Charged particle beam lithography system

Abstract

This suppresses static charge and thermal deformation of the stopping aperture substrate. [Solution] A charged particle beam lithography apparatus according to one aspect of the present invention comprises a charged particle source that generates and emits a beam; a blanker that controls the on / off state of the beam; a stopping aperture substrate having a first aperture through which the beam controlled to be on by the blanker and irradiated onto the substrate passes; a scattering section through which the beam controlled to be off by being deflected by the blanker is transmitted while being scattered; and an absorbing member that absorbs the beam that has passed through the scattering section.

Description

Technical Field

[0001] The present invention relates to a charged particle beam lithography apparatus.

Background Art

[0002] With the high integration of LSIs, the circuit line widths required for semiconductor devices have been continuously miniaturized year by year. In order to form a desired circuit pattern on a semiconductor device, a method of reducing and transferring a high-precision original pattern formed on quartz onto a wafer using a reduction projection exposure apparatus is adopted. The high-precision original pattern is drawn by an electron beam lithography apparatus, and so-called electron beam lithography technology is used.

[0003] For example, there is a lithography apparatus using a multi-beam. Compared with the case of drawing with a single electron beam, by using a multi-beam, many beams can be irradiated at once, so the throughput can be significantly improved. In a multi-beam type lithography apparatus, for example, an electron beam emitted from an electron source is passed through a shaping aperture array substrate having a plurality of apertures to form a multi-beam, and each beam is individually blanked and deflected by a blanking aperture array substrate for on / off control. The beam blanked and deflected by the blanking aperture array substrate is shielded by a stopping aperture substrate, and the beam that is not deflected passes through the aperture of the stopping aperture substrate and is irradiated to a desired position on the sample.

[0004] In addition, the lithography apparatus is provided with a batch blanking deflector (common blanker) that collectively blanks and deflects the entire multi-beam for on / off control. The multi-beam deflected by the batch blanking deflector is shielded by a stopping aperture substrate.

[0005] When a stopping aperture substrate shields a blanking-bent beam, it can become charged and its temperature can rise. The charging of the stopping aperture substrate affects the beam trajectory, shifting the beam irradiation position on the sample, and the temperature rise causes the substrate to bend due to thermal expansion, which can change the aperture position and reduce the accuracy of the drawing. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2006-93579 [Patent Document 2] Japanese Patent Publication No. 2012-151305 [Patent Document 3] Japanese Patent Application Publication No. 11-354406 [Patent Document 4] Japanese Patent Application Publication No. 6-163371 [Patent Document 5] Patent No. 2979163 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention has been made in view of the above-mentioned conventional problems, and aims to provide a charged particle beam lithography apparatus that can suppress charging and thermal deformation of the stopping aperture substrate and enable high-precision lithography. [Means for solving the problem]

[0008] A charged particle beam lithography apparatus according to one aspect of the present invention comprises a charged particle source that generates and emits a beam; a blanker that controls the on / off state of the beam; a stopping aperture substrate having a first aperture through which the beam controlled to be on by the blanker and irradiated onto the substrate passes; a scattering section through which the beam controlled to be off by being deflected by the blanker is scattered and transmitted; and an absorbing member that absorbs the beam that has passed through the scattering section. [Effects of the Invention]

[0009] According to one aspect of the present invention, static charge and thermal deformation of the stopping aperture substrate are suppressed, enabling high-precision drawing. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic diagram of a drawing apparatus according to an embodiment of the present invention. [Figure 2] This is a plan view of a molded aperture array substrate. [Figure 3] This is a schematic diagram of the stopping aperture substrate and the electron absorption member. [Figure 4] This is a schematic diagram of the stopping aperture substrate and the electron absorption member. [Figure 5] This is a schematic diagram of an electron-absorbing component based on a modified example. [Figure 6] This is a schematic diagram of the stopping aperture substrate and the scattering thin film. [Figure 7] This is a schematic diagram of the stopping aperture substrate and the scattering thin film. [Modes for carrying out the invention]

[0011] In the following embodiments, an electron beam configuration will be described as an example of a charged particle beam. However, the charged particle beam is not limited to an electron beam; it may also be a beam using charged particles such as an ion beam.

[0012] FIG. 1 is a schematic configuration diagram of a multi-beam lithography apparatus according to an embodiment of the present invention. As shown in FIG. 1, the multi-beam lithography apparatus includes a drawing unit W and a control unit C. The drawing unit W includes an electron optical column 102 and a drawing chamber 103. Inside the electron optical column 102, an electron source 201, an illumination lens 202, a shaping aperture array substrate 203, a blanking aperture array substrate 204, a reduction lens 205, a stopping aperture substrate 206, a batch blanking deflector 207, an electron absorption member 30, a deflector 208, and an objective lens 210, which constitute the electron optical system of the multi-beam lithography apparatus, are arranged.

[0013] An XY stage 105 movable in the XY direction is arranged in the drawing chamber 103. The XY stage 105 may be movable in the Z direction. On the XY stage 105, a substrate 10 to be drawn is arranged. The substrate 10 includes an exposure mask for manufacturing a semiconductor device, a semiconductor substrate (silicon wafer) on which a semiconductor device is manufactured, and the like. Further, the substrate 10 includes mask blanks on which a resist is applied and nothing has been drawn yet.

[0014] Also, a mirror 106 for measuring the position of the stage is arranged on the XY stage 105.

[0015] The control unit C includes a control computer 110, a control circuit 120, and a stage position detector 124. The stage position detector 124 irradiates a laser, receives the reflected light from the mirror 106, and detects the position of the XY stage 105 based on the principle of laser interferometry.

[0016] In FIG. 1, the configuration necessary for explaining the embodiment is shown, and the illustration of other configurations is omitted.

[0017] Figure 2 is a conceptual diagram showing the configuration of the shaping aperture array substrate 203. In Figure 2, on the shaping aperture array substrate 203, openings 203a arranged in a matrix are formed at a predetermined array pitch in p columns in the vertical (y direction) × q rows in the horizontal (x direction) (p, q ≧ 2). For example, openings 203a of 512 columns × 512 rows are formed. Each of the openings 203a is formed as a rectangle with the same dimensional shape. The openings 203a may be circular. A multi-beam MB is formed by a part of the electron beam 200 emitted from the electron source 201 passing through each of these plurality of openings 203a.

[0018] The blanking aperture array substrate 204 is provided below the shaping aperture array substrate 203, and through-holes are formed in accordance with the arrangement positions of the respective openings 203a of the shaping aperture array substrate 203. In each through-hole, an individual blanker composed of a pair of two electrodes is arranged. One electrode of the individual blanker is fixed at the ground potential, and the other electrode is switched between the ground potential and another potential. The electron beam passing through each through-hole is independently deflected by the voltage applied to the individual blanker. Thus, the plurality of individual blankers perform blanking deflection of the corresponding beams among the multi-beam MB that has passed through the plurality of openings 203a of the shaping aperture array substrate 203.

[0019] The multi-beam MB that has passed through the blanking aperture array substrate 204 is reduced by the reduction lens 205 and travels toward the opening 206a formed in the stopping aperture substrate 206.

[0020] The batch blanking deflector 207 performs batch blanking control on the multi-beam that has passed through the blanking aperture array substrate 204.

[0021] The beams that have not been deflected by the individual blankers of the blanking aperture array substrate 204 and the batch blanking deflector 207 (the beams controlled to be beam ON) pass through the opening 206a of the stopping aperture substrate 206.

[0022] The multi-beams that pass through the aperture 206a of the stopping aperture substrate 206 are focused by the objective lens 210 to form a pattern image with a desired reduction ratio, which is then deflected together by the deflector 208 and irradiated onto the substrate 10. For example, when the XY stage 105 is moving continuously, the deflector 208 controls the beam irradiation position so that it follows the movement of the XY stage 105.

[0023] The control computer 110 of the control unit C reads drawing data from a storage device (not shown) and generates shot data by performing multiple stages of data conversion. The shot data defines, for example, whether or not each irradiation area is irradiated when the drawing surface of the substrate 10 is divided into multiple grid-like irradiation areas by beam size, and the irradiation time. Based on the shot data, the control computer 110 outputs a control signal to the control circuit 120. The control circuit 120 controls the drawing unit W based on the control signal. For example, the control circuit 120 controls the on / off state of the beam by controlling the voltage applied to the electrodes of the individual blankers and the collective blanking deflector 207 of the blanking aperture array substrate 204. The control circuit 120 also controls the amount of deflection of the deflector 208 based on the position of the XY stage 105, and controls the movement speed of the XY stage 105.

[0024] The beam deflected (blanked) by the individual blankers of the blanking aperture array substrate 204 (a beam controlled to be beam-off) is moved away from the opening 206a of the stopping aperture substrate 206 and is shielded by the stopping aperture substrate 206.

[0025] The stopping aperture substrate 206 is a plate-like component with a thickness of approximately 300 to 500 μm and is made of tantalum or ruthenium. The stopping aperture substrate 206 is, for example, circular, with an opening 206a formed in the center.

[0026] Furthermore, as shown in Figure 3, a recess is formed in the stopping aperture substrate 206 where a beam controlled to be beam-off strikes, creating a thin scattering section 206b. The thickness of the scattering section 206b is approximately 1 to 20 μm. The multi-beam deflected by the batch blanking deflector 207 is scattered by the scattering section 206b as it passes through it.

[0027] An electron-absorbing member 30 is provided below the stopping aperture substrate 206 (downstream in the beam propagation direction). The material of the electron-absorbing member 30 is preferably low density and highly conductive compared to the stopping aperture substrate 206, and for example, titanium or aluminum can be used. The electron-absorbing member 30 is connected to ground.

[0028] The electron absorbing member 30 is positioned to absorb the beam (electrons) scattered by the scattering section 206b. For example, the electron absorbing member 30 has a rectangular parallelepiped shape and absorbs the beam scattered by the scattering section 206b with its side surface 30a. Here, the side surface 30a is a plane parallel to the beam propagation direction (the direction of propagation of the beam that is not blanked or deflected).

[0029] By scattering the beam at the scattering section 206b, the beam array size absorbed by the electron absorbing member 30 can be increased compared to the beam array size on the stopping aperture substrate 206. Furthermore, by absorbing the beam onto the side surface 30a of the electron absorbing member 30, the area receiving the beam (electrical receiving area) can be increased.

[0030] When the distance L between the stopping aperture substrate 206 and the electron absorbing member 30 is 2 mm, and the scattering angle of electrons by the scattering portion 206b is 30°, the beam array size on the side surface 30a of the electron absorbing member 30 can be expanded to approximately 200 times the beam array size on the stopping aperture substrate 206.

[0031] Furthermore, if the angle between the side surface 30a of the electron-absorbing member 30 and the central beam of the multi-beam that has been blanked and deflected by the unified blanking deflector 207 is set to 5°, the power receiving area on the side surface 30a can be expanded to about 10 times the power receiving area on the stopping aperture substrate 206.

[0032] Since the electron-absorbing member 30 is made of a highly conductive material, it can efficiently absorb electrons. In addition, by absorbing the scattered beam with the angled side surface 30b, the local temperature rise of the electron-absorbing member 30 is suppressed.

[0033] In this way, by scattering the beam, which is controlled to be beam-off, with the scattering unit 206b and then absorbing it with the electron absorption member 30, the charging and temperature rise of the stopping aperture substrate 206 are suppressed, enabling high-precision drawing.

[0034] The beam scattered by the scattering section 206b may be absorbed by the upper surface 30b of the electron absorbing member 30. In this case, it is preferable to position the electron absorbing member 30 so that the beam reflected by the upper surface 30b does not reach the stopping aperture substrate 206.

[0035] In the above embodiment, a configuration was described in which the side surface 30a of the electron absorbing member 30 that absorbs the beam scattered by the thin film portion 206b is parallel to the direction of propagation of the beam that is not blanked or deflected. However, as shown in Figure 4, the electron absorbing member 30 may be installed so that the side surface 30b is oblique to the direction of beam propagation.

[0036] As shown in Figure 5, the electron absorbing member 30 may be cylindrical in shape. The cylindrical electron absorbing member 30 is installed so that a beam that is not blanked or deflected passes through its center. The beam scattered by the scattering section 206b is absorbed by the inner surface 30c of the cylinder.

[0037] The beam, which has been blanked and deflected by the individual blankers of the blanking aperture array substrate 204, may also be scattered by the scattering section 206b and absorbed by the electron absorption member 30.

[0038] In the above embodiment, a configuration was described in which the beam is scattered by a scattering portion 206b provided in the stopping aperture substrate 206. However, as shown in Figure 6, instead of the scattering portion 206b, a through hole 206c that penetrates the stopping aperture substrate 206 may be formed, and a scattering thin film 212 may be formed as a scattering portion on the upper or lower surface of the stopping aperture substrate 206. The material of the scattering thin film 212 may be, for example, tantalum, ruthenium, silicon, etc., and may be the same as or different from the material of the stopping aperture substrate 206. The thickness of the scattering thin film 212 is preferably about 1 to 20 μm.

[0039] The multi-beams, deflected by the batch blanking deflector 207, pass through the through-hole 206c and are scattered by the scattering thin film 212.

[0040] The scattering thin film 212 only needs to be formed so as to block the through-hole 206c. When the scattering thin film 212 is formed over the entire lower surface of the stopping aperture substrate 206, an opening 212a is formed in the scattering thin film 212 so as not to block the opening 206a.

[0041] The scattering thin film 212 may be integrated with the stopping aperture substrate 206, placed in contact with it, or separated from it. For example, as shown in Figure 7, the scattering thin film 212 may be placed at a distance from the lower surface of the stopping aperture substrate 206.

[0042] The stopping aperture substrate 206 shown in Figure 3 has a configuration in which the scattering portion 206b is located on the lower side (downstream side in the beam propagation direction), but the scattering portion 206b may be located on the upper side, or may be spaced apart from the upper and lower surfaces. It may also be formed inside the through hole 206c. In addition to a thin film, the scattering portion may be made of a grid or mesh. These may be made of metal and grounded. Alternatively, they may be formed of a porous insulating material.

[0043] In the above embodiment, a configuration was described in which an electron beam emitted from an electron source 201 passes through a shaped aperture array substrate 203 to form a multibeam. However, the method of forming a multibeam is not limited to this, and other configurations may be used, such as emitting beams from multiple electron sources or photocathodes to form a multibeam.

[0044] Although the above embodiment describes a lithography apparatus using a multi-beam system, it may also be applied to a lithography apparatus using a single beam system.

[0045] It should be noted that the present invention is not limited to the embodiments described above, and the components can be modified and implemented in practice without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining the multiple components disclosed in the above embodiments. For example, some components may be deleted from all the components shown in the embodiments. Moreover, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0046] 10 circuit boards 30 Electron-absorbing material 102 Electro-optical lens barrel 103 Drawing room 105 XY Stages 110 Control Computer 120 Control circuits 200 electron beam 201 Electron source 202 Illumination Lens 203 Molded aperture array substrate 204 Blanking Aperture Array Substrate 206 Stopping Aperture Substrate 207 Batch blanking deflector 208 Deflector 210 Objective Lens

Claims

1. A charged particle source that generates and emits a beam, A blanker that controls the on / off switching of the aforementioned beam, A stopping aperture substrate having a first aperture through which a beam controlled to be turned on by the Blanker and irradiated onto the substrate passes, The beam, which is controlled to be turned off by the aforementioned blanker, is scattered and transmitted through a scattering region, An absorbing member that absorbs the beam that has passed through the scattering portion, A charged particle beam lithography apparatus equipped with the following features.

2. The charged particle beam lithography apparatus according to claim 1, wherein a second opening is formed in the stopping aperture substrate, and the scattering portion is provided so as to block the second opening.

3. The charged particle beam lithography apparatus according to claim 1, wherein the scattering portion is provided at a distance from the stopping aperture substrate.

4. The aforementioned beam is a multi-beam, The charged particle beam lithography apparatus according to any one of claims 1 to 3, wherein the blanker is at least one of a blanking aperture array substrate including a plurality of individual blankers that individually blank the multibeams, and a batch blanking deflector that blanks the multibeams together.

5. The charged particle beam lithography apparatus according to claim 1 or 2, wherein the scattering portion comprises tantalum, ruthenium, and silicon, and the absorbing member comprises at least one of titanium and aluminum.

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