved. The damper itself is small in size, and moreover, it is possible to surely absorb the rolling.

FIG. 3 shows an example of a damper mechanism suitable for use in the air mount system of the present invention. The damper mechanism 6 includes a first member 62 and a second member 64 screwed to the first member 62 with screws 63, 63. First
A working oil (for example, silicon oil) filling cylinder 65 having a predetermined volume is formed between the member 62 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. The rod 61 has a disk-shaped piston 66 in the 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 has six rods.
It is provided to restore 1 to the base board side when 1 moves to the gantry frame side. In order to prevent leakage of the filled hydraulic oil in the cylinder, an O-ring 6 is provided on the boundary surface of each member.
9 are provided. This damper mechanism is, for example, a screw 9
The upper end surface 3 of the gantry frame via the first member 62.
It can be fixed to 4. A suitable cushioning material 91 can be arranged between the first member and the gantry frame 3. FIG. 5 is a front view of the damper mechanism of FIG. 3 of FIG. 4. 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. 5, as the disc-shaped piston 66 moves left and right, the filled hydraulic oil can flow through the gap as indicated by the dotted line. As a result, the roll of the base board is quickly attenuated.

The air mount system having the damper mechanism of the present invention is not limited to the optical surface inspection apparatus, but has a horizontal moving table on the upper surface and all measuring instruments (for example, a flat surface) having a possibility of rolling. It can be used for a degree measuring device, an ellipsometer), a semiconductor manufacturing device (for example, an ion implantation device, a pattern generator, a photo repeater, a wafer exposure device, an electron beam drawing device, etc.) and a testing device.

[0015]

As described above, the air mount system of the present invention symmetrically abuts at least two damper mechanisms on the side wall of the base board. For this reason, the rolling mechanism is disposed on the base board, and the lateral vibration generated when the moving stage is moved is quickly absorbed by the damper mechanism. Therefore, if such an air mount system is used in an optical surface inspection device, the inspection accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of an example of an air mount system of the present invention.

2 is a plan view of the air mount system of FIG. 1. FIG.

FIG. 3 is a partial cutaway sectional view of an example of a damper mechanism suitable for use in the air mount system of the present invention.

FIG. 4 is a front view of the damper mechanism of FIG.

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

FIG. 6 is a partial cutaway schematic perspective view of an example of a conventional air mount system.

7 is a partial enlarged cross-sectional view showing how the air spring of the air mount system shown in FIG. 6 is attached.

FIG. 8 is a schematic perspective view of an air spring.

[Explanation of symbols]

 1 Air Mount System of the Present Invention 2 Wafer 3 Frame Frame 4 Base Board 5 Air Spring 6 Damper Mechanism 7 X Stage 8 Y Stage

Claims (4)

[Claims] 1. An air mount system in which a base plate having a moving table disposed on an upper surface thereof is supported by an air spring, and damper mechanisms are respectively brought into contact with at least two opposing side wall faces of the base plate. An air mount system that is characterized by 2. A cylinder is formed by the first member and the second member, and a biaxial piston is mounted in the cylinder,
The air mount system according to claim 1, wherein a damper mechanism consisting of being filled with hydraulic oil is used. 3. An optical surface inspection apparatus having a base board supported by an air spring fixed to a gantry frame, and an XY stage disposed on the base board.
The surface inspection apparatus, wherein a damper mechanism is in contact with the side wall surface of the base board from four directions of front, rear, left and right. 4. A cylinder is formed by the first member and the second member, and a biaxial piston is mounted in the cylinder,
The surface inspection apparatus according to claim 3, wherein a damper mechanism that is filled with hydraulic oil is used.