JPH09199413A - Method and apparatus for exposure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent a bad influence on the alignment accuracy and the positional controlling accuracy of a substrate stage by the generation of heat of a sensor on the substrate stage and a circuit board connected to the sensor. SOLUTION: When a small portion of a pattern of a mask R is exposed at a time and the small image area is stepped over a photosensitive substrate to cover the entire surface of the substrate through a projection optical system PL, a substrate stage 14 is stepped with the power supply to sensors 30, 34 on the substrate stage 14 and an electric circuit board 36 connected to the sensors being turned off. By this method, the sensors 30, 34 and the electric circuit board 36 do not become sources of heat generation at the time of exposure and there is no uneven temperature distribution caused by the generation of heat by these devices and therefore a bad influence is not given to the alignment accuracy and the positional control accuracy of the stage 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure method and an exposure apparatus, and more specifically, to moving a substrate stage on which a photosensitive substrate is mounted while moving a mask pattern onto a photosensitive substrate via a projection optical system. The present invention relates to an exposure method and an exposure apparatus that sequentially transfer.

[0002]

2. Description of the Related Art Conventionally, an exposure apparatus such as a so-called stepper has been used in a photolithography process for manufacturing a semiconductor integrated circuit, a liquid crystal display substrate and the like. In this type of exposure apparatus, a dose monitor sensor and an unevenness sensor are installed on a substrate stage on which a substrate such as a wafer is mounted.

The irradiation amount monitor sensor is a sensor for measuring the image plane power on the substrate surface which changes depending on the illumination conditions (normal illumination, annular illumination, etc.) and the type of reticle.
To measure the image plane power, move the substrate stage so that the irradiation amount monitor sensor is positioned within the exposure field of the projection optical system under the same illumination conditions as during exposure with the mask (or reticle) set. It will be done. The measured value of this irradiation amount monitor sensor is sent to the controller, and an irradiation fluctuation correction amount calculation for correcting fluctuations (irradiation fluctuations) such as magnification and focus due to absorption of exposure light by the projection lens (projection optical system) is calculated. Used as basic data.

The unevenness sensor is a sensor for measuring unevenness of illumination in an exposure field caused by maintenance work such as replacement of a mercury lamp as an exposure light source and replacement of a chamber of an excimer laser. The measurement of the illumination unevenness is performed while the substrate stage is two-dimensionally moved so that the unevenness sensor moves within the exposure field under the same illumination condition as the exposure without setting the reticle. Fine adjustment of the illumination unevenness adjusting optical member (mirror, herbing glass, relay lens, etc.) in the illumination optical system is performed based on the measured value of the unevenness sensor so as not to affect the line width control.

Photodiodes and pyroelectric sensors are used as the irradiation amount monitor sensor and the unevenness sensor, and a signal processing circuit such as AD conversion is provided so that detection signals from these sensors are less likely to receive noise from the outside. It is provided near the sensor (on the stage or on the side surface of the stage). When pulsed light such as an excimer laser is used as the light source, an electric circuit for signal processing suitable for pulsed light detection processing such as a peak hold circuit is also required.

By the way, in the exposure apparatus, in order to control the position of the substrate stage with high accuracy, a highly accurate position sensor such as a laser interferometer and a highly accurate sensor such as an alignment sensor are used. In order to stabilize the exposure apparatus for a long period of time, the exposure apparatus main body including the substrate stage is housed in a chamber adjusted to a constant temperature.

[0007]

As described above, the main body of the exposure apparatus has a high accuracy (for example, a target temperature range of ± 0.1 ° C.).
Since it is housed in a chamber whose temperature has been adjusted, the alignment accuracy has been sufficiently secured for a long time. However, the pattern line width is becoming finer year by year with the higher integration of semiconductor integrated circuits, and recently, a finer line width is realized. Therefore, it is necessary to secure a higher alignment accuracy corresponding to the narrow line width. It's coming. In order to achieve even higher precision of alignment accuracy, it is essential to correct the amount of variation in the imaging characteristics of the projection optical system and to adjust the unevenness of illumination. Of course, it is necessary, but on the other hand, these sensors and the accompanying electric circuit board act as a heat source, and during wafer alignment and exposure, they move with the stage, causing uneven temperature distribution in the chamber. However, the adverse effect of this on the alignment accuracy and the position control accuracy of the stage cannot be ignored.

The present invention has been made under the above circumstances, and an object thereof is that heat generated by a sensor on a substrate stage and a circuit board associated therewith adversely affects alignment accuracy and stage position control accuracy. It is an object of the present invention to provide an exposure method and an exposure apparatus capable of effectively suppressing the above.

[0009]

According to a first aspect of the present invention, exposure is performed by sequentially transferring a mask pattern onto a photosensitive substrate through a projection optical system while moving a substrate stage on which the photosensitive substrate is mounted. A method for exposing the mask pattern through the projection optical system while moving the substrate stage with power supply to a sensor on the substrate stage and an electric circuit substrate associated with the sensor being turned off. It is characterized in that the images are sequentially transferred onto the substrate.

According to this, when the mask pattern is sequentially transferred onto the photosensitive substrate through the projection optical system, the power supply to the sensor on the substrate stage and the electric circuit substrate accompanying it is turned off. Since the substrate stage is moved, the sensor and its associated electric circuit board do not become a heat source during exposure, and the uneven temperature distribution due to these heat generation does not affect alignment accuracy or stage position control accuracy. Never give.

According to a second aspect of the present invention, in the exposure method according to the first aspect, prior to the transfer of the mask pattern onto the photosensitive substrate, the sensor of the substrate stage within the exposure field of the projection optical system. Is used to detect the exposure light.

According to this, the sensor and the electric circuit board associated therewith do not become a heat source during exposure as in the case of the first aspect of the invention, and the mask pattern is transferred to the photosensitive substrate. Prior to this, since the exposure light is detected using the sensor of the substrate stage in the exposure field of the projection optical system, the detection result is used to determine, for example, the irradiation fluctuation amount of the imaging characteristics of the projection optical system during exposure. To correct
The uneven illumination can be adjusted prior to the exposure.

According to a third aspect of the present invention, there is provided an exposure device for transferring a mask pattern onto a photosensitive substrate via a projection optical system, the substrate stage mounting the photosensitive substrate and moving two-dimensionally; At least one sensor arranged on the substrate stage and an electric circuit board associated therewith; switching means for turning on and off power supply to the sensor and the electric circuit board; and during transfer of the mask pattern to the photosensitive substrate, Control means for controlling the switching means so that power supply to the sensor and the electric circuit board is turned off.

According to this, the switching means is controlled so that the power supply to the sensor and the electric circuit board is turned off during the transfer of the mask pattern onto the photosensitive substrate by the control means, so that the stage moves during the transfer. However, the sensor and the electric circuit board associated therewith do not serve as a heat source, and the temperature distribution unevenness due to the heat generation does not occur, so that the alignment accuracy and the position control accuracy of the stage are not adversely affected.

According to a fourth aspect of the present invention, in the exposure apparatus according to the third aspect, the sensor is an optical sensor for detecting the exposure light within the exposure field of the projection optical system. . According to this, when the exposure light is detected in the exposure field of the projection optical system using the optical sensor before the transfer of the mask pattern to the photosensitive substrate, the detection result is used to, for example, project during the exposure. It is possible to correct the irradiation variation amount of the image forming characteristic of the optical system and adjust the illumination unevenness prior to the exposure. Also in this case, even if the stage moves during the transfer, the sensor and the electric circuit board attached to the sensor do not become a heat source.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
A description will be given with reference to FIG.

FIG. 1 schematically shows a configuration of a step-and-repeat type exposure apparatus 10 according to one embodiment. In this exposure apparatus 10, an illumination system including a light source 12, a reticle stage RS on which a reticle R as a mask is mounted, and a circuit pattern on a pattern surface PA of the reticle R are reduced to a predetermined size on a wafer W as a photosensitive substrate. A projection optical system PL for projection exposure at a magnification, a wafer stage 14 as a substrate stage on which a wafer W is mounted, a drive system 16 for the wafer stage 14, and a magnification adjusting mechanism 18 for adjusting the magnification of the projection optical system PL. A main control unit 20 is provided as a control unit for comprehensively controlling the entire apparatus including the drive system 16 and the magnification adjusting mechanism 18. The exposure apparatus 10 is housed in a chamber (not shown) whose temperature is adjusted with high accuracy.

The illumination system is a light source 1 composed of a mercury lamp.
2, an elliptical mirror 22, and an illumination optical system 24. Although the illumination optical system 24 is configured to include a single lens 26 and a beam splitter 28 in the figure, in reality, it includes various lenses such as a fly-eye lens, a relay lens, and a condenser lens, and these lenses are used. Is typically represented by lens 26. In addition, a shutter, a field stop, a blind and the like (not shown) are also provided. Therefore, the exposure light emitted from the light source 12 is converged on the second focal point by the elliptical mirror 22, and then, while passing through the illumination optical system 24, the luminous flux is uniformized and speckles are reduced. The pattern area PA of the reticle R is illuminated as light. As a light source, a KrF excimer laser or an ArF excimer laser may be used instead of the mercury lamp.

The beam splitter 28 is actually disposed inside the illumination optical system 26, for example, between a shutter (not shown) and a fly's eye lens, and a part of the exposure extracted by the beam splitter 28. The amount of light is detected by the photoelectric detector 32. The detection value of the photoelectric detector 32 is input to the main controller 20 and is used as a basis for calculating the irradiation variation amount of the image forming characteristic of the projection optical system PL.

The reticle stage RS is constructed so that it can be finely moved in a horizontal plane by a drive system (not shown), and the reticle R is held on the reticle stage RS. A circuit pattern is drawn on the pattern surface PA of the reticle R.

The projection optical system PL holds a plurality of lens elements (none of which are shown) arranged at a predetermined interval along the optical axis AX direction having a common optical axis AX and holding these lens elements. And a lens barrel that does.

The magnification adjusting mechanism 18 changes the refractive index of the gas in the airtight chamber by changing the pressure in the airtight chamber between the lens elements at predetermined positions forming the projection optical system PL, thereby changing the refractive index of the projection optical system. The magnification of the system PL is adjusted. The airtight chamber whose pressure is adjusted by the magnification adjusting mechanism 18 is provided, for example, between the lens elements closer to the reticle, which have a greater influence on the magnification than other lens elements.

The wafer stage 14 is driven in a two-dimensional direction in a horizontal plane by a drive system 16 and is also finely driven in the optical axis AX direction. The two-dimensional position of the wafer stage 14 is constantly measured by a laser interferometer (not shown), and the output of this laser interferometer is monitored by the main controller 20.

An irradiation amount monitor sensor 30 and an unevenness sensor 34 as optical sensors are arranged at one end of the wafer stage 14. These sensors 30,
The light receiving surface of 34 has substantially the same height as the surface of the wafer W. The irradiation amount monitor sensor 30 and the unevenness sensor 34 are each configured by a photodiode here, and the light receiving surface of the unevenness sensor 34 has a pinhole shape.
The irradiation amount monitor sensor 30 has a light receiving surface with a certain area. An electric circuit board 36 for signal processing of the sensors 30 and 34 is provided on the front surface of the wafer stage 14 in the drawing.

FIG. 2 conceptually shows the internal structure of the electric circuit board 36.
The detection signal of the irradiation amount monitor sensor 30 is subjected to predetermined processing, and the detection signal of the first signal processing circuit 38 for sending the processed detection signal to the main controller 20 and the detection signal of the unevenness sensor 34 are subjected to predetermined processing, and after processing The second signal processing circuit 40 for sending the detection signal of No. 2 to the main controller 20, the first switch 42 and the second switch 42 as switching means interposed between the signal processing circuits 38, 40 and the power supply circuit 46, respectively. Switch 44
And

The first switch 42 and the second switch 44
For example, a circuit or element such as a relay circuit or a semiconductor switching element that can be turned on / off (ON / OFF) by an electric signal is used. These switches 42, 4
4 is turned on / off by the main controller 20, as will be described later. When the first switch 42 is turned on, power is supplied from the power supply circuit 46 to the first signal processing circuit 38 and the irradiation amount monitor sensor 30 via the first signal processing circuit 38, and the first switch 42 is turned off. Then, the power supply to these is stopped. Similarly, when the second switch 44 is turned on, power is supplied from the power supply circuit 46 to the second signal processing circuit 40 and the mura sensor 34 via the second signal processing circuit 40, and when the second switch 44 is turned off, power is supplied to these. The power supply of is stopped.

The main controller 20 includes a CPU, ROM, RA
The ROM in the main controller 20 stores a control program corresponding to the flowcharts of FIGS. 3 and 4, which will be described later, and the like. Further, in the RAM, the magnification of the projection optical system PL, the magnification determined based on the irradiation variation characteristic of the focus, and the formula for calculating the variation in the irradiation of the focus are stored in the RAM. The light amount (image plane power) is included as a parameter) and the like are stored.

Next, an exposure method by the exposure apparatus 10 configured as described above will be described with reference to the flowchart of FIG. 3 showing the main control algorithm of the CPU in the main controller 20. Note that this flowchart is drawn on the premise that preparation for wafer exposure, that is, setting of exposure conditions such as reticle loading and alignment, and baseline measurement is completed. At the stage when the control algorithm is started, both the first flag F1 and the second flag F2 are reset (F1 ← 0,
F2 ← 0).

First, in step 100, it is judged whether or not the illumination condition is a new condition, and if it is a new condition, step 10
2 and the first flag F1 (not shown) is set (F1 ←
After 1), the process proceeds to step 104. Step 10
If the lighting condition is 0 and the lighting condition is not new, that is, if the lighting condition is not changed, the process proceeds to step 104.

In step 104, it is judged whether or not the reticle to be used has been exchanged. If the reticle has been exchanged with a new reticle, the process proceeds to step 106 and a second flag F2 (not shown) is set (F2 ← 1), and then the step is performed. Proceed to 108.
On the other hand, if the reticle has not been replaced in step 104, the process proceeds to step 108.

In step 108, the first flag F1 and the second flag
If both flags F2 are "0", and if this determination is negative (when at least one of illumination condition change and reticle exchange is being performed), the routine proceeds to step 110, Steps 110-114
The basis for measuring the power of the image plane on the wafer W at the time of exposure, which changes depending on the illumination condition and the type of reticle, and controlling the focus and magnification variation of the projection optical system PL caused by the irradiation of the exposure light. Main controller 2 as data
A series of operations for feeding back to 0 is performed. That is,
In step 110, the first switch 42 in the electric circuit board 36 described above is turned on, and the dose monitor sensor 30 arranged on the wafer stage 14 and the first signal processing circuit 38 in the electric circuit board 36 associated therewith. Supply power to. In the next step 112, the dose monitor sensor 30
Is moved to the exposure position (in the exposure field of the projection optical system PL) while moving the wafer stage 14 while monitoring the output of the interferometer (not shown), and then turning on the light source 12 via the exposure controller (not shown). To Thereby, the light source 1
The exposure light from 2 illuminates the reticle R via the illumination optical system, and the exposure light (illumination light) transmitted through this reticle R
Is incident on the irradiation amount monitor sensor 30 via the projection optical system PL, and this amount of light (image surface power) is measured by the irradiation amount monitor sensor 3
The detected light amount is sent to the main controller 20 via the first signal processing circuit 38. At this time,
The detection value of the light amount of the photoelectric detector 32 is also input to the main control device 20, and the CPU in the main control device 20 obtains the ratio of the two so that the deterioration of the light source can be dealt with. Has become. In the next step 114, the first switch 42 is turned off to stop the power supply to the irradiation amount monitor sensor 30 and the associated first signal processing circuit 38. The second switch 44 remains off while the image surface power measurement is being performed. In the next step 116, both the first flag F1 and the second flag F2 are reset (F1 ← 0, F2 ← 0), and then step 11
Proceed to 8.

At step 118, the wafer W is loaded on the wafer stage 14 using a wafer loader (not shown) and center-up on the wafer stage 14 (the detailed description thereof is omitted), and then the process proceeds to step 120. Based on the information of the selected exposure file in the RAM, it is determined whether the operator has selected the first exposure. Then, when the first exposure is selected,
Since alignment for superposition is not necessary, the process proceeds to step 124, but if the exposure of the first layer is not selected, that is, if the exposure of the second and subsequent layers is selected, the process proceeds to step 122, so-called. After performing the enhanced global alignment (EGA) measurement, the process proceeds to step 124. Here, the EGA measurement means the wafer W.
The positions of alignment marks attached to a plurality of representative areas of the shot area already formed above are detected by an interferometer (not shown) and an alignment detection system (not shown), and the least squares is used by using the detection result. This is a method of calculating the positional deviation (X, Y offset, rotation) and deformation (X, Y scaling, orthogonality error) of the wafer W in the two-dimensional plane by the approximation method.

In step 124, the pattern of the reticle R is sequentially transferred to the shot area on the wafer W by the so-called step-and-repeat method. That is, exposure is performed while stepping the wafer stage 14 to sequentially position the shot areas on the wafer W within the exposure field of the projection optical system PL. At this time, in the case of exposure of the second and subsequent layers, the shot area is positioned using the result of the EGA measurement in step 122.

During this exposure, the operation of correcting the image forming characteristic is performed as follows. Here, as a premise, the position of the wafer stage 14 in the optical axis AX direction is set to a position serving as a reference for focus correction.

The light emitted from the light source 12 is the illumination optical system 2
While passing through 4, a part of the beam is split by the beam splitter 28 and is incident on the photoelectric detector 32, and the rest is irradiated on the reticle R. The light amount value detected by the photoelectric detector 32 is input to the main controller 20.

The CPU in the main controller 20 calculates the magnification and focus irradiation variation based on a predetermined magnification and a focus radiation variation calculation formula (including the previously measured image plane power value as a parameter). Is calculated, and a magnification correction amount and a focus correction amount for correcting these are calculated.
In this case, it is possible to deal with deterioration of the light source and the like by using a calculation formula that also considers the output of the photoelectric detector 32.
Alternatively, the amount of light actually applied to the reticle R is obtained based on the output of the photoelectric detector 32 and the known division ratio of the beam splitter 28, and the thermal expansion of the reticle R is calculated using this. good.

Then, the CPU in the main controller 20 gives the magnification correction amount to the magnification adjusting mechanism 18 as a command value. As a result, the magnification adjusting mechanism 18 corrects the magnification of the projection optical system PL, and the influence of the irradiation variation due to the projection optical system PL absorbing the exposure light is canceled. Also,
The CPU in the main controller 20 gives the above-mentioned focus correction amount to the drive system 16. As a result, the wafer stage 14 is driven by the drive system 16 in the optical axis AX direction, and the fluctuation in focus irradiation is corrected.

When the exposure of all the shot areas of the wafer W loaded on the wafer stage 14 is completed as described above, the process proceeds to the next step 126, using a wafer loader (not shown) and center-up on the wafer stage 14. The wafer W is unloaded from the wafer stage 14.

At the next step 128, it is judged whether or not the exposure of the planned number of sheets is completed. If the exposure of the planned number of sheets is not completed, the procedure returns to step 118, and the above-mentioned processing is carried out until the determination at step 128 is affirmed. If the judgment in step 128 is affirmed after the predetermined number of exposures has been completed and the judgment in step 128 is affirmed, the series of processes of this routine is ended.

When there is a possibility of uneven illumination in the exposure field due to maintenance work such as replacement of the mercury lamp 12 which is the exposure light source (or replacement of the chamber of the excimer laser), measurement of uneven illumination using the unevenness sensor 34. Is performed. Here, the measurement of the illumination unevenness will be described with reference to the flowchart of FIG. 4 showing the control algorithm of the CPU in the main controller 20. This flowchart starts when the operator starts the illumination unevenness measurement software. As a premise, reticle R is reticle stage R
The illumination conditions are not set on S, and the illumination conditions are adjusted to the actual exposure of the wafer.

At step 202, the second switch 44 is turned on.
When turned on, power is supplied to the unevenness sensor 34 arranged on the wafer stage 14 and the second signal processing circuit 40 associated therewith. In the next step 204, the unevenness sensor 34
While stepping the wafer stage 14 while monitoring the output of the interferometer so that the two-dimensional movement in the exposure field follows a predetermined map for measuring unevenness,
The light source 12 is turned on to irradiate the exposure light, and the illumination unevenness is measured. During this unevenness measurement, the value detected by the unevenness sensor 34 is the second value.
Are sequentially sent to the main controller 20 via the signal processing circuit 44 of FIG. The CPU in the main controller 20 uses this measurement value as the coordinate position of the wafer stage 14 at that time (measurement value of the interferometer).
Are stored in the RAM in a one-to-one correspondence with.

After the illumination unevenness measurement is completed, the routine proceeds to step 208, where the second switch 44 is turned off and the unevenness sensor 34.
And the power supply to the second signal processing circuit 40 associated therewith is stopped. During the measurement of this illumination unevenness, the first switch 42 remains off.

In the next step 210, it is judged whether or not the illumination unevenness measured based on the contents stored in the RAM is within the allowable range. If it is not within the allowable range, the illumination unevenness adjusting optical in the illumination optical system 24 is adjusted. The member is finely adjusted to adjust the illumination unevenness, and the process returns to step 204. After that, step 20 is performed.
The loop of 4 to step 212 is repeated until the determination in step 210 is affirmed. If the determination in step 210 is affirmative, the series of processes of this routine is ended.

As described above, according to the exposure apparatus 10 of the present embodiment, the power supply is turned on / off to the irradiation amount monitor sensor 30, the unevenness sensor 34 and the electric circuit board 36 attached to them, which are arranged on the wafer stage 14. Since the first switch 38 and the second switch 40 are provided, and the control method is used in which the power supply is turned on only when the sensor is used during image surface power measurement or illumination unevenness measurement, and the others are turned off. The sensor 3 is used for most of the time when the exposure apparatus is in use.
0, 34 and the electric circuit board 36 can be turned off, and the chamber (not shown) of the exposure apparatus 10 can be turned off.
In particular, it is possible to minimize the heat generated by the heat source around the wafer stage 14. As a result, the static temperature stability around the wafer stage 14 is increased, and the wafer stage 14 is aligned when the wafer W is aligned and exposed.
The unevenness of the temperature distribution caused by the movement of the can be prevented, and the dynamic temperature stability can be improved. Furthermore,
For the above reasons, it is possible to improve the stepping accuracy and the position control accuracy of the wafer stage 14, improve the alignment accuracy, and stabilize the baseline.

In the above description of the embodiment, the case where the present invention is applied to the stepper which is a kind of the batch exposure type exposure apparatus has been described, but the scope of application of the present invention is not limited to this. The same can be applied to a so-called scanning type exposure apparatus, and even such a scanning type exposure apparatus can improve temperature distribution unevenness and dynamic temperature stability due to movement of the substrate stage. Therefore, it is possible to improve alignment accuracy and stage position accuracy control.

[0046]

As described above, according to the present invention,
There is an unprecedented excellent effect that the heat generated by the sensor on the substrate stage and the circuit board associated therewith can be effectively suppressed from adversely affecting the alignment accuracy and the position control accuracy of the stage.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a configuration of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an internal configuration example of the circuit board of FIG. 1 together with a sensor and a power supply circuit.

FIG. 3 is a flowchart showing a main control algorithm (exposure processing algorithm) of the CPU in the main control device.

FIG. 4 is a flowchart showing a control algorithm of the CPU in the main control unit when measuring uneven illumination.

[Explanation of symbols]

 10 Exposure Device 14 Wafer Stage (Substrate Stage) 20 Main Controller (Control Means) 30 Irradiation Monitor Sensor (Optical Sensor) 34 Mura Sensor (Optical Sensor) 36 Electric Circuit Board 42 First Switch (Switching Means) 44 Second Switch ( Switching means) W wafer (photosensitive substrate) R reticle (mask) PL projection optical system

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location H01L 21/30 516F 525R

Claims (4)

[Claims] 1. An exposure method for sequentially transferring a mask pattern onto a photosensitive substrate through a projection optical system while moving a substrate stage on which the photosensitive substrate is mounted. An exposure method in which the pattern of the mask is sequentially transferred onto the photosensitive substrate via the projection optical system while the substrate stage is moved with power supply to the electric circuit substrate associated with 1. being turned off. 2. The exposure light is detected using a sensor of the substrate stage within an exposure field of the projection optical system prior to the transfer of the mask pattern onto the photosensitive substrate. The exposure method according to 1. 3. An exposure apparatus for transferring a mask pattern onto a photosensitive substrate via a projection optical system, the substrate stage having the photosensitive substrate mounted thereon and moving two-dimensionally; arranged on the substrate stage. At least one sensor and its associated electric circuit board; switching means for turning on and off the power supply to the sensor and the electric circuit board; and for the sensor and the electric circuit board during transfer of the mask pattern to the photosensitive substrate An exposure apparatus comprising: a control unit that controls the switching unit so that power supply is turned off. 4. The exposure apparatus according to claim 3, wherein the sensor is an optical sensor that detects exposure light in an exposure field of the projection optical system.