JPH07307270A - Projection magnification adjusting device and projection exposure device - Google Patents

Abstract

PURPOSE:To enable movement and control with high accuracy at a place to be corrected of a lens for adjusting the projection magnification of a projection exposure device, and to enable stable correction extending over a prolonged term. CONSTITUTION:Detectors 16, 17 detecting the movement start point and movement end point of a lens moving body 6 for moving a lens 1 in the direction of an optical axis for adjusting projection magnification respectively are mounted, the change with time of the movement of the lens moving body 6 between the detectors 16, 17 is detected by comparing the change with time with a reference value previously stored in a storage device, and the required time of the correction of the absolute place of a movement reference needing operation, in which a pattern is transferred actually on a wafer, is decided on the basis of the result of the detection.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection magnification adjusting apparatus and a projection exposure apparatus having the same, and more particularly to a projection magnification adjusting apparatus for a projection exposure apparatus for semiconductor manufacturing.

[0002]

2. Description of the Related Art As disclosed in, for example, Japanese Patent Laid-Open No. 62-32613, in a projection exposure apparatus for semiconductor manufacturing, the focus position is adjusted by changing the distance between the projection optical system and the exposed wafer. It is well known that a predetermined specific lens of the lens group of the projection optical system is driven in the optical axis direction by a necessary movement amount to adjust the projection magnification.

By the way, as shown in the publication,
The focus position and projection magnification of the projection optical system (lens) are temperature,
It changes depending on the environmental conditions such as humidity and atmospheric pressure. The reason is that the refractive index of air changes due to changes in each environmental condition, the relative refractive index of glass that is a constituent member of the projection lens changes, the optical characteristics of glass change with temperature, and the lens changes with temperature. This is because the lens barrel thermally expands or contracts and the air gap changes.

The standard temperature is T ₀ [° C.] and the humidity is R
₀ [%] and atmospheric pressure are P ₀ [hpa], and the amounts of change from the standard state are ΔT [° C.] and ΔR, respectively.
Assuming [%] and ΔP [hpa], the amount of focus position change ΔZ (focus position correction amount) and the amount of magnification change ΔM (magnification correction amount) from the standard state of the projection lens optical system are as follows with k11 to k23 as constants. Is asked.

ΔZ = k11ΔT + k12ΔR + k13ΔP (1) ΔM = k21ΔT + k22ΔR + k23ΔP (2)

Further, when the position of at least one correction lens in the projection lens is changed in the optical axis direction, the air gap changes, so that the focus position and projection magnification of the projection lens in the projection exposure apparatus can be adjusted. . For example, when the amount of displacement of the correcting lens from the standard position is ΔX, the amount of change in focal position ΔZ and the amount of change in projection magnification ΔM are k14 and k24.
Is calculated as a constant as follows.

ΔZ = k14ΔX (3) ΔM = k24ΔX (4)

From the equations (1) to (4), the change amounts of temperature, humidity and atmospheric pressure with respect to the standard state are ΔT [° C.] and ΔR, respectively.
In the case of [%] and ΔP [hpa], if the displacement amount of the projection lens from the standard state is ΔX, the focal position shift amount ΔZ
Is the sum of the right sides of equations (1) and (3), and the magnification change amount ΔM is the sum of the right sides of equations (2) and (4). That is, ΔZ = k11ΔT + k12ΔR + k13ΔP + k14ΔX (5) ΔM = k21ΔT + k22ΔR + k23ΔP + k24ΔX (6) In order to make the magnification change amount ΔM zero, ΔM = 0 in the equation (6), ΔX is obtained by the following equation (7), and the correction lens is displaced from the standard position by that amount.

ΔX = − (k21 / k24) ΔT− (k22 / k24) ΔR− (k23 / k24) ΔP (7) At this time, the focal position shift amount ΔZ is expressed by the formula (7) and the formula (6). Substituting into ΔZ = (k11− (k14k21 / k24)) ΔT + (k12− (k14k22 / k24)) ΔR + (k13− (k14k23 / k24)) ΔP ・ ・ ・ (8) The focus position is corrected by the amount ΔZ.

In the projection exposure apparatus, the temperature T [° C.], the humidity R [%] and the atmospheric pressure P [hpa] around the projection lens are detected, and the change amount from each standard value is ΔT = T−T ₀ ,
It is calculated by ΔR = R−R ₀ and ΔP = P−P ₀ . Furthermore,
ΔX is calculated according to the equation (7), and the lens position is adjusted so that the displacement amount of the correction lens becomes ΔX. As a result, the change in magnification of the projection lens is maintained at zero. Also,
The correction is performed by calculating ΔZ according to the equation (8) and giving a drive command to the focus system to maintain the position of the best focus of the projection lens.

[0011]

When a projection lens having such a correction function is incorporated in a projection exposure apparatus to correct the projection magnification and the focus position, the temperature, humidity, and
Measure the amount of change in atmospheric pressure from at least one standard state, calculate the amount of movement from the standard position of the lens and focus system required for magnification and focus correction, and drive the lens and focusing system for correction. There is a need to do.

At this time, if there is no means for detecting the standard position of the correction lens with high accuracy and moving the lens with high accuracy, the lens cannot be correctly driven to the correction position calculated above, and If the detection accuracy of the standard position is poor, or if the detection position changes over time, it causes a magnification and focus correction error.

Conventionally, a lens is moved to a standard position by a mechanical method in which a lens barrel that moves integrally with the lens is brought into close contact with a reference surface. However, in this method, if the surface accuracy and parallelism of the end surface of the lens barrel and the reference surface are not very high, the lens and lens barrel will tilt with respect to the optical axis when the lens is moved to the standard position, and the exposure accuracy will increase. Had a negative effect on.

Further, if there is a difference between the height of the reference surface with which the lens barrel is in close contact with the ideal height that should be due to the accuracy of the reference surface mounting, etc., it has been a factor of correction error. Alternatively,
Provide a sensor that detects the standard position of the lens or lens barrel,
There is also a method of setting the standard position at the detection position of the sensor, but the detection position of the sensor changes over time during long-term use, and the standard position also changes accordingly, causing a correction error. was there.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to enable highly accurate movement control of a projection magnification adjusting lens to a position to be corrected and to perform stable correction for a long period of time. It is an object of the present invention to provide a projection magnification adjusting device and a projection exposure apparatus having the same.

[0016]

To achieve the above object, the present invention provides a projection magnification for adjusting the projection magnification of the projection optical system by moving a part of the projection optical system along the optical axis direction thereof. In the adjustment device, a moving member (lens moving body or lens driving body) that moves together with a part of the projection optical system, and a start point detector (lower sensor) that non-contact detects that the moving member is at the movement start point position. An end point detector (upper sensor) for non-contact detecting that the moving member is at the movement end point position, and a storage unit (storage device) for storing a reference distance between the movement start point position and the movement end point position. Control means (arithmetic unit) for controlling the movement of the moving member so that the movement amount of the moving member from the movement starting point position becomes equal to a command value when adjusting the projection magnification of the projection optical system.
And a movement amount when the movement member is moved from one of the movement start point position and the movement end point position to the other and the reference distance, thereby comparing the magnification adjustment amount of the projection optical system and the movement of the movement member. It is characterized in that it has a judging means (calculator) for judging whether or not the relationship with the movement amount from the starting point position is within a predetermined range.

In order to achieve the above-mentioned object, the present invention is a projection exposure apparatus for projecting a pattern previously formed on an original plate onto a substrate through a projection optical system, and adjusting the projection magnification of the projection optical system. A moving member (a lens moving body or a lens driving body) that moves together with a part of the projection optical system when moving, and a start-point detector (lower sensor) that non-contact detects that the moving member is at the movement start-point position. An end point detector (upper sensor) that non-contact detects that the moving member is at the movement end point position, and a storage unit (storage device) that stores a reference distance between the movement start point position and the movement end point position.
A control means (calculator) for controlling the movement of the moving member so that the movement amount of the moving member from the movement starting point position becomes equal to a command value; and one of the movement starting point position and the movement ending point position. Whether the relationship between the amount of magnification adjustment of the projection optical system and the amount of movement of the moving member from the movement start point position is within a predetermined range by comparing the amount of movement when the moving member is moved to the other side with the reference distance. It is characterized by having a judging means (arithmetic unit) for judging whether or not it is.

In each of the above inventions, it is desirable that the control means and the determination means be used by an arithmetic unit. Further, the arithmetic unit controls a pulse motor and calculates the movement amount of the moving member based on the number of pulses added to the pulse motor, or the arithmetic unit controls a DC motor with an encoder. The moving amount of the moving member is calculated based on the output of the encoder, or the computing unit calculates the moving amount of the moving member based on the output of a movement measurement sensor provided for the moving member. It may be one. The moving member is preferably one of a lens moving body that moves integrally with a part of the projection optical system and a lens driving body that moves the lens moving body.

Further, in each of the above inventions, an environment measuring device for measuring at least one of atmospheric pressure, temperature and humidity around the projection optical system is further provided, and the command value is output to the environment measuring device. You may make it based on this.

[0020]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 shows an embodiment of a projection magnification adjusting apparatus of the present invention, in which A is a plan view and B is a plan view.
FIG. 4 is a sectional view taken along the line CC of FIG. The main structure of this embodiment is described in Japanese Patent Application No. 5-374 filed by the applicant.
It is similar to the one proposed in No. 21.

In this embodiment, the lens moving device has a double ring-shaped lens moving body 2 for holding the lens 1 and an annular lens fixing body 3 for supporting the lens moving body. It has an upright cylindrical fixed guide 4 and an actuator support plate 5 integrally provided on the outer peripheral edge of the lens fixing body 3.

As shown in FIG. 1B, between the lens moving body 2 and the lens fixed body 3, a wedge-shaped cross section (partially dotted line) is formed in the direction indicated by the line CC in FIG. 1A (hereinafter referred to as the X direction). Shown), and a direction perpendicular to this (hereinafter referred to as Y direction)
A lens drive body 6 having a ring shape whose thickness does not change is arranged at. A connecting member 7 projecting outward in the radial direction is integrally provided at one end in the X direction of the lens driving body 6, and the connecting member 7 is integrally formed with a connecting rod 9 of an actuator 8 supported by an actuator support plate 5. It is fixed. The actuator 8 serving as a driving unit is, for example, a pulse motor, a DC motor with an encoder, a linear motor, or the like. Also,
A guide member 10 projecting outward in the radial direction is integrally provided at the other end of the lens driving body 6 in the X direction, and similarly, the lens moving body 2 is stopped at a position overlapping the guide member 10 of the lens driving body 6. It has a guide 11.

A pair of guide blocks 12a, 12b, 12c, 12d, whose lower ends in the figure are fixed to the lens fixing body 3, are arranged at both ends of the lens driving body 6 in the X direction,
The guide blocks 12c and 12d provided on one side face both side surfaces of the connecting member 7 of the lens driving body 6, and the guide blocks 12a and 12b provided on the other side are the guide member 10 of the lens driving body 6 and The anti-rotation guides 11 of the lens moving body 2 are arranged so as to face each side surface.

Hydrostatic bearing pads 13a and 13b, which are annular first and second hydrostatic bearing means, are provided on the upper surface of the lens fixing body 3 and the lower surface of the lens moving body 2, respectively, as shown in FIG. The pads 13a and 13b support the lens driving body 6 between them in a reciprocating manner without contact. The upper surface of the lens driving body 6 is inclined in the X direction, and the lower surface of the lens moving body 2 is also inclined at the same inclination angle.
Therefore, the lens driver 6 is driven by the actuator 8.
When moved in the X direction, the lens moving body 2 moves in a direction perpendicular to the X direction and the Y direction (hereinafter referred to as the Z direction) while maintaining the parallel state with the lens fixed body 3. Here, the amount of movement ΔX of the lens driving body 6 in the X direction, the respective tilt angles Q of the lens driving body 6 and the lens moving body 2, and the lens moving body 2
Between the movement amounts ΔZ in the Z direction, ΔZ = ΔX · tan (Q) (9).

The cylindrical fixed guide 4 has on its inner peripheral surface a static pressure bearing pad 13c which is a cylindrical third static pressure bearing surface facing the inner peripheral surface of the lens moving body 2. Supports the lens moving body 2 in a reciprocating manner in the optical axis direction of the lens 1 in a non-contact manner, and the guide blocks 12a to 12d respectively face the connecting member 7 of the lens driving body 6 and the guiding member of the lens driving body 6. 10 and hydrostatic bearing pads 13d-1 on the surface of the lens moving body 2 facing the rotation-stop guide 11.
3g, by means of which the connecting member 7, the guide member 1
0 and the rotation stop guide 11 are supported in a non-contact manner.

Each of the hydrostatic bearing pads 13a to 13g is a known porous hydrostatic bearing pad, and has a cavity 14a to 14c on the back surface thereof, and an internal pipe 15a to 15c from a pressurized air supply source (not shown). The pressurized air supplied through the air is dispersed by the pores and jetted to the opposing surface, and the fluid lubricating film formed by the static pressure supports the opposing surface in a non-contact manner. Instead of the porous static pressure bearing pad, a known self-made throttle type or surface throttle type static pressure bearing may be used.

The upper sensor 16 is attached to the lens fixing body 3.
Further, the lower sensor 17 is fixed, the lens driving body 6 is driven by the actuator 8 in the positive direction of the X direction in the drawing (right direction in FIG. 1), and the tip of the connecting member 7 of the lens driving body 6 becomes the lower sensor 17. Having moved to the position where it will start,
Similarly, it is possible to detect that the lens driving body 6 is driven in the negative direction in the X direction in the drawing (left direction in FIG. 1) and the tip of the guide member 10 of the lens driving body 6 moves to a position where it reaches the upper sensor 16. The position (height) of the lens 1 when the lens driving body 6 is driven in the positive X direction by the actuator 8 and the connecting member 7 of the lens driving body 6 approaches the lower sensor 17 and is detected It shall be determined as the reference position (height) of 1.

From the above reference position, the positive direction in the Z direction in the drawing (see FIG. 1).
If the lens 1 is to be further moved by ΔZ in the upward direction of B, if the actuator 8 drives the lens driving body 6 in the negative direction in the X direction by ΔX = ΔZ / tan (Q) according to the equation (1). Good.

The control of the drive amount may be controlled so that the drive amount of the actuator 8 becomes ΔX, the movement amount of the lens driving body 6 becomes ΔX, or the lens 1 or the lens. The moving amount of the moving body 2 may be controlled to be ΔZ. Here, when the actuator 8 is a pulse motor, the amount of movement is detected and controlled by the number of pulses applied to the pulse motor, and when the actuator 8 is a motor with an encoder, the movement is performed according to the output from the encoder. It is possible to detect and control the quantity. When a separate displacement sensor is provided, the displacement sensor directly measures (detects) the amount of movement of the lens 1 or the lens moving body 2 in the optical axis direction, and the actuator 8 is operated based on the measurement (detection) output. It is also possible to control.

As the reference position of the lens 1, the lens driving body 6 is driven by the actuator 8 in the negative direction of the X direction, and the guide member 10 of the lens driving body 6 is detected by the upper sensor 16. The position (height) may be used.

If ΔZ is 10 μm and Q is 2 degrees, ΔX is about 286.36 μm, which is about 1 / 28.6.
The driving amount is reduced to 4. For this reason, when it is desired to control the movement accuracy of the lens 1 in the Z direction to ± 0.1 μm, the drive accuracy of the lens driving body 6 may be ± 2.836 μm, and thus the lens 1 or the lens moving body 2 is directly driven in the Z direction. It is easier to control than If the lower sensor 17 or the upper sensor 16 can detect the position of the lens driver 6 with an accuracy of ± 1.0 μm, the reference position of the lens 1 is ± 1 / 28.3.
This is equivalent to being able to detect with an accuracy of 6 μm.

In this way, the lens moving means is the upper sensor 1
6 or the position of the lens 1 detected by the lower sensor 17 can be used as a movement reference to control the movement of the position of the lens 1 with high accuracy.

FIG. 2 shows an example in which the lens moving means is incorporated in a projection exposure apparatus to correct magnification and focus. In the figure, 18 is a mask on which a pattern to be transferred is drawn, 19 is a mask stage that holds the mask 1, and 20a to 20d are projection optical systems (hereinafter referred to as projection lenses) that project the pattern of the mask 18. Each lens. In this embodiment, the lens 20b is a correction lens having the above-mentioned lens moving means. Further, 21 is the hydrostatic bearing pads 13a to 13 in FIG.
Numeral 22 is a static pressure air supply source for applying a static pressure to g. Reference numeral 23 is a lens surface plate that supports the projection lenses 20 (a to d), and is supported by a surface plate 24 that is the basis of the entire apparatus.

Reference numeral 25 denotes a wafer onto which the pattern of the mask 18 is projected and transferred through the projection lens 20 (a to d).
Focusing is performed by a focus position detection system including 26a and 26b. Of these, 26a is a measuring unit fixed to the lower end of the projection lens 20 and for measuring the distance between the focus position of the projection lens 20 and the wafer 25, and 26b is a driving unit for adjusting the height of the wafer 25. Focus system drive unit 26b
Are further supported by a wafer stage 27 that can be moved in parallel and rotated in a horizontal plane, and the wafer stage 27 is supported by a surface plate 24.

Reference numeral 28 denotes an environmental condition detector for detecting at least one of temperature, humidity and atmospheric pressure around the projection lens 20,
Reference numeral 29 is an arithmetic unit (controller) for controlling the apparatus of this embodiment as a whole, and the storage unit 3 is provided therein.
Has 0. 31 is the pattern of the mask 18 on the wafer 25
An illumination system that emits exposure light for printing on, and an alignment scope 32 that detects the amount of relative deviation between the mask 18 and the wafer 25 in the X and Y directions. Reference numeral 33 is a storage device for inputting information from the outside to the computing unit 29.

A general alignment exposure operation in the above configuration will be described. First, the wafer 25 is placed on the wafer stage 27 by a wafer transfer system (not shown), and the wafer stage 27 is moved to be positioned immediately below the projection lens 20 (a to d). Here, in the focus system measurement unit 26a, the Z between the projection lens 20 and the wafer 25 is
Detect the spacing in the direction. This interval value is compared with a predetermined target value, and the focus system drive unit 26b is driven so that the interval with the wafer 25 matches the target value, and the focusing operation is completed.

Next, the amount of relative deviation between the alignment mark on the mask 18 and the alignment mark on the wafer 25 is detected through the alignment scope 32. At least one of the wafer stage 27 and the mask stage 19 is finely moved so that the relative displacement amount becomes zero, and the X,
The alignment operation in the Y direction is completed. After that, lighting system 3
The shutter in 1 is opened and the exposure operation is executed.

Next, the focus position correction and the magnification correction will be described. As described in the above-mentioned prior art, changes in the focus positions and projection magnifications of the projection lenses 20a to 20d due to environmental changes of temperature, humidity, and atmospheric pressure are caused by at least one lens in each lens group of the projection lens 20. This can be corrected by changing the position of (or the glass member) in the optical axis direction.

In the embodiment shown in FIG. 2, the lens 20b (lens 1 in FIG. 1) is held by the lens moving body 2 shown in FIG. 1, and the lens driving body 6 is driven in the X direction so as to be positioned in the optical axis direction. It can be adjusted. When the position of the lens 1 is changed in the optical axis direction by this position adjusting mechanism, the air gap between the lenses changes, so that the focus position and the magnification of the projection lens 20 (a to d) in the projection exposure apparatus of FIG. Can be adjusted.

In the projection exposure apparatus of FIG. 2, the environmental condition detector 28 detects at least one of the temperature T [° C.], the humidity R [%] and the atmospheric pressure P [hpa] around the projection lens 20, for example, the atmospheric pressure. , And transfers the data to the arithmetic unit 29. Based on this transfer data, the computing unit 29 calculates the amount of change from the standard value as ΔT = T−T ₀ , ΔR = R−R ₀ , ΔP = P−P.
₀ (T ₀ , R ₀ , and P ₀ are standard values of temperature, humidity, and atmospheric pressure, respectively). Further, the computing unit 29 calculates the amount of displacement ΔX from the standard state of the lens 1 necessary for correcting the amount of change in magnification according to the above equation (8), and moves the lens 20b constituting the projection lens 20 in the optical axis direction. A drive command is given to the actuator 8 to move. Then, due to the action of the actuator 8, the displacement amount of the lens 20b is Δ.
It is driven so as to be X and its position is adjusted. As a result, the change in magnification of the projection lens 20 (a to d) is maintained at zero. The displacement amount at this time is detected based on the number of pulses applied from the calculator 29 to the pulse motor when the actuator 8 is a pulse motor, and based on the output of the encoder when the actuator 8 is a motor with an encoder. It is calculated by the computing unit 29. In addition, the amount of movement of the lens 1 or the lens moving body 2 in the optical axis direction is measured (detected).
When a separate displacement sensor is provided, the displacement sensor directly measures (detects) the amount of movement of the lens 1 or the lens moving body 2 in the optical axis direction, and the actuator 8 is based on the measured (detected) output. To control.

Further, the calculator 29 calculates the focus position shift amount ΔZ according to the above equation (9) and gives a drive command to the focus systems 26a, 26b. Then, the focus systems 26a and 26b correctively drive the position of the wafer 25 by ΔZ, and the projection lens 20 (a
The wafer 25 is maintained at the best focus position in steps (d) to (d).

By the way, in this embodiment, the lens driver 6 in FIG. 1 is driven in the positive direction of the X direction by the actuator 8 at the standard position of the lens 20a (lens 1 in FIG. 1) for correcting the magnification. The position of the lens 1 when it is detected that the connecting member 7 of the driving body 6 approaches the lower sensor 17 is determined, and drive control is performed so that the movement amount of the lens 1 from this standard position is ΔX. Further, the amount of movement of the lens 1 up to the time when it is detected that the lens driving body 6 is driven in the negative direction of the X direction by the actuator 8 from the standard position and the guide member 10 of the lens driving body 6 is approaching the upper sensor 16. ΔX _S0 or the drive amount ΔX _S0 'of the actuator 8 is stored in the storage device 3 of the computing unit 29.
Store it in 0.

The height of the lens 1 is moved from the standard position by ΔX.
In this state, after performing the focus position correction, the alignment exposure operation is performed to change the pattern of the mask 18 to the wafer 2
Transfer to 5. This wafer is developed, the transferred pattern image is inspected, and the transfer magnification is measured. If the transfer magnification value measured here does not match the ideal value of the projection magnification, it is expected that the height of the standard position does not match the ideal value of the standard position.

Here, the temperature during the alignment exposure operation,
At least one of humidity and atmospheric pressure is used for the environmental condition detector 28.
Measured by, and the amount of change from the standard state is ΔT1, ΔR1, Δ
If P1 and the difference between the transfer magnification value obtained by the pattern image inspection and the ideal value is ΔM1, then the deviation amount ΔX1 from the ideal value at the standard position is ΔM, ΔT, Δ in the equation (6).
It can be obtained by substituting ΔM1, ΔT1, ΔR1, and ΔP1 into R and ΔP and solving ΔX. Therefore, ΔX1 = (ΔM1 −k21 ΔT1 −k22 ΔR1 −k23 ΔP
1) / k24 is required. This deviation amount is input from the input device 33 to the calculator 2
9 and stores it in the storage device 30. When performing a magnification correction operation thereafter, the amount of deviation ΔX1 is added and the lens 1 is driven for correction, so that more accurate magnification correction can be performed. It becomes possible to do.

By the way, the lower sensor 1 for detecting the standard position
If a detector such as a photo interrupter is used as 7, a detection characteristic gradually changes during a long period of use due to deterioration of an internal light emitting diode, and a detection position of the connecting member 7, that is, a standard position of the lens 1 changes. Sometimes. And
If this amount of change exceeds the allowable amount, the accuracy of magnification correction is adversely affected.

Also in the embodiment of FIG. 1, the lower sensor 17
When a photo interrupter is used for the connection, and the connecting member 7 of the lens driving body 6 moves in the positive direction (right side) in the X direction of FIG. When the brightness of the light emitting diode inside the interrupter decreases, the detection position of the connecting member 7 will be as shown in FIG.
It shifts in the negative X direction (left side). Similarly, the position at which the upper sensor 16 detects the guide member 10 of the lens driving body 6 is displaced in the positive direction (right side) in the X direction of FIG. For this reason,
In this embodiment, the lens 1 is connected to the connecting member 7 by the lower sensor 17.
The amount of movement ΔX _S1 of the lens 1 or the amount of drive ΔX _S1 ′ of the actuator 8 from the state in which the upper sensor 16 detects the guide member 10 is measured, is measured in advance, and is stored in the storage device 30. ΔX _S0 or ΔX _S0 'of the above to determine if the relationship or difference exceeds an acceptable amount.

This determination is performed under the control of the computing unit 29. If the computing unit 29 determines that the allowable amount is exceeded, it can be determined that the change over time in the detection characteristics of the sensor affects the magnification correction accuracy. In order to maintain the accuracy, it is necessary to perform alignment exposure again and to correct and update the lens standard position by inspection of the transfer magnification value of the pattern transferred onto the wafer 25. Therefore, this embodiment outputs this to the output of the calculator 29. Based on the above, a warning is given by displaying or notifying the operator.

The correction and update work of the lens standard position by the inspection of the transfer pattern takes time for the preparation of the inspection mask and the wafer, the alignment exposure work, the development work of the exposed wafer, the inspection work of the transfer pattern on the wafer, and the like. For,
Considering the productivity of the exposure apparatus itself, we want to keep it to the minimum necessary number. However, the above-mentioned movement amount ΔX _S1 or Δ
Since the stroke measurement of X _S1 'can be performed in a short time of about 10 seconds, it does not affect the productivity of the exposure apparatus even if it is regularly performed once a day.

Therefore, the above-mentioned stroke measurement result is used as a judgment criterion for updating the lens standard position, and only when necessary for maintaining magnification correction accuracy, the actual pattern transfer operation of the lens standard position is required. Correction update work may be performed.

FIG. 3 is a sectional view showing another embodiment of the present invention. In the figure, 34 is a glass member of the lens, 35 is a lens barrel that holds the lens 34, 36 is an air bearing guide that guides the lens barrel 35, 37 is a static pressure conduit that applies static pressure to the air bearing, and 38 is a lens barrel 35. Is a driving pressure pipe for supplying a pressure for driving the lens barrel along the optical axis, and 39 is a spring that supports the lens barrel 35.

In this embodiment, the lens barrel 35 holding the lens 34 is reciprocally guided in the optical axis direction by an air bearing guide 36 to which static pressure is applied from a static pressure supply source (not shown) through a static pressure conduit 37. The position can be adjusted in the optical axis direction by the driving pressure that has passed through the driving pressure pipe 38 from a driving pressure supply source (not shown). When the driving pressure is increased, the lens 34 moves downward in the figure together with the lens barrel 35, and when the driving pressure is decreased, it moves upward in the figure.

Further, the upper sensor 40 and the lower sensor 41 are fixed to the inner peripheral surface of the air bearing 35, and the pressure of the driving pressure is increased to move the lens barrel 35 downward in the drawing to cause the lower sensor 41 to move. It is possible to detect the arrival at the approaching position and the fact that the lens barrel 35 is moved upward in the figure by lowering the driving pressure to reach the position approaching the upper sensor 40. Since the amount of movement of the lens 34 and the lens barrel 35 in the optical axis direction corresponds to the pressure of the drive pressure described above, it is possible to detect the pressure of the drive pressure and calculate the amount of movement.
A displacement sensor that directly detects the amount of movement of the lens 34 or the lens barrel 35 may be provided and detected.

This lens moving means is incorporated into the lens 20b of the projection lens 20 (a to d) of the projection exposure apparatus shown in FIG. 2, the pressure of the lens driving pressure is increased, and the lens barrel 35 moves downward in the figure. Then, the position of the lens 34 when it is detected that the lower sensor 41 is approaching is set as the standard position of the lens, and the magnification correction is performed in the same manner as in the above-described embodiment.

The driving means in the optical axis direction of the lens includes
In addition to the example shown in the above embodiment, a means for driving the lens barrel held by the air bearing guide by applying a voltage to the piezo element may be used.

[0055]

As described above, according to the present invention,
The projection magnification adjusting lens can be moved to a position to be corrected with high precision, and stable correction can be performed for a long period of time. Further, for that reason, it is not necessary to finish the reference surface of the lens member with high accuracy, which can reduce the cost, and there is no fear of tilting due to contact when the lens member is moved to the reference position.

Further, according to the present invention, the change over time of the movement amount of the lens driving member between the two detectors is detected by comparing it with the stored reference value, and the movement reference value is detected based on this detection result. Since the time required for the absolute position correction can be easily determined, it is possible to maintain the correction accuracy of the projection magnification and / or the focus position for a long period of time without lowering the productivity of the projection exposure apparatus.

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of a projection magnification adjusting device of the present invention, in which A is a plan view thereof and B is a sectional view thereof.

FIG. 2 is a plan view showing an embodiment of the projection exposure apparatus of the present invention.

FIG. 3 is a sectional view showing another embodiment of the present invention.

[Explanation of symbols]

 1 Lens 2 Lens Moving Body 3 Lens Fixed Body 4 Cylindrical Fixed Guide 5 Actuator Support Plate 6 Lens Driver 7 Connecting Member 8 Actuator 9 Connecting Rod 10 Guide Member 16 Upper Sensor 17 Lower Sensor 18 Mask 20 Projection Lens 25 Wafer 29 Calculation Container 30 storage device

Claims (14)

[Claims] 1. A projection magnification adjusting device for adjusting a projection magnification of the projection optical system by moving a part of the projection optical system along an optical axis direction thereof, the movement moving together with the part of the projection optical system. A member, a start point detector for non-contact detection that the moving member is at the movement start point position, an end point detector for non-contact detection that the moving member is at the movement end point position, the movement start point position and the movement Storage means for storing a reference distance between end point positions, and movement of the moving member so that the amount of movement of the moving member from the movement start point position becomes equal to a command value when adjusting the projection magnification of the projection optical system. And a control unit for controlling the movement start point position and the movement end point position from one to the other of the movement amount when moving the moving member and the reference distance by comparing the magnification adjustment amount of the projection optical system. A projection magnification adjusting device, comprising: a determining unit that determines whether or not the relationship between the moving amount of the moving member and the moving amount from the starting position is within a predetermined range. 2. The projection magnification adjusting apparatus according to claim 1, wherein the control unit and the determination unit are also used by an arithmetic unit. 3. The projection magnification adjusting apparatus according to claim 2, wherein the arithmetic unit controls a pulse motor and calculates the movement amount of the moving member based on the number of pulses applied to the pulse motor. . 4. The projection magnification adjusting apparatus according to claim 2, wherein the arithmetic unit controls a DC motor with an encoder and calculates the movement amount of the moving member based on the output of the encoder. 5. The projection magnification adjusting apparatus according to claim 2, wherein the arithmetic unit calculates a movement amount of the moving member based on an output of a movement measuring sensor provided for the moving member. . 6. The moving member is one of a lens moving body that moves integrally with a part of the projection optical system and a lens driving body for moving the lens moving body. The projection magnification adjusting device described in. 7. An environment measuring device for measuring at least one of atmospheric pressure, temperature and humidity around the projection optical system, and the command value is obtained based on an output of the environment measuring device. The projection magnification adjusting device according to claim 1. 8. A projection exposure apparatus which projects and exposes a pattern previously formed on an original plate onto a substrate via a projection optical system, together with a part of the projection optical system when adjusting a projection magnification of the projection optical system. A moving member that moves, a start point detector that detects non-contact that the moving member is at the movement start point position, an end point detector that non-contact detects that the moving member is at the movement end point position, and the movement start point position And storage means for storing a reference distance between the movement end point position, control means for controlling the movement of the movement member so that the movement amount of the movement member from the movement start point position becomes equal to a command value, and the movement The amount of magnification adjustment of the projection optical system and the starting position of the moving member by comparing the moving amount when the moving member is moved from one of the starting point position and the moving end point position to the other with the reference distance. A projection exposure apparatus having a determination means for determining whether or not the relationship with the movement amount from the position is within a predetermined range. 9. The projection exposure apparatus according to claim 8, wherein the control means and the determination means are shared by a computing unit. 10. The arithmetic unit controls a pulse motor,
The projection exposure apparatus according to claim 9, wherein the movement amount of the moving member is calculated based on the number of pulses applied to the pulse motor. 11. The projection exposure apparatus according to claim 9, wherein the arithmetic unit controls a DC motor with an encoder and calculates the movement amount of the moving member based on the output of the encoder. 12. The projection exposure apparatus according to claim 9, wherein the arithmetic unit calculates a movement amount of the moving member based on an output of a movement measuring sensor provided for the moving member. 13. The moving member is one of a lens moving body that moves integrally with a part of the projection optical system and a lens driving body that moves the lens moving body. The projection exposure apparatus according to. 14. The atmospheric pressure and temperature around the projection optical system,
9. The projection exposure apparatus according to claim 8, further comprising an environment measuring device that measures at least one of humidity, and the command value is obtained based on an output of the environment measuring device.