JPH0817702A - Apparatus and method for charged-particle-beam - Google Patents

Abstract

PURPOSE:To correct the astigmatism and the image-surface curve of a crossover image by an electron gun so as not to generate an exposure irregularity on a transmitted pattern image and to perform an exposure operation with high accuracy regarding a charged-particle-beam aligner which is used in the manufacturing process or the like of an integrated circuit, e.g. an electron beam aligner. CONSTITUTION:Every block pattern for measurement of a sample-current-density distribution as shown in Fig. 2E is formed in blocks 221, 222,... 2248 in a deflector area 1712 for a block mask 13. The driving value of a mask deflector, the driving value of an astigmatism correction coil and the driving value of an image-surface-curve correction coil are found in such a way that the sample- current-density distribution in the peripheral part in every block pattern is made uniform or nearly uniform, and a regular exposure operation is performed on the basis of them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged particle beam exposure apparatus and an exposure method used in manufacturing processes of integrated circuits.

[0002]

2. Description of the Related Art Conventionally, as a charged particle beam exposure apparatus, for example, an electron beam exposure apparatus, exposure in which a cross section of an electron beam is shaped into a desired shape by a mask plate having various transmission patterns, that is, so-called It is known that block exposure can be performed.

When block exposure is performed in such an electron beam exposure apparatus, an electron beam generated from an electron gun is arranged upstream of a mask plate after being shaped into a rectangular cross section by a rectangular aperture. The mask deflector deflects the light into a desired transmission pattern on the mask plate.

The electron beam whose cross-sectional shape is shaped by a desired transmission pattern is returned to the optical axis by a mask deflector arranged downstream of the mask plate, and is reduced and rotated by a reduction / rotation lens. A desired position on the sample is exposed by the deflector and the sub-deflector.

In this way, when the block exposure is performed, the electron beam is deflected into a desired transmission pattern on the mask plate and passes through a portion distant from the optical axis, so that a crossover image of the electron gun is obtained. Astigmatism and curvature of field will occur.

Therefore, in an electron beam exposure apparatus capable of performing block exposure, an astigmatism correction coil and a field curvature correction coil are provided, and astigmatism correction and an image of a crossover image of an electron gun are performed. It is said that the surface curvature will be corrected.

In this case, the drive value of the mask deflector, the drive value of the astigmatism correction coil and the drive value of the field curvature correction coil are obtained so that the sample current value becomes maximum, and these drive values are set by the electron gun. An exposure method of performing regular exposure has been adopted as data for performing astigmatism correction and field curvature correction of a crossover image.

[0008]

However, the drive value of the mask deflector, the drive value of the astigmatism correction coil, and the drive value of the field curvature correction coil that maximize the sample current value are obtained, and based on these values. In the case of performing regular exposure by using the standard exposure method, the sample current density distribution is not always uniform, and uneven exposure may occur in the transmission pattern image depending on the selected transmission pattern. .

In view of the above point, the present invention performs astigmatism correction and field curvature correction of a crossover image of a charged particle beam source so as to prevent exposure unevenness from occurring in a transmission pattern image, thereby performing highly accurate exposure. An object of the present invention is to provide a charged particle beam exposure apparatus and an exposure method that can be performed.

[0010]

A charged particle beam exposure apparatus according to the present invention comprises a charged particle beam generation source and a rectangular aperture for shaping the cross-sectional shape of the charged particle beam generated by the charged particle beam generation source into a rectangular shape. A rectangular aperture plate having, and a plurality of charged particle beam deflectable regions arranged downstream of the rectangular aperture plate and having a width capable of deflecting the charged particle beam and selectable by movement. And a mask plate having a plurality of rectangular transmission pattern forming regions in which transmission patterns selectable by deflection of the charged particle beam are formed at positions corresponding to the plurality of charged particle beam deflectable regions, respectively. , The charged particle beam shaped into a rectangle by the rectangular aperture plate can be deflected by the movement of the mask plate. And a second deflection means for deflecting the charged particle beam passing through the desired transmission pattern of the charged particle beam deflectable region selected by the movement of the mask plate back to the optical axis. Means, a circular aperture plate disposed downstream of the mask plate and having a circular aperture on which a crossover image of the charged particle beam source is formed, and a circular aperture plate disposed upstream of the circular aperture plate, the charged particle beam Astigmatism correction means for correcting astigmatism of the crossover image on the circular aperture surface of the generation source, and field curvature of the crossover image on the circular aperture surface of the charged particle beam generation source, which is arranged upstream of the circular aperture plate. To improve a charged particle beam exposure apparatus having a field curvature correction means for correcting a plurality of charged particle beam deflections of a mask plate. In some or all of the transmission pattern forming regions of one charged particle beam deflectable region of the active region, at least along the opposite sides of the transmission pattern forming region, the same shape and the same size are formed. The transmission pattern for measuring the sample current density distribution is formed by arranging a plurality of transmission holes in line symmetry.

A first charged particle beam exposure method according to the present invention uses the charged particle beam exposure apparatus according to the present invention, wherein a charged particle beam is provided for each transmission pattern of a sample current density distribution measurement transmission pattern. Of the sample current density distribution is uniform or substantially uniform, and the drive values of the first and second deflecting means, the drive value of the astigmatism correcting means, and the field curvature correcting means that maximize the sample current value. When performing exposure using a transmission pattern other than the transmission pattern for measuring the sample current density distribution, the corresponding sample current density distribution of the transmission patterns for measuring the sample current density distribution is included. The drive values of the first and second deflecting means, the drive value of the astigmatism correction means, and the drive value of the field curvature correction means searched for the transmission pattern for measurement are used, and the first and second drive values are used.
The deflecting means, the astigmatism correcting means, and the field curvature correcting means are driven.

The second charged particle beam exposure method according to the present invention also uses the charged particle beam exposure apparatus according to the present invention. The charged particle beam is used for each transmission pattern of the transmission pattern for measuring the sample current density distribution. Of the sample current density distribution is uniform or substantially uniform, and the drive values of the first and second deflecting means, the drive value of the astigmatism correcting means, and the field curvature correcting means that maximize the sample current value. The first step of calculating the drive value of, and calculating the irradiation position of the charged particle beam on the sample surface, and the irradiation position of the charged particle beam on the sample surface for the transmission pattern for measuring the sample current density distribution match. Or a second step of calculating a drive value of the second deflecting means that substantially coincides with each other, and when exposure is performed using a transmission pattern other than the transmission pattern for measuring the sample current density distribution, the sample current density is reduced. Of transmission pattern for distribution measurement,
The drive value of the first deflecting unit, the drive value of the astigmatism correcting unit, the drive value of the field curvature correcting unit, and the second step obtained for the corresponding transmission pattern for measuring the sample current density distribution were obtained. Using the drive value of the second deflection means, the first,
The second deflection means, the astigmatism correction means, and the field curvature correction means are driven.

[0013]

The charged particle beam exposure apparatus according to the present invention can be used like the first and second charged particle beam exposure methods according to the present invention. When used for, for each transmission pattern of the transmission pattern for measuring the sample current density distribution,
The drive values of the first and second deflecting means, the drive values of the astigmatism correction means, and the image plane such that the sample current density distribution of the charged particle beam is uniform or substantially uniform and the sample current value is maximized. The drive values of the curvature correcting means are searched, and exposure using a transmission pattern other than the transmission pattern for measuring the sample current density distribution, that is, regular exposure is performed based on these drive values, so that the transmission pattern image is exposed. To prevent unevenness,
Astigmatism correction and field curvature correction of the crossover image of the charged particle beam generation source can be performed to perform highly accurate exposure.

Further, when used like the second charged particle beam exposure method according to the present invention, the sample current density distribution of the charged particle beam is measured for each transmission pattern of the transmission pattern for measuring the sample current density distribution. Searches are made for the drive values of the first and second deflecting means, the drive values of the astigmatism correction means, and the drive values of the field curvature correction means that are uniform or substantially uniform and that maximize the sample current value. At the same time, the irradiation position of the charged particle beam on the sample surface is calculated, and the irradiation position on the sample surface of the charged particle beam coincides or substantially coincides with the transmission pattern for measuring the sample current density distribution. Driving value of the second deflecting means is calculated,
Since normal exposure is performed using this drive value, astigmatism correction and field curvature correction of the crossover image of the charged particle beam source are performed to prevent uneven exposure in the transmission pattern image, and accuracy is improved. It is possible to perform high-exposure exposure and minimize the deviation of the irradiation position of the charged particle beam on the sample surface.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the charged particle beam exposure apparatus and exposure method of the present invention will be described below with reference to FIGS.

FIG. 1 is a diagram schematically showing a main part of an electron beam exposure apparatus which is an embodiment of a charged particle beam exposure apparatus according to the present invention, in which 1 is an electron gun serving as an electron beam generating source and 2 is an electron. Electron beam generated from gun 1, 3 is optical axis, 4-1
Reference numeral 0 is an electromagnetic lens.

Reference numeral 11 designates a rectangular aperture plate having a rectangular aperture 11A for shaping the electron beam 2 into a rectangular shape, and reference numeral 12 is used when the electron beam 2 passing through the rectangular aperture 11A is subjected to variable rectangular shaping. It is a slit deflector.

Further, 13 is a plurality of transmission patterns (hereinafter,
A mask plate (hereinafter referred to as a block mask) on which a block pattern is formed, 14 is a mask stage for fixing the block mask 13, and the block mask 13 is configured as shown in FIG. 2, for example.

In FIG. 2A, 16 is, for example, 50 mm × 5
Silicon substrates having a size of 0 mm, 17 _{1 to} 17 ₁₂
Is an area called a deflector area having a size of, for example, 5 mm × 5 mm.

These deflector areas 17 _{1 to} 17 ₁₂
Each of these areas is an area that can be selected by moving the block mask 13 horizontally, and the electron beam 2 can be deflected by a mask deflector described later.

The deflector areas 17 _{1 to} 17 ₁₁
Is an area used when performing regular exposure for pattern formation, and the deflector area 17 ₁₂ is an area used when obtaining data necessary for performing astigmatism correction and field curvature correction. Is.

These deflector areas 17 _{1 to} 17 ₁₂
Have the same coordinate system in terms of deflection of the electron beam 2, and a transmission pattern and a block pattern for calibration are formed at the same coordinate position.

Here, FIG. 2B shows the deflector area 17
Schematically shows an enlarged ₁₁ portion of 18 _{1-18 4}
Are rectangular transmission holes for calibration, 19 ₁ and 19 ₂
... 19 ₄₈ is a region called a block having a size of 460 μm × 460 μm, for example.

The blocks 19 ₁ , 19 ₂ , 19 ₅ and 1
Blocks other than 9 ₁₆ , 19 ₂₉ , 19 ₃₃ , 19 ₄₄ , and 19 ₄₈ should be shown 19 ₃ , 19 ₄ , 19 _{6 to} 19 ₁₅ , 19 ₁₇ to 1
9 ₂₈ , 19 _{30 to} 19 ₃₂ , 19 _{34 to} 19 ₄₃ , 19 _{45 to} 19
The description of ₄₇ is omitted in FIG.

These blocks 19 ₁ , 19 ₂ ... 19 ₄₈
In this area, block patterns of various shapes are formed for shaping the sectional shape of the electron beam 2 whose sectional shape is shaped by the rectangular aperture 11A into a desired shape.

FIG. 2C is an enlarged view of the portion of the block 19 ₂₉ , and 20 _{1 to} 20 ₁₆ are rectangular transmission holes for forming contact holes.
The six transmission holes 20 _{1 to} 20 _{16 form} one block pattern.

In the deflector areas 17 _{1 to} 17 ₁₀ as well, as in the case of the deflector area 17 ₁₁ , rectangular transparent holes for calibration are formed, and
Various block patterns are formed.

Further, FIG. 2D shows the deflector area 17 ₁₂
Is enlarged and schematically shown. 21 _{1 to} 21 ₄ are rectangular transmission holes for calibration, 22 ₁ and 22 _2.
... ₂₂₄₈ is a block.

The blocks 22 ₁ , 22 ₂ , 22 ₅ , 2
2 _16, 22 ₂₈ to 22 _30, 22 _33, 22 _44, 22 should indicate ₄₈ other block 22 _3, 22 _4, 22 ₆ to 19 _15, 2
2 _{17 to} 22 ₂₇ , 22 ₃₁ , 22 ₃₂ , 22 _{34 to} 22 ₄₃ , 22
_{45-22 47} are omitted in FIG.

These blocks 22 ₁ , 22 ₂ ... 22 ₄₈
A block pattern for measuring the sample current density distribution having the same shape and the same size, which is used to obtain the data necessary for performing the astigmatism correction and the field curvature correction, is formed on the.

FIG. 2E is an enlarged view of the portion of the block 22 _29. Reference numerals 23 ₁ to 23 ₉ denote rectangular transmission holes of the same size formed in a matrix, and the blocks 22 ₁ to 2 2.
2 ₂₈ , 22 _{30 to} 22 ₄₈ are also formed with block patterns for measuring the sample current density distribution, which are formed of similar transmission holes.

[0032] Incidentally, 24 and 25 opposite sides in the X-axis direction of the block 22 _29, the 26, 27 block 22 ₂₉
Of a side opposed in the Y-axis direction, transmitting hole 23 ₅ it may not be provided.

Further, in FIG. 1, 29 to 32 are mask deflectors, and the mask deflectors 29 and 30 are the electron beam 2.
Is a deflector for deviating from the optical axis 3 and deflecting it to a desired block pattern position on the block mask 13.

The mask deflectors 31 and 32 are deflectors for returning the electron beam 2 deflected outside the optical axis 3 by the mask deflectors 29 and 30 onto the optical axis 3.

Reference numeral 33 is an astigmatism correction for correcting the astigmatism of the crossover image of the electron gun 1 caused by the electron beam 2 being deflected outside the optical axis 3 by the mask deflectors 29 and 30. It is a coil (mask stig coil).

Reference numeral 34 is a field curvature correction for correcting the field curvature of the crossover image of the electron gun 1 caused by the electron beam 2 being deflected outside the optical axis 3 by the mask deflectors 29 and 30. It is a coil (mask focus coil).

FIG. 3 is an enlarged schematic perspective view of the astigmatism correction coil 33 and the field curvature correction coil 34.

In FIG. 3, reference numerals 36 to 43 are single coils constituting the astigmatism correction coil 33, and 44 is coils 36 to 39.
Is a drive current supply circuit that supplies the drive current ix to the coil, and 45 is a drive current supply circuit that supplies the drive current iy to the coils 40 to 43.

Further, 46 is a drive current supply circuit for supplying a drive current if to the field curvature correction coil 34, and 47 to 54 are electrodes constituting the mask deflector 31.

FIG. 4 shows the magnetic field generated when the coils 36 to 39 are supplied with the positive current i _x and the coils 40 to 43 are not supplied with the current i _y , and FIG. Shows the direction of the electromagnetic force applied to the electron beam 2.

FIG. 6 shows the magnetic field generated when the coils 40 to 43 are supplied with the positive current i _y and the coils 36 to 39 are not supplied with the current i _x , and FIG. The direction of the electromagnetic force applied to the electron beam 2 is shown.

Further, the Figure 8 supplies a positive current i _x to the coil 36 to 39, positive current i _y to coil 40-43
Shows the magnetic field generated when the
In this case, the direction of the electromagnetic force applied to the electron beam 2 is shown.

FIG. 10 is a diagram for explaining the operation of the field curvature correction coil 34.
For example, 4 increases the effective focal length of the electromagnetic lens 8 and acts so that the image of the electron gun 1 is accurately formed on a circular aperture described later.

Further, in FIG. 1, 56 is the electron beam 2
And a blanking deflector 57 for controlling the passage of the circular aperture plate 57, which is a circular aperture plate formed with a circular aperture 57A.

The circular aperture plate 57 functions as a diaphragm for utilizing only the portion of the electron beam 2 having the same current density, and blocks the passage of the electron beam 2 deflected by the blanking deflector 56. It also functions as a board.

Reference numeral 58 is a main deflector composed of an electromagnetic deflector for deflecting the electron beam 2 in a relatively large range, and 59 is a sub-deflector composed of an electrostatic deflector for deflecting the electron beam 2 in a relatively small range. Reference numeral 60 is a wafer to be exposed, 61 is a wafer holder for holding the wafer 60, and 62 is a wafer stage.

Here, in the mark formation region of the wafer holder 61, a line shape parallel to the Y-axis is shown as shown in a plan view of FIG. 11 and a sectional view taken along line AA of FIG. A mark (hereinafter referred to as a line mark) 64 is formed, and a line mark 65 parallel to the X-axis as shown in a plan view of FIG. 13 and a cross-sectional view taken along the line BB of FIG. 13 is shown in FIG.
Are formed.

[0048] Incidentally, FIG. 11, 13, 66 shows an image of a block pattern shown in FIG. 2E, a rectangular image 67 _{1-67 9} corresponds to transmitting hole 23 _{1-23 9} shown in FIG. 2E There is.

The line marks 64 and 65 are formed of tantalum Ta on the silicon substrate 68, and the length L _A thereof is sufficiently longer than the length L _B of one side of the block pattern image 66. It is sufficiently smaller than the length W _B of one side of the rectangular image _67i to 674 ₉ of the width W _a block pattern image 66.

When block exposure is performed in the electron beam exposure apparatus of this embodiment having such a configuration, the electron beam 2 generated from the electron gun 1 has a rectangular cross-sectional shape by the rectangular aperture plate 11. After the shaping, the mask deflectors 29 and 30 deflect the desired block pattern portion on the block mask 13.

Then, the electron beam 2 whose cross-sectional shape is shaped by a desired block pattern is applied to the mask deflector 3
It is swung back on the optical axis 3 by 1, 32, reduced / rotated by the electromagnetic lens (reduction / rotation lens) 8, and exposed to a desired position on the wafer 60 by the main deflector 58 and the sub-deflector 59.

When the block exposure is performed in this way, the electron beam 2 is deflected to a desired block pattern on the block mask 13 and passes through a portion away from the optical axis, so that the electron gun 1 crosses. Although astigmatism and field curvature will occur in the over image, in the present embodiment, the data for correcting the astigmatism and field curvature of these crossover images of the electron gun 1 are as follows. Is asked for.

First, as shown in FIG. 15, the electron beam 2 whose cross-sectional shape is rectangular by the rectangular aperture plate 11 is shaped by the block pattern shown in FIG. 2E and is formed in the line mark forming region of the wafer holder 61. An image 66 of the block pattern shown in FIG. 2E is irradiated, and this is scanned in parallel with the X axis as indicated by an arrow 70 to obtain a reflected electron waveform by the line mark 64.

In this case, when the current density distribution in the block pattern image 66 is uniform, the reflected electron waveform as shown in FIG. 16 is obtained.

In FIG. 16, 72 is a rectangular image 67.
₁ , 67 ₄ , 67 ₇ reflected electron waveforms; 73, rectangular image 67 ₂ , 67 ₅ , 67 ₈ reflected electron waveforms; 74, rectangular images 67 ₃ , 67 ₆ , 67 ₉ reflected electron waveforms. It is a waveform.

In this case, the average values ρl and ρr of the reflected electron waveform intensities of the reflected electron waveforms 72 and 74 are ρl = ρr as shown in FIG.

On the other hand, as shown in FIG. 18, when there is a shadow 75 on the right side of the block pattern image 66, the reflected electron waveform as shown in FIG. 19 is obtained, and the reflected electron waveforms 72 and 74 are obtained. Average value of backscattered electron waveform intensity ρ
As shown in FIG. 20, l and ρr are ρl> ρr.

Next, as shown in FIG. 21, an image 66 of the block pattern shown in FIG. 2E, which is irradiated on the wafer holder 61, is scanned in parallel with the Y axis as shown by an arrow 77,
The reflected electron waveform by the line mark 65 is obtained.

In this case, when the current density distribution in the block pattern image 66 is uniform, the reflected electron waveform as shown in FIG. 22 is obtained.

In FIG. 22, 79 is a rectangular image 67.
_1, 67 _2, 67 reflected electron wave of ₃ parts, 80 a rectangular image 67 _4, 67 _5, 67 ₆ reflected electron wave portions of 81 rectangular image 67 _7, 67 _8, 67 ₉ parts of the reflected electrons It is a waveform.

In this case, the average values ρl and ρr of the reflected electron waveform intensities of the reflected electron waveforms 79 and 81 are ρu = ρd as shown in FIG.

On the other hand, as shown in FIG. 24, when there is a shadow 83 on the lower side of the block pattern image 66, a reflected electron waveform as shown in FIG. 25 is obtained, and a reflected electron waveform 79, Average value ρ of backscattered electron waveform intensity at 81
u and ρd are ρu> ρd as shown in FIG.

Here, ρl, ρr, ρu, and ρd are shown in FIG.
As shown in the block pattern image 66,
Peripheral part 85 (rectangular image 67₁, 67_Four, 67₇Part),
Peripheral portion 86 (rectangular image 67₃, 67₆, 67₉Part), Zhou
Side 87 (rectangular image 67₁, 67 ₂, 67₃Part), around
Part 88 (rectangular image 67₇, 67₈, 67₉Part)
It shows the average value distribution of the flow density.

Therefore, next, the evaluation value VAL is defined as shown in the equation 1, and this evaluation value VAL is obtained. Note that C
1 and C2 are constants obtained by experiments.

[0065]

[Equation 1]

Here, the evaluation value VAL is ρl, ρr,
The larger the variation of ρu and ρd is, the smaller it is.
It is defined that the larger each of r, ρu, and ρd, the larger.

Therefore, the maximum value of the evaluation value VAL has the smallest variation in ρl, ρr, ρu, and ρd, and the maximum of each of ρl, ρr, ρu, and ρd, that is, the periphery of the block pattern image 66. Parts 85, 86, 87, 88
This means that the sample current density distribution has the smallest variation and the sample current value becomes the maximum.

Therefore, the drive values of the mask deflectors 29 to 32, the drive value of the astigmatism correction coil 33, and the drive value of the field curvature correction coil 34 such that the evaluation value VAL takes a maximum value are set in the electron gun 1. It is obtained as data for correcting astigmatism and field curvature of the crossover image.

The above procedure is carried out for all the block patterns 22 _{1 to} 22 ₄₈ for measuring the sample current density distribution formed in the deflector area 17 ₁₂ and these block patterns 22 _{1 to} 22 for measuring the sample current density distribution are carried out. The drive values of the mask deflectors 29 to 32, the drive value of the astigmatism correction coil 33, and the drive value of the field curvature correction coil 34 such that the evaluation value VAL takes the maximum value are set for each of the _48. It is stored as data for correcting astigmatism and field curvature of the crossover image.

When performing a normal exposure, that is, when using a block pattern formed in the deflector areas 17 _{1 to} 17 ₁₁ , the sample current density of the corresponding deflector area 17 ₁₂ is to be measured. By using the drive values of the mask deflectors 29 to 32, the drive value of the astigmatism correction coil 33, and the drive value of the field curvature correction coil 34, which are stored for the block patterns 22 _{1 to} 22 ₄₈ for distribution measurement, Deflectors 29 to 32, astigmatism correction coil 3
3 and the field curvature correction coil 34 are driven.

Here, block patterns 22 _{1 to} 22 ₄₈ for measuring the sample current density distribution in the deflector area 17 ₁₂ are provided.
The drive values of the mask deflectors 29 to 32, the drive value of the astigmatism correction coil 33, and the drive value of the field curvature correction coil 34, which are stored for the above, are the block patterns 22 _{1 to} 22 ₄₈ for measuring the sample current density distribution. Since the variation in the sample current density distribution of the image is the minimum, and the sample current value is the maximum drive value, in this case, the exposure unevenness does not occur in the regular block pattern image, Electron gun 1
It is possible to perform astigmatism correction and field curvature correction of the crossover image and to perform highly accurate exposure.

As described above, the mask deflectors 29 to 32 are arranged so that the sample current density distribution in the peripheral portion of the image of the block pattern of the deflector area 17 ₁₂ is minimized and the sample current is maximized. The drive value, the drive value of the astigmatism correction coil 33, and the drive value of the field curvature correction coil 34 are obtained, and the irradiation position of the electron beam 2 on the surface of the wafer 60 with respect to the image of the block pattern of the deflector area 17 ₁₂ is determined. Mask deflectors 31 and 3 that are substantially matched
The drive value of 2 is calculated, and when the mask deflectors 31 and 32 are sometimes used, the electron gun 1 is used so that the exposure unevenness does not occur in the regular block pattern image.
Astigmatism correction and field curvature correction of the crossover image can be performed to perform highly accurate exposure, and the deviation of the irradiation position of the electron beam 2 on the wafer 60 surface can be minimized.

[0073]

The charged particle beam exposure apparatus according to the present invention can be used like the first and second charged particle beam exposure methods according to the present invention, but the first charged particle beam exposure method according to the present invention. When used as described above, astigmatism correction and field curvature correction of the crossover image of the charged particle beam source should be performed to prevent exposure unevenness in the block pattern image, and highly accurate exposure be performed. You can

When used as in the second charged particle beam exposure method according to the present invention, the astigmatism of the crossover image of the charged particle beam generation source is adjusted so that uneven exposure does not occur in the block pattern image. By performing the correction and the field curvature correction, it is possible to perform highly accurate exposure, and it is possible to minimize the deviation of the irradiation position of the charged particle beam on the sample surface.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a main part of an electron beam exposure apparatus which is an embodiment of a charged particle beam exposure apparatus of the present invention.

FIG. 2 is a diagram showing a block mask included in an electron beam exposure apparatus which is an embodiment of the charged particle beam exposure apparatus of the present invention.

FIG. 3 is a perspective view showing a portion of an astigmatism correction coil and a field curvature correction coil included in an electron beam exposure apparatus which is an embodiment of the charged particle beam exposure apparatus of the present invention.

FIG. 4 is a diagram for explaining the action of an astigmatism correction coil provided in an electron beam exposure apparatus which is an embodiment of the charged particle beam exposure apparatus of the present invention.

FIG. 5 is a diagram for explaining the operation of the astigmatism correction coil provided in the electron beam exposure apparatus which is an embodiment of the charged particle beam exposure apparatus of the present invention.

FIG. 6 is a diagram for explaining the operation of the astigmatism correction coil provided in the electron beam exposure apparatus which is an example of the charged particle beam exposure apparatus of the present invention.

FIG. 7 is a diagram for explaining the action of the astigmatism correction coil provided in the electron beam exposure apparatus which is an example of the charged particle beam exposure apparatus of the present invention.

FIG. 8 is a diagram for explaining the action of the astigmatism correction coil provided in the electron beam exposure apparatus which is an example of the charged particle beam exposure apparatus of the present invention.

FIG. 9 is a view for explaining the action of the astigmatism correction coil provided in the electron beam exposure apparatus which is an example of the charged particle beam exposure apparatus of the present invention.

FIG. 10 is a diagram for explaining the action of the field curvature correction coil provided in the electron beam exposure apparatus which is an example of the charged particle beam exposure apparatus of the present invention.

FIG. 11 is a plan view showing line marks parallel to the Y-axis direction formed on a wafer holder included in an electron beam exposure apparatus which is an embodiment of the charged particle beam exposure apparatus of the present invention.

12 is a cross-sectional view taken along the line AA of FIG.

FIG. 13 is a plan view showing line marks parallel to the X-axis direction formed on a wafer holder included in an electron beam exposure apparatus which is an example of the charged particle beam exposure apparatus of the present invention.

FIG. 14 is a cross-sectional view taken along the line BB of FIG.

FIG. 15 is a diagram for explaining a procedure for obtaining data necessary for correction of astigmatism and curvature of field of a crossover image of an electron gun.

16 is a diagram showing a backscattered electron waveform of a sample current density distribution measurement block pattern image obtained in the case shown in FIG.

FIG. 17 is a diagram showing an average value of backscattered electron waveform intensities of a peripheral portion in the block pattern image for measuring the sample current density distribution in the case of FIG. 16;

FIG. 18 is a diagram for explaining a procedure for obtaining data necessary for correction of astigmatism and curvature of field of a crossover image of an electron gun.

19 is a diagram showing a backscattered electron waveform of a sample current density distribution measurement block pattern image obtained in the case shown in FIG.

20 is a diagram showing an average value of backscattered electron waveform intensities of a peripheral portion in a block pattern image for measuring sample current density distribution in the case of FIG. 19;

FIG. 21 is a diagram for explaining a procedure for obtaining data necessary for correction of astigmatism and curvature of field of a crossover image of an electron gun.

22 is a diagram showing a backscattered electron waveform of a sample current density distribution measuring block pattern image obtained in the case shown in FIG. 21.

FIG. 23 is a diagram showing an average value of backscattered electron waveform intensities in a peripheral portion in a block pattern image for measuring sample current density distribution in the case of FIG. 22.

FIG. 24 is a diagram for explaining a procedure for obtaining data necessary for correction of astigmatism and curvature of field of a crossover image of an electron gun.

FIG. 25 is a diagram showing a backscattered electron waveform of a sample current density distribution measuring block pattern image obtained in the case shown in FIG. 24.

FIG. 26 is a diagram showing an average value of backscattered electron waveform intensities of a peripheral portion in the sample current density distribution measurement block pattern image in the case of FIG. 25.

FIG. 27 is an average value ρl, ρr of backscattered electron waveform intensities in the peripheral portion in the block pattern image for measuring the sample current density distribution.
It is a figure for explaining the meaning of ρu and ρd.

[Explanation of symbols]

 (FIG. 1) 33 astigmatism correction coil 34 field curvature correction coil

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroshi Yasuda 1015 Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Fujitsu Limited

Claims (3)

[Claims] 1. A rectangular aperture plate having a charged particle beam source, a rectangular aperture plate for shaping a charged particle beam generated from the charged particle beam source into a rectangular cross section, and a rectangular aperture plate of the rectangular aperture plate. It has a plurality of charged particle beam deflectable regions which are arranged downstream and have a width capable of deflecting the charged particle beam and which can be selected by movement. A mask plate having a plurality of rectangular transmission pattern forming regions in which transmission patterns selectable by deflection of the charged particle beam are formed at corresponding positions, and a charged particle beam shaped into a rectangle by the rectangular aperture plate. For deflecting the beam into a desired transmission pattern in the charged particle beam deflectable region selected by moving the mask plate. Second deflecting means for returning to the optical axis the charged particle beam that has passed through the desired transmission pattern of the charged particle beam deflectable area selected by the movement of the mask plate, and is disposed downstream of the mask plate, A circular aperture plate having a circular aperture on which a crossover image of the charged particle beam source is formed, and a crossover on the circular aperture plane of the charged particle beam source, which is arranged upstream of the circular aperture plate. Astigmatism correction means for correcting astigmatism of an image, and field curvature arranged upstream of the circular aperture plate to correct the field curvature of a crossover image at the circular aperture surface of the charged particle beam source. A charged particle beam exposure apparatus comprising a correction means, wherein one charged particle beam out of the plurality of charged particle beam deflectable regions is provided. In some or all of the transmission pattern forming regions of the deflectable region, a plurality of transmission holes of the same shape and the same size are arranged line-symmetrically along at least the opposite sides of the transmission pattern forming region. A charged particle beam exposure apparatus, wherein a transmission pattern for measuring the sample current density distribution is formed. 2. A charged particle beam generation source, a rectangular aperture plate having a rectangular aperture for shaping a charged particle beam generated from the charged particle beam generation source into a rectangular shape, and a rectangular aperture plate of the rectangular aperture plate. It has a plurality of charged particle beam deflectable regions which are arranged downstream and have a width capable of deflecting the charged particle beam and which can be selected by movement. It has a plurality of rectangular transmission pattern formation regions in which transmission patterns selectable by deflection of the charged particle beam are formed at respective corresponding positions, and one of the plurality of charged particle beam irradiation possible regions is provided. Identical to a part or all of the transmission pattern forming area of the charged particle beam irradiation area, at least along the opposite sides of the transmission pattern forming area. A mask plate having a transmission pattern for measuring the sample current density distribution, which is formed by arranging a plurality of rectangular transmission holes having the same shape and the same size in line symmetry, and a charge shaped into a rectangle by the rectangular aperture plate. First deflecting means for deflecting the particle beam into a desired transmission pattern of the charged particle beam deflectable region selected by moving the mask plate; and desired charged particle beam deflectable region selected by moving the mask plate Second deflecting means for returning the charged particle beam that has passed through the transmission pattern to the optical axis, and a circular aperture arranged downstream of the mask plate for forming a crossover image of the charged particle beam source. And a cross-sectional image of the cross-sectional image on the circular aperture plane of the charged particle beam generation source arranged upstream of the circular aperture plate. Astigmatism correction means for correcting point aberration, and field curvature correction means arranged upstream of the circular aperture plate for correcting field curvature of a crossover image on the circular aperture surface of the charged particle beam generation source. A charged particle beam exposure method for performing exposure using a charged particle beam exposure apparatus comprising: a sample current density of a charged particle beam for each transmission pattern of the transmission pattern for measuring the sample current density distribution. The drive values of the first and second deflecting means, the drive values of the astigmatism correcting means, and the field curvature correcting means of which the distribution is uniform or substantially uniform and the sample current value is maximized. Having a step of searching a driving value, when performing exposure using a transmission pattern other than the transmission pattern for measuring the sample current density distribution, among the transmission patterns for measuring the sample current density distribution, The drive values of the first and second deflecting means, the drive value of the astigmatism correction means, and the drive value of the field curvature correction means searched for the corresponding transmission pattern for measuring the sample current density distribution are used. A charged particle beam exposure method comprising: driving the first and second deflection means, the astigmatism correction means, and the field curvature correction means. 3. A charged particle beam generation source, a rectangular aperture plate having a rectangular aperture for shaping the cross-sectional shape of a charged particle beam generated from this charged particle beam generation source into a rectangular shape, and a rectangular aperture plate of the rectangular aperture plate. It has a plurality of charged particle beam deflectable regions which are arranged downstream and have a width capable of deflecting the charged particle beam and which can be selected by movement. It has a plurality of rectangular transmission pattern formation regions in which transmission patterns selectable by deflection of the charged particle beam are formed at respective corresponding positions, and one of the plurality of charged particle beam irradiation possible regions is provided. Identical to a part or all of the transmission pattern forming area of the charged particle beam irradiation area, at least along the opposite sides of the transmission pattern forming area. A mask plate on which a transmission pattern for measuring a sample current density distribution is formed, in which a plurality of rectangular transmission holes having the same shape and the same size are arranged in line symmetry, and a charge shaped into a rectangle by the rectangular aperture plate. First deflecting means for deflecting the particle beam into a desired transmission pattern of the charged particle beam deflectable region selected by moving the mask plate; and desired charged particle beam deflectable region selected by moving the mask plate Second deflecting means for returning the charged particle beam that has passed through the transmission pattern to the optical axis, and a circular aperture arranged downstream of the mask plate for forming a crossover image of the charged particle beam source. And a cross-sectional image of the cross-sectional image on the circular aperture plane of the charged particle beam generation source arranged upstream of the circular aperture plate. Astigmatism correction means for correcting point aberration, and field curvature correction means arranged upstream of the circular aperture plate for correcting field curvature of a crossover image on the circular aperture surface of the charged particle beam generation source. A charged particle beam exposure method for performing exposure using a charged particle beam exposure apparatus comprising: a sample current density of a charged particle beam for each transmission pattern of the transmission pattern for measuring the sample current density distribution. The drive values of the first and second deflecting means, the drive values of the astigmatism correcting means, and the field curvature correcting means of which the distribution is uniform or substantially uniform and the sample current value is maximized. The first step of searching the drive value and calculating the irradiation position of the charged particle beam on the sample surface, and the transmission pattern for measuring the sample current density distribution,
A second step of calculating a drive value of the second deflecting means so that the irradiation positions of the charged particle beam on the sample surface coincide or substantially coincide with each other, except the transmission pattern for measuring the sample current density distribution. In the case of performing exposure using a transmission pattern, the first one obtained for the corresponding transmission pattern for measuring the sample current density distribution among the transmission patterns for measuring the sample current density distribution
Drive value of the deflection means, drive value of the astigmatism correction means,
Using the drive value of the field curvature correction means and the drive value of the second deflection means obtained in the second step, the first and second deflection means, the astigmatism correction means and the image are used. A charged particle beam exposure method characterized by driving a surface curvature correction means.