JPS60201413A - Stage - Google Patents

Abstract

PURPOSE:To correct at a low cost a measuring error caused by a variation of an atmosphere such as a temperature, etc. by providing a means for detecting a temperature of a scale and correcting a temperature error. CONSTITUTION:First of all, when a moving command value of an X table 8 is impressed from a motor driving circuit 20, the X table 8 moves by the command value in the X direction, and this moving extent is measured by detecting heads 10a, 10b through scales 9a, 9b. In this case, a temperature of the scales 9a, 9b is detected by temperature sensors 14a, 14b, respectively, and inputted to correcting circuits 22a, 22b through a scale temperature detecting circuit 21. The correcting circuits 22a, 22b obtain a corrected value from the inputted temperature, and execute an operation by an arithmetic circuit 24 together with a yawing corrected value. Based on this operated value, a correcting circuit 25 drives a piezoelectric element driving circuit 26, and corrects yawing and a temperature by driving devices 19a, 19b.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a stage for transferring a sample or a device.

[Prior art]

Conventionally, this type of device has been used in the X direction and Y direction as shown in FIG.
Optical reflecting mirrors 2 that are orthogonal to each other are mounted on a table 7 that is movable in the direction, and the reflecting mirrors 2 are used as reference surfaces for two laser interferometers 3, and the X and Y coordinates of the table 7 moved are 2, respectively. Measurement was performed using two detectors 4. In the figure, 1 is a laser head, and 5 is a beam splitter for splitting laser light from the laser head 1.

6 is a beam bender for bending the laser beam.

In addition, as a device for measuring the △θ acid component when the table 7 rotates by △θ in the XY plane and yawing occurs, there are two locations for measurement in either the X or Y direction, as shown in Figure 2. Some use laser interferometers.

However, with this type of device that uses a laser interferometer, changes in the temperature, humidity, or air pressure of the air in the area corresponding to the optical path between the reflecting mirror and the interferometer will cause length measurement errors. It is necessary to control the atmosphere of the place where it is installed, which has disadvantages such as increasing the size of the entire device and increasing cost.

〔the purpose〕

The present invention has been made in order to eliminate the drawbacks of the above-mentioned conventional examples, and an object of the present invention is to provide an XY stage that can inexpensively correct length measurement errors due to changes in the atmosphere such as temperature.

〔Example〕

The present invention will be described in detail below with reference to the drawings.

FIG. 3 is a perspective view of one embodiment of the present invention, and FIG. 4 is a block diagram for explaining the operation of the embodiment of FIG.

Scales 9a and 9b are attached to the rectangular X stage 8 in parallel on both side edges in the X direction.
, 9b are each provided with a temperature sensor 14a.

14b (Fig. 4) has been investigated. scale 9a
, 9b are arranged on both side lines of the X stage 80 because it is easier to detect the amount of yawing if the distances are as far apart as possible. The scales 9a and 9b may be of a magnetic type, in which length information is recorded on a magnetic tape, or of an optical type, in which slits are formed to read interference fringes.

Drive devices 19a and 19b (FIG. 4) each using a piezoelectric element are fixed on the lower surface of the X stage 8 in the X direction.
It is slidably in contact with a guide lia extending in the X direction on the stage 11 in the Y direction.

On the rectangular X stage 11, there is an
Guides Ilb and IIC extending parallel to the direction are provided,
Further, a motor 17a is attached to one end in the X direction. Therefore, the X stage 8 moves on the X stage 11 by rotating the guides 11a, Jlb, 11c.
It is configured to function in the direction K f tth ET . Further, magnetic or optical detection heads 10a and 10b are fixed on the X stage 11 to read the scales ga and gb of the X stage 8, respectively, and the amount of movement of the X stage 8 in the X direction with respect to the X stage 11 is fixed. Detected.

On the lower surface of the X stage 8 in the Y direction, like the drive devices 19a and 19b of the X stage 8, there are two drive devices 1.
9C (one not shown) is fixed, and two magnetic or optical detection heads 12a (one not shown) are fixed similarly to the above-mentioned detection heads 10a and 10b. The drive device 19C is slidable on the base fi 16 with respect to a guide 16a extending in the Y direction, as will be described later.
It is in contact with the direction. The detection head 12a is for reading length information of scales 13a and 13b, which are similarly attached to the base 16.

A guide 16 b r 16 C extending in the Y direction, like the guide 16a, is provided on the rectangular substrate 16, and a motor 17b is further attached to one end in the Y direction.

Therefore, the X stage 11, together with the X stage 8,
6 by the rotation of the motor 17b, the guides 16a, ], 6
b, 16CKff are configured to be movable in the Y direction. Magnetic or optical scales 13a, 13b are attached to both edges of the base 16 in the Y direction, similar to the scales 9a, 9b of the X stage 8, and each of the scales 13a, 3b is equipped with a temperature sensor 15a. (
A temperature sensor (not shown) is attached to the scale 131).

FIG. 4 is a block diagram of a circuit for driving and controlling the X table 8 of the embodiment shown in FIG. Since the drive control circuit for the Y table 11 is the same as the block diagram shown in FIG. 4, illustration and explanation of its operation will be omitted.

First, when a command value for the amount of movement X of the X table 8 is applied from the outside to the motor drive circuit 20, the motor 17a drives the X table 8 by X in the X direction in accordance with this command value X. The amount of movement of the X table 8 is determined by scales 9a attached to both side edges thereof.

9b and are measured by detection heads 10a and 10b, respectively. Here, if yawing occurs in the X table 8, the measured values will be different values xai and xb2,
Therefore, the measured movement amounts xaz and xb2 are printed on the first correction circuits 22a and 22b, respectively. Here, the temperatures Ta and Tb of the scales 9a and 9b are detected by temperature sensors 14a and 14b, respectively, and are sent to the first correction circuit 22a+221 via the scale temperature detection circuit 21.
) is entered.

The first correction circuits 22a and 22b take into account the temperature difference and thermal expansion coefficient between the input temperatures Ta and Tb and the scales 9a and 9b, which are guaranteed to have accurate lengths at the time of manufacture, etc., as described above. Correct to correction values xa2 and xb2.

The 29th correction circuits 23a and 23b are provided with each scale 9 in advance.
Mechanical errors such as pitch errors specific to a and 9b are inputted, and therefore, this input value is used to adjust the first correction value Xa2 from the first correction circuit 22a and 22b.
.

Further correct xb2. Second correction circuit 23a, 23b
The second correction value xa3. xba is applied to the arithmetic circuit 24.

Next, the calculation circuit 24 calculates the amount of horizontal rotation (amount of yawing) Δθ of the X table 8. L is the distance between scales 9a and 9b.

The horizontal rotation amount correction signal (△θ) from the arithmetic circuit 24 is
The signal is input to the third correction circuit 25 and the motor drive circuit 20.

The third correction circuit 25 calculates which of the drive devices 19a and 19b to select based on the correction signal (Δθ) and the displacement amount (Y direction) of the selected drive device, and calculates the amount of displacement (Y direction) of the selected drive device, and 26. The piezoelectric element of the selected drive device changes according to the voltage corresponding to /\θ and comes into contact with the guide 11a of the Y table 11, and therefore the X table 8
The amount of yawing is corrected.

As mentioned above (when the rotation direction of the X table 8 is corrected, the X table 8 moves in the X direction and the scale 9
The detected values of a, 9b may change.

In this case, either the detected value of the scale 9a or gb (specifically, the second correction circuit 23a).

23b correction value xa3. xba) For example, using scale 9a as a reference, close loop (20 → 17a
→9a→10a→22a→23a→24→20) By constantly performing the feedback control, the correction operation is automatically performed.

In the above embodiment, a piezoelectric element is used as a drive device to correct the horizontal rotational component, but if air pressure is used as a guide for each stage, the supply pressure of the two air pads at both ends can be changed. It is also possible to correct the horizontal rotation component by doing this. Furthermore, a direct-acting linear motor, a magnetostrictive element, or the like may be used instead of the piezoelectric element.

〔effect〕

As explained above, according to the present invention, length measurement errors due to temperature changes can be corrected at low cost.

[Brief explanation of drawings]

1 and 2 are configuration diagrams of a conventional XY table, FIG. 3 is a perspective view of an embodiment of the present invention, and FIG.
FIG. 3 is an operational block diagram of the stage. 8...X stage 9a19b, 13al13b-X scale 10a,
10b, 12a, ], 2b detection head 11...X stage 14a, 14b, ■5a-tA degree sensor 22a, 22
b...First correction circuit patent applicant Canon Co., Ltd. 9-1 Diagram 2

Claims (1)

[Claims] A stage comprising: a scale for detecting a movement amount; a means for detecting a temperature of the scale; and a means for correcting an error in the scale based on the temperature detected by the temperature detecting means.