JP3703774B2 - Charged beam exposure apparatus, exposure method using charged beam, and semiconductor device manufacturing method using this exposure method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a charged beam exposure apparatus, an exposure method using a charged beam, and a method of manufacturing a semiconductor device using the exposure method, and particularly to aperture type exposure using a low acceleration charged beam.
[0002]
[Prior art]
The charged beam exposure apparatus has a function of forming a high-resolution pattern because it can draw with a resolution of the wavelength level of electrons (ions) shorter than the light wavelength. On the other hand, unlike the mask drawing method by light exposure, the completed pattern is directly drawn by a small divided pattern beam, so that the exposure method by the charged beam has a problem that it takes a long time for drawing. However, attention has been paid to the feature of being able to form high-precision fine line patterns, and the charged beam exposure technology has developed as a powerful tool for the manufacture of semiconductors for high-mix low-volume production such as ASIC, or the next technology of lithography technology for optical exposure. are doing.
[0003]
There are mainly two methods for directly drawing a pattern with a charged beam. That is, there are a method of drawing a pattern by scanning the entire wafer surface while controlling ON / OFF of a small round beam, and a VSB drawing method of drawing a pattern of a charged beam that has passed through a stencil aperture. As a charged beam line drawing technology developed from VSB drawing, a stencil in which a repetitive pattern is formed as one block is prepared, and a batch drawing method that enables high-speed drawing by selecting and drawing a pattern in the stencil. Technology has also been developed.
[0004]
First, as a conventional charged beam drawing apparatus, a representative example of an electron beam drawing apparatus of a VSB drawing type is shown in FIG. 9 (H. Sunaoshi et al; Jpn. J. Appl. Phys. Vol. 34 (1995), pp. 199). 6679-6633, Part 1, No. 128. December 1995). In the following drawings, the same portions are denoted by the same reference numerals, and the description thereof is omitted as appropriate.
[0005]
In the electron beam drawing apparatus 120 shown in FIG. 9, the accelerated electron beam 7 emitted from the electron gun 11 is adjusted to a uniform electron beam by the illumination lens 15, and is shaped into a rectangle by passing through the first forming aperture 85. Then, it is projected by the projection lens 87 onto the second shaping aperture 89 made of a rhombus and a rectangle. At this time, the beam deflecting position on the second shaping aperture 89 is controlled by the shaping deflector 21 so that the shape and area of the beam pattern are emitted according to the CAD data. The electron beam 7 that has passed through the second shaping aperture 89 is reduced and projected by the reduction lens 64 and the objective lens 66, but the beam position relative to the drawing position of the wafer 14 is controlled by the main deflector 95 and the sub deflector 93. In this case, the main deflector 95 controls the wafer 14 with reference to the position of an XY stage (not shown) in the stripe of the drawing irradiation area (hereinafter referred to as main field), and the sub deflector 93 controls the inside of the stripe. Position control is performed on a finely divided drawing range (hereinafter referred to as a subfield). Below the objective lens 66, an electron detector 33 that detects secondary electrons, reflected electrons, backscattered electrons, etc. (hereinafter referred to as secondary electrons) generated when the electron beam 7 is irradiated onto the wafer 14. And a control signal (not shown) detects an SEM image and executes various controls such as beam trajectory adjustment based on the detected SEM image by processing the detection signal acquired by the electron detector 33.
[0006]
Since the electron optical system included in the electron beam drawing apparatus 120 shown in FIG. 9 is composed of electromagnetic lenses and electrostatic deflectors, the overall optical characteristics, mechanical assembly accuracy, and contamination of these lenses and deflectors. A design that fully considers the influence of the above is required. Further, in order to improve the beam resolution, a method is employed in which the electron beam 7 accelerated to high acceleration is driven into the resist on the wafer 14. Therefore, a proximity effect is generated, which is a phenomenon in which the irradiated electron beam 7 is reflected by various multilayer thin films formed on the lower surface of the resist of the wafer 14 and is directed upward again. This proximity effect causes blur and resolution degradation in the drawing pattern. Therefore, in the design of the electron beam drawing apparatus, control for correcting the proximity effect is essential, and a large-scale system is required for the control unit in addition to the electron optical system. For this reason, there is a problem that the entire system becomes complicated, and the accuracy is lowered as a result of inducing other troubles due to this. Furthermore, since a highly accelerated electron beam was used, there was a concern about damage to the wafer surface.
[0007]
In order to overcome the above-described problems in the high acceleration voltage charged beam VSB method, an aperture type charged beam drawing method using a low acceleration voltage charged beam has been proposed (Japanese Patent Laid-Open No. 2000-173529, J. Vac). Sci.Technol.B14 (6), 1996, 3802). An electron beam drawing method proposed in Japanese Patent Laid-Open No. 2000-173529 is shown in FIG. In the electron beam apparatus 110 shown in the figure, the accelerated electron beam 67 emitted from the electron gun 11 is irradiated to the first aperture 13 having a rectangular or circular opening. The electron beam 67 that has passed through the first aperture 13 is directed to the cell aperture 19 in which a plurality of batch exposure cell patterns are arranged. The beam diameter of the electron beam 67 is adjusted to a size that is sufficiently large with respect to any one cell pattern and does not interfere with an adjacent cell pattern by the illumination lenses 15a and 15b having the expanding beam function. The illumination lenses 15a and 15b are composed of two electrostatic lenses (Einzel lenses), and are used by applying a negative voltage to the central electrode. The electron beam 67 that has passed through the second illumination lens 15b is controlled to be deflected to a target position by the first shaping deflector 17 so that a target cell pattern can be selected from among a plurality of cell patterns formed in the cell aperture 19. The The electron beam 67 that has passed through the first shaping deflector 17 and the cell aperture 19 starts as a cell pattern beam starting from the cell aperture 19, and is reduced in a state of being swung back on the optical axis by the second shaping deflector 21. It passes through the lens 64. A second aperture 62 is provided above the reduction lens 64, and cuts unnecessary beams scattered by the cell aperture 19 and the like. The electron beam 67 reduced by the reduction lens 64 passes through the pre-sub deflector 93 ′, pre-main deflector 95 ′, sub-deflector 93, main deflector 95, and objective lens 66 and is mounted on an XY stage (not shown). The projected image is reduced and projected onto the upper surface of the wafer 14. The irradiation position of the beam with respect to the position where the pattern on the wafer is to be drawn is controlled by the main deflector 95 and the sub deflector 93, and the control voltage of the pre-main deflector 95 'with respect to the main deflector 95 is increased in the addition direction. The total aberration is minimized by controlling the control voltage of the deflector 93 'in the subtraction direction. The main deflector 95 controls the deflection of the position of the main field with reference to the position of an XY stage (not shown) with respect to the wafer 14, and the sub deflector 93 controls the position of the subfield. A beam trajectory downstream from the cell aperture 19 is shown in FIG.
[0008]
Since the electron optical system of the electron beam drawing apparatus 110 uses an Einzel lens for the reduction projection optical system, as shown in FIG. 11, the electron beam 67 passes through an orbit rotationally symmetric with respect to the optical axis. Therefore, the orbits of the electron beam 67 are all deflected with the same deflection sensitivity by the pre-main deflector 95 ′, the main deflector 95, the pre-sub-deflector 93 ′, and the sub-deflector 93. Occurs rotationally symmetrically.
[0009]
[Problems to be solved by the invention]
However, in the reduction projection optical system of the electron beam drawing apparatus 110, as shown in FIG. 11, crossovers 98 and 99 having a high current density are formed below the cell aperture 19. Further, in this projection optical system, the rotationally symmetrical electrostatic lenses (Einzel) 93 and 95 are employed in the decelerating focusing mode, so that the electron beam 67 is decelerated in the lens. Due to these two points, beam blur due to chromatic aberration and space charge effect (particularly the Boersch effect) occurs in the electron beam drawing apparatus 110 shown in FIG. 10, and the cell aperture image is blurred on the wafer 14. As a result, there is a problem that the drawing characteristics deteriorate.
[0010]
In order to overcome the above-described problems in the aperture-type charged beam drawing method using a charged beam with a low acceleration voltage, a drawing method in which the reduction projection optical system is composed of multiple multipole lenses has been proposed (special feature). No. 2001-093825, Japanese Patent Application 2000-237163, Japanese Patent Application 2000-283396, Japanese Patent Application 2001-012697). A charged beam drawing apparatus 100 shown in FIG. 12 has a reduction projection optical system in an electron optical system configured by a quadruple multipole lens (Japanese Patent Application No. 2000-237163). When an electron beam is used as the charged beam, the electron beam 8 accelerated from the electron gun 11 is applied to the first aperture 13 having a rectangular or circular opening. The electron beam 8 having passed through the first aperture 13 is directed to a cell aperture 19 in which a plurality of batch exposure cell patterns are arranged. The electron beam 8 is shaped by the illumination lens 15 into a beam diameter that is sufficiently large for any one cell pattern and does not interfere with the adjacent cell pattern. The illumination lens 15 includes two electrostatic lenses 15a and 15b (Einzel lenses), and is used by applying a negative voltage to the central electrode. The electron beam 8 that has passed through the second illumination lens 15b is deflected and controlled by the first shaping deflector 17 so that a target cell pattern can be selected within the cell aperture 19. The cell aperture image is returned on the optical axis by the deflector 21. The electron beam 8 that has passed through the first shaping deflector 17 and the cell aperture 19 started as a cell pattern beam starting from the cell aperture 19 and was turned back onto the optical axis of the optical system by the second shaping deflector 21. Illuminated into the multipole lens 23 in the state. The multipole lens 23 includes quadruple electrostatic lenses Q1 to Q4, and generates a quadrupole field (multipole lens field) using an octupole electrode.
[0011]
Here, the optical axis is the Z axis, two planes orthogonal to each other with the Z axis are the X plane and the Y plane, the electron beam trajectory on the X plane is the X trajectory, and the electron beam trajectory on the Y plane is the Y trajectory. In the quadruple multipole lenses Q1 to Q4, electric fields in two directions of the X direction and the Y direction are divergent electric field, divergent electric field, convergent electric field, divergent electric field, Y direction in order from the first to the fourth in the X direction. A voltage is applied so that a convergence electric field, a convergence electric field, a diverging electric field, and a convergence electric field are obtained. Shield electrodes 36 and 39, which are ground electrodes, are arranged in the vicinity of both ends in the optical axis direction of the multipole lens 23, the first shaping deflector 17, the second shaping deflector 21, and the pre-main deflectors 25a and 25b. The shield electrode 36 between the first and second multipole lenses 23 and the shield electrode 39 immediately above the pre-main deflector 25 serve as the apertures 38 and 41, respectively, and the apertures 38 and 41 detect the beam current. The beam alignment of the illumination lens 15, the first shaping deflector 17, the second shape deflector 21, and the multipole lens 23 (Q1, Q2) is performed. FIG. 13 shows the trajectory of the electron beam 8 between the cell aperture 19 and the wafer 14 at this time. The electron beam 8 passes through different trajectories 8X and 8Y in the X direction and the Y direction by the action of each electric field formed by the Q1 to Q4 of the multipole lens 23, and without forming a region having a high electron density. 14 is condensed. The pre-main deflector 25a and the multipole lens 23 are mounted on the XY stage while referring to the position of the XY stage (not shown) by main deflection control in which a deflection electric field is superposed on the Q3 and Q4 of the multi-pole lens 23 and controlled as a deflector. The deflection of the position of the main field with respect to the wafer 14 is controlled by the sub deflector 31. A deflection voltage ratio for main deflection control in which a deflection electric field is superimposed on the pre-main deflector 25 between Q2 and Q3 of the multipole lens 23 and Q3 and Q4 of the multipole lens 23, and the multipole lenses 23Q3 and Q4 are controlled as deflectors. Is adjusted so that the deflection aberration generated on the wafer 14 is minimized. The inner diameters of the multipole lenses Q3 and Q4 on which the deflection electric field is superimposed are designed to be larger than those of the quadrupole lenses Q1 and Q2 (see FIG. 12). Thereby, deflection aberration can be reduced. For example, as shown in FIG. 14, the deflection in the X direction is performed using the pre-main deflector 25a, the main deflector 23 (Q3, 27), and the sub-deflect 31 (X-direction deflected beam trajectory 48X). For deflection in the Y direction, deflection is performed only by the main deflector 23 (Q3, 27) and the sub deflection 31 (Y direction deflection beam trajectory 48Y), and the deflection aberration is minimized by adjusting the deflection voltage ratio.
[0012]
However, in the optical system using the multipole lens 23 in the reduction projection optical system, the electron beam 8 passes through a largely asymmetric path with respect to the optical axis, and the generated aberration is also largely asymmetric with respect to the optical axis. As a result, the cell aperture image is greatly asymmetrically blurred on the wafer 14.
[0013]
As described above, in a conventional charged beam drawing apparatus with a low acceleration voltage, when a decelerating focusing mode is employed using rotationally symmetric electrostatic lenses (Einzel) 64 and 66 as an electro-optic lens, an electrostatic type is shown. Since the electron beam is decelerated in the lenses 64 and 66, chromatic aberration and space charge effect (particularly the Boersch effect) occur, and the electron beam that has passed through the cell aperture 19 forms a region 99 having a high electron density. A space charge effect (especially the Boersch effect) occurs in this region 99, which causes a problem that the cell aperture image is blurred on the wafer 14 and deteriorates the drawing characteristics.
[0014]
On the other hand, when a multipole lens is applied to the electro-optic lens and an electron beam trajectory that is largely asymmetric with respect to the optical axis is formed so that the electron beam does not form a region 99 having a high electron density in order to reduce the space charge effect. The aberration performance differs greatly between the X direction and the Y direction, and there is a problem that the drawing characteristics are deteriorated.
[0015]
The present invention has been made in view of the above circumstances, and its object is to significantly reduce the influence of the space charge effect with a low-acceleration charged beam and to provide a charged beam exposure apparatus, an exposure method, and an excellent aberration performance. An object of the present invention is to provide a method for manufacturing a semiconductor device using this exposure method.
[0016]
[Means for Solving the Problems]
The present invention aims to solve the above problems by the following means.
[0017]
That is, according to the present invention,
A charged beam emitting means for generating a charged beam and irradiating the substrate;
An illumination optical system for adjusting the beam diameter of the charged beam;
A cell aperture having a cell pattern of a shape corresponding to a desired drawing pattern;
A first deflecting means for deflecting the charged beam by an electric field so as to be incident on a desired cell pattern of the cell aperture, and for returning the charged beam that has passed through the cell pattern onto its optical axis;
The charged beam on the optical axis, which is provided between the cell aperture and the substrate and passes through the cell aperture among the charged beams, is substantially symmetrical about the optical axis in two planes orthogonal to the optical axis. And a reduction projection optical system that forms an electric field so as to reduce an image by passing through different trajectories in the two planes and forming an image on the substrate;
Among the charged beams, a charged beam that has passed through any point outside the optical axis in the cell aperture and entered the reduced projection optical system is on one of the two planes orthogonal to the optical axis. An illumination position that is a position where a principal ray of a charged beam from an arbitrary point outside the optical axis intersects the optical axis in the reduced projection optical system so as to pass a substantially symmetrical trajectory about the optical axis. Lighting position adjusting means to adjust;
Second deflecting means for deflecting the charged beam having passed through the cell aperture by an electric field and scanning the substrate,
With
The charged beam emitting means is configured to adjust the exposure amount of a drawing pattern in which the secondary charged particles or the reflected charged particles generated from the surface of the substrate that has been irradiated with the charged beam or the secondary charged particles and the reflected charged particles are close to each other. There is provided a charged beam exposure apparatus that emits the charged beam at an acceleration voltage that is less than an amount in which the influence of the influencing proximity effect occurs.
[0018]
Moreover, according to the present invention,
Charged beam emitting means for generating a charged beam and irradiating the substrate, an illumination optical system for adjusting the beam diameter of the charged beam, a cell aperture having a cell pattern having a shape corresponding to a desired drawing pattern, and the charged beam Is deflected by an electric field and incident on a desired cell pattern of the cell aperture, and the charged beam that has passed through the cell aperture and the charged beam that has passed through the cell aperture are returned to the optical axis. A reduction projection optical system that reduces the beam by an electric field and forms an image on the substrate; and a second deflection unit that deflects the charged beam that has passed through the cell aperture by the electric field and scans the substrate. The charged beam emitting means includes secondary charged particles or reflected charged particles generated from the surface of the substrate that has been irradiated with the charged beam. Alternatively, the charged beam is emitted at an accelerating voltage that is lower than an amount that causes an influence of a proximity effect that affects an exposure amount of a drawing pattern in which the secondary charged particle and the reflected charged particle are close to each other. The aberration performance of the charged beam in the first direction orthogonal to the first beam and the aberration performance of the charged beam in the second direction orthogonal to the first direction and the optical axis are substantially the same on the substrate. Further, the magnification in the first direction and the magnification in the second direction are controlled independently of each other by the reduction projection optical means, and the cell aperture is controlled by the reduction projection optical system. A charged beam dew formed so that the cell pattern has a shape corresponding to a difference between the magnification in the first direction and the magnification in the second direction of the charged beam. Apparatus is provided.
[0019]
Moreover, according to the present invention,
A charged beam irradiation step of generating a charged beam and irradiating the substrate;
A beam diameter adjusting step for adjusting the beam diameter of the charged beam;
The charged beam is deflected by an electric field, is incident on a desired cell pattern of a cell aperture having a cell pattern having a shape corresponding to a desired drawing pattern, and the charged beam that has passed through the cell pattern is turned back on its optical axis. A first deflection step;
By forming an electric field between the cell aperture and the substrate, the charged beam on the optical axis out of the charged beam that has passed through the cell pattern is moved in two planes orthogonal to the optical axis. A reduction projection step that is substantially symmetric with respect to the center and is reduced by passing through different trajectories in the two planes, and imaged on the substrate;
The charged beam that has passed through any point outside the optical axis within the cell aperture of the charged beam has a substantially symmetrical trajectory around the optical axis on one of two planes orthogonal to the optical axis. An illumination position adjusting step for adjusting an illumination position that is a position where a principal ray of a charged beam from an arbitrary point outside the optical axis intersects the optical axis in the reduction projection step so as to pass;
A second deflection step of deflecting the charged beam, the illumination position of which is adjusted, by an electric field and scanning on the substrate;
With
The charged beam has a proximity effect that affects the exposure amount of a secondary charged particle or a reflected charged particle generated from the surface of the substrate that has been irradiated, or a drawing pattern in which the secondary charged particle and the reflected charged particle are close to each other. There is provided an exposure method using a charged beam that is generated at an acceleration voltage lower than the amount of the influence of the above.
[0020]
Moreover, according to the present invention,
A charged beam irradiation process for generating a charged beam and irradiating the substrate, a beam diameter adjusting process for adjusting the beam diameter of the charged beam, and a cell having a shape corresponding to a desired drawing pattern by deflecting the charged beam by an electric field A first deflection step in which the charged beam that has passed through the cell pattern is caused to enter the desired cell pattern of the cell aperture having a pattern, and the charged beam that has passed through the cell aperture is applied by an electric field. A reduced projection step of reducing the image to form an image on the substrate, and a second deflection step of deflecting the charged beam that has passed through the cell aperture by an electric field and scanning the substrate, wherein the charged beam comprises: Secondary charged particles or reflected charged particles generated from the surface of the substrate subjected to the irradiation, or the secondary charged particles and the reflected charged particles Is generated at an accelerating voltage that is lower than the amount of influence of the proximity effect that affects the exposure amount of the adjacent drawing pattern, and the second deflection step is performed by the charged beam in the first direction orthogonal to the optical axis. The charged beam in the first direction is deflected so that the deflection aberration of the charged beam in the first direction and the second direction orthogonal to the optical axis is substantially the same on the substrate. An exposure method using a charged beam is provided, which includes a step of independently controlling a deflection width and a deflection width of the charged beam in the second direction.
[0021]
Moreover, according to the present invention,
A charged beam irradiation process for generating a charged beam and irradiating the substrate, a beam diameter adjusting process for adjusting the beam diameter of the charged beam, and a cell having a shape corresponding to a desired drawing pattern by deflecting the charged beam by an electric field A first deflection step in which the charged beam that has passed through the cell pattern is caused to enter the desired cell pattern of the cell aperture having a pattern, and the charged beam that has passed through the cell aperture is applied by an electric field. A reduction projection step of reducing the image to form an image on the substrate, and a second deflection step of deflecting the charged beam that has passed through the cell aperture by an electric field and scanning the substrate, wherein the charged beam comprises: , Secondary charged particles or reflected charged particles generated from the surface of the substrate subjected to the irradiation, or the secondary charged particles and the reflected load The reduced projection step is generated with an acceleration voltage lower than the amount of the influence of the proximity effect that affects the exposure amount of the drawing pattern in which the particles are close, and the reduction projection step includes the aberration of the charged beam in the first direction orthogonal to the optical axis. The magnification of the charged beam in the first direction so that the performance and the aberration performance of the charged beam in the second direction orthogonal to the optical axis are substantially the same on the substrate. And an exposure method using a charged beam, including the steps of independently controlling the magnification of the charged beam in the second direction.
[0022]
Furthermore, according to the present invention,
A semiconductor device manufacturing method using the above-described exposure method using a charged beam is provided.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following embodiments, electron beam exposure for drawing a pattern on a wafer using an electron beam will be described.
[0024]
FIG. 1 is a schematic block diagram showing a main part of an embodiment of a charged beam exposure apparatus according to the present invention. The electron beam exposure apparatus 1 shown in the figure includes an electron optical system and an illumination position adjustment unit. The electron optical system includes an electron gun 11, a first aperture 13, an illumination lens 15 (15a, 15b), a first shaping deflector 17 (17a, 17b), a cell aperture 19, and a second shaping deflector 21. (21a, 21b), quadruple multipole lens 23 (Q1-Q4), pre-main deflector 25 (25a, 25b), sub-deflector 31, and shield electrodes 36, 38, 39, 41, 42. And a secondary electron detector 33. The illumination position adjustment unit includes a control computer 40, an ammeter 42, an A / D converter 44, a deflection control circuit 46, an illumination lens control circuit 48, and power supplies PS1 and PS2.
[0025]
The electron gun 11 generates a low acceleration electron beam 8 and irradiates it toward the substrate 14.
The electron beam 8 passes through a first aperture 13 having a rectangular or circular opening and travels toward a cell aperture 19 in which a plurality of batch exposure cell patterns are arranged. The illumination lens 15 is composed of two electrostatic lenses (Einzel lenses), and is used by applying a negative voltage to the central electrode, and the electron beam 8 is sufficiently large for any one cell pattern. The electron beam 8 is shaped so as to have a beam diameter that does not interfere with adjacent cell patterns. The first shaping deflector 17 controls the deflection of the target position so that the target cell pattern is selected in the cell aperture 19 by the electron beam 8 that has passed through the second illumination lens 15b. The second shaping deflector 21 swings the cell aperture image that has passed through the cell aperture 19 back on the optical axis. The electron beam 8 that has passed through the first shaping deflector 17 and the cell aperture 19 starts as a cell pattern beam starting from the cell aperture 19, and is reflected back on the optical axis by the second shape deflector 21. Illuminated into the pole lens 23. The multipole lens 23 (Q1 to Q4) is composed of a quadruple electrostatic multipole lens disposed with the pre-main deflectors 25a and 25b interposed therebetween. Each multipole lens generates an electric field called a quadrupole field (multipole lens field) and controls the trajectory of the electron beam 8 independently in the X direction and the Y direction. Some specific shapes of the multipole lens 23 are shown in FIG.
[0026]
FIG. 2 (a) shows a quadrupole lens composed of four electrodes. Electrode Q1 of the quadrupole lens shown in the figure _1a ~ Q1 _1d Each have a cylindrical shape and are arranged at an angle of 90 degrees with respect to each other. FIG. 2B shows a configuration example of an octupole lens, and eight cylindrical electrodes Q1 arranged at an angle of 45 degrees with respect to each other. _2a ~ Q1 _2h It is shown. FIG. 2C shows another configuration example of an octupole lens, and eight electrodes Q1 having a fan-like planar shape. _3a ~ Q1 _3h Are arranged at an angle of 45 degrees to each other.
[0027]
In the cases shown in FIGS. 2B and 2C, the multipole lens 23 as a whole is made to function as a quadrupole lens by using two adjacent electrodes as one quadrupole electrode for the eight-pole electrodes. For example, electrode Q1 _3a , Q1 _3b Are both applied with a voltage of + V, whereby the electrode Q1 shown in FIG. _1a Is controlled to function as
[0028]
Here, the optical axis is the Z axis, and two planes orthogonal to each other when the Z axis is the center are the X plane and the Y plane, the electron beam trajectory on the X plane is the X trajectory, and the electron beam trajectory on the Y plane is the Y trajectory. To do. The electric field in the X direction and the Y direction generated by the quadruple multipole lens 23 is a diverging electric field (Q1), a diverging electric field (Q2), and a converging electric field in order from the first to the fourth in the X direction. (Q3), a diverging electric field (Q4), and the Y direction is controlled to be a converging electric field (Q1), a converging electric field (Q2), a diverging electric field (Q3), and a converging electric field (Q4) (see FIG. 13). In the present embodiment, these multipole lenses 23 (Q1 to Q4) are controlled such that the reduction magnification is different between the X direction and the Y direction. This point will be described in detail later.
[0029]
Returning to FIG. 1, Q3 and Q4 of the pre-main deflector 25 and the multipole lens 23 perform main deflection control on the electron beam 8 by superimposing the deflection electric field on the diverging electric field and the converging electric field that control the electron beam trajectory. Then, the deflection control of the position of the main field of the wafer 14 mounted on the XY stage (not shown) is performed with reference to the position of the XY stage. The sub deflector 31 is disposed between the Q4 of the quadrupole quadrupole lens 23 and the wafer 14, and controls the position of the electron beam 8 with respect to the subfield of the wafer 14. As shown in FIG. 14, the deflection in the X direction is performed using the pre-main deflector 25a, the main deflectors 23 (Q3, 27) (Q4, 27) and the sub-deflector 31, and the deflection in the Y direction. Deflection is performed only by the main deflector 23 (Q 3, 27) (Q 4, 27) and the sub deflection 31. In this way, deflection aberration can be reduced by using different main deflectors in the X direction and the Y direction and adjusting the deflection voltage ratio independently in the X direction and the Y direction. Here, as shown in FIG. 1, the inner diameters of Q3 and Q4 of the multipole lens 23 on which the deflection electric field is superimposed are designed to be larger than those of the multipole lenses Q1 and Q2. Thereby, the deflection aberration can be further reduced.
[0030]
In the electron beam exposure apparatus 1 of the present embodiment, these main deflector and sub deflector are controlled so as to deflect the electron beam 8 with different deflection widths in the X direction and the Y direction. This point will also be described in detail later.
[0031]
The shield electrode 36 is disposed between the second shaping deflectors 21a and 21b, on the lower surface in the optical axis direction of the second shaping deflector 21b, on the upper surface in the optical axis direction of the multipole lens lens 23Q1, and on the lower surface in the optical axis direction of the multipole lens lens Q2. They are installed close to each other. The shield electrode 38 is disposed between Q1 and Q2 of the multipole lens 23. The shield electrode 39 is disposed between the pre-main deflectors 25a and 25b, the lower surface in the optical axis direction of the pre-main deflector 25b, between Q3 and Q4 of the multipole lens lens 23, and close to the lower surface in the optical axis direction of Q4. Be placed. The shield electrode 41 is disposed close to the upper surface in the optical axis direction of the pre-main deflector 25a, and the shield electrode 42 is disposed close to the upper surface in the optical axis direction of the multipole lens lens 23Q3. These shield electrodes 36, 38, 39, 41, 42 are all connected to the ground, and prevent the seepage of the electrostatic field excited by each electrode, thereby preventing static electricity formed from each lens or each deflector. The possibility that the electric fields interfere with each other is greatly eliminated. The shield electrodes 38, 41, and 42 also serve as apertures. By detecting the beam current using these apertures, the illumination lens 15, the first shaping deflector 17, the second shaping deflector 21, and the multipole lens are used. The alignment with the electron beam 8 can be adjusted for each of the 23Q1 and Q2 and the pre-main deflector 25.
[0032]
The illumination position adjustment unit of the electron beam exposure apparatus 1 of the present embodiment adjusts the illumination position of the electron beam 8 on the multipole lens 23 using the shield electrode 38. This adjustment method will be described with reference to FIGS.
[0033]
FIG. 3 is a flowchart showing a schematic procedure of a method for adjusting the illumination position of the electron beam 8. First, the control computer 40 turns off the lens of the multipole lens 23, supplies a control signal to the illumination lens control circuit 48, and applies a negative voltage to the illumination lens 15 from the power source PS1, thereby the electron beam 8 Is illuminated onto the aperture 38 (step S1). Next, the control computer 40 supplies a control signal to the deflection control circuit 46 and applies a voltage from the power source PS2 to the second deflector 21. As a result, as shown by an arrow in FIG. 8 is scanned on the aperture 38 (step S2). The ammeter 42 measures the absorption current I absorbed by the aperture 38 by irradiation of the electron beam 8, and the measurement result is converted into a digital signal by the A / D converter 44 and supplied to the control computer 40. The control computer 40 calculates the rising (falling) time D of the absorption current I at the aperture edge (step S3).
[0034]
Here, when the electron beam 8 is at an appropriate illumination position and the beam diameter is sufficiently small, the absorption current I decreases (increases) abruptly as the electron beam 8 passes through the aperture edge. Therefore, as shown in FIG. 4B, the fall (rise) time D in the waveform of the absorption current I is short. On the other hand, when the electron beam 8 is not at an appropriate illumination position and the beam diameter is large, the absorption current I gradually decreases (increases) even if the electron beam 8 passes through the aperture edge. Therefore, as shown in FIG. 4C, the fall (rise) time D in the waveform of the absorption current I becomes longer.
[0035]
The control computer 40 compares the calculated rise (fall) time D with a predetermined threshold W (step S4), and if the rise (fall) time D is equal to or less than the threshold W, the illumination position of the electron beam 8 is appropriate. It is judged that. On the other hand, if the rise (fall) time D exceeds the threshold value W, the control computer 40 determines that the illumination position of the electron beam 8 is inappropriate, adjusts the supply signal to the illumination lens control circuit 48, and Thus, the lens voltage of the illumination lens 15 is adjusted (step S5), and the above-described steps S2 to S4 are repeated until the rising (falling) time D becomes the threshold value W or less.
[0036]
In the above-described method for adjusting the illumination position, the beam diameter of the electron beam 8 is adjusted using the threshold value W. However, the present invention is not limited to this. For example, the beam diameter may be adjusted until the cross-sectional shape of the minimum circle of confusion is obtained. good. Further, in the electron beam exposure apparatus 1 of the present embodiment, the illumination position of the electron beam 8 is automatically adjusted by the illumination position adjustment unit, but this is a case where such an illumination position adjustment unit is not provided. In addition, the illumination position of the electron beam 8 can also be detected by visually monitoring the absorption current of the aperture 38 using a display (not shown). When the beam diameter of the electron beam 8 that scans the aperture 38 is sufficiently small, the aperture opening can be clearly confirmed, for example, as shown in an image Im1 in FIG. On the other hand, when the beam diameter of the electron beam 8 that scans the aperture 38 is large, for example, as shown in an image Im <b> 2 in FIG. 5B, an image with a very unclear aperture edge is displayed. Therefore, the illumination position of the electron beam 8 can also be adjusted by the operator adjusting the lens voltage of the illumination lens 15 until a clear image of the edge of the aperture 38 is obtained.
[0037]
FIGS. 6 and 7 show the trajectory of the electron beam 8 between the cell aperture 19 and the wafer 14 when an appropriate illumination position is obtained. FIG. 6A shows the trajectory of the electron beam 8 in the X direction, and FIG. 7 shows the trajectory in the Y direction at that time. FIG. 6B is an enlarged view of a region indicated by a symbol R in FIG. As apparent from the comparison between FIG. 6A and FIG. 7, the electron beam 8 passes through different trajectories in the X direction and the Y direction by the action of the multipole lens 23 (Q1 to Q4), and the electrons. The light is condensed on the wafer 14 without forming a high density region. The illumination position of the electron beam 8 is a region on the downstream side including the first multipole lens 23Q1 in the reduction projection optical system. As a result, a trajectory that does not form a region with a high electron density can be formed even at the illumination position of the electron beam 8, and the space charge effect can be further reduced.
[0038]
According to the illumination position adjustment unit provided in the electron beam exposure apparatus 1 of the present embodiment, the electron beam 8 in the X direction with poor aberration performance opens from any point on the cell aperture 19 as shown in FIG. Angle α ₀ The angle from the optical axis (Z axis) is α + α ₀ 8X _{(Α + α0)} The angle from the orbit and the optical axis is α-α ₀ 8X _(Α-α0) The trajectories are all beam trajectories that are symmetric with respect to the optical axis. Thereby, the aberration performance in the X direction of the electron beam 8 can be improved.
[0039]
In the electron beam exposure apparatus 1 of the present embodiment, a reduction projection optical system that forms different trajectories in the X direction and the Y direction is used. Therefore, the deflection control to the electron beam 8 is performed with the deflection sensitivity in the X direction and the Y direction, The deflection aberration characteristics are greatly different. More specifically, as shown in FIG. 6A, since the electron beam 8 in the X direction receives a divergent electric field immediately before the wafer 14, the deflection aberration performance in the X direction is deteriorated. Therefore, for each deflection voltage in the main deflection region and the sub deflection region, the deflection aberration characteristics in the X direction and the Y direction can be made substantially the same by reducing the X direction with poor deflection aberration performance and increasing the Y direction. . More specifically, the pre-main deflector 25a, the main deflector 23 (Q3, 27) (Q4, 27), the deflection voltage in the X direction applied to the sub-deflector 31, and the main deflector 23 (Q3, 27). The ratio (deflection voltage ratio) between (Q4, 27) and the deflection voltage in the Y direction applied to the sub deflection 31 is adjusted so that the deflection width in the X direction is smaller than the deflection width in the Y direction. The specific adjustment amount of the deflection width is calculated by, for example, simulating the X-direction and Y-direction aberrations generated when the deflection is performed with the same width in both the X-direction and the Y-direction. It is obtained by calculating a ratio that is equal to the aberration in the Y direction.
[0040]
FIG. 8 is a schematic diagram for explaining a drawing area by a deflection control method using the electron beam exposure apparatus 1 of the present embodiment. As shown in the figure, for example, when the entire drawing area is a rectangular drawing area 101, deflection control is performed so that the deflection width in the X direction is smaller than the deflection width in the Y direction. Both the field) and the sub-deflection drawing area 103 (sub-field) are rectangular with the Y direction as the longitudinal direction. However, since the adjustment of the deflection width in each direction is a relative adjustment between the X direction and the Y direction, the areas of the main deflection drawing region 102 and the sub deflection drawing region 103 themselves are the same as the area of the conventional deflection region. Each is the same. Thus, according to the present embodiment, the overall aberration performance can be improved without reducing the area of each deflection region.
[0041]
In general, the aberration characteristic becomes worse as the magnification M (M ≦ 1) of the reduction projection optical system becomes smaller. As described above, in this embodiment, different trajectories are formed in the X direction and the Y direction, and the electron beam 8X in the X direction receives a divergent electric field immediately before the wafer 14, so that the aberration performance in the X direction is deteriorated. Therefore, the voltage applied to the multipole lens 23 (Q1 to Q4) is adjusted so that the magnification in the X direction with poor aberration performance is relatively large and the magnification in the Y direction is relatively small. Thereby, the aberration performance can be improved while the magnification M is kept small. The specific ratio of the magnifications in the X direction and the Y direction can be obtained, for example, by a method similar to the above-described deflection amount simulation. The cell pattern on the cell aperture 19 is manufactured in advance so that the magnification differs from the desired drawing pattern projected onto the wafer 14 in the X direction and the Y direction in correspondence with the magnification adjustment.
[0042]
According to the present embodiment, the influence of the space charge effect is significantly reduced, and exposure with excellent aberration performance can be realized. Therefore, by using such an exposure apparatus or exposure method, the integration is further integrated. Semiconductor devices can be manufactured with high yield.
[0043]
Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope thereof. In the above-described embodiment, the pre-main deflector 25a, the main deflector 23, and the sub deflector 31 are used for deflecting the electron beam in the X direction, and the main deflector 23 and the sub deflector are used for deflecting in the Y direction. However, the present invention is not limited to this, and the electron beam in the multipole lens 23 is changed by changing the reduction magnification, changing the arrangement of the multipole lens 23, or the like. When the trajectory changes, for example, the pre-main deflector 25b, the main deflector 23, and the sub-deflector 31 are used for deflection in the X direction, and the pre-main deflector 25a is used for deflection in the Y direction. The deflector used for the deflection may be changed in the X direction and the Y direction, for example, by deflecting using the main deflector 23 and the sub deflector 31, and the deflection interlocking ratio may be changed accordingly. Further, in the above-described embodiment, the form using the electron beam as the charged beam has been described. However, the present invention is not limited to this, and can be applied to a charged beam exposure apparatus using an ion beam as the charged beam.
[0044]
【The invention's effect】
As described above in detail, according to the present invention, the influence of the space charge effect can be greatly reduced and the aberration performance can be further improved with a low acceleration charge beam under a stigmatic imaging condition with a reduction ratio. .
[Brief description of the drawings]
FIG. 1 is a schematic block diagram showing a main part of an embodiment of a charged beam exposure apparatus according to the present invention.
FIG. 2 is a plan view for explaining electrode shapes of a multipole lens provided in the electron beam drawing apparatus shown in FIG.
FIG. 3 is a flowchart showing a schematic procedure of one method for adjusting an illumination position of an electron beam.
4 is an explanatory diagram of the adjustment method shown in FIG. 3. FIG.
FIG. 5 is an explanatory diagram of another method for adjusting the illumination position of an electron beam.
FIG. 6 is a diagram showing a trajectory in the X direction of an electron beam when an appropriate illumination position is obtained.
FIG. 7 is a diagram showing a trajectory in the Y direction of an electron beam when an appropriate illumination position is obtained.
FIG. 8 is a schematic diagram for explaining a drawing region by a deflection control method using the electron beam drawing apparatus shown in FIG. 1;
FIG. 9 is a schematic configuration diagram illustrating an example of a VSB drawing type electron beam drawing apparatus according to a conventional technique.
FIG. 10 is a schematic configuration diagram showing an example of an aperture type electron beam writing apparatus using a low acceleration voltage electron beam according to a conventional technique.
11 is an explanatory diagram showing a beam trajectory in the reduced projection optical system of the electron beam drawing apparatus shown in FIG. 10;
FIG. 12 is a schematic configuration diagram showing another example of an aperture type electron beam drawing apparatus using an electron beam with a low acceleration voltage according to a conventional technique.
13 is an explanatory view showing an electron beam trajectory in the electrostatic multipole lens optical system of the electron beam drawing apparatus shown in FIG. 12;
14 is an explanatory diagram showing an electron beam deflection trajectory in an electrostatic multipole lens optical system of the electron beam drawing apparatus shown in FIG. 12;
[Explanation of symbols]
1 Electron beam exposure system
8X, 9X X-direction electron beam trajectory
8Y, 9Y Y-direction electron beam trajectory
10, 20 Charged beam exposure system
11 Charged particle gun (electron gun)
13 First aperture
14 Wafer
15a, 15b Lighting lens
17a, 17b First shaping deflector
19 Cell aperture
21a, 21b Second shaping deflector
23 (Q1-Q4) Quadrupole lens
25a, 25b Pre-main deflector
27 Main deflector
31 Sub deflector
33 Electronic detector
36,39 Shield electrode
38, 41, 42 Aperture for beam alignment that doubles as shield electrode
40 Control computer
42 Ammeter
44 A / D converter
46 Deflection control circuit
48 Illumination lens control circuit
48X X-direction deflected beam trajectory
48Y Y-direction deflected beam trajectory
PS1, PS2 power supply

Claims (18)

A charged beam emitting means for generating a charged beam and irradiating the substrate;
An illumination optical system for adjusting the beam diameter of the charged beam;
A cell aperture having a cell pattern of a shape corresponding to a desired drawing pattern;
A first deflecting means for deflecting the charged beam by an electric field so as to be incident on a desired cell pattern of the cell aperture, and returning the charged beam that has passed through the cell pattern back to its optical axis;
Provided between the cell aperture and the substrate, of the charged beams, the charged beams on the optical axis that have passed through the cell aperture are substantially symmetrical about the optical axis in two planes orthogonal to the optical axis. And a reduction projection optical system which reduces an electric field by passing through different trajectories in the two planes and forms an electric field so as to form an image on the substrate;
The charged beam that passes through any point outside the optical axis in the cell aperture and enters the reduced projection optical system is on one surface of the two planes orthogonal to the optical axis. An illumination position that is a position where a principal ray of a charged beam from an arbitrary point outside the optical axis intersects the optical axis in the reduced projection optical system so as to pass a substantially symmetric trajectory about the optical axis. Lighting position adjusting means to adjust;
Second deflecting means for deflecting the charged beam that has passed through the cell aperture by an electric field and scanning the substrate.
With
The charged beam emitting means adjusts the exposure amount of a drawing pattern in which secondary charged particles or reflected charged particles generated from the surface of the substrate irradiated with the charged beam or the secondary charged particles and the reflected charged particles are close to each other. A charged beam exposure apparatus that emits the charged beam at an acceleration voltage that is less than an amount in which an influence of an influencing proximity effect occurs. The reduction projection optical system includes a first direction orthogonal to the optical axis in a region closest to the substrate in the optical system, and a diverging electric field in the first direction and a second direction orthogonal to the optical axis. Forming a convergent electric field,
The charged beam exposure apparatus according to claim 1, wherein one of the two planes is a plane defined by a straight line along the first direction and the optical axis. The reduction projection optical system includes a double multipole lens disposed between the first deflecting unit and the second deflecting unit,
It further comprises an aperture arranged between the first and double multipole lenses,
The illumination position adjusting means adjusts the illumination position of the charged beam by scanning the charged beam on the aperture and detecting a change in current flowing through the aperture by scanning the charged beam. The charged beam exposure apparatus according to claim 1 or 2. The charged beam has the aberration performance of the charged beam in the first direction and the aberration performance of the charged beam in the second direction substantially equal on the substrate by the reduction projection means. The magnification in one direction and the magnification in the second direction are controlled independently of each other;
The cell aperture has a shape corresponding to that the magnification of the charged beam in the first direction and the magnification of the charged beam in the second direction are different from each other by the control of the reduction projection optical system. 4. The charged beam exposure apparatus according to claim 1, wherein the charged beam exposure apparatus is formed so as to have. A charged beam emitting means for generating a charged beam and irradiating the substrate;
An illumination optical system for adjusting the beam diameter of the charged beam;
A cell aperture having a cell pattern of a shape corresponding to a desired drawing pattern;
A first deflecting means for deflecting the charged beam by an electric field so as to be incident on a desired cell pattern of the cell aperture, and returning the charged beam that has passed through the cell pattern back to its optical axis;
A reduced projection optical system that reduces the charged beam that has passed through the cell aperture by an electric field to form an image on the substrate;
Second deflecting means for deflecting the charged beam that has passed through the cell aperture by an electric field and scanning the substrate.
With
The charged beam emitting means adjusts the exposure amount of a drawing pattern in which secondary charged particles or reflected charged particles generated from the surface of the substrate irradiated with the charged beam or the secondary charged particles and the reflected charged particles are close to each other. The charged beam is emitted at an accelerating voltage that is less than the amount of influence of the influencing proximity effect,
The charged beam has an aberration performance of the charged beam in a first direction orthogonal to the optical axis and an aberration performance of the charged beam in the first direction and a second direction orthogonal to the optical axis. The magnification in the first direction and the magnification in the second direction are controlled independently of each other by the reduction projection optical means so as to be substantially the same as above.
The cell aperture has a shape corresponding to that the magnification of the charged beam in the first direction and the magnification of the charged beam in the second direction are different from each other by the control of the reduction projection optical system. A charged beam exposure apparatus formed to have A charged beam irradiation step of generating a charged beam and irradiating the substrate;
A beam diameter adjusting step for adjusting the beam diameter of the charged beam;
The charged beam is deflected by an electric field, is incident on a desired cell pattern of a cell aperture having a cell pattern having a shape corresponding to a desired drawing pattern, and the charged beam that has passed through the cell pattern is turned back on its optical axis. A first deflection step;
By forming an electric field between the cell aperture and the substrate, the charged beam on the optical axis out of the charged beam that has passed through the cell pattern is moved along two planes orthogonal to the optical axis. A reduction projection step that is substantially symmetric with respect to the center and that is reduced by passing through different trajectories in the two planes and forming an image on the substrate;
The charged beam that has passed through any point outside the optical axis within the cell aperture of the charged beam has a substantially symmetrical trajectory around the optical axis in one of two planes orthogonal to the optical axis. An illumination position adjusting step for adjusting an illumination position that is a position where a principal ray of a charged beam from an arbitrary point outside the optical axis intersects the optical axis in the reduction projection step so as to pass;
A second deflection step of deflecting the charged beam, the illumination position of which is adjusted, by an electric field and scanning on the substrate;
With
The charged beam has a proximity effect that affects an exposure amount of a secondary charged particle or a reflected charged particle generated from the surface of the substrate that has been irradiated, or a drawing pattern in which the secondary charged particle and the reflected charged particle are close to each other. An exposure method using a charged beam that is generated at an accelerating voltage that is lower than the amount of the influence of. The reduction projection step forms a diverging electric field and a converging electric field in a first direction orthogonal to the optical axis in a region close to the substrate and in a first direction orthogonal to the first direction and the optical axis, respectively. Including the final reduction projection process,
The illumination position of the charged beam is substantially symmetrical about the optical axis in a plane where the charged beam from an arbitrary point outside the optical axis is defined by a straight line along the first direction and the optical axis. The exposure method according to claim 6, wherein the exposure method is controlled so as to pass through a proper trajectory.   In the second deflection step, the charged beam is deflected so that the deflection aberration of the charged beam in the first direction and the deflection aberration of the charged beam in the second direction are substantially the same on the substrate. The exposure method according to claim 6, further comprising a step of independently controlling the deflection width of the first and second directions in the first direction and the second direction. The reduction projection step includes a final reduction projection step of forming a diverging electric field and a converging electric field in the first direction and the second direction, respectively, in a region close to the substrate,
9. The exposure method according to claim 8, wherein a deflection width of the charged beam in the first direction is smaller than a deflection width of the charged beam in the second direction.   The reduction projection step is performed in the first direction so that the aberration performance of the charged beam in the first direction and the aberration performance of the charged beam in the second direction are substantially the same on the substrate. 10. The exposure method according to claim 6, further comprising a step of independently controlling a magnification of the charged beam and a magnification of the charged beam in the second direction. The reduction projection step includes a final reduction projection step of forming a diverging electric field and a converging electric field in the first direction and the second direction, respectively, in a region close to the substrate,
The exposure method according to claim 10, wherein a magnification of the charged beam in the first direction is larger than a magnification of the charged beam in the second direction. A charged beam irradiation step of generating a charged beam and irradiating the substrate;
A beam diameter adjusting step for adjusting the beam diameter of the charged beam;
The charged beam is deflected by an electric field, is incident on a desired cell pattern of a cell aperture having a cell pattern having a shape corresponding to a desired drawing pattern, and the charged beam that has passed through the cell pattern is turned back on its optical axis. A first deflection step;
A reduction projection step of forming an image on the substrate by reducing the charged beam that has passed through the cell pattern by an electric field;
A second deflection step in which the charged beam that has passed through the cell pattern is deflected by an electric field and scanned on the substrate;
With
The charged beam has a proximity effect that affects an exposure amount of a secondary charged particle or a reflected charged particle generated from the surface of the substrate that has been irradiated, or a drawing pattern in which the secondary charged particle and the reflected charged particle are close to each other. Generated at an accelerating voltage lower than the amount of
The second deflection step includes deflection aberration of the charged beam in a first direction orthogonal to the optical axis, and deflection aberration of the charged beam in the first direction and a second direction orthogonal to the optical axis. Including a step of independently controlling a deflection width of the charged beam in the first direction and a deflection width of the charged beam in the second direction so that the two are substantially the same on the substrate. An exposure method using a beam. The reduction projection step includes a final reduction projection step of forming a diverging electric field and a converging electric field in the first direction and the second direction, respectively, in a region close to the substrate,
The exposure method according to claim 12, wherein a deflection width of the charged beam in the first direction is smaller than a deflection width of the charged beam in the second direction.   The reduction projection step is performed in the first direction so that the aberration performance of the charged beam in the first direction and the aberration performance of the charged beam in the second direction are substantially the same on the substrate. 14. The exposure method according to claim 12, further comprising a step of independently controlling a magnification of the charged beam and a magnification of the charged beam in the second direction. The reduction projection step includes a final reduction projection step of forming a diverging electric field and a converging electric field in the first direction and the second direction, respectively, in a region close to the substrate,
The exposure method according to claim 14, wherein a magnification of the charged beam in the first direction is larger than a magnification of the charged beam in the second direction. A charged beam irradiation step of generating a charged beam and irradiating the substrate;
A beam diameter adjusting step for adjusting the beam diameter of the charged beam;
The charged beam is deflected by an electric field, is incident on a desired cell pattern of a cell aperture having a cell pattern having a shape corresponding to a desired drawing pattern, and the charged beam that has passed through the cell pattern is turned back on its optical axis. A first deflection step;
A reduction projection step of forming an image on the substrate by reducing the charged beam that has passed through the cell pattern by an electric field;
A second deflection step in which the charged beam that has passed through the cell pattern is deflected by an electric field and scanned on the substrate;
With
The charged beam has a proximity effect that affects an exposure amount of a secondary charged particle or a reflected charged particle generated from the surface of the substrate that has been irradiated, or a drawing pattern in which the secondary charged particle and the reflected charged particle are close to each other. Generated at an accelerating voltage lower than the amount of
In the reduction projection step, the aberration performance of the charged beam in a first direction orthogonal to the optical axis and the aberration performance of the charged beam in the second direction orthogonal to the first direction and the optical axis are A charged beam is used, which includes a step of independently controlling a magnification of the charged beam in the first direction and a magnification of the charged beam in the second direction so as to be substantially the same on the substrate. Exposure method. The reduction projection step includes a final reduction projection step of forming a diverging electric field and a converging electric field in the first direction and the second direction, respectively, in a region close to the substrate,
The exposure method according to claim 16, wherein a magnification of the charged beam in the first direction is larger than a magnification of the charged beam in the second direction.   A method for manufacturing a semiconductor device using the exposure method using a charged beam according to claim 6.

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