JP2004158630A - Charged particle beam aligning method and charged particle beam aligniner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charged particle beam exposure method and a charged particle beam aligner in which degradation of pattern accuracy dependent on the error in the Z axis position of a wafer stage can be prevented. <P>SOLUTION: The aligner is provided with a detector for detecting the Z axis position of a sensitive substrate 23, a stage 24 for correcting the Z axis (beam axis) position of the sensitive substrate 23, and a lens for correcting focus of a projection optical system. A shot cycle is set with a moderate margin. When correction error in the Z axis position of the sensitive substrate 23 exceeds an allowance in a subfield, the subfield is exposed after waiting until that error falls within the allowance. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a charged beam exposure method and a charged beam exposure apparatus for projecting and exposing an original pattern on an original (mask, reticle) onto a sensitive substrate (wafer or the like) using a charged beam.
[0002]
[Prior art]
The prior art will be described using electron beam exposure as an example.
The drawback of electron beam exposure is high accuracy but low throughput, and various technical developments have been made to solve the drawback. At present, a pattern part batch exposure method called cell projection, character projection or block exposure has been put to practical use. In the figure partial batch exposure method, a small circuit pattern having repeatability (about 5 μm square on a wafer (sensitive substrate)) is repeatedly transferred and exposed using a reticle on which a plurality of similar small patterns are formed. However, even in this method, since the patterning having no repeatability is performed by the variable molding method, the throughput is still low for a wafer exposure apparatus for mass production.
[0003]
A batch transfer method has been studied as an electron beam transfer exposure method aiming at a much higher throughput than the figure partial collective exposure method. This is a method of exposing one die (chip) or a plurality of dies at a time. However, this method has problems in that it is difficult to manufacture a reticle serving as a master for transfer, and it is difficult to keep aberration within an allowable range in a large optical field such as one or more dies. is there.
For these reasons, studies of this type of apparatus have recently been declining.
[0004]
Therefore, a method that has been recently studied is to perform transfer exposure by dividing the pattern of one entire die into small areas (subfields) instead of exposing one or more dies requiring a large optical field at a time. (Herein, referred to as a division transfer method). In this method, exposure is performed for each divided small area while correcting aberrations such as a focal point of an image formed on a surface to be exposed and field distortion. This makes it possible to perform exposure with high resolution and accuracy over an optically wider area than batch transfer.
[0005]
[Problems to be solved by the invention]
In the above-described split transfer type exposure apparatus, the position of the sensitive substrate (wafer) stage in the Z-axis direction (beam axis direction) is measured almost in real time for each exposure in each subfield. If the position is shifted, the wafer stage is mechanically moved to perform Z-axis direction correction. However, the movement of the wafer stage in the Z-axis direction has a slow response, and the desired Z position may not be set until the next subfield is exposed.
[0006]
Therefore, a slight residue in the Z-axis direction is optically corrected by the projection optical system. That is, three correction lenses are arranged on the lens of the projection optical system, and these lenses are used to optically correct the deviation of the focus, rotation, and magnification of the subfield caused by the residue in the Z-axis direction. However, the range in the Z-axis direction that can be optically corrected is narrow, and the correction range may not be within the allowable range. For this reason, deviations in the focus, rotation, magnification, etc. of the subfield may occur on the wafer, and the positional accuracy, the joining accuracy, and the resolution of the subfield may be degraded.
[0007]
The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a charged beam exposure method and a charged beam exposure apparatus that prevent deterioration of pattern accuracy depending on an error in a position of a wafer stage in a Z-axis direction. Aim.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, a first charged beam exposure method according to the present invention forms a pattern to be transferred onto a sensitive substrate on an original, and sequentially forms the pattern for each partial area (subfield). The charged particle beam is illuminated while being deflected, and the charged particle beam that has passed through the subfield is sequentially projected and imaged on the sensitive substrate via a projection optical system, and an image of each subfield is formed on the sensitive substrate. A method of transferring the entire pattern by joining them together, and performing transfer exposure while correcting the position of the sensitive substrate in the Z-axis direction (beam axis direction) and the focus of the projection optical system for each subfield; When an error in correcting the position of the sensitive substrate in the Z-axis direction in a certain subfield exceeds an allowable value, the subfield is waited until the error falls within the allowable value. And performing exposure.
[0009]
A shot cycle (exposure interval between a certain subfield and the next subfield) is set with a relatively large margin, and the subfield is waited until the position of the sensitive substrate in the Z-axis direction falls within an allowable value during this shot cycle. Exposure. Therefore, deviations in focus, rotation, and magnification due to errors in the Z-axis direction position fall within the allowable range, and pattern accuracy can be improved.
[0010]
According to a second charged beam exposure method of the present invention, transfer exposure is performed while correcting the position of the sensitive substrate in the Z-axis direction (beam axis direction) and the focus of the projection optical system for each of the subfields. If the error in correcting the position of the sensitive substrate in the Z-axis direction in the subfield exceeds an allowable value, the exposure is stopped.
If the error in the position of the sensitive substrate in the Z-axis direction is out of the allowable value, the exposure is temporarily stopped, and after the error falls within the allowable value, the exposure is restarted. For this reason, at the time of exposure, deviations in focus, rotation, and magnification due to errors in the position in the Z-axis direction are within an allowable range, and pattern accuracy can be improved.
[0011]
A first charged beam exposure apparatus according to the present invention includes a stage on which an original plate on which a pattern to be transferred onto a sensitive substrate is formed is placed, and the pattern is sequentially charged for each partial area (subfield). An illumination optical system for illuminating while deflecting the beam, a projection optical system for sequentially projecting and imaging the charged particle beam passing through the subfield on the sensitive substrate, and a stage for mounting the sensitive substrate An exposure apparatus for transferring and exposing the entire pattern by joining images of respective sub-fields on the sensitive substrate, wherein: a unit for detecting a position in the Z-axis direction of the sensitive substrate; and a Z-axis of the sensitive substrate. Means for correcting the position in the direction (beam axis direction), and means for correcting the focus of the projection optical system, wherein a certain sub-field detected by the Z-axis direction position detecting means is provided. If the error of the position of the sensitive substrate in the Z-axis direction exceeds the allowable value, the correction means waits for exposure of the subfield until the error of the position of the sensitive substrate in the Z-axis direction falls within the allowable value. Features.
[0012]
A second charged beam exposure apparatus according to the present invention includes: means for detecting a position of the sensitive substrate in the Z-axis direction; means for correcting the position of the sensitive substrate in the Z-axis direction (beam axis direction); Means for correcting the focus, wherein the exposure operation is stopped when an error in the Z-axis direction position of the sensitive substrate in a certain subfield detected by the Z-axis direction position detection means exceeds an allowable value. It is characterized.
[0013]
A third charged beam exposure apparatus according to the present invention includes: a stage on which an original plate on which a pattern to be transferred on a sensitive substrate is formed is placed; and the pattern is sequentially charged for each partial area (subfield). An illumination optical system for illuminating while deflecting the beam, a projection optical system for sequentially projecting and imaging the charged particle beam passing through the subfield on the sensitive substrate, and a stage for mounting the sensitive substrate An exposure apparatus for transferring and exposing the entire pattern by joining images of respective sub-fields on the sensitive substrate, wherein: a unit for detecting a position in the Z-axis direction of the sensitive substrate; and a Z-axis of the sensitive substrate. Means for correcting the direction (beam axis direction) position; and means for correcting the focus of the projection optical system. The position of the sensitive substrate in the Z-axis direction and / or the position of the projection optical system Wherein the Okasu shot cycle in consideration of a time required for correction is set.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, description will be made with reference to the drawings.
Note that the following description is made by taking, as an example, the electron beam projection exposure of the division transfer system.
FIG. 1 is a diagram showing an outline of an image forming relationship and a control system in an entire optical system of an electron beam projection exposure apparatus of a division transfer system.
FIG. 2 is a diagram illustrating details of the projection optical system and the vicinity of the wafer of the exposure apparatus of FIG.
The electron gun 1 arranged at the uppermost stream of the optical system emits an electron beam downward. Below the electron gun 1, two stages of condenser lenses 2 and 3 are provided, and the electron beam is converged by these condenser lenses 2 and 3 and crossed over to a blanking aperture 7 by a C.C. O. Is imaged.
[0015]
A rectangular opening 4 is provided below the second-stage condenser lens 3. The rectangular aperture (illumination beam shaping aperture) 4 allows only an illumination beam that illuminates one subfield (a pattern small area to be one unit of exposure) of the reticle (mask) 10 to pass. The image of the opening 4 is formed on the reticle 10 by the lens 9.
[0016]
A blanking deflector 5 is arranged below the beam shaping opening 4. The deflector 5 deflects the illumination beam when necessary to hit the non-opening portion of the blanking opening 7 so that the beam does not hit the reticle 10.
An illumination beam deflector (main deflector of the illumination optical system) 8 is arranged below the blanking opening 7. The deflector 8 mainly scans the illumination beam sequentially in the horizontal direction (X direction) in FIG. 1 to illuminate each subfield of the reticle 10 within the field of view of the illumination optical system. An illumination lens 9 is arranged below the deflector 8. The illumination lens 9 forms an image of the beam shaping aperture 4 on the reticle 10.
[0017]
The reticle 10 actually extends in the plane perpendicular to the optical axis (the XY plane) (described later with reference to FIG. 3). On the reticle 10, a pattern (chip pattern) forming one semiconductor device chip as a whole is formed. Needless to say, a pattern forming one semiconductor device chip may be divided and arranged on a plurality of reticles.
The pattern on the reticle 10 is divided into a number of subfields.
[0018]
The reticle 10 is mounted on a movable reticle stage 11. By moving the reticle 10 in a direction perpendicular to the optical axis (XY directions), each subfield on the reticle extending over a wider area than the field of view of the illumination optical system can be illuminated.
The reticle stage 11 is provided with a position detector 12 using a laser interferometer, so that the position of the reticle stage 11 can be accurately grasped in real time.
[0019]
Below the reticle 10, there are provided projection lenses 15 and 19, a main deflector (image position adjusting deflector) 16 of the projection optical system, and the like. The electron beam passing through one subfield of the reticle 10 is imaged at a predetermined position on the wafer 23 by the projection lenses 15 and 19 and the main deflector 16. Detailed operations of the projection lenses 15 and 19 and the main deflector 16 (image position adjusting deflector) will be described later with reference to FIG.
[0020]
The point at which the reticle 10 and the wafer 23 are internally divided at the reduction ratio is crossover C. O. Are formed, and a contrast opening 18 is provided at the crossover position. The contrast aperture 18 blocks the electron beam scattered by the non-pattern portion of the reticle 10 from reaching the wafer 23.
[0021]
The wafer 23 is placed on a wafer stage 24 that can move in the XYZ directions via an electrostatic chuck (not shown). By synchronously scanning the reticle stage 11 and the wafer stage 24 in directions opposite to each other, each part in the chip pattern extending beyond the field of view of the projection optical system can be sequentially exposed. Note that the wafer stage 24 is also provided with a position detector 25 similar to the reticle stage 11 described above.
[0022]
An appropriate resist is applied on the wafer 23, an electron beam is given to the resist, and the pattern on the reticle is reduced and transferred onto the wafer 23.
[0023]
Above the wafer 23, a backscattered electron detector 22 is arranged. The backscattered electron detector 22 detects the amount of electrons reflected on a surface to be exposed of the wafer 23 and a mark on the stage. For example, by scanning a mark on the wafer 23 with a beam that has passed through a mark pattern on the reticle 10 and detecting reflected electrons from the mark at that time, the relative positional relationship between the reticle 10 and the wafer 23 and the electron beam (beam) ) You can know the properties.
[0024]
The lenses 2, 3, 9, 15, 19 and the deflectors 5, 8, 16 are controlled by the controller 31 via the respective coil power control units 2a, 3a, 9a, 15a, 19a and 5a, 8a, 16a. Controlled. The reticle stage 11 and the wafer stage 24 are also controlled by the controller 31 via the stage controllers 11a and 24a. The stage position detectors 12 and 25 send signals to the controller 31 via interfaces 12a and 25a including an amplifier and an A / D converter. The backscattered electron detector 22 also sends a signal to the controller 31 via the same interface 22a.
[0025]
The controller 31 grasps the control error of the stage position and corrects the error by the main deflector 16. Thus, control can be performed such that the reduced image of the subfield on the reticle 10 matches the target position on the wafer 23. Then, the subfield images are joined on the wafer 23, and the entire chip pattern on the reticle 10 is transferred onto the wafer 23.
[0026]
Next, details of the projection optical system and the vicinity of the wafer of the exposure apparatus of FIG. 1 will be described with reference to FIG.
The first projection lens 15 is provided with three correction lenses 35-1 to 35-3.
The second projection lens 19 is also provided with three correction lenses 37-1 to 37-3. These correction lenses perform various aberration corrections and magnification / shape corrections. A wafer stage Z position detector 39 is provided on the wafer stage 24.
The Z position detector 39 has a light transmitting system 39a and a light receiving system 39b, each of which is disposed at a position facing each other across a lens barrel of the projection optical system. The signal light sent from the light transmitting system 39a is applied to the upper surface of the wafer 23 of the wafer stage 24, reflected on the same surface, and the reflected light is received by the light receiving system 39b. Then, a signal is sent from the light receiving system 39b to the controller 31, and the height of the upper surface of the wafer 23 of the wafer stage 24 is detected from the intensity of the reflected light.
[0027]
Next, a detailed example of a reticle used for the electron beam projection exposure of the division transfer system will be described with reference to FIG.
FIG. 3 is a diagram schematically illustrating a configuration example of a reticle for electron beam projection exposure. (A) is an overall plan view, (B) is a partial perspective view, and (C) is a plan view of one small membrane region.
Such a reticle can be manufactured, for example, by drawing and etching an electron beam on a silicon wafer.
[0028]
FIG. 3A shows the entire pattern divided arrangement state of the reticle 10. The area indicated by a large number of squares 41 in the figure is a small membrane area (0.1 μm to several μm in thickness) including a pattern area corresponding to one subfield. As shown in FIG. 3C, the small membrane region 41 is composed of a central pattern region (subfield) 42 and a surrounding frame-shaped non-pattern region (skirt 43). The subfield 42 is a portion where a pattern to be transferred is formed. The skirt 43 is a portion where no pattern is formed, and corresponds to an edge portion of the illumination beam. As a form of pattern formation, there are a stencil type in which a hole is formed in the membrane and a scattering membrane type in which a pattern layer made of a high electron beam scatterer is formed on the membrane.
[0029]
One subfield 42 has a size of about 1 mm square on a reticle, as it is currently under consideration. Assuming that the reduction ratio of the projection is 1/4, the size of the projected image in which the subfield is reduced and projected on the wafer is 0.25 mm square. An orthogonal lattice-shaped minor strut portion 45 around the small membrane region 41 is a beam having a thickness of, for example, about 0.7 mm to maintain the mechanical strength of the reticle. The width of the minor strut 45 is, for example, about 0.1 mm. The width of the skirt 43 is, for example, about 0.05 mm.
[0030]
As shown in FIG. 3A, a number of small membrane regions 41 are arranged side by side in the horizontal direction (X direction) of the figure to form one group (electrical stripe 44), and such an electrical stripe 44 is formed in the vertical direction of the figure. One mechanical stripe 49 is formed side by side in a large number in the (Y direction). The length of the electrical stripe 44 (the width of the mechanical stripe 49) is limited by the size of the deflectable visual field of the illumination optical system.
[0031]
A plurality of mechanical stripes 49 exist in parallel in the X direction.
The wide beams shown as the major struts 47 between the adjacent mechanical stripes 49 are for keeping the deflection of the whole reticle small.
The major strut 47 is integral with the minor strut 45.
[0032]
According to a system considered to be currently influential, a row of the subfields 42 (electrical stripes 44) in the X direction in one mechanical stripe (hereinafter simply referred to as a stripe) 49 is sequentially exposed by electron beam deflection. On the other hand, the columns in the Y direction in the stripe 49 are sequentially exposed by continuous stage scanning.
[0033]
Next, an electron beam exposure method according to an embodiment of the present invention will be described.
FIG. 4 is a perspective view schematically showing a state of pattern transfer from a reticle to a wafer.
At the top of the figure, one mechanical stripe 49 on the reticle 10 is shown. As described above, the mechanical stripe 49 is formed with a number of electrical stripes 44, subfields 42 (skirts are not shown), and minor struts 45. In the lower part of the figure, a wafer 23 facing the reticle 10 is shown.
[0034]
In this figure, a subfield 42-1 at the left corner of the electrical stripe 44 in front of the stripe 49 on the reticle is illuminated by the illumination beam IB from above. Then, the pattern beam PB that has passed through the subfield 42-1 is reduced and projected onto a predetermined area 52-1 on the wafer 23 by the operation of the two-stage projection lenses 15, 19 and the main deflector 16 (see FIG. 1). ing.
The pattern beam PB is deflected twice between the reticle 10 and the wafer 23 by a two-stage projection lens from a direction parallel to the optical axis to a direction intersecting the optical axis and vice versa.
[0035]
Each subfield 42 in the electrical stripe 44 is sequentially exposed by the deflection of the electron beam by the main deflector 16 as described above, and is sequentially reduced and projected on the electrical stripe 54 on the wafer 23. The time interval from the end of exposure of one subfield 42-1 in the electrical stripe 44 to the exposure of the next subfield 42-2 is called a shot cycle.
[0036]
In the case of the first embodiment of the present invention, this shot cycle is set with a margin more than a general shot cycle. Then, at the time of exposure of each subfield 42, the Z position of the wafer stage 24 is detected in real time by the Z position detector 39 (see FIG. 2). If the Z position of the stage 24 is not within the allowable range, the Z position of the stage 24 is mechanically corrected by the stage control unit 24a in accordance with the error, and the correction provided to each of the projection lenses 15 and 19 is performed. The lenses 35 and 37 perform focus correction of the projection optical system. As described above, the shot cycle is set longer than a general shot cycle, and during this cycle, the Z position of the stage 24 is expected to fall within an allowable range due to mechanical and optical corrections. Then, exposure is performed after the stage 24 has reached an appropriate Z position.
In this method, the shot time (exposure time of one subfield) and the shot cycle in each subfield are constant, and the wafer stage 24 runs at a constant speed sequence.
[0037]
When the Z position of the wafer stage 24 enters the allowable range without any problem in many subfields, it is not necessary to wait for exposure. In this case, too, the blanking time between the subfield exposures by the blanking deflector 5 is extended to adjust the exposure position so as not to shift.
[0038]
In the case of the second embodiment of the present invention, if the Z position of the wafer stage does not fall within the allowable range, the blanking deflector 5 deflects the illumination beam so that the beam does not hit the reticle 10. Stop exposure. Then, after the Z position falls within the allowable range, exposure is performed again from the subfield.
[0039]
When the exposure of one electrical stripe 44 is completed, the mask stage and the wafer stage are continuously scanned in the Y direction at a speed according to the reduction ratio, and the next electrical stripe 44 (the Y direction row in the mechanical stripe 49) is scanned. ) Is exposed, and the electrical stripe 44 is reduced and projected on the electrical stripe 54 on the wafer 23. Thus, all the subfields 42 in the mechanical stripe 44 are exposed. Thus, one mechanical stripe 44 is exposed by one stage scan.
[0040]
【The invention's effect】
As is apparent from the above description, according to the present invention, since exposure is performed when the Z position of the wafer stage falls within the allowable error range, focus, magnification, rotation depending on the error of the Z position of the wafer stage are performed. Thus, a charged particle beam exposure method and an exposure apparatus can be provided in which the sub-field position accuracy on the wafer, the joining accuracy, and the resolution are improved without error.
[Brief description of the drawings]
FIG. 1 is a diagram showing an outline of an imaging relationship and a control system in an entire optical system of an electron beam projection exposure apparatus of a division transfer system.
FIG. 2 is a diagram illustrating details of a projection optical system and a vicinity of a wafer of the exposure apparatus of FIG. 1;
FIG. 3 is a diagram schematically illustrating a configuration example of a reticle for electron beam projection exposure. (A) is an overall plan view, (B) is a partial perspective view, and (C) is a plan view of one small membrane region.
FIG. 4 is a perspective view schematically showing a pattern transfer from a reticle to a wafer.
[Explanation of symbols]
Reference Signs List 1 electron gun 2, 3 condenser lens 4 rectangular aperture 5 blanking deflector 7 blanking aperture 8 illumination beam deflector 9 illumination lens 10 reticle 11 reticle stage 12 position detector 15, 19 projection lens 16 main deflector 17 for mark scanning Deflector 18 Contrast aperture 22 Backscattered electron detector 23 Wafer 24 Wafer stage 25 Position detector 31 Controller 35, 37 Correction lens 39 Z position detector 41 Small membrane area 42 Subfield 43 Skirt 44 Electrical stripe 45 Minor strut 49 Mechanical strut 52 Subfield 54 Electrical stripe 59 Mechanical stripe

Claims (5)

Form the pattern to be transferred on the sensitive substrate on the original plate,
The pattern is illuminated while sequentially deflecting the charged particle beam for each partial area (subfield),
The charged particle beam passing through the subfield is sequentially projected and imaged on the sensitive substrate via a projection optical system,
A method of transferring the entire pattern by joining images of each subfield on the sensitive substrate,
For each subfield, transfer exposure is performed while correcting the position of the sensitive substrate in the Z-axis direction (beam axis direction) and the focus of the projection optical system;
At this time, if an error in the correction of the position of the sensitive substrate in the Z-axis direction in a certain subfield exceeds an allowable value, the subfield is exposed after the error is within the allowable value. Charged beam exposure method. Form the pattern to be transferred on the sensitive substrate on the original plate,
The pattern is illuminated while sequentially deflecting the charged particle beam for each partial area (subfield),
The charged particle beam passing through the subfield is sequentially projected and imaged on the sensitive substrate via a projection optical system,
A method of transferring the entire pattern by joining images of each subfield on the sensitive substrate,
For each subfield, transfer exposure is performed while correcting the position of the sensitive substrate in the Z-axis direction (beam axis direction) and the focus of the projection optical system;
At this time, if the error in correcting the position of the sensitive substrate in the Z-axis direction in a certain subfield exceeds an allowable value, the exposure is stopped. A stage on which an original having a pattern to be transferred onto the sensitive substrate is placed;
An illumination optical system that illuminates the pattern while sequentially deflecting the charged particle beam for each partial area (subfield);
A projection optical system for sequentially projecting and imaging the charged particle beam passing through the subfield on the sensitive substrate;
A stage on which the sensitive substrate is placed,
With
An exposure apparatus that transfers and exposes the entire pattern by joining images of each subfield on the sensitive substrate,
Means for detecting the position of the sensitive substrate in the Z-axis direction;
Means for correcting the position of the sensitive substrate in the Z-axis direction (beam axis direction);
Means for correcting the focus of the projection optical system,
If the error in the Z-axis position of the sensitive substrate in a certain subfield detected by the Z-axis direction position detector exceeds an allowable value, the error in the Z-axis direction position of the sensitive substrate is corrected by the correction unit to the allowable value. A charged beam exposure apparatus wherein the exposure of the subfield is waited until the value becomes within the value. A stage on which an original having a pattern to be transferred onto the sensitive substrate is placed;
An illumination optical system that illuminates the pattern while sequentially deflecting the charged particle beam for each partial area (subfield);
A projection optical system for sequentially projecting and imaging the charged particle beam passing through the subfield on the sensitive substrate;
A stage on which the sensitive substrate is placed,
With
An exposure apparatus that transfers and exposes the entire pattern by joining images of each subfield on the sensitive substrate,
Means for detecting the position of the sensitive substrate in the Z-axis direction;
Means for correcting the position of the sensitive substrate in the Z-axis direction (beam axis direction);
Means for correcting the focus of the projection optical system,
A charged beam exposure apparatus wherein the exposure operation is stopped when an error in the Z-axis direction position of the sensitive substrate in a certain subfield detected by the Z-axis direction position detection means exceeds an allowable value. A stage on which an original having a pattern to be transferred onto the sensitive substrate is placed;
An illumination optical system that illuminates the pattern while sequentially deflecting the charged particle beam for each partial area (subfield);
A projection optical system for sequentially projecting and imaging the charged particle beam passing through the subfield on the sensitive substrate;
A stage on which the sensitive substrate is placed,
With
An exposure apparatus that transfers and exposes the entire pattern by joining images of each subfield on the sensitive substrate,
Means for detecting the position of the sensitive substrate in the Z-axis direction;
Means for correcting the position of the sensitive substrate in the Z-axis direction (beam axis direction);
Means for correcting the focus of the projection optical system,
A charged beam exposure apparatus, wherein a shot cycle is set in consideration of a position of the sensitive substrate in a Z-axis direction and / or a time required for focus correction of the projection optical system.

Images