JPH11307416A - Exposure control method and aligner using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an exposure control method for applying proper exposure to a substrate such as a wafer even when an illumination condition for a mask such as a reticule is changed, and an aligner. SOLUTION: When an illumination condition for a reticule R is changed by an illumination system opening diaphragm 16, control characteristics for setting a driven power for obtaining an exposure beam with desired illuminance from an exposing light source 1 are changed according to the changed illumination condition. Then, the driving power to be supplied from a driving power source 33 to the exposing light source 1 during the exposure of a substrate W is controlled according to the changed control characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus used in a lithography process for manufacturing, for example, a semiconductor device, an imaging device (such as a CCD), a liquid crystal display device, or a thin film magnetic head. The present invention relates to an exposure amount control method for controlling the exposure amount.

[0002]

2. Description of the Related Art When manufacturing a semiconductor device or the like, a reticle as a mask and a wafer coated with a resist are moved in synchronization with a projection optical system together with a batch exposure type projection exposure apparatus such as a stepper. Accordingly, a step-and-scan type scanning exposure apparatus that transfers a reticle pattern to each shot area on a wafer is being used. In a scanning exposure apparatus (scanning exposure apparatus), similarly to the batch exposure apparatus, an exposure amount control function for keeping the exposure amount (integrated exposure energy) for each point in each shot area on a wafer within an appropriate range. Is one of the important functions.

In this regard, the target exposure amount D to be given to each point on the wafer in the scanning exposure type is the width of the slit-shaped exposure area (hereinafter, referred to as “illumination field”) on the wafer in the scanning direction. H, and proportional to the image plane illuminance PI of the exposure light,
It is inversely proportional to the scanning speed V of the wafer. That is, D = PI
The relational expression of H / V holds. Further, since the width H of the illuminated field is usually fixed, conventionally, in order to simplify the exposure control sequence, the scanning speed and the image plane illuminance of the wafer are kept constant during scanning exposure to each shot area. The scanning speed or the image plane illuminance is controlled in accordance with the target exposure amount.

For example, when an i-line (wavelength: 365 nm) of an ultra-high pressure mercury lamp is used as the exposure light, the mercury lamp as the exposure light source has an arc fluctuation and the like even when the injection power is constant as shown in FIG. It is known that there is a characteristic that the illuminance fluctuates, and that the amplitude of the fluctuation of the illuminance increases as the power injected into the mercury lamp increases. Therefore, to accurately control the image plane illuminance,
A beam splitter is arranged in the optical path of the exposure light, and a part of the exposure light branched by the beam splitter is received by an integrator sensor as a photoelectric detector arranged at a position optically conjugate with the reticle and the wafer, So-called constant illuminance control is performed, in which the power injected into the mercury lamp is servo-controlled so that the output is constant.

In order to perform this constant illuminance control, the relationship between the illuminance of the exposure light detected by the integrator sensor and the illuminance on the image plane of the projection optical system, and the power injected into the mercury lamp as shown in FIG. And the illuminance of the exposure light detected by the integrator sensor, and the relationship needs to be stored in advance as a control characteristic. The operation for obtaining these relations is hereinafter referred to as lamp calibration. This lamp calibration is performed periodically to accurately control the exposure amount of the wafer and to maintain the life of the mercury lamp.

[0006]

In recent exposure apparatuses,
To improve the resolution and increase the depth of focus, change the NA of the exposure optical system according to the pattern on the reticle, or insert a special stop with a ring shape or multiple apertures on the pupil plane of the projection optical system. The so-called deformed illumination technique of changing the angle of the exposure light incident on the reticle is employed.

However, the above-mentioned integrator sensor has a characteristic that its detection sensitivity changes depending on the angle of the incident light. In some cases, the angle of light incident on the integrator sensor disposed at a position optically conjugate with the angle also changes, resulting in a difference in the detection sensitivity of the integrator sensor. Therefore, if the relationship between the power injected into the mercury lamp and the illuminance of the exposure light used for constant illuminance control in normal illumination is used for constant illuminance control in modified illumination, accurate constant illuminance control can be performed based on the detection sensitivity difference of the integrator sensor. Therefore, there is a possibility that the exposure amount cannot be accurately controlled for the wafer.

The lamp calibration described above is
It is necessary to perform the operation with the brightness of the mercury lamp stable.
As shown in FIG. 8, since the mercury lamp does not immediately become a stable luminance even when the injected power is changed, the illuminance of the exposure light cannot be measured during that time, and the time required for lamp calibration becomes longer. The processing capacity (productivity) of the exposure apparatus as a whole deteriorates.

In view of the above, the present invention provides an exposure amount control method capable of giving an accurate exposure amount to a substrate when a mask pattern such as a reticle is transferred onto the substrate such as a wafer. The purpose is to provide. Another object of the present invention is to provide an exposure apparatus capable of implementing such an exposure amount control method.

[0010]

In order to achieve the above object, the present invention illuminates a mask (R) with an exposure beam from an exposure light source (1) and projects a pattern of the mask (R) on a projection optical system. In the exposure amount control method for controlling the exposure amount on the substrate (W) to transfer the light onto the substrate (W) via the (PL), the illumination condition on the mask (R) is changed, and the illumination condition after the change is changed. At the same time, the control characteristics (44, 46) for setting the driving power for obtaining the exposure beam of the desired illuminance from the exposure light source (1) are changed, and the substrate (W) is changed based on the changed control characteristics. The exposure light source (1) is driven during exposure.

[0011] In order to achieve the above object, the present invention provides:
In an exposure apparatus for illuminating a mask (R) with an exposure beam and transferring a pattern of the mask (R) onto a substrate (W), an exposure light source (1) for generating an exposure beam and an exposure light source (1) are provided. A driving power supply (33) for supplying driving power, an illumination condition setting system (16, 17) for changing an illumination condition of an exposure beam to the mask (R), and a mask (R) by an illumination condition setting system (16, 17). Is changed, the control characteristics (44, 46) for setting the drive power for obtaining an exposure beam of a desired illuminance from the exposure light source (1) are changed in accordance with the changed illumination condition. And an exposure control system (31) for setting drive power supplied from the drive power supply (33) to the exposure light source (1) during exposure of the substrate (W) based on the changed control characteristics. It was to be.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In the present embodiment, the present invention is applied to a case where exposure control is performed in a step-and-scan type scanning exposure apparatus using a mercury lamp as an exposure light source. FIG. 1 shows a scanning type exposure apparatus of the present embodiment. In FIG. 1, a mercury lamp 1 as an exposure light source is disposed near a first focal point of an elliptical mirror 2, and the exposure light emitted from the exposure light source 1 is Is reflected and condensed at point A by the elliptical mirror 2. A shutter 4 that is opened and closed by a shutter driving mechanism 5 is disposed near the light condensing point A. When the shutter 4 is open, the exposure light is converted into a substantially parallel light beam via the mirror 3 and the input lens 6 and then reaches the field stop 7. Immediately after the field stop 7, a dimming plate 36 which can be put in and out freely is arranged, and the dimming plate 36 can change the amount of exposure light passing through the field stop 7 stepwise or continuously within a predetermined range. As an example of the light attenuating plate 36, a transparent (100% transmittance) opening and a plurality of ND filters whose transmittance changes stepwise are arranged at equal angular intervals around the rotating plate, and an exposure control system is provided. 31 rotates the rotary plate via the dimming plate driving mechanism 37 to set the amount of exposure light to a desired value.

In this embodiment, it is the exposure control system 31 that controls the exposure of the wafer W, and the operations of the dimming plate driving mechanism 37 and the shutter driving mechanism 5 are controlled by the exposure control system 31. You. Exposure control system 3
1 is a mercury lamp 1 via a power supply 33 for the mercury lamp 1
Control the injected power supplied to the. Exposure light having passed through the field stop 7 and the dimming plate 36 enters the first fly-eye lens 9 via the relay lens 8. First fly-eye lens 9
A light quantity stop (a so-called σ stop) 10 of an illumination system is disposed on the exit surface of. The size of the aperture of the light amount aperture 10 can be adjusted to an arbitrary size by the first aperture driving mechanism 11. The exposure light that has passed through the aperture stop 10 is guided to a second fly-eye lens 14 via a relay lens 12.
In the present embodiment, the operation of the first aperture driving mechanism 11 is also controlled by the exposure amount control system 31, and the size of the aperture of the light amount aperture 10 is adjusted so that the first fly eye lens 9 to the second fly eye lens 14 Can be adjusted.

The second fly-eye lens 14 has lens elements arranged in close contact with each other in a mosaic shape, and two lens bundles 14a and 14b having a flat surface on one side are brought close to each other so that the respective flat portions face each other. It is arranged. The details of the mosaic fly-eye lens are disclosed in Japanese Patent Application Laid-Open No. 8-316133, and are omitted here.

In the vicinity of the exit surface of the second fly-eye lens 14, there is arranged an illumination system aperture stop plate 16 in which a plurality of types of aperture stops are disposed. FIG. 3 shows an illumination system aperture stop plate 1.
6 is a plan view. In FIG. 3, the illumination system aperture stop plate 1
6, an aperture stop 16A consisting of a normal circular aperture at substantially equal intervals; an aperture stop 16B consisting of a small circular aperture for reducing the σ value, which is a coherence factor; a ring-shaped aperture stop 16C for modified illumination; An aperture stop 16D in which a plurality of apertures are eccentrically arranged for deformed illumination is arranged.

Returning to FIG. 1, the rotation angle of the illumination system aperture stop plate 16 is controlled by the main control system 34 via the second aperture drive mechanism 17, and a desired one of the four aperture stops is used for exposing the exposure light. It is located in the optical path. Exposure light that has passed through the illumination system aperture stop plate 16 is incident on a beam splitter 20 that has a small reflectance and a large transmittance, and the exposure light that has passed through the beam splitter 20 passes through a relay lens 21 and is movable with two movable blades. The blind (variable field stop) 22 is reached. The arrangement surface of the movable blind 22 is a reticle R described later.
Optically conjugate with the surface on which the pattern is formed. In the vicinity of the movable blind 22, a fixed blind (fixed illumination field stop) 23 whose opening shape is fixed is arranged. The fixed blind 23 is, for example, a field stop having a rectangular opening formed by four knife edges. The rectangular opening defines the shape of the illumination area 40 on the reticle R in a rectangular slit shape. Movable blind 22 and fixed blind 2
Exposure light passing through 3 illuminates illumination region 40 on reticle R supported by reticle stage 27 via relay lens 24, condenser lens 25, and mirror 26 with a uniform illuminance distribution.

In this case, the surface on which the fixed blinds 23 are arranged is slightly defocused from the surface conjugate with the pattern forming surface of the reticle R, so that the illuminance distribution (light intensity distribution) of the illumination area 40 is Scan direction (X direction)
Changes with a gradient at the end of. Further, the movable blind 22 plays a role in preventing the exposure light from being irradiated onto the area not to be illuminated on the reticle R at the start and end of the scanning exposure. Therefore, the movable blind 22 is movably supported by the slide mechanism 42. The movable blind 22 is used for a reticle stage 27 during scanning exposure.
The operation of the slide mechanism 42 is controlled by the stage control system 35 in order to move in synchronization with the wafer stage 29 and the wafer stage 29. Note that the details of the operation of the movable blind 22 are also described in Japanese Patent Application Laid-Open No. 8-316133, and will not be described here.

An image obtained by reducing the pattern in the illumination area 40 on the reticle R by the projection optical system PL with a projection magnification β (β is, for example, ４ ，, ５, etc.) is formed on a wafer W coated with a photoresist. Is projected on the Teruno field. Hereinafter, the Z axis is taken in parallel with the optical axis AX of the projection optical system PL, and the optical axis A
A scanning direction of the reticle R with respect to the illumination area 40 in a plane perpendicular to X (that is, a direction parallel to the paper surface of FIG. 1) is an X direction.
A non-scanning direction perpendicular to the scanning direction will be described as a Y direction.

In this embodiment, the reticle R is held on a reticle base 28 via a reticle stage 27 movable in the X direction. The wafer W can be moved in the X direction for scanning exposure, and is held on a wafer stage 29 that can be moved in the Y direction for step movement between shots on the wafer W. The operations of reticle stage 27 and wafer stage 29 are controlled by stage control system 35. During scanning exposure, the stage control system 35
The wafer W is moved with respect to the exposure light via the wafer stage 29 in synchronization with the movement of the reticle R with respect to the exposure light via the reticle stage 27. Thereby, the pattern of reticle R is transferred onto the wafer.

In FIG. 1, near the wafer W on the wafer stage 29, an illuminance sensor 30 including a photoelectric conversion element is provided. The light receiving surface of the illuminance sensor 30 is set at the same height as the surface of the wafer W, and detects the illuminance of the exposure light on the image plane of the projection optical system PL. Illuminance sensor 3
The 0 detection signal is supplied to the main control system 34 and further to the exposure control system 31.

Further, in FIG. 1, the beam splitter 2
The exposure light reflected at 0 is received by an integrator sensor 19 composed of a photoelectric conversion element via a condenser lens 18, and the light receiving surface of the integrator sensor 19 is a reticle R
And is arranged on a surface optically substantially conjugate with the pattern formation surface of the reticle R, and detects the illuminance of the exposure light applied to the reticle R. The detection signal of the integrator sensor 19 is also supplied to the exposure control system 31.

Next, the operation of the exposure control in the scanning exposure apparatus of the present embodiment configured as described above will be described with reference to FIGS. In this embodiment, the aperture stop 1 for normal illumination is used in the above-mentioned scanning exposure apparatus.
A case in which exposure is performed using the aperture stop 16D for deformed illumination after performing exposure using 6A will be described. First, the main control system 34 rotates the illumination system aperture stop plate 16 via the second aperture drive mechanism 17, arranges the aperture stop 16 A in the optical path of the exposure light, and sets the wafer stage 29 via the stage control system 35. To place the illuminance sensor 30 in the illumination field of the exposure light. Main control system 3
4 instructs the exposure control system 31 to perform lamp calibration at the aperture stop 16A for normal illumination. The exposure control system 31 that has received the command from the main control system 34 adjusts the injection power supplied to the mercury lamp 1 via the power supply 33 to a value E1 slightly larger than the minimum value of the adjustable range and a value larger than the maximum value. The values are sequentially set to a slightly smaller value E2. Then, at each power set value, the integrator sensor 19
And the illuminance sensor 30 performs illuminance detection. At this time, at each power set value, the illuminance detection is performed by each sensor after waiting for the mercury lamp 1 to stabilize. The exposure control system 31 includes the integrator sensor 1
9 and the detection signal of the illuminance sensor 30, when the aperture stop 16 </ b> A (normal illumination) is used, the projection optical system P is used based on the illuminance of the exposure light incident on the integrator sensor 19.
A conversion coefficient K1 for obtaining the illuminance of the exposure light on the image plane of L is obtained. Thereby, the illuminance of the exposure light on the image plane of the projection optical system PL can be accurately detected from the detection signal of the integrator sensor 19. Further, the exposure control system 31 uses the illuminance of the exposure light detected by the integrator sensor 19 and the set powers E1 and E2 to calculate the power injected into the mercury lamp 1 when the aperture stop 16A (normal illumination) is used and the integrator sensor 19 The relationship with the illuminance of the exposure light detected in step (1) is obtained.
FIG. 3 shows the relationship between the power injected into the mercury lamp and the illuminance detected by the integrator sensor 19. 3, the horizontal axis represents the power E injected into the mercury lamp 1, and the vertical axis represents the illuminance P of the exposure light detected by the integrator sensor 19.
It is. In this case, the exposure control system 31 determines the slope a and the offset b of the straight line 44 indicating the control characteristics of the mercury lamp 1 when the aperture stop 16A for normal illumination is used. Thus, the illuminance P is expressed as a linear function of the injected power E as follows.

P = a · E + b (1) When equation (1) is solved for the injection power E, E = (P−b) / a (2), and this equation (2) is obtained from the mercury lamp 1. This is a control formula for determining the power E for setting the illuminance of the exposure light to the desired illuminance P. Since the relationship between the illuminance of the exposure light detected by the integrator sensor 19 and the illuminance on the image plane of the projection optical system PL (conversion coefficient K1) has also been determined, the exposure detected by the integrator sensor 19 according to equation (2). If the power injected into the mercury lamp 1 is adjusted so that the light illuminance P becomes a desired value, the illuminance PI on the image plane of the projection optical system PL can be maintained at a desired value. It should be noted that the set value of the electric power E for obtaining the relationship between the electric power E injected into the mercury lamp 1 and the illuminance P detected by the integrator sensor 19 is set to three or more different values, and instead of the equation (1), 2
A higher order function may be used instead of the expression (2) based on the higher order function.

When this control formula is determined, the exposure control system 3
Reference numeral 1 denotes a target exposure amount (target integrated exposure energy) to be given to each point on the wafer W during scanning exposure, and a projection optical system P
The illuminance on the image plane of L (the surface of the wafer W) is PI, the width of the illumination field on the wafer side in the moving direction (X direction) of the wafer stage 29 is H, and the scanning speed of the wafer stage 29 with respect to the illumination field is H. As V, the target illuminance PI01 and the target scanning speed V01 of the wafer stage are determined so that D = PI · H / V = (K1 · P) · H / V (3) That is, in this embodiment, since the width H of the illuminated field is fixed, it is necessary to control the image plane illuminance PI and / or the scanning speed V in accordance with the target exposure amount D for the wafer W. is there. The target scanning speed V01 is supplied to a main control system 34. The main control system 34 controls the wafer stage 29 via the stage control system 35 so that the scanning speed of the wafer stage 29 becomes the target scanning speed. Scanning exposure of the wafer W on the stage 29 is performed. During the scanning exposure, the illuminance PI on the wafer W is set to a predetermined target value PI01.
The power injected from the power supply 33 into the mercury lamp 1 is adjusted so as to be maintained.

That is, in the present embodiment, the illuminance of the exposure light on the wafer W during the scanning exposure finally reaches the integrator sensor 19.
Is fed back to the mercury lamp. When the exposure of a predetermined number of wafers is completed by the normal illumination using the aperture stop 16A, the main control system 34 rotates the illumination system aperture stop plate 16 via the second aperture drive mechanism 17, and sets the aperture for the modified illumination. The stop 16D is arranged in the optical path of the exposure light.

When the illumination condition for the reticle R is switched as described above, the light receiving surface of the integrator sensor 19 is optically conjugate with the pattern forming surface of the reticle R, and thus the exposure light (part) to the integrator sensor 19 is changed. May change, and an error may occur in the detection sensitivity of the integrator sensor 19 due to the incident angle. That is,
The control line 44 used for exposure at the aperture stop 16A for normal illumination in FIG. 3 is detected by the power E injected into the mercury lamp 1 and the integrator sensor 19 when the aperture stop 16D for modified illumination is used. The relationship with the illuminance P of the exposure light is not accurately represented. Therefore, in this embodiment, the lamp calibration is performed every time the illumination condition is switched.

More specifically, in the same manner as described above, the illuminance sensor 30 is arranged in the field of exposure light, and the power supplied to the mercury lamp 1 via the power supply 33 is adjusted within the adjustable range. Value E slightly larger than minimum value
1, and sequentially set to a value E2 slightly smaller than the maximum value. Then, at each power set value, illuminance detection is performed by the integrator sensor 19 and the illuminance sensor 30, respectively. At this time, at each power set value, the illuminance detection is performed by each sensor after waiting for the mercury lamp 1 to stabilize. The exposure control system 31 uses the detection signal of the integrator sensor 19 and the detection signal of the illuminance sensor 30 to detect the illuminance of the exposure light incident on the integrator sensor 19 when using the aperture stop 16D (deformed illumination). A conversion coefficient K2 for obtaining the illuminance of the exposure light on the image plane is obtained. Thus, the illuminance of the exposure light on the image plane of the projection optical system PL can be detected from the detection signal of the integrator sensor 19. Further, the exposure control system 31 determines the aperture stop 16D (deformed illumination) from the illuminance of the exposure light detected by the integrator sensor 19 and the set powers E1 and E2.
Is used, the relationship between the power injected into the mercury lamp 1 and the illuminance of the exposure light detected by the integrator sensor 19 is determined. In FIG. 3, the straight line 46 is the aperture stop 1 for the modified illumination.
The control characteristics of the mercury lamp 1 when 6D is used are shown.
The exposure control system 31 newly determines the inclination a 'and the offset b' of the control line 46 for the modified illumination. Thereafter, control of the power injected into the mercury lamp 1 is performed by a control formula in which the coefficients a and b in the formula (2) are replaced by the newly determined slope a 'and offset b'. Then, the exposure control system 31 determines the target illuminance PI02 and the target scanning speed V02 of the wafer stage so that D = (K2 · P) · H / V (4) is satisfied. The main control system 34
The scanning exposure of the wafer W on the wafer stage 29 is performed by controlling the wafer stage 29 via the stage control system 35 so that the scanning speed of the wafer stage 29 becomes the target scanning speed V02. During this scanning exposure, the illuminance PI on the wafer W is maintained at a predetermined target value PI02.
The power injected from the power supply 33 into the mercury lamp 1 is adjusted.

As described above, in this embodiment, the lamp calibration is performed every time the illumination condition for the reticle is switched, so that the exposure amount of the wafer W can always be accurately controlled. By the way, when the illumination conditions are switched as described above, the path of the exposure light on the pupil plane of the projection optical system PL (light intensity distribution on the pupil plane of the projection optical system PL) changes. Partial thermal deformation newly occurs, and continuity is lost in changes in the imaging characteristics (magnification, focal position, and the like) of the projection optical system PL due to exposure light exposure. That is, when the illumination condition is switched, the effect of the exposure under the previous illumination condition remains in the projection optical system PL. Therefore, immediately after switching to the new illumination condition, the desired imaging characteristics are not generated in the projection optical system PL. I can't get it.

FIG. 4 shows how the imaging characteristics of the projection optical system PL change when the illumination conditions for the reticle are switched. In FIG. 4, the horizontal axis represents time T, and the vertical axis represents the amount of change in the imaging characteristics of the projection optical system PL due to exposure light exposure. In FIG. 4, the illumination condition is switched at time Ta after the exposure under the previous illumination condition ends. As shown by the solid line 48 in FIG. 4, at the time Ta when the illumination condition is switched, the change A of the imaging characteristic due to the exposure under the previous illumination condition remains. Therefore, if the exposure under the new illumination condition is started immediately after the time Ta, as shown by a broken line 50 in FIG.
Will change from the state of A, which may affect exposure under a new illumination condition. Therefore, when the switching of the illumination condition is performed, usually, as shown by the solid line 52 in FIG. 4, the variation of the imaging characteristic of the projection optical system PL due to the exposure under the previous illumination condition is a predetermined threshold. The exposure operation is paused for a predetermined time ΔT after switching the illumination condition so that the exposure starts from a value below the value. The change of the image forming characteristic due to the change of the illumination condition and the halt of the exposure operation due to the change of the illumination condition are disclosed in Japanese Patent Application Laid-Open No. 6-45217, and the detailed description is omitted.

In the present embodiment, the imaging characteristic of the projection optical system PL is not changed during the lamp calibration operation during the pause time ΔT of the exposure operation after the switching of the illumination condition, ie, the projection optical system PL Some operations are performed so that exposure light does not enter. Specifically, the operation of arranging the exposure light of the illuminance sensor 30 in the illumination field, setting the injection power supplied to the mercury lamp 1 by the power supply 33 (for example, E1), and waiting for the mercury lamp 1 to stabilize. At least part of the pause time Δ
Try to do it at T. As a result, the time required for substantial lamp calibration can be reduced, and the overall processing performance of the exposure apparatus can be improved.

In the above-described embodiment, the illumination condition is changed from the normal illumination (the aperture stop 16A) to the modified illumination (the aperture stop 16A).
Although the case of switching to D) has been described, the switching of the illumination conditions of the present invention is not limited to this, and various switching such as switching from deformed illumination (aperture stop 16D) to normal illumination (aperture stop 16A) is possible. Corresponding.

In the exposure apparatus according to the present embodiment, the mask pattern is exposed while the mask and the substrate are almost stationary, and the substrate is moved step by step.
The present invention can also be applied to a repeat type exposure apparatus. Further, the present invention can also be applied to a proximity exposure apparatus that exposes a mask pattern by bringing a mask and a substrate into close contact without using a projection optical system.

The application of the exposure apparatus is not limited to an exposure apparatus for manufacturing a semiconductor. For example, an exposure apparatus for a liquid crystal for exposing a liquid crystal display element pattern to a square glass plate and a thin film magnetic head are manufactured. It can be widely applied to an exposure apparatus for performing the above. Further, the light source of the exposure apparatus of this embodiment is not only an i-line (365 nm) but also a g-line (436n).
m), KrF excimer laser (248 nm), ArF excimer laser (193 nm), F ₂ laser (157 n)
m), X-rays can be used.

As a projection optical system, when far ultraviolet rays such as an excimer laser are used, a material that transmits far ultraviolet rays such as quartz or fluorite is used as a glass material, and when an F ₂ laser or X-ray is used, a catadioptric system is used. Alternatively, a refraction type optical system is used (a reticle is of a reflection type), and the magnification of the projection optical system is not limited to a reduction system but may be any one of an equal magnification and an enlargement system.

A linear motor (see USP 5,623,853 or USP 5,528,118) for the wafer stage or reticle stage
In the case of using an air bearing, either an air floating type using an air bearing or a magnetic floating type may be used. The stage may be of a type that moves along a guide or a guideless type that does not have a guide. The reaction force generated by the movement of the wafer stage may be mechanically released to the floor (ground) using a frame member (as described in US Pat. No. 5,528,118).

The reaction force generated by the movement of the reticle stage is (as described in S / N 416558)
You may mechanically escape to the floor (ground) using a frame member. In addition, the illumination optical system composed of multiple lenses and the projection optical system are incorporated in the main body of the exposure apparatus to perform optical adjustment. The exposure apparatus of the present embodiment can be manufactured by electrically and optically connecting and further performing overall adjustment (electrical adjustment, operation confirmation, etc.). It is desirable that the manufacture of the exposure apparatus be performed in a clean room in which the temperature, cleanliness, and the like are controlled.

As described above, the present invention is not limited to the above-described embodiment, and can take various configurations without departing from the gist of the present invention.

[0038]

As described above, according to the present invention, when the illumination condition for a mask such as a reticle is switched, lamp calibration is performed, and the relationship between the power supplied to the light source and the illuminance of the exposure beam is expressed. The control formula and the like are updated according to the changed lighting conditions. Therefore, there is an advantage that the exposure amount control when transferring the pattern onto the substrate can be performed with high accuracy.

Since the lamp calibration is performed using the pause time of the exposure operation after the switching of the illumination condition, a decrease in the processing capability of the exposure apparatus due to the lamp calibration can be minimized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a scanning exposure apparatus used in an example of an embodiment of the present invention.

FIG. 2 is a plan view showing a plurality of aperture stops arranged on an illumination system aperture stop plate.

FIG. 3 is a diagram showing that the relationship between the power injected into an exposure light source and the illuminance of exposure light incident on an integrator sensor changes between a case where normal illumination is used and a case where modified illumination is used.

FIG. 4 is a diagram for explaining a state of a change in an imaging characteristic of a projection optical system due to irradiation of exposure light and a pause of an exposure operation performed after switching of illumination conditions.

FIG. 5 shows an exposure operation in a time series when the illumination condition is switched.

FIG. 6 is a diagram showing a change in illuminance that occurs when constant power is supplied to a mercury lamp.

FIG. 7 is a diagram showing the relationship between the power injected to an exposure light source and the illuminance of exposure light incident on an integrator sensor.

FIG. 8 is a diagram illustrating a temporal change in illuminance when the injection power to the exposure light source is changed.

[Explanation of symbols]

 Reference Signs List 1 mercury lamp 16 illumination system aperture stop plate 19 integrator sensor 20 beam splitter 30 illuminance sensor 31 exposure control system 33 power supply 34 main control system 35 stage control system R reticle PL projection optical system W wafer

Claims (8)

[Claims] 1. An exposure amount control method for illuminating a mask with an exposure beam from an exposure light source and controlling an exposure amount on the substrate to transfer a pattern of the mask onto the substrate via a projection optical system, Changing an illumination condition for the mask, changing a control characteristic for setting a driving power for obtaining an exposure beam of a desired illuminance from the exposure light source in accordance with the changed illumination condition, An exposure control method, wherein the exposure light source is driven during exposure of the substrate based on characteristics. 2. The method according to claim 1, wherein the changing of the illumination condition changes a light intensity distribution in a pupil plane of the projection optical system or a plane optically conjugate with the pupil plane. Exposure control method. 3. A relationship between driving power to the light source for exposure under the changed illumination condition and illuminance of an exposure beam from the light source for exposure is measured, and the control characteristic of the control characteristic is determined based on the measured relationship. 3. The exposure amount control method according to claim 1, wherein the change is performed. 4. At least a part of the operation for determining the relationship between the driving power to the exposure light source and the illuminance of the exposure beam from the exposure light source while the exposure operation is suspended due to the change of the illumination condition. 4. The exposure control method according to claim 3, wherein: 5. An exposure apparatus for illuminating a mask with an exposure beam and transferring a pattern of the mask onto a substrate, comprising: an exposure light source for generating the exposure beam; and a drive power supply for supplying drive power to the exposure light source. And an illumination condition setting system for changing the illumination condition of the exposure beam with respect to the mask; and when the illumination condition for the mask is changed by the illumination condition setting system, the exposure condition is adjusted in accordance with the changed illumination condition. A control characteristic for setting a driving power for obtaining an exposure beam having a desired illuminance from a light source is changed, and the driving power is supplied from the driving power source to the exposure light source during exposure of the substrate based on the changed control characteristic. An exposure apparatus comprising: an exposure amount control system that sets driving power. 6. A photodetector arranged on a surface substantially conjugate to a pattern forming surface of the mask and detecting an illuminance of the exposure light, wherein the exposure amount control system has the changed control characteristic and The exposure apparatus according to claim 5, wherein a driving power supplied from the driving power supply to the exposure light source during exposure of the substrate is set based on a detection result of the photoelectric detector. 7. An exposure apparatus according to claim 6, wherein said photoelectric detector has a different detection sensitivity according to an illumination condition for said mask. 8. The exposure apparatus according to claim 5, wherein a pattern of the mask is transferred onto the substrate while moving the mask and the substrate synchronously.