JP2018032791A - Multi-charged particle beam exposure device - Google Patents

Abstract

PURPOSE: To provide a multi-charged particle beam exposure device capable of suppressing trouble caused by scattered electrons or the like while suppressing aberration of a multi-beam.CONSTITUTION: A multi-charged particle beam exposure device comprises: a first molding aperture array substrate for forming a first multi-beam passing through multiple first openings by receiving irradiation of a beam on a first region; and a second molding aperture array substrate for forming a second multi-beam by passing a part of each beam of the first multi-beam through each corresponding opening among multiple second openings. A distance between the first molding aperture array substrate and the second molding aperture array substrate becomes a value equal to or more than triple as great as a maximum dimension of a second region in a direction of a beam diameter from an intersection of a central axis along an orbit of the first multi-beam passing a center of the beam diameter of the entire first multi-beam and the second region including the entire multiple second openings on a surface of the second molding aperture array substrate.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multi-charged particle beam exposure apparatus, for example, an exposure apparatus that irradiates a sample with a multi-beam formed from the same beam.

  Lithography technology, which is responsible for the progress of miniaturization of semiconductor devices, is an extremely important process for generating a pattern among semiconductor manufacturing processes. In recent years, with the high integration of LSI, circuit line widths required for semiconductor devices have been reduced year by year. Here, the electron beam (electron beam) drawing technique has an essentially excellent resolution, and drawing is performed on a wafer or the like using an electron beam.

  For example, there is a drawing apparatus using a multi-beam. Compared with the case of drawing with one electron beam, the use of multi-beams enables irradiation with many beams at a time, so that the throughput can be significantly improved. In such a multi-beam type drawing apparatus, for example, an electron beam emitted from an electron gun is passed through a mask having a plurality of holes to form a multi-beam, and each of the unshielded beams is blanked. The desired position on the sample is irradiated. In such a multi-beam drawing apparatus, a high-energy electron beam is irradiated onto a mask (multi-beam forming aperture) having a plurality of holes. A multi-beam is formed by passing the beam through the plurality of holes of the mask. At that time, since many of the irradiated high energy electron beams are shielded by the mask, scattered electrons and x-rays are generated from the mask. Such scattered electrons and x-rays flow into a blanking deflection electrode array that is disposed near the mask substrate and is subjected to blanking control, and charge the insulating portion of the blanking deflection electrode array. There has been a problem that the individual control circuit for each electrode formed on the substrate on which the deflection electrode array is arranged is damaged. Therefore, a doublet lens is arranged between the multi-beam forming aperture and the blanking deflection electrode array, a crossover is formed between electromagnetic lenses constituting the doublet lens, and an aperture (contrast aperture) is arranged in the vicinity of the crossover. A technique has been devised that eliminates scattered electrons entering the blanking deflection electrode array (see, for example, Patent Document 1).

  However, in multi-beam drawing, the beam size of the entire multi-beam becomes large, so that the aberration on the optical axis of the crossover imaging system becomes large. In particular, when the number of beams is increased, the beam size is increased accordingly, and aberrations are further increased. By using a doublet lens, it becomes possible to reduce distortion, but when the beam size of the multi-beam is large, a new problem arises that the spherical aberration of the crossover image due to the doublet lens becomes large. Therefore, the multi-beam diameter at the crossover position becomes large.

JP 2013-093566 A

  Therefore, the present invention provides a multi-charged particle beam exposure apparatus that can suppress problems caused by scattered electrons and the like while suppressing multi-beam aberration.

A multi-charged particle beam exposure apparatus according to an aspect of the present invention includes:
An emission part for emitting a charged particle beam;
An illumination lens for illuminating a charged particle beam;
A first region in which a plurality of first openings are formed and the whole of the plurality of first openings is irradiated with the irradiated charged particle beam, and the plurality of first openings are charged to the charged particle beam. A first shaped aperture array substrate that forms a first multi-beam by passing a part of each of
A plurality of second openings corresponding to the trajectory of each beam of the first multi-beam are formed, and a part of each beam of the first multi-beam has a corresponding opening of the plurality of second openings, respectively. A second shaped aperture array substrate that passes to form a second multi-beam;
A stage on which a sample to be irradiated with at least a part of a beam group of the second multi-beam that has passed through the second shaping aperture array substrate is placed;
With
The distance between the first shaped aperture array substrate and the second shaped aperture array substrate is such that the central axis along the trajectory of the first multi-beam passing through the center of the beam diameter of the entire first multi-beam and the second The value is not less than three times the maximum dimension of the second region in the direction of the beam diameter from the intersection with the second region including the entire plurality of second openings on the surface of the shaped aperture array substrate. It is characterized by being configured.

An electron beam column that internally arranges the first molded aperture array substrate and the second molded aperture array substrate;
An electron which is disposed in the electron beam column and between the first shaping aperture array substrate and the second shaping aperture array substrate, and an opening larger than the beam diameter of the entire first multi-beam is formed. Or an absorbing structure that absorbs at least one of the x-rays;
It is preferable to further include

  It is also preferable to further include a grating lens that uses the first molded aperture array substrate as a grating.

Also, the absorption structure is
An inner absorber made of an atom having an atomic number of 13 or less and having a recess formed on the inner wall surface, and an atomic number of 13 or less;
An outer absorber disposed outside the inner absorber and having an atomic number of 74 or more atoms as a material;
It is preferable to have

Alternatively, the absorbent structure is
An inner absorber made of an atom having an atomic number of 13 or less and having a stationary blade on the inner wall surface and an atomic number of 13 or less as a material;
An outer absorber disposed outside the inner absorber and having an atomic number of 74 or more atoms as a material;
It is preferable to have

  According to one embodiment of the present invention, it is possible to suppress problems caused by scattered electrons or the like while suppressing multi-beam aberration.

1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to Embodiment 1. FIG. FIG. 3 is a conceptual diagram showing a configuration of a molded aperture array substrate in the first embodiment. FIG. 3 is a cross-sectional view showing a configuration of a molded aperture array substrate in the first embodiment. FIG. 3 is a cross-sectional view showing a configuration of a blanking aperture array mechanism in the first embodiment. FIG. 3 is a top conceptual view showing a part of the configuration in the membrane region of the blanking aperture array mechanism in the first embodiment. FIG. 6 is a diagram for explaining a relationship between a distance between a collimator shaping aperture array substrate and a shaping aperture array substrate and an arrival distribution of scattered electrons in the first embodiment. 6 is a diagram for explaining a drawing order according to Embodiment 1. FIG. 5 is a diagram for explaining an example of a configuration and a beam trajectory in a comparative example of the first embodiment. FIG. 6 is a conceptual diagram illustrating a configuration of a drawing apparatus according to Embodiment 2. FIG. FIG. 10 is a conceptual diagram illustrating a configuration of a drawing apparatus according to a third embodiment. FIG. 10 is a conceptual diagram illustrating a configuration of a drawing apparatus according to a fourth embodiment.

  Hereinafter, in the embodiment, a configuration using an electron beam will be described as an example of a charged particle beam. However, the charged particle beam is not limited to an electron beam, and a beam using charged particles such as an ion beam may be used.

Embodiment 1 FIG.
FIG. 1 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the first embodiment. In FIG. 1, the drawing apparatus 100 includes a drawing mechanism 150 and a control system circuit 160. The drawing apparatus 100 is an example of a multi charged particle beam apparatus and an example of a multi charged particle beam drawing apparatus. The drawing mechanism 150 includes an electron column 102 (also referred to as “electron beam column” or “column”) and a drawing chamber 103. In the electron column 102, an electron gun 201, an illumination lens 202, a collimator shaping aperture array substrate 224, an electrostatic lens 212, an absorption structure 210, a shaping aperture array substrate 203, a blanking aperture array mechanism 204, a reduction lens 205, A limiting aperture substrate 206 (blanking aperture), an objective lens 207, and a deflector 208 are disposed. An XY stage 105 is disposed in the drawing chamber 103. On the XY stage 105, a sample 101 such as a mask to be a drawing target substrate at the time of drawing is arranged. The sample 101 is held on the XY stage 105 by, for example, three-point support (not shown). The sample 101 includes an exposure mask for manufacturing a semiconductor device, or a semiconductor substrate (silicon wafer) on which the semiconductor device is manufactured. Further, the sample 101 includes mask blanks to which a resist is applied and nothing is drawn yet.
Here, a magnetic lens is used as the illumination lens 202. In order to reduce the spherical aberration, it is preferable to set the change of the magnetic field distribution to be small. Further, it is preferable that the gradient of the magnetic field distribution and the change in the magnetic field distribution with respect to the axis of the on-axis trajectory in the illumination lens 202 are reduced. In order to realize these, within a permissible range, the distance to the optical axis direction is longer than the size (maximum dimension) of a region (opening region) including a plurality of holes 22 to be described later of the molded aperture array substrate 203 as a whole. Have a magnetic field distribution. The length of the magnetic field distribution is further determined so that the spherical aberration itself by the illumination lens 202 or the spherical aberration after the aberration correction when the aberration correction described later is performed is within an allowable range.

  The collimator shaping aperture array substrate 224 is arranged on a rotation stage (not shown) whose rotation axis is parallel to the central axis of the electron column 102, and the direction of the collimator shaping aperture array substrate 224 can be changed by control from outside the electron column 102. It is desirable to be configured as follows. Although the structure is complicated, it is more desirable to use a stage that can also be translated in the two-dimensional horizontal direction perpendicular to the axis of the optical system, and further in the axial direction of the optical system.

  The electrostatic lens 212 is arranged in the vicinity of the electron gun 201 side with respect to the collimator shaping aperture array substrate 224 (first shaping aperture array substrate). The electrostatic lens 212 becomes a grating lens 220 (first grating lens) using the collimator-shaped aperture array substrate 224 as a grating.

  The molded aperture array substrate 203 is arranged at a distance D from the back surface of the collimator molded aperture array substrate 224. An absorption structure 210 is disposed in the electron column 102 and between the collimator shaping aperture array substrate 224 and the shaping aperture array substrate 203. The absorption structure 210 has an opening that is larger than the beam diameter of the entire multi-beam 20 (20a to 20e), and absorbs electrons (scattered electrons) and / or x-rays. Here, mainly scattered electrons and / or x-rays generated when the collimator-shaped aperture array substrate 224 is irradiated with the electron beam 200 are absorbed. The absorbent structure 210 includes an outer absorbent body 214 and an inner absorbent body 216.

  For example, the inner absorbent body 216 is formed in a circular cylindrical shape having a predetermined thickness. The inner absorbent body 216 has at least one stationary blade 218 extending toward the upper side in the central direction on the inner wall surface side. In the example of FIG. 1, for example, a case where five stages of stationary blades 218 are arranged at different height positions is shown. It is preferable that each stationary blade 218 is angle-adjusted so as to face the center of the entire area of a plurality of openings described later formed on the collimator-shaped aperture array substrate 224. By adjusting the angle, scattered electrons and x-rays can be taken in efficiently. Further, each stage of the stationary blades 218 may be formed in a truncated cone shape connected in the circumferential direction, or a plurality of blades may be arranged side by side along the circumferential direction.

  The inner absorber 216 including the stationary blade 218 is made of atoms (low-Z material) having an atomic number of 13 (aluminum: Al) or less. In addition to aluminum (Al), for example, carbon (C) or the like is preferably used. The inner absorber 216 including the stationary blade 218 is made of a conductive material so as not to be charged. By using the low-Z material, it is possible to reduce the generation of further scattered electrons and x-rays from the collision point when the scattered electrons collide. Moreover, even if the scattered electrons colliding with the inner wall surface of the inner absorber 216 are reflected, the trajectory is interfered by the stationary blade 218 located on the reflection trajectory and energy is consumed. Therefore, it is difficult to return to the central region of the electron barrel 102 (the passage region of the multibeam 20). Thus, the inner absorber 216 absorbs scattered electrons by collecting (trapping) the scattered electrons.

  The outer absorbent body 214 is formed in, for example, a circular cylinder having a predetermined thickness. The outer absorbent body 214 is disposed outside the inner absorbent body 216. The outer absorber 214 is made of an atom (high-Z material) having an atomic number of 74 (tungsten: W) or more. The outer absorber 214 is made of a conductive material so as not to be charged. In addition to tungsten (W), for example, a refractory metal such as tantalum (Ta) and molybdenum (Mo) is preferably used. By using the high-Z material, the x-ray absorption rate can be increased, and the x-rays that have passed through the inner absorber 216 can be absorbed. Further, the outer absorber 214 is disposed outside the inner absorber 216, so that direct collision of scattered electrons can be avoided and emission of new x-rays due to electron collision can be avoided.

  In the above-described example, the absorption structure 210 is disposed so as to substantially cover the entire inner wall of the inner wall of the electron barrel 102 between the collimator shaping aperture array substrate 224 and the shaping aperture array substrate 203. Although shown, it is not limited to this. It may be a part of the inner wall of the electron lens barrel 102 between the remeter forming aperture array substrate 224 and the forming aperture array substrate 203. Even if it is such a part, it is desirable to arrange it in the whole circumferential direction. More preferably, the inner wall of the electron column 102 between the collimator shaping aperture array substrate 224 and the shaping aperture array substrate 203 may be disposed so as to substantially cover the entire inner wall.

  The control system circuit 160 includes a control computer 110, a memory 112, a lens control circuit 120, a deflection control circuit 130, a deflection control circuit 132, a digital / analog conversion (DAC) amplifier 136, and a storage device 140 such as a magnetic disk device. ing. The control computer 110, the memory 112, the lens control circuit 120, the deflection control circuit 130, the deflection control circuit 132, and the storage device 140 are connected to each other via a bus (not shown). A DAC amplifier 136 is connected to the deflection control circuit 132. Drawing data is input from the outside of the drawing apparatus 100 and stored in the storage device 140 (storage unit). The lens control circuit 120 and the deflection control circuits 130 and 132 are controlled by the control computer 110.

  The electrostatic lens 212 is connected to the lens control circuit 120 and controlled. The blanking aperture array mechanism 204 is connected to the deflection control circuit 130 and controlled. The deflector 208 is connected to the deflection control circuit 132 via the DAC amplifier 136 and controlled.

  Here, FIG. 1 shows a configuration necessary for explaining the first embodiment. The drawing apparatus 100 may normally have other necessary configurations.

FIG. 2 is a conceptual diagram showing the configuration of the molded aperture array substrate in the first embodiment.
FIG. 3 is a cross-sectional view showing the configuration of the molded aperture array substrate in the first embodiment. 2 and 3, the size, the position of the opening 22 (226), and the like are not shown to be coincident. As shown in FIG. 3, a substrate 331 made of silicon or the like is disposed on the molded aperture array substrate 203. For example, the central portion of the substrate 331 is thinly cut from the back surface side and processed into a membrane region 23 (second region) having a thin film thickness h. The periphery surrounding the membrane region 23 is an outer peripheral region 21 having a thick film thickness H. The upper surface of the membrane region 23 and the upper surface of the outer peripheral region 21 are formed at the same height position or substantially at the height position. 2A, in the membrane region 23 of the molded aperture array substrate 203, holes 22 (second opening portions) of vertical (y direction) m rows × horizontal (x direction) n rows (m, n ≧ 2) are formed. ) Are formed in a matrix at a predetermined arrangement pitch. For example, 512 rows × 512 rows of holes 22 are formed. In the example of FIG. 2A, for example, a case where 8 rows × 8 rows of holes 22 are formed is shown. Each hole 22 is formed of a rectangle having the same size and shape. Alternatively, it may be a circle having the same outer diameter. A part of each beam of a provisional multi-beam 19 (first multi-beam) to be described later passes through the plurality of holes 22 to form a multi-beam 20 (second multi-beam). Become. Here, an example in which two or more holes 22 are arranged in both the vertical and horizontal directions (x and y directions) is shown, but the present invention is not limited to this. In addition, for example, one of the vertical and horizontal directions (x and y directions) may be a plurality of rows and the other may be only one row.

  Further, the collimator molding aperture array substrate 224 is configured in the same manner as the molding aperture array substrate 203. As shown in FIG. 3, a substrate 333 made of silicon or the like is disposed on the collimator shaping aperture array substrate 224. For example, the central portion of the substrate 333 is thinned from the back surface side and processed into a membrane region 323 (first region) having a thin film thickness h. The periphery surrounding the membrane region 323 is an outer peripheral region 321 having a thick film thickness H. The upper surface of the membrane region 323 and the upper surface of the outer peripheral region 321 are formed to be at the same height position or substantially at the height position. In FIG. 2A, the membrane region 323 of the collimator-shaped aperture array substrate 224 has vertical (y direction) m rows × horizontal (x direction) n rows (m, n ≧ 2) holes 322 (first opening). Are formed in a matrix at a predetermined arrangement pitch. The pitch may differ depending on the location so that the beam group that has passed through the collimator shaping aperture array substrate 224 passes through the corresponding hole 22 (opening) on the shaping aperture array substrate 203. For example, 512 rows × 512 rows of holes 322 are formed. In the example of FIG. 2A, for example, a case where 8 rows × 8 rows of holes 322 are formed is shown. Each hole 322 is formed of a rectangle having the same size and shape. Alternatively, it may be a circle having the same outer diameter. Further, for example, the hole 322 (opening) in the outer peripheral portion is enlarged so that the beam group that has passed through the collimator shaping aperture array substrate 224 passes through the corresponding hole 22 (opening) on the shaping aperture array substrate 203. It can also be made easier. In this case, the beam that has passed through one of the holes in the outer peripheral portion may be incident on a plurality of holes on the shaping aperture array substrate 203. When a part of the electron beam 200 passes through each of the plurality of holes 322, a temporary multi-beam 19 (first multi-beam) is formed. Here, an example in which two or more holes 22 are arranged in both the vertical and horizontal directions (x and y directions) is shown, but the present invention is not limited to this. In addition, for example, one of the vertical and horizontal directions (x and y directions) may be a plurality of rows and the other may be only one row.

  The plurality of holes 322 (first openings) formed in the collimator shaping aperture array substrate 224 are formed to have the same positional relationship as the plurality of corresponding holes 22 formed in the shaping aperture array substrate 203. However, the plurality of holes 323 formed in the collimator shaping aperture array substrate 224 have a cross-sectional dimension of the beam that has passed through the shaping aperture array substrate 203 that is larger than the corresponding plurality of holes 22 formed in the shaping aperture array substrate 203. It is formed to be a large size. Thereby, the shape of the multi-beam 20 is determined by the shaping aperture array substrate 203. It is desirable that the current distribution of the beam in the holes 22 on the shaped aperture array substrate 203 is made to be substantially uniform.

FIG. 4 is a cross-sectional view showing the configuration of the blanking aperture array mechanism in the first embodiment.
FIG. 5 is a top conceptual view showing a part of the configuration in the membrane region of the blanking aperture array mechanism in the first exemplary embodiment. 4 and 5, the positional relationship among the control electrode 24, the counter electrode 26, the control circuit 41, and the pad 43 is not shown to be the same. The blanking aperture array mechanism 204 is preferably arranged on the back surface (downstream side of the electron beam) of the shaped aperture array substrate 203 and in the vicinity of the shaped aperture array substrate 203. In the blanking aperture array mechanism 204, as shown in FIG. 4, the semiconductor substrate 31 made of silicon or the like is disposed on the support base 33. For example, the central portion of the substrate 31 is thinly cut from the back side and processed into a membrane region 30 having a thin film thickness h. The periphery surrounding the membrane region 30 is an outer peripheral region 32 having a thick film thickness H. The upper surface of the membrane region 30 and the upper surface of the outer peripheral region 32 are formed to have the same height position or substantially the height position. The substrate 31 is held on the support base 33 on the back surface of the outer peripheral region 32. The central part of the support base 33 is open, and the position of the membrane region 30 is located in the open area of the support base 33.

  In the membrane region 30, passage holes 25 (openings) for the passage of the multi-beams are opened at positions corresponding to the holes 22 of the shaped aperture array substrate 203 shown in FIG. 2. Each passage hole 25 is formed larger than the hole 22 formed in the shaping aperture array substrate 203. On the membrane region 30, as shown in FIGS. 4 and 5, a set of a blanking deflection control electrode 24 and a counter electrode 26 sandwiching the passage hole 25 corresponding to the position in the vicinity of each passage hole 25 ( (Blanker: Blanking deflector) is arranged. A control circuit 41 (logic circuit) that applies a deflection voltage to the control electrode 24 for each passage hole 25 is disposed in the vicinity of each passage hole 25 on the membrane region 30. The counter electrode 26 for each beam is grounded. Each control circuit 41 is processed in the substrate 31.

  Further, as shown in FIG. 5, each control circuit 41 is connected with n-bit (for example, 10-bit) parallel wiring for control signals. Each control circuit 41 is connected to a clock signal line and a power supply line in addition to an n-bit parallel line for a control signal. As the clock signal line and the power supply wiring, a part of the parallel wiring may be used. An individual blanking mechanism 47 including the control electrode 24, the counter electrode 26, and the control circuit 41 is configured for each beam constituting the multi-beam. In the example of FIG. 4, the control electrode 24, the counter electrode 26, and the control circuit 41 are arranged in the membrane region 30 where the substrate 31 is thin. However, the present invention is not limited to this. Further, the plurality of control circuits 41 formed in an array in the membrane region 30 are grouped by, for example, the same row or the same column, and the control circuit 41 groups in the group are connected in series as shown in FIG. Is done. Then, a signal from the pad 43 arranged for each group is transmitted to the control circuit 41 in the group.

  The electron beam 20 passing through each passage hole 25 is deflected by a voltage applied to the two electrodes 24 and 26 that form a pair independently. Blanking is controlled by such deflection. In other words, the set of the control electrode 24 and the counter electrode 26 respectively blanks and deflects the corresponding beam among the multi-beams that have passed through the plurality of holes 22 (openings) of the shaping aperture array substrate 203.

  Next, the operation of the drawing mechanism 150 in the drawing apparatus 100 will be described. The electron beam 200 emitted from the electron gun 201 (emission unit) illuminates the entire collimator shaping aperture array substrate 224 (first shaping aperture array substrate) almost vertically by the illumination lens 202. The collimator-shaped aperture array substrate 224 is formed with a plurality of rectangular holes 22 (first openings), and the electron beam 200 is an area within the membrane area 23 that includes the membrane area 23 or all of the plurality of holes 22. Illuminate. Each part of the electron beam 200 irradiated to the positions of the plurality of holes 22 passes through the plurality of holes 22 of the collimator-shaped aperture array substrate 224, thereby, for example, a plurality of rectangular electron beams (provisional multi-beams). Beams) 19a-e are formed. The multi-beam 19 is projected on the shaping aperture array substrate 203 while being substantially vertical.

  A plurality of rectangular holes 22 (second openings) are formed in the molded aperture array substrate 203 (second molded aperture array substrate), and a plurality of electron beams (temporary multibeams) 19a to 19e are molded. By passing through the corresponding holes 22 of the plurality of holes 22 (second openings) of the aperture array substrate 203, the plurality of electron beams (multi-beams) 20a to 20e having a desired size, for example, are formed. Molded. In other words, at least some of the corresponding beams among the multi-beams 19a to 19e pass through the plurality of holes 22 of the shaped aperture array substrate 203 (second shaped aperture array substrate). In other words, an aperture array image (first aperture array image) that has passed through the collimator shaped aperture array substrate 224 (first aperture array member) is formed on the shaped aperture array substrate 203 (second aperture array member). .

  Here, the positional deviation in the rotation direction of the temporary multi-beams 19a to 19e with respect to the downstream shaping aperture array substrate 203 may be adjusted by operating a rotation mechanism (not shown) for the upstream collimator shaping aperture array substrate 224. . As for the positional deviation in the horizontal direction, the trajectories of the temporary multi-beams 19a to 19e may be adjusted by using one or more alignment coils (not shown). Alternatively, the position of the upstream collimator shaping aperture array substrate 224 can be adjusted by operating a horizontal or vertical moving mechanism.

  In the first embodiment, the collimator-shaped aperture array substrate 224 is arranged on the upstream side, and the remaining part of the single electron beam 200 that is not used for forming the temporary multi-beam 19 is shielded by the collimator-shaped aperture array substrate 224. To do. The portion (the remaining portion) where the electron beam 200 is shielded corresponds to the most part of the electron beam 200. For example, it corresponds to 70 to 90%. Therefore, the energy amount of the entire beam of the temporary multi-beam 19 that reaches the downstream shaped aperture array substrate 203 can be greatly reduced. Therefore, the amount of energy of the electron beam that collides with the downstream shaped aperture array substrate 203 can be greatly reduced, so that the amount of deformation of the opening 22 can be greatly reduced. Therefore, it is possible to form the multi-beam 20 having a highly accurate dimension. Here, in Embodiment 1, the size of the hole 322 of the collimator shaping aperture array substrate 224 is set so that the cross-sectional dimension of the beam passing through the hole 322 on the shaping aperture array substrate 203 on the downstream side is the downstream. So as to be larger than the size of the hole 22. Therefore, the beam shape (size) of the multi-beam 20 can be determined by the downstream shaped aperture array substrate 203. Therefore, even if the large beam energy of the electron beam 200 is applied to the collimator shaping aperture array substrate 224 and the size of the hole 322 is deformed due to a temperature rise, the final beam shape (size) of the multi-beam 20 is affected. I can not.

  The multi-beams 20a to 20e that have passed through the shaping aperture array substrate 203 pass through the corresponding blankers (first deflector: individual blanking mechanism 47) of the blanking aperture array mechanism 204, respectively. Each of these blankers deflects the electron beam 20 that individually passes (performs blanking deflection).

  The multi-beams 20a to 20e that have passed through the blanking aperture array mechanism 204 are focused by a reduction lens 205 (electromagnetic lens). In other words, the reduction lens 205 focuses the multi-beams 20a to 20e that have passed through the shaping aperture array substrate 203. At that time, the size of the multi-beams 20 a to 20 e is reduced by the reduction lens 205. The multi-beams 20a to 20e refracted in the focusing direction by the reduction lens 205 (electromagnetic lens) travel toward a central hole formed in the limiting aperture substrate 206. The limiting aperture substrate 206 is disposed at the focal point position of the multi-beams 20a to 20e focused by the reduction lens 205, and restricts the passage of the electron beam 20 off the focal point of the multi-beams 20a to 20e. Here, the electron beam 20 deflected by the blanker of the blanking aperture array mechanism 204 deviates from the center hole of the limiting aperture substrate 206 and is blocked by the limiting aperture substrate 206. On the other hand, the electron beam 20 that has not been deflected by the blanker of the blanking aperture array mechanism 204 passes through the hole at the center of the limiting aperture substrate 206 as shown in FIG. Blanking control is performed by ON / OFF of the individual blanking mechanism 47, and ON / OFF of the beam is controlled. In this manner, the limiting aperture substrate 206 blocks each beam deflected so as to be in the beam OFF state by the individual blanking mechanism 47. Then, for each beam, one shot beam is formed by the beam that has passed through the limiting aperture substrate 206 formed from when the beam is turned on to when the beam is turned off. The multi-beam 20 that has passed through the limiting aperture substrate 206 is focused on the surface of the sample 101 by the objective lens 207 and becomes a pattern image having a desired reduction ratio, and each beam that has passed through the limiting aperture substrate 206 by the deflector 208. The entire multi-beam 20 is deflected all at once in the same direction, and is irradiated to each irradiation position on the sample 101 of each beam. In other words, the sample 101 placed on the XY stage 105 (stage) is at least a part of the multi-beam 20 (second multi-beam) that has passed through the shaping aperture array substrate 203 (second shaping aperture array substrate). Irradiation of the beam group. For example, when the XY stage 105 is continuously moving, the beam irradiation position is controlled by the deflector 208 so as to follow (track) the movement of the XY stage 105. The position of the XY stage 105 is measured by irradiating a laser from a stage position detector (not shown) toward a mirror (not shown) on the XY stage 105 and using the reflected light. The multi-beams 20 irradiated at a time are ideally arranged at a pitch obtained by multiplying the arrangement pitch of the plurality of holes 22 of the shaping aperture array substrate 203 by the desired reduction ratio. The drawing apparatus 100 irradiates each beam one pixel at a time along the drawing sequence by moving the beam deflection position by the deflector 208 while following the movement of the XY stage 105 during each tracking operation. The drawing operation is performed. When drawing a desired pattern, a beam required according to the pattern is controlled to be turned on by blanking control.

FIG. 6 is a diagram for explaining the relationship between the distance between the collimator shaped aperture array substrate and the shaped aperture array substrate and the arrival distribution of scattered electrons in the first embodiment. When the electron beam 200 collides with the collimator-shaped aperture array substrate 224, scattered electrons and x-rays are emitted from the collimator-shaped aperture array substrate 224. When the distribution of the scattered electrons and the x-ray is approximated by a cosine distribution, the shaped aperture array substrate 203 with respect to the expected angle θ from the generation point (for example, the center of the entire region of the plurality of holes 322 of the collimator shaped aperture array substrate 224). On the surface, the ratio of scattered electrons and x-rays that reach the region enclosed when the intersection with the line of the prospective angle θ is rotated about the optical axis can be approximated by the square of sin θ. The optical axis here is a central axis along the trajectory of the multi-beam 19 passing through the center of the beam diameter of the entire multi-beam 19 (first multi-beam). Here, the distance D between the collimator shaping aperture array substrate 224 and the shaping aperture array substrate 203, the central axis (optical axis) of the multi-beam 19, and the entire plurality of holes 22 on the surface of the shaping aperture array substrate 203 are included. For example, when the square of sin θ is expressed using a dimension r from the intersection with the membrane region 23 (second region) in the direction of the beam diameter, it can be defined by the following equation (1).
(1) (sin θ) ² = r ² / (D ² + r ² )

Therefore, in order to suppress the ratio of scattered electrons and x-rays that reach the membrane region 23 of the shaped aperture array substrate 203 to an order of magnitude less than 10%, Expression (2) should be satisfied.
(2) r ² / (D ² + r ² ) <(1/10)

  Therefore, if D> 3r, the ratio of scattered electrons and x-rays that reach, for example, the membrane region 23 of the shaped aperture array substrate 203 can be suppressed to less than 10%. Therefore, at least three times the maximum dimension r of this region in the direction of the beam diameter from the intersection of the central axis (optical axis) of the multi-beam 19 and the region including the entire plurality of holes 22 on the surface of the shaped aperture array substrate 203 What is necessary is just to set the distance D so that it may become the value of. As shown in FIG. 2, the maximum dimension r of the region including the whole of the plurality of holes 22 is the distance from the center of the whole of the plurality of holes 22 to the corner of the rectangular region, that is, the maximum distance in the diagonal direction (maximum dimension). )And it is sufficient. As described above, even if scattered electrons and x-rays are generated on the collimator-shaped aperture array substrate 224, the ratio of reaching the plurality of holes 22 of the shaped aperture array substrate 203 can be reduced by orders of magnitude. The deformation of the hole 22 due to the energy of the wire can be sufficiently suppressed. Further, since the rate of arrival can be reduced by orders of magnitude, the influence of the x-ray on the control circuit 41 of the blanking aperture array mechanism 204 can be sufficiently suppressed.

Furthermore, since the scattered electrons and x-rays that collide with the inner wall surface of the electron column 102 are absorbed by the absorption structure 210 as described above, the scattered electrons and x-rays reflected from the inner wall surface of the electron column 102. The influence on the shaping aperture array substrate 203 and the blanking aperture array mechanism 204 due to the above can be substantially ignored.
In the above description, the upstream base point is evaluated as being in the center of the region including the entire plurality of holes 322 of the upstream collimator shaping aperture array substrate 224, that is, on the central axis. In general, as the base point position moves away from the center, the solid angle for looking into the central region of the downstream shaping aperture array substrate 203 is smaller than when the base point is at the center, and thus the above evaluation is based on the upstream collimator shaping aperture array substrate 224. It is reasonable to carry out at the center of the region including the whole of the plurality of holes 322.

  FIG. 7 is a diagram for explaining the drawing order in the first embodiment. The drawing area 10 (or the chip area to be drawn) of the sample 101 is divided into a plurality of stripe areas 35 (another example of the drawing area) on the strip with a predetermined width. Each stripe region 35 is divided into a plurality of mesh pixel regions 36 (pixels). The size of the pixel region 36 (pixel) is preferably, for example, a beam size or a size smaller than that. For example, a size of about 10 nm is preferable. The pixel region 36 (pixel) is an irradiation unit region per beam of the multi-beam 20.

  When the sample 101 is drawn with the multi-beam 20, the irradiation region 34 is irradiated by one irradiation with the multi-beam 20. As described above, during the tracking operation, the entire multi-beam 20 that becomes a shot beam follows the movement of the XY stage 105 and is irradiated in succession sequentially, for example, one pixel at a time by moving the beam deflection position by the deflector 208. To go. Then, which pixel of the multi-beam is irradiated to which pixel on the sample 101 is determined by the drawing sequence. Using the beam pitch between the beams adjacent to each other in the x and y directions of the multi-beam, the beam pitch between the beams adjacent to each other in the x and y directions on the surface of the sample 101 (x direction) × beam pitch (y direction). The region is composed of an n × n pixel region (sub-pitch region). For example, when the XY stage 105 moves in the −x direction by the beam pitch (x direction) in one tracking operation, the irradiation position is shifted by one beam in the x direction or the y direction (or oblique direction). Pixels are drawn. The other n pixels in the same n × n pixel region are similarly drawn by a beam different from the beam described above in the next tracking operation. In this way, by drawing n pixels by different beams in n tracking operations, all the pixels in one n × n pixel area are drawn. The same operation is performed at the same time for other n × n pixel areas in the multi-beam irradiation area, and drawing is performed in the same manner. With this operation, all the pixels in the irradiation region 34 can be drawn. By repeating these operations, the entire corresponding stripe region 35 can be drawn. The drawing apparatus 100 can draw a desired pattern by a combination of pixel patterns (bit patterns) formed by irradiating a necessary pixel with a beam having a necessary irradiation amount.

  FIG. 8 is a diagram for explaining an example of a configuration and a beam trajectory in the comparative example of the first embodiment. In FIG. 8, in the comparative example, doublet lenses 312 and 314 are arranged between a shaping aperture array 203 and a blanking aperture array mechanism 204 for forming a multi-beam, and a crossover is performed between electromagnetic lenses constituting the doublet lenses 312 and 314. And a contrast aperture 316 is disposed near the crossover. In the comparative example, the electron beam 200 is received by the shaping aperture array 203 without using the collimator shaping aperture array substrate 224. Other configurations are the same as those in FIG. With this configuration, the scattered electrons generated in the shaping aperture array 203 are shielded by the contrast aperture 316. This eliminates scattered electrons entering the blanking deflection electrode array. In the comparative example, since the electron beam 200 is received by the shaping aperture array 203, the temperature of the shaping aperture array 203 rises due to the large energy of the colliding beam. Therefore, the size of the hole 22 is deformed, and an error occurs in the size of the formed multi-beam.

  In addition, as described above, in multi-beam drawing, the beam size of the entire multi-beam is increased, so that the aberration on the optical axis of the crossover imaging system is increased. Therefore, in the comparative example, even when the doublet lenses 312 and 314 are excited so that the magnetic fields are opposite to each other and have the same magnitude, the crossover diameter at the focusing point is designed by the spherical aberration in each electromagnetic lens 312 and 314. It will be larger than the value. Due to the spherical aberration of the electromagnetic lens 312, the crossover diameter at the focusing point on the surface of the contrast aperture 316 increases. Due to the spherical aberration of the electromagnetic lens 314, the crossover diameter at the focusing point on the surface of the limiting aperture substrate 206 becomes large. As described above, in the crossover imaging system, if the focal length of the doublet lens is shortened so that the doublet lens region can be narrowed and the image is refracted greatly by the doublet lenses 312 and 314, spherical aberration due to the lens 312 results. The crossover diameter formed in the meantime becomes larger than the design value. Such a point similarly occurs even when the collimator shaping aperture array substrate 224 is arranged on the upstream side of the shaping aperture array 203. The same occurs when the doublet lenses 312 and 314 are arranged between the collimator shaping aperture array substrate 224 and the shaping aperture array 203. Although it is possible to suppress the spherical aberration to an allowable range by increasing the axial magnetic field region of the electromagnetic lenses 312, 314, in this case, the electron lens barrel becomes long.

  On the other hand, in Embodiment 1, since the electron beam 200 is once received by the collimator shaping aperture array substrate 224, the temperature rise of the shaping aperture array 203 can be suppressed. Further, the arrival of scattered electrons and x-rays can be reduced by controlling the distance between the collimator shaping aperture array substrate 224 and the shaping aperture array 203. Further, scattered electrons and x-rays that collide with the inner wall surface of the electron column 102 can be absorbed by the absorption structure 210 as described above. Therefore, it is possible to suppress problems caused by scattered electrons and x-rays.

  Further, in the first embodiment, the doublet lenses 312 and 314 are not arranged between the collimator shaping aperture array substrate 224 and the shaping aperture array 203 and between the shaping aperture array 203 and the blanking aperture array mechanism 204. . Therefore, in the crossover imaging system, an electron beam crossover is formed between the collimator shaping aperture array substrate 224 and the shaping aperture array 203 and between the shaping aperture array 203 and the blanking aperture array mechanism 204. Do not have such a large refraction. Therefore, generation of spherical aberration due to the doublet lenses 312 and 314 can be avoided, and a crossover is not formed by the doublet lenses 312 and 314, so that the crossover diameter does not increase.

  Therefore, it is possible to suppress the multi-beam aberration as compared with the case where the doublet lenses 312 and 314 are disposed, and it is possible to suppress problems due to scattered electrons and the like.

  Even when the doublet lenses 312 and 314 are not arranged, spherical aberration is still generated by the illumination lens 202. Thus, in the first embodiment, the grating lens 220 causes spherical aberration having a negative aberration coefficient. This cancels out the spherical aberration at the illumination lens 202. The electromagnetic lenses such as the illumination lens 202, the reduction lens 205, and the objective lens 207 all function as a convex lens that refracts the multi-beam 20 toward the inner side (optical axis center side) of the lens. Therefore, in order to cancel the spherical aberration effect caused by the electromagnetic lens, the grating lens 220 acts as a concave lens that refracts the multi-beam 20 toward the outside of the lens. With this configuration, spherical aberration due to the illumination lens 202 can be reduced. Therefore, even if spherical aberration is generated by the reduction lens 205, the crossover diameter formed at the height position of the limiting aperture member 216 can be sufficiently reduced.

  As described above, according to the first embodiment, it is possible to suppress problems caused by scattered electrons and the like while suppressing multi-beam aberration.

Embodiment 2. FIG.
In the first embodiment, the case where the reflected orbit of scattered electrons is inhibited by disposing the stationary blade 218 on the inner absorber 216 has been described, but the method of inhibiting the reflected orbit of scattered electrons is not limited to this. . In the second embodiment, different methods will be described.

  FIG. 9 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the second embodiment. 9 is the same as FIG. 1 except that the stationary blade 218 is not disposed and the structure of the inner absorbent body 216 is different. The contents other than those specifically described below are the same as those in the first embodiment.

  In FIG. 9, the inner side absorber 216 is formed in the circular cylinder shape with predetermined | prescribed thickness, for example. However, the inner absorbent body 216 has at least one recess 219 formed on the inner wall surface side. The recess 219 is formed in a shape that is recessed from the inner wall surface of the inner absorbent body 216 toward the outer wall surface side (outer side). In the example of FIG. 9, for example, the case where the eight-level recess 219 is arranged with the height position shifted is shown. By adjusting the width (size in the height direction in the drawing apparatus 100) and the formation pitch of the recess 219, scattered electrons and x-rays can be taken in efficiently. Moreover, the recessed part 219 of each step | paragraph may be formed in the groove shape connected in the circumferential direction, and it is suitable even if it arrange | positions along with the circumferential direction several recessed parts.

  The inner absorber 216 is made of an atom (low Z material) having an atomic number of 13 (aluminum: Al) or less. In addition to aluminum (Al), for example, carbon (C) or the like is preferably used. The inner absorber 216 is made of a conductive material so as not to be charged. By using the low-Z material, it is possible to reduce the generation of further scattered electrons and x-rays from the collision point when the scattered electrons collide. Moreover, even if the scattered electrons colliding with the inner wall surface of the inner absorber 216 are reflected, the orbit is interfered by the inner wall surface of the concave portion 219 located on the reflection orbit and energy is consumed. Therefore, it is difficult to return to the central region of the electron barrel 102 (the passage region of the multibeam 20). Thus, the inner absorber 216 absorbs scattered electrons by collecting (trapping) the scattered electrons.

  As described above, according to the second embodiment, similarly to the first embodiment, it is possible to suppress problems caused by scattered electrons and the like while suppressing multi-beam aberration.

Embodiment 3 FIG.
In the first embodiment, the case where the aberration is corrected by the one-stage grating lens 220 has been described, but the present invention is not limited to this. In the third embodiment, different methods will be described.

  FIG. 10 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the third embodiment. In FIG. 10, the electrostatic lens 212 is disposed on the side opposite to the electron gun 201 side (molded aperture array substrate 203 side) with respect to the collimator molded aperture array substrate 224 (first molded aperture array substrate). 1 is the same as FIG. 1 except that the electrostatic lens 232 is disposed in the immediate vicinity of the electron gun 201 with respect to the molded aperture array substrate 203 and the lens control circuit 122 is added. The contents other than those specifically described below are the same as those in the first embodiment.

  The electrostatic lens 212 becomes a grating lens 220 (first grating lens) using the collimator-shaped aperture array substrate 224 as a grating. The electrostatic lens 232 is a grating lens 230 (second grating lens) using the molded aperture array substrate 203 as a grating. In the third embodiment, the potential applied to one grating lens can be reduced by providing the grating lens with a plurality of stages of grating lenses 220 and 230. With a two-stage configuration, the potential applied per grating lens can be halved. The electrostatic lens 232 is connected to the lens control circuit 122 and controlled. In the third embodiment, as in the first embodiment, both the grating lens 220 and the grating lens 230 act as concave lenses, and a spherical aberration having a negative aberration coefficient is generated.

  As in FIG. 1, the electrostatic lens 212 may be arranged in the vicinity of the electron gun 201 side with respect to the collimator shaping aperture array substrate 224 (first shaping aperture array substrate). The two-stage lattice lens of the third embodiment can also be applied to the configuration of the second embodiment.

  As described above, according to the third embodiment, the potential applied to the grating lens can be reduced, and similarly to the first embodiment, it is possible to suppress problems caused by scattered electrons and the like while suppressing multi-beam aberration.

Embodiment 4 FIG.
In the third embodiment, the case where the lens control circuit is arranged for each grating lens has been described, but the present invention is not limited to this. In the fourth embodiment, different methods will be described.

  FIG. 11 is a conceptual diagram illustrating a configuration of a drawing apparatus according to the fourth embodiment. 11, the lens control circuit 120 is the same as FIG. 10 except that the electrostatic lens 212 and the electrostatic lens 232 are connected to the same lens control circuit 120 and controlled together. The contents other than those specifically described below are the same as those in the third embodiment.

  If the same voltage is applied from the lens control circuit 120 to the electrostatic lens 212 and the electrostatic lens 232, a single power source can be obtained.

  As described above, according to the fourth embodiment, the number of power supplies can be reduced, and, similarly to the third embodiment, problems due to scattered electrons and the like can be suppressed while suppressing multi-beam aberration.

  The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In the above-described example, the case where the grating lenses 220 and 230 use the shaping aperture array substrate 203 (collimator shaping aperture array substrate 224) as a grating has been described. However, the present invention is not limited to this. Separately, a lattice material may be prepared. Alternatively, a foil lens serving as a concave lens may be arranged in place of the grating lenses 220 and 230 using a material that transmits an electron beam as a foil. Further, the grating lens 230 may be used by grating the blanking aperture array mechanism 204 instead of the molded aperture array substrate 203. In such a case, the electrostatic lens 232 may be disposed on the flat surface side that is not the surface on which the electrodes 24 and 26 are formed of the blanking aperture array mechanism 204.

  Further, in order to make the grating lens act as a concave lens, the electrostatic lens is configured by, for example, a three-stage annular electrode, a positive potential is applied to the electrode on the most grating side, and the remaining electrodes are connected to the ground potential. .

  In the above-described example, the drawing apparatus 100 has been described as an example. However, the present invention is not limited to the drawing apparatus, and can be applied to general multi-charged particle beam apparatuses including an inspection apparatus and the like.

  In addition, although descriptions are omitted for parts and the like that are not directly required for the description of the present invention, such as a device configuration and a control method, a required device configuration and a control method can be appropriately selected and used. For example, although the description of the control unit configuration for controlling the drawing apparatus 100 is omitted, it goes without saying that the required control unit configuration is appropriately selected and used.

  In addition, all multi-charged particle beam apparatuses that include elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Drawing area | region 19, 20 Multi-beam 22,322 Hole 24 Control electrode 25 Passing hole 26 Counter electrode 31,331,333 Substrate 23,323,30 Membrane area | region 21,32,321 Outer periphery area 33 Support stand 34 Irradiation area 35 Stripe area 36 pixel area 41 control circuit 43 pad 47 individual blanking mechanism 100 drawing device 101 sample 102 electron column 103 drawing room 105 XY stage 110 control computer 112 memory 120, 122 lens control circuit 130 deflection control circuit 132 deflection control circuit 136 DAC amplifier 140 Storage Device 150 Drawing Mechanism 160 Control System Circuit 200 Electron Beam 201 Electron Gun 202 Illumination Lens 203 Molding Aperture Array Substrate 204 Blanking Aperture Array Mechanism 205 Reduction Lens 206 Limiting Aperture Substrate 207 Objective lens 208 Deflector 212, 232 Electrostatic lens 220, 230 Lattice lens 224 Collimator shaping aperture array substrate

Claims (5)

An emission part for emitting a charged particle beam;
An illumination lens for illuminating the charged particle beam;
A plurality of first openings are formed, and a first region including the whole of the plurality of first openings is irradiated with the illuminated charged particle beam, and the plurality of first openings are A first shaped aperture array substrate that forms a first multi-beam by passing a part of the charged particle beam;
A plurality of second openings matching the trajectory of each beam of the first multi-beam are formed, and a part of each beam of the first multi-beam corresponds to an opening corresponding to the plurality of second openings. A second shaped aperture array substrate that forms a second multi-beam by passing through each of the sections;
A stage for placing a sample to be irradiated with at least a part of the beam group of the second multi-beam that has passed through the second shaping aperture array substrate;
With
The distance between the first shaped aperture array substrate and the second shaped aperture array substrate is a center along the trajectory of the first multi-beam passing through the center of the overall beam diameter of the first multi-beam. 3 of the maximum dimension of the second region from the intersection of the axis and the second region including the whole of the plurality of second openings on the surface of the second shaping aperture array substrate toward the beam diameter. A multi-charged particle beam exposure apparatus characterized by being configured to have a value that is twice or more. An electron beam column for disposing the first molded aperture array substrate and the second molded aperture array substrate inside;
An opening that is disposed in the electron beam column and between the first shaping aperture array substrate and the second shaping aperture array substrate and that is larger than the beam diameter of the entire first multi-beam is formed. An absorbing structure that absorbs at least one of electrons or x-rays;
The multi-charged particle beam exposure apparatus according to claim 1, further comprising:   The multi-charged particle beam exposure apparatus according to claim 1, further comprising a grating lens using the first shaped aperture array substrate as a grating. The absorbent structure is
An inner absorber made of an atom having an atomic number of 13 or less and having a recess formed on the inner wall surface, and an atomic number of 13 or less;
An outer absorber disposed outside the inner absorber and having an atomic number of 74 or more atoms as a material;
The multi-charged particle beam exposure apparatus according to claim 2, comprising: The absorbent structure is
An inner absorber made of an atom having an atomic number of 13 or less and having a stationary blade on the inner wall surface and an atomic number of 13 or less as a material;
An outer absorber disposed outside the inner absorber and having an atomic number of 74 or more atoms as a material;
The multi-charged particle beam exposure apparatus according to claim 2, comprising:

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