JP6750981B2 - Multi charged particle beam exposure system - Google Patents

Description

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

Lithography technology, which is responsible for the progress of miniaturization of semiconductor devices, is a very important process that generates a pattern only in the semiconductor manufacturing process. 2. Description of the Related Art In recent years, circuit line widths required for semiconductor devices have been miniaturized year by year with the high integration of LSIs. Here, the electron beam (electron beam) drawing technique has essentially excellent resolution, and drawing is performed on a wafer or the like using an electron beam.

For example, there is a drawing device using a multi-beam. As compared with the case of writing with one electron beam, a large number of beams can be irradiated at one time by using a multi-beam, 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, each of which is blanked and is not shielded. The desired position on the sample is irradiated. In such a multi-beam type drawing apparatus, a mask having a plurality of holes (multi-beam forming aperture) is irradiated with a high-energy electron beam. Then, the beams pass through the plurality of holes of the mask to form a multi-beam. At this time, most of the irradiated high-energy electron beam is shielded by such a mask, so that scattered electrons and x-rays are generated from the mask. Such scattered electrons and x-rays flow into a blanking deflection electrode array for blanking control, which is arranged in a position close to the mask substrate, and electrically charges the insulator portion of the blanking deflection electrode array, and also causes blanking. There is 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, by arranging a doublet lens between the multi-beam forming aperture and the blanking deflection electrode array, forming a crossover between the electromagnetic lenses forming the doublet lens, and arranging an aperture (contrast aperture) near the crossover. , A method of eliminating scattered electrons that enter the blanking deflection electrode array has been devised (see, for example, Patent Document 1).

However, in multi-beam writing, the beam size of the entire multi-beam is large, so that the aberration on the optical axis of the crossover imaging system becomes large. Particularly, if the number of beams is increased, the beam size is increased accordingly, and the aberration is further increased. Although it is possible to reduce the distortion aberration by using the doublet lens, there is a new problem that the spherical aberration of the crossover image due to the doublet lens becomes large when the beam size of the multi-beam is 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 capable of suppressing defects due to scattered electrons while suppressing multi-beam aberrations.

A multi-charged particle beam exposure apparatus according to one embodiment of the present invention is
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 all of the plurality of first openings is irradiated with the illuminated charged particle beam, and the plurality of first openings are charged to the charged particle beam. A first shaping aperture array substrate for forming a first multi-beam by passing a part of each of
A plurality of second openings corresponding to the trajectories of the respective beams of the first multi-beam are formed, and a part of each beam of the first multi-beam respectively forms corresponding openings of the plurality of second openings. A second shaped aperture array substrate that forms a second multi-beam by passing through;
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;
Equipped with
The distance between the first shaping aperture array substrate and the second shaping aperture array substrate is equal to the central axis along the trajectory of the first multi-beam passing through the center of the beam diameter of the first multi-beam and the second axis. So as to have a value that is three times or more of the maximum dimension of the second region extending in the beam diameter direction from the intersection with the second region including the entire plurality of second apertures on the surface of the shaping aperture array substrate. It is characterized by being configured.

Also, an electron beam lens barrel in which the first shaping aperture array substrate and the second shaping aperture array substrate are arranged,
The electron beam is arranged in the electron beam column between the first shaping aperture array substrate and the second shaping aperture array substrate and has an opening larger than the beam diameter of the entire first multi-beam. Or an absorbing structure that absorbs at least one of the x-rays,
It is preferable to further include

Further, it is preferable to further include a grating lens using the first shaping aperture array substrate as a grating.

Also, the absorbent structure is
An inner absorber made of atoms having an atomic number of 13 or less and having a concave portion formed on the inner wall surface side, and made of atoms having an atomic number of 13 or less,
An outer absorber that is arranged outside the inner absorber and has an atomic number of 74 or more as a material,
Is preferred.

Alternatively, the absorbent structure is
An inner absorber made of atoms having an atomic number of 13 or less and having a vane on the inner wall surface side and made of atoms having an atomic number of 13 or less,
An outer absorber that is arranged outside the inner absorber and has an atomic number of 74 or more as a material,
Is preferred.

According to one embodiment of the present invention, defects due to scattered electrons or the like can be suppressed while suppressing multi-beam aberrations.

FIG. 3 is a conceptual diagram showing the configuration of the drawing device in the first embodiment. FIG. 3 is a conceptual diagram showing a configuration of a shaping aperture array substrate in the first embodiment. FIG. 3 is a cross-sectional view showing the configuration of the shaping aperture array substrate in the first embodiment. FIG. 3 is a cross-sectional view showing the configuration of the blanking aperture array mechanism in the first embodiment. FIG. 5 is a conceptual top view showing a part of the configuration in the membrane region of the blanking aperture array mechanism in the first embodiment. FIG. 5 is a diagram for explaining the relationship between the distance between the collimator shaping aperture array substrate and the shaping aperture array substrate and the arrival distribution of scattered electrons in the first embodiment. FIG. 6 is a diagram for explaining a drawing order in the first embodiment. FIG. 6 is a diagram for explaining an example of a configuration and a beam trajectory in a comparative example of the first embodiment. FIG. 7 is a conceptual diagram showing the configuration of the drawing device according to the second embodiment. FIG. 10 is a conceptual diagram showing the configuration of a drawing device according to a third embodiment. FIG. 16 is a conceptual diagram showing the configuration of the drawing device in the 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 the electron beam, and may be a beam using charged particles such as an ion beam.

Embodiment 1.
FIG. 1 is a conceptual diagram showing the configuration of the 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 lens barrel 102 (also referred to as “electron beam lens barrel” or “column”) and a drawing chamber 103. Inside the electron lens barrel 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 arranged. An XY stage 105 is arranged in the drawing chamber 103. On the XY stage 105, a sample 101 such as a mask that is a drawing target substrate is arranged at the time of drawing. 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, a semiconductor substrate (silicon wafer) on which the semiconductor device is manufactured, and the like. Further, the sample 101 includes mask blanks on which a resist is applied and on which nothing is drawn yet.
Here, a magnetic lens is used as the illumination lens 202. Then, in order to reduce the spherical aberration, it is preferable to set the change in the magnetic field distribution to be small. Further, it is preferable that the inclination 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, in the allowable range, the molding aperture array substrate 203 is set to have a longer distance in the optical axis direction than the size (maximum dimension) of the region (opening region) including all of a plurality of holes 22 to be described later. 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 later-described aberration correction is performed falls within the allowable range.

The collimator shaping aperture array substrate 224 is arranged on a rotating stage (not shown) whose rotation axis is parallel to the central axis of the electron lens barrel 102, and the orientation of the collimator shaping aperture array substrate 224 can be changed by control from outside the electron lens barrel 102. It is desirable to be configured as follows. Although the structure becomes complicated, it is more desirable to use a stage that is capable of parallel movement in a 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 near the electron gun 201 side with respect to the collimator shaping aperture array substrate 224 (first shaping aperture array substrate). Then, the electrostatic lens 212 becomes a grating lens 220 (first grating lens) using the collimator-shaped aperture array substrate 224 as a grating.

The shaping aperture array substrate 203 is arranged at a distance D from the back surface of the collimator shaping aperture array substrate 224. Then, the absorption structure 210 is arranged inside the electron lens barrel 102 and between the collimator shaping aperture array substrate 224 and the shaping aperture array substrate 203. The absorption structure 210 has an opening 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 by irradiating the collimator-shaped aperture array substrate 224 with the electron beam 200 are absorbed. The absorbent structure 210 has an outer absorbent body 214 and an inner absorbent body 216.

The inner absorber 216 is formed, for example, in a circular tubular shape having a predetermined wall thickness. Further, the inner absorber 216 has, on the inner wall surface side, at least one vane 218 extending slightly toward the center direction. In the example of FIG. 1, for example, a case is shown in which five stages of stationary vanes 218 are arranged with their height positions displaced. It is preferable that each vane 218 be angle-adjusted so as to face the center of a region of a plurality of openings to be described later formed on the collimator shaping aperture array substrate 224. By such angle adjustment, scattered electrons and x-rays can be taken in efficiently. The stationary blades 218 in each stage may be formed in a circular truncated cone shape connected in the circumferential direction, or a plurality of blades may be arranged side by side in the circumferential direction.

The inner absorber 216 including the vanes 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 vanes 218 is made of a conductive material so as not to be charged. By using a low-Z material, when scattered electrons collide, it is possible to further reduce the generation of scattered electrons and x-rays from the collision point. Further, even if the scattered electrons that collide with the inner wall surface of the inner absorber 216 are reflected, the orbits are interfered by the stationary vanes 218 located on the reflection orbits, and energy is consumed. Therefore, it is difficult to return to the central region (passage region of the multi-beam 20) of the electron lens barrel 102. Thus, the inner absorber 216 absorbs the scattered electrons by collecting (trapping) the scattered electrons.

The outer absorber 214 is formed, for example, in a circular tubular shape having a predetermined wall thickness. The outer absorber 214 is arranged outside the inner absorber 216. The outer absorber 214 is made of atoms (high Z material) having an atomic number of 74 (tungsten: W) or more. Further, the outer absorber 214 is made of a conductive material so as not to be charged. In addition to tungsten (W), it is preferable to use a refractory metal such as tantalum (Ta) and molybdenum (Mo). By using a 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 arranged outside the inner absorber 216, so that direct collision of scattered electrons can be avoided, and new x-ray emission due to electron collision can be avoided.

In the above-described example, the case where the absorption structure 210 is arranged so as to cover substantially the entire inner wall of the inner wall of the electron lens 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 reaming shaping aperture array substrate 224 and the shaping aperture array substrate 203. Even such a part is preferably arranged over the entire surface in the circumferential direction. More desirably, the inner wall of the electron lens barrel 102 between the collimator shaping aperture array substrate 224 and the shaping aperture array substrate 203 is preferably 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 and controlled by the lens control circuit 120. The blanking aperture array mechanism 204 is connected to and controlled by the deflection control circuit 130. The deflector 208 is connected to and controlled by the deflection control circuit 132 via the DAC amplifier 136.

Here, in FIG. 1, a configuration necessary for explaining the first embodiment is described. The drawing apparatus 100 may be provided with other configurations that are usually necessary.

FIG. 2 is a conceptual diagram showing the configuration of the shaping aperture array substrate in the first embodiment.
FIG. 3 is a sectional view showing the configuration of the shaping 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 in a matched manner. A substrate 331 made of silicon or the like is arranged on the shaping aperture array substrate 203, as shown in FIG. The central portion of the substrate 331 is thinly cut, for example, from the back surface side and processed into the membrane region 23 (second region) having a thin film thickness h. The periphery surrounding the membrane region 23 is the 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 same height position. In FIG. 2A, in the membrane area 23 of the shaping aperture array substrate 203, there are m rows of vertical (y direction)×n columns of horizontal (x direction) holes 22 (m, n≧2) (second opening portions). ) Are formed in a matrix with a predetermined arrangement pitch. For example, holes 22 of 512 rows×512 rows are formed. In the example of FIG. 2A, for example, 8 rows×8 rows of holes 22 are formed. Each hole 22 is formed in a rectangular shape having the same size and shape. Alternatively, it may be circular with the same outer diameter. A part of each beam of a temporary multi-beam 19 (first multi-beam), which will be described later, passes through the plurality of holes 22 to form a multi-beam 20 (second multi-beam). Become. Here, an example is shown in which the holes 22 are arranged in two or more rows in the vertical and horizontal directions (x, y directions), but the example is not limited to this. In addition, for example, one of the vertical and horizontal directions (x, y directions) may be plural rows and the other may be only one row.

Further, the collimator shaping aperture array substrate 224 is also configured similarly to the shaping aperture array substrate 203. As shown in FIG. 3, a substrate 333 made of silicon or the like is arranged on the collimator shaping aperture array substrate 224. The central portion of the substrate 333 is thinly shaved from the back surface side, for example, and processed into a membrane region 323 (first region) having a thin film thickness h. The periphery surrounding the membrane region 323 becomes an outer peripheral region 321 having a thick film thickness H. The upper surface of the membrane area 323 and the upper surface of the outer peripheral area 321 are formed at the same height position or substantially the same height position. In FIG. 2A, in the membrane area 323 of the collimator shaping aperture array substrate 224, m (vertical) rows (y direction)×n (horizontal (x direction)) n rows (m, n≧2) of holes 322 (first openings) Parts) are formed in a matrix at a predetermined arrangement pitch. The pitch may be different from place to place so that the beam group that has passed through the collimator shaping aperture array substrate 224 passes through the corresponding holes 22 (openings) 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, 8 rows×8 rows of holes 322 are formed. Each of the holes 322 is formed as a rectangle having the same size and shape. Alternatively, it may be circular with the same outer diameter. Further, for example, the holes 322 (openings) on the outer peripheral portion are enlarged so that the beam group that has passed through the collimator shaping aperture array substrate 224 passes through the corresponding holes 22 (openings) on the shaping aperture array substrate 203. It can be made easy. In this case, the beam that has passed through one of the holes on the outer peripheral portion may be made incident on a plurality of holes on the shaping aperture array substrate 203. A part of the electron beam 200 passes through each of these holes 322 to form a temporary multi-beam 19 (first multi-beam). Here, an example in which the holes 22 are arranged in two or more rows in the vertical and horizontal directions (x, 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, y directions) may be plural rows and the other may be only one row.

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

FIG. 4 is a 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 embodiment. 4 and 5, the control electrode 24, the counter electrode 26, the control circuit 41, and the pad 43 are not shown to have the same positional relationship. The blanking aperture array mechanism 204 is preferably arranged on the back surface (downstream side of the electron beam) of the shaping aperture array substrate 203 and in the vicinity of the shaping aperture array substrate 203. In the blanking aperture array mechanism 204, as shown in FIG. 4, a semiconductor substrate 31 made of silicon or the like is arranged on a support base 33. For example, the central portion of the substrate 31 is thinly shaved from the back surface side and processed into the 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 at the same height position or substantially at the same height position. The substrate 31 is held on the support table 33 on the back surface of the outer peripheral region 32. The central portion of the support base 33 is open, and the position of the membrane region 30 is located in the open region of the support base 33.

In the membrane region 30, passage holes 25 (openings) for passage of each of the multi-beams are opened at positions corresponding to the holes 22 of the shaping aperture array substrate 203 shown in FIG. Each passage hole 25 is formed larger than the hole 22 formed in the shaping aperture array substrate 203. Then, as shown in FIGS. 4 and 5, on the membrane area 30, a set of a control electrode 24 for blanking deflection and a counter electrode 26 (( Blanker: Blanking deflector) is arranged respectively. Further, a control circuit 41 (logic circuit) that applies a deflection voltage to the control electrode 24 for each passage hole 25 is arranged near 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 an n-bit (for example, 10-bit) parallel wiring for a control signal. Each control circuit 41 is connected to an n-bit parallel wiring for control signals, a clock signal line and a power wiring. 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 formed for each beam forming the multi-beam. Further, 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 of the substrate 31 where the film thickness is thin. However, it is not limited to this. Further, the plurality of control circuits 41 formed in an array in the membrane region 30 are grouped, for example, in the same row or the same column, and the control circuit 41 groups in the group are connected in series as shown in FIG. To be done. Then, the 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 independently deflected by the voltage applied to the pair of two electrodes 24 and 26. Blanking control is performed by such deflection. In other words, the set of the control electrode 24 and the counter electrode 26 blanking-deflects corresponding beams of 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 (emitter) illuminates the entire collimator shaping aperture array substrate 224 (first shaping aperture array substrate) substantially vertically by the illumination lens 202. A plurality of rectangular holes 22 (first openings) are formed in the collimator shaping aperture array substrate 224, and the electron beam 200 is applied to the membrane region 23 or a region within the membrane region 23 including all the plurality of holes 22. Illuminate. Each part of the electron beam 200 irradiated on the positions of the plurality of holes 22 passes through the plurality of holes 22 of the collimator shaping aperture array substrate 224, respectively. Beams 19a-e are formed. The multi-beam 19 is projected onto the shaping aperture array substrate 203 while being substantially vertical.

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

Here, the positional deviation of the provisional multi-beams 19a to 19e in the rotational direction 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 moving mechanism in the horizontal or vertical direction.

In the first embodiment, by arranging the collimator shaping aperture array substrate 224 on the upstream side, the remaining portion of one electron beam 200 which is not used for forming the temporary multi-beam 19 is shielded by the collimator shaping aperture array substrate 224. To do. The shielded portion (remaining portion) of the electron beam 200 corresponds to most of the electron beam 200. For example, it corresponds to 70 to 90%. Therefore, the energy amount of the entire beam of the provisional multi-beam 19 that reaches the shaping aperture array substrate 203 on the downstream side can be significantly reduced. Therefore, the amount of energy of the electron beam that strikes the shaping aperture array substrate 203 on the downstream side can be significantly reduced, and the amount of deformation of the opening 22 can be greatly reduced. Therefore, the multi-beam 20 with highly accurate dimensions can be formed. Here, in the first embodiment, the size of the holes 322 of the collimator shaping aperture array substrate 224 is set so that the cross-sectional dimension of the beam passing through the holes 322 on the shaping aperture array substrate 203 on the downstream side is the downstream side. It should be larger than the size of the hole 22 of. Therefore, the beam shape (size) of the multi-beam 20 can be determined by the shaping aperture array substrate 203 on the downstream side. Therefore, even if the large beam energy of the electron beam 200 is applied to the collimator-shaped aperture array substrate 224 and the size of the hole 322 is deformed due to the temperature rise, the final beam shape (size) of the multi-beam 20 is affected. You can avoid it.

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. Each of the blankers individually deflects the electron beam 20 passing therethrough (performs blanking deflection).

The multi-beams 20a to 20e that have passed through the blanking aperture array mechanism 204 are focused by the 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 sizes of the images of the multi-beams 20a to 20e are 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 arranged at the focal point position of the multi-beams 20a to 20e focused by the reduction lens 205, and restricts passage of the electron beam 20 deviating from 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 shielded 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 central hole of the limiting aperture substrate 206 as shown in FIG. By turning on/off the individual blanking mechanism 47, blanking control is performed, and ON/OFF of the beam is controlled. In this way, the limiting aperture substrate 206 shields each beam deflected by the individual blanking mechanism 47 so that the beam is turned off. Then, a beam for one shot is formed by the beam that has passed through the limited aperture substrate 206 and is formed from the beam ON to the beam OFF for each beam. 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 with 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 collectively deflected in the same direction, and each beam is irradiated to each irradiation position on the sample 101. 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). Received the beam group of. Further, 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 on a mirror (not shown) on the XY stage 105 from a stage position detector (not shown) and using the reflected light. Ideally, the multi-beams 20 irradiated at one time are 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 above-mentioned desired reduction rate. The drawing apparatus 100 irradiates the multi-beam 20, which becomes a shot beam, while following the movement of the XY stage 105 during each tracking operation, by moving the beam deflection position by the deflector 208 so that each beam one pixel at a time along the drawing sequence. Perform drawing operation. When drawing a desired pattern, the beam required for the pattern is controlled to be beam ON by blanking control.

FIG. 6 is a diagram for explaining the relationship between the distance between the collimator shaping aperture array substrate and the shaping aperture array substrate and the arrival distribution of scattered electrons in the first embodiment. When the electron beam 200 collides with the collimator shaping aperture array substrate 224, scattered electrons and x-rays are emitted from the collimator shaping aperture array substrate 224. When the distribution of such scattered electrons and x-rays is approximated by a cosine distribution, the shaping aperture array substrate 203 is formed with respect to the prospective angle θ from the generation point (for example, the center of the area of the plurality of holes 322 of the collimator shaping aperture array substrate 224). The ratio of scattered electrons and x-rays that reach the enclosed area on the surface 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 that passes 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, if the square of sin θ is expressed using the dimension r that goes from the intersection with the membrane region 23 (second region) in the direction of the beam diameter, it can be defined by the following formula (1).
(1) (sin θ) ² =r ² /(D ² +r ² ).

Therefore, in order to suppress the proportion of scattered electrons and x-rays reaching the membrane region 23 of the shaping aperture array substrate 203 to less than 10%, which is an order of magnitude, it is sufficient to satisfy the expression (2).
(2) r ² /(D ² +r ² )<(1/10)

Therefore, if D>3r, the proportion of scattered electrons and x-rays that reach the membrane area 23 of the shaping aperture array substrate 203 can be suppressed to less than 10%, which is an order of magnitude. Therefore, three times or more of the maximum dimension r of the area extending from the intersection of the central axis (optical axis) of the multi-beam 19 and the area including the entire plurality of holes 22 on the surface of the shaping aperture array substrate 203 in the beam diameter direction. The distance D may be set so that As shown in FIG. 2, the maximum dimension r of the area including the entire plurality of holes 22 is the distance from the center of the entire plurality of holes 22 to the corner of the rectangular area, that is, the maximum distance in the diagonal direction (the maximum dimension). )And it is sufficient. As described above, even if scattered electrons and x-rays are generated in the collimator shaping aperture array substrate 224, the rate of reaching the plurality of holes 22 in the shaping aperture array substrate 203 can be reduced by an order of magnitude, so scattered electrons and x It is possible to sufficiently suppress the deformation of the hole 22 due to the energy of the wire. Further, since the arrival rate can be reduced by an order of magnitude, it is possible to sufficiently suppress the influence of x-rays on each control circuit 41 of the blanking aperture array mechanism 204.

Further, the scattered electrons and x-rays that collide with the inner wall surface of the electron lens barrel 102 are absorbed by the absorption structure 210 as described above, and thus the scattered electrons and x-rays reflected from the inner wall surface of the electron lens barrel 102 are absorbed. The influence on the shaping aperture array substrate 203 and the blanking aperture array mechanism 204 due to is also substantially negligible.
In the above description, the upstream base point is evaluated as being located at the center of the region of the upstream collimator shaping aperture array substrate 224 including the entire plurality of holes 322, that is, on the central axis. In general, as the base point position becomes farther from the center, the solid angle that looks into the central region of the downstream shaping aperture array substrate 203 is smaller than when the base point is at the center. Therefore, the above-described evaluation is based on the upstream collimator shaping aperture array substrate 224. It is reasonable to do this in the center of the area containing the entire plurality of holes 322 of

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 striped areas 35 (other examples of drawing areas) on a strip with a predetermined width. Then, each stripe region 35 is divided into a plurality of mesh-shaped pixel regions 36 (pixels). The size of the pixel region 36 (pixel) is preferably, for example, a beam size or a size smaller than the beam size. For example, a size of about 10 nm is suitable. The pixel area 36 (pixel) is an irradiation unit area for one beam of the multi-beam 20.

When the sample 101 is drawn by the multi-beam 20, the irradiation region 34 is irradiated by the single irradiation of the multi-beam 20. As described above, while tracking the movement of the XY stage 105 during the tracking operation, the entire multi-beam 20 serving as a shot beam is collectively and sequentially irradiated, for example, pixel by pixel by the movement of the beam deflection position by the deflector 208. To go. Then, which pixel of the multi-beam irradiates which pixel on the sample 101 is determined by the drawing sequence. By using the beam pitches 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) x beam pitch (y direction) The area is composed of an area of n×n pixels (sub-pitch area). 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 diagonal direction) while n Pixels are drawn. Other n pixels in the same n×n pixel area are similarly drawn by the beam different from the above-mentioned beam in the next tracking operation. In this way, n pixels are drawn by different beams by n tracking operations, so that all pixels in one n×n pixel area are drawn. The same operation is performed in the other n×n pixel area in the multi-beam irradiation area at the same time, and the same drawing is performed. By this operation, all pixels in the irradiation area 34 can be drawn. By repeating these operations, it is possible to draw the entire corresponding stripe region 35. Then, in the drawing apparatus 100, a desired pattern can be drawn 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 the configuration and beam trajectory in the comparative example of the first embodiment. 8, in the comparative example, the doublet lenses 312 and 314 are arranged between the shaping aperture array 203 forming the multi-beam and the blanking aperture array mechanism 204, and the crossover between the electromagnetic lenses forming the doublet lenses 312 and 314 is performed. And a contrast aperture 316 is arranged near the crossover. Further, 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 such a configuration, the scattered electrons generated in the shaping aperture array 203 are shielded by the contrast aperture 316. This eliminates scattered electrons that enter 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.

Further, as described above, in multi-beam writing, the beam size of the entire multi-beam is large, so that the aberration on the optical axis of the crossover imaging system becomes large. Therefore, in the comparative example, even when the doublet lenses 312 and 314 are excited so that their magnetic fields are opposite to each other and have the same magnitude, the crossover diameter at the focusing point is designed due to the spherical aberration of 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 becomes large. 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, when the doublet lens focal length is shortened so that the doublet lens area can be narrowed and the images are largely refracted by the doublet lenses 312 and 314, the spherical aberration by the lens 312 causes The crossover diameter formed during that time 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 also occurs when the doublet lenses 312 and 314 are arranged between the collimator shaping aperture array substrate 224 and the shaping aperture array 203. It is possible to suppress the spherical aberration within the allowable range by lengthening the axial magnetic field regions of the electromagnetic lenses 312 and 314, but in that case, the electron lens barrel becomes long.

On the other hand, in the first embodiment, the collimator shaping aperture array substrate 224 receives the electron beam 200 once, so that 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 lens barrel 102 can be absorbed by the absorption structure 210, as described above. Therefore, problems due to scattered electrons and x-rays can be suppressed.

Further, in the first embodiment, neither of the doublet lenses 312 and 314 is 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. It does not have the big refraction that it does. Therefore, it is possible to avoid the occurrence of spherical aberration by the doublet lenses 312 and 314, and since the doublet lenses 312 and 314 do not form a crossover, the crossover diameter does not increase.

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

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

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

Embodiment 2.
In the first embodiment, the case where the stationary blade 218 is arranged in the inner absorber 216 to obstruct the reflection trajectory of scattered electrons has been described, but the method of obstructing the reflection trajectory of scattered electrons is not limited to this. .. In the second embodiment, a different method will be described.

FIG. 9 is a conceptual diagram showing the configuration of the drawing apparatus according to the second embodiment. 9 is the same as FIG. 1 except that the vane 218 is not arranged and the structure of the inner absorber 216 is different. Further, the contents other than the points to be particularly described below are the same as those in the first embodiment.

In FIG. 9, the inner absorber 216 is formed, for example, in a circular tubular shape having a predetermined thickness. However, the inner absorber 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 absorber 216 toward the outer wall surface side (outer side). In the example of FIG. 9, for example, the case is shown in which the recesses 219 of eight stages are arranged with their height positions displaced. 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 efficiently captured. Further, the recessed portions 219 of each step may be formed in a groove shape that is continuous in the circumferential direction, or it is also preferable that a plurality of recessed portions be arranged side by side along the circumferential direction.

The inner absorber 216 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 is made of a conductive material so as not to be charged. By using a low-Z material, when scattered electrons collide, it is possible to further reduce the generation of scattered electrons and x-rays from the collision point. Further, 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 recess 219 located on the reflection orbit, and energy is consumed. Therefore, it is difficult to return to the central region (passage region of the multi-beam 20) of the electron lens barrel 102. Thus, the inner absorber 216 absorbs the scattered electrons by collecting (trapping) the scattered electrons.

As described above, according to the second embodiment, similar to the first embodiment, it is possible to suppress the aberrations of the multi-beams and suppress the defects due to scattered electrons and the like.

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

FIG. 10 is a conceptual diagram showing the configuration of the drawing apparatus according to the third embodiment. In FIG. 10, the electrostatic lens 212 is arranged in the immediate vicinity of the electron gun 201 side (the shaping aperture array substrate 203 side) with respect to the collimator shaping aperture array substrate 224 (first shaping aperture array substrate). 1 is the same as that of FIG. 1 except that an electrostatic lens 232 is arranged in the vicinity of the electron gun 201 side with respect to the shaping aperture array substrate 203, and a lens control circuit 122 is added. Further, the contents other than the points to be particularly described below are the same as in the first embodiment.

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

Note that the electrostatic lens 212 may be arranged near the electron gun 201 side with respect to the collimator shaping aperture array substrate 224 (first shaping aperture array substrate), as in FIG. 1. The two-staged grating lens of the third embodiment can also be applied to the structure of the second embodiment.

As described above, according to the third embodiment, it is possible to reduce the potential applied to the grating lens, and similarly to the first embodiment, it is possible to suppress the aberrations of the multi-beam and suppress the defects due to scattered electrons and the like.

Fourth Embodiment
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, a different method will be described.

FIG. 11 is a conceptual diagram showing the structure of the 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 are controlled together. The contents other than the points particularly 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, the number of power supplies can be one.

As described above, according to the fourth embodiment, it is possible to reduce the number of power sources and, like the third embodiment, it is possible to suppress defects due to scattered electrons and the like while suppressing aberrations of multi-beams.

The embodiments have been described above with reference to the specific examples. However, the present invention is not limited to these specific examples. In the example described above, 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, but the present invention is not limited to this. A grid material may be prepared separately. Alternatively, a foil lens that serves as a concave lens may be disposed instead of the grating lenses 220 and 230 by using a material that transmits an electron beam as the foil. Further, as for the grating lens 230, instead of the shaping aperture array substrate 203, a blanking aperture array mechanism 204 may be used as a grating. In such a case, the electrostatic lens 232 may be arranged on the flat surface side of the blanking aperture array mechanism 204, which is not the surface on which the electrodes 24 and 26 are formed.

Further, in order to make the lattice lens act as a concave lens, the electrostatic lens may be composed of, for example, three-stage annular electrodes, a positive potential is applied to the electrode closest to the lattice, and the remaining electrodes are connected to the ground potential. ..

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

Further, although the description of the parts such as the device configuration and the control method that are not directly necessary for the description of the present invention is omitted, the required device configuration and the 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 a required control unit configuration is appropriately selected and used.

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

10 Drawing Area 19, 20 Multi Beam 22, 322 Hole 24 Control Electrode 25 Through Hole 26 Counter Electrode 31, 331, 333 Substrate 23, 323, 30 Membrane Area 21, 32, 321 Peripheral 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 lens barrel 103 drawing chamber 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 shaping aperture array substrate 204 blanking aperture array mechanism 205 reduction lens 206 limiting aperture substrate 207 objective lens 208 deflectors 212, 232 electrostatic lens 220 , 230 Lattice lens 224 Collimator molding 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 all of the plurality of first openings is irradiated with the illuminated charged particle beam to open the plurality of first openings. A first shaping aperture array substrate for forming a first multi-beam by passing a part of the charged particle beam respectively;
A plurality of second openings corresponding to the trajectories of the respective beams of the first multi-beam are formed, and a part of each beam of the first multi-beam corresponds to the openings of the plurality of second openings. A second shaping aperture array substrate for forming a second multi-beam by passing through the respective portions,
A stage on which 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 is placed;
Equipped with
The distance between the first shaping aperture array substrate and the second shaping aperture array substrate is the center along the trajectory of the first multi-beam passing through the center of the beam diameter of the first first multi-beam. 3 of the maximum dimension of the second region extending in the direction of the beam diameter from the intersection of the axis and the second region on the surface of the second shaping aperture array substrate that includes the entire second openings. A multi-charged particle beam exposure apparatus, which is configured to have a value more than double. An electron beam column in which the first shaping aperture array substrate and the second shaping aperture array substrate are arranged,
An opening is formed in the electron beam column and between the first shaping aperture array substrate and the second shaping aperture array substrate, and has an opening larger than the beam diameter of the entire first multi-beam. 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 or 2, further comprising a grating lens using the first shaping aperture array substrate as a grating. The absorbent structure is
An inner absorber made of atoms having an atomic number of 13 or less and having a concave portion formed on the inner wall surface side, and made of atoms having an atomic number of 13 or less,
An outer absorber that is arranged outside the inner absorber and has an atomic number of 74 or more as a material;
The multi-charged particle beam exposure apparatus according to claim 2, further comprising: The absorbent structure is
An inner absorber made of atoms having an atomic number of 13 or less and having a vane on the inner wall surface side and made of atoms having an atomic number of 13 or less,
An outer absorber that is arranged outside the inner absorber and has an atomic number of 74 or more as a material;
The multi-charged particle beam exposure apparatus according to claim 2, further comprising:

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