JP6248134B2 - Charged particle beam lithography system - Google Patents

Description

  The present invention relates to a charged particle beam drawing apparatus.

  2. Description of the Related Art In recent years, circuit line widths required for semiconductor elements have become increasingly narrower as large scale integrated circuits (LSIs) have been highly integrated and increased in capacity.

  The semiconductor element uses an original pattern pattern (a mask or a reticle, which will be collectively referred to as a mask hereinafter) on which a circuit pattern is formed, and the circuit is exposed and transferred onto a wafer by a reduction projection exposure apparatus called a stepper. Manufactured by forming. Here, a charged particle beam drawing apparatus such as an electron beam drawing apparatus is used for manufacturing a mask for transferring a fine circuit pattern onto a wafer (see, for example, Patent Document 1).

  FIG. 12 is a schematic diagram for explaining the configuration of a conventional electron beam drawing apparatus. In FIG. 12, an electron beam drawing apparatus 1001 includes a drawing chamber 1011, a stage 1021 provided in the drawing chamber 1011 on which a mask 1022 is placed, and an electron optical column 1031 disposed on the ceiling of the drawing chamber 1011. And. An electron gun 1032, deflectors 1033 and 1035, and an aperture 1034 are provided in the electron optical column 1031. The shape and size of the electron beam B emitted from the electron gun 1032 are adjusted by the deflectors 1033 and 1035 and the aperture 1034, and the irradiation position on the mask 1022 can be determined.

  In FIG. 12, a stage 1021 on which a mask 1022 is placed is attached to the bottom plate of the drawing chamber 1011. Further, the stage 1021 is configured to be movable in the X direction and the Y direction orthogonal to each other by the drive unit 1025. A laser interferometer 1023 is fixed to the side wall of the drawing chamber 1011. The position of the stage 1021 is grasped by measuring the position of the mirror 1024 provided near the end of the stage 1021 by the laser interferometer 1023.

JP-A-5-144711 Japanese Utility Model Publication No. 53-13070

  When drawing is performed, the inside of the electron optical column and the drawing chamber is evacuated by a vacuum pump (not shown) or the like. For this reason, a pressure difference arises between these inside and outside. In the conventional electron beam drawing apparatus 1001 shown in FIG. 12, when this pressure difference increases due to fluctuations in atmospheric pressure, a minute deformation occurs in the drawing chamber 1011 and the electron optical column 1031 is tilted. As a result, the shape, size, and irradiation position of the electron beam B may deviate from desired values, and the drawing accuracy may be reduced.

  The present invention has been made in view of these problems. That is, an object of the present invention is to provide a charged particle beam drawing apparatus capable of suppressing a reduction in drawing accuracy caused by a change in pressure.

  Other objects and advantages of the present invention will become apparent from the following description.

The present invention comprises a chamber having an opening on the top surface;
A stage placement section provided in the chamber;
A drawing room including a stage placed on the stage placement unit;
An optical barrel containing a beam irradiation means for irradiating a charged particle beam toward the stage through the opening;
The stage mounting section relates to a charged particle beam drawing apparatus characterized in that the stage mounting section is connected to an optical barrel independently of a chamber.

In the present invention, the drawing chamber includes a mirror provided on the stage,
A laser interferometer that is provided in the stage mounting unit and receives the light incident on and reflected from the mirror and measures the position of the stage;
The stage placement unit includes a first member on which the stage is placed, and a second member that is disposed on the first member and connected to the opening of the optical barrel,
The laser interferometer is preferably attached to the second member.

In the present invention, the chamber and the stage mounting part are preferably made of a material having a linear expansion coefficient of 2 × 10 ⁻⁶ / K or less at room temperature.

In this case, the optical lens barrel has a convex portion that fits into the opening of the chamber,
A flange that is provided around the convex portion and forms a seal portion with the chamber;
The seal portion of the chamber is preferably made of a material having a lower concentration of phosphorus and sulfur than other portions.

Further, the chamber is configured by joining a plurality of members,
It is preferable that each joint part of a some member is comprised with the material whose density | concentration of phosphorus and sulfur is lower than another part.

  ADVANTAGE OF THE INVENTION According to this invention, the charged particle beam drawing apparatus which can suppress the fall of the drawing precision caused by the change of pressure is provided.

1 is a configuration diagram of an electron beam drawing apparatus according to Embodiment 1. FIG. It is explanatory drawing of the drawing method by an electron beam. FIG. 3 is a cross-sectional view for illustrating the configuration inside the drawing chamber in the first embodiment. FIG. 3 is an upper cross-sectional view for describing the configuration of the drawing chamber in the first embodiment. FIG. 3 is an enlarged cross-sectional view for explaining a connection portion between the electron optical barrel and the suspension member in the first embodiment. FIG. 3 is a diagram for explaining a configuration example in the vicinity of a drive unit in the first embodiment. 3 is a conceptual diagram for explaining the stability of the drawing accuracy of the electron beam drawing apparatus according to Embodiment 1. FIG. FIG. 10 is a transverse cross-sectional view for describing the configuration of the drawing chamber in the second embodiment. FIG. 10 is an enlarged cross-sectional view for explaining a connection portion between an electron optical column and a suspension member in the second embodiment. FIG. 10 is an enlarged cross-sectional view for explaining another configuration example of a connection portion between the electron optical barrel and the suspension member in the second embodiment. It is a cross-sectional view for explaining another configuration example of the electron beam drawing apparatus. It is a schematic diagram for demonstrating the structure of the conventional electron beam drawing apparatus. It is a conceptual diagram for demonstrating stability of the drawing precision in the conventional electron beam drawing apparatus.

Embodiment 1 FIG.
FIG. 1 is a configuration diagram of a drawing unit of the electron beam drawing apparatus according to the first embodiment. FIG. 3 is a cross-sectional view illustrating the configuration of the drawing chamber in the electron beam drawing apparatus of FIG.

  FIG. 1 shows a drawing unit of the electron beam drawing apparatus 101. The drawing unit is a part that generates the electron beam B and irradiates the sample 102 with the electron beam B. Note that a control unit (not shown) is connected to the drawing unit, and the control unit controls the shape, irradiation position, irradiation timing, or position of the sample 102 in the drawing unit.

  The drawing unit includes a drawing chamber 300 and an electro-optical column (also referred to as a column) 301 provided on the ceiling of the drawing chamber 300. The drawing chamber 300 includes a chamber 300 a having an opening 318, a stage 302 disposed in the chamber 300 a, and a mirror 302 a provided on the stage 302. Further, the electron optical column 301 has a convex portion 330 that fits into the opening 318 of the chamber 300a. An opening is provided at the end of the convex portion 330, and the electron beam B is irradiated from the opening toward the stage 302.

  An electron beam irradiation means for irradiating the electron beam B toward the stage 302 is provided inside the electron optical column 301. In FIG. 1, in order from the top, an electron gun 303, an illumination lens 304, a blanking deflector 305, a blanking aperture 306, a first shaping aperture 307, a projection lens 308, a shaping deflector 309, a second shaping aperture 310, and a main deflector. 311, an objective lens 312 and a sub deflector 313 are arranged. These are components of the electron beam irradiation means.

  The electron beam B emitted from the electron gun 303 is irradiated to the first shaping aperture 307 by the illumination lens 304. Note that when blanking is on (non-drawing time), the electron beam B is deflected by the blanking deflector 305 and irradiated onto the blanking aperture 306, and is not irradiated onto the first shaping aperture 307.

  The first shaping aperture 307 is provided with a rectangular opening. Thereby, when the electron beam B passes through the first shaping aperture 307, the cross-sectional shape thereof is shaped into a rectangle. Thereafter, the electron beam B is projected onto the second shaping aperture 310 by the projection lens 308. Here, the shaping deflector 309 changes the projection location of the electron beam B onto the second shaping aperture 310. Thereby, the shape and size of the electron beam B are controlled.

  The focus of the electron beam B transmitted through the second shaping aperture 310 is focused on the sample 102 by the objective lens 312. The irradiation position of the electron beam B on the sample 102 is controlled by the main deflector 311 and the sub deflector 313.

  A stage 302 is provided in the drawing chamber 300. The sample 102 is supported by pins (not shown) provided on the stage 302. The sample 102 is, for example, a mask in which a light shielding film such as a chromium film and a resist film are stacked on a glass substrate.

  The stage 302 is provided with a mirror 302a. The position of the stage 302 is measured by entering and reflecting the laser beam from the laser interferometer 402 by the mirror 302a.

  Next, the operation of the electron beam drawing apparatus 101 will be described. As shown in FIG. 2, the pattern 5 drawn on the sample 102 is divided into a plurality of strip-like stripes 51 having a width in the Y direction that can be deflected by main deflection. Are divided into subfields 52. When the pattern 5 is drawn, the stage 302 is continuously moved in the X direction orthogonal to the width direction of the stripe 51, and the electron beam B is positioned in each subfield 52 by the main deflection, and the predetermined position of the subfield 52 by the subdeflection. Is irradiated with an electron beam B. In this way, the graphic 53 is drawn. When drawing of one stripe 51 is completed, the stage 302 is moved stepwise in the Y direction, and then the next stripe 51 is drawn. By repeating this process, the pattern 5 can be drawn on the entire sample 102.

  In the electron beam drawing apparatus 101 of the present embodiment, a hanging member 404 is provided inside the drawing chamber 300 as shown in FIG. In the present specification, the suspension member is also referred to as a stage placement portion. The suspension member 404 is connected to the electron optical barrel 301, and the stage 302 is disposed on the suspension member 404. A laser interferometer 402 is attached to the suspension member 404 via an attachment member 407.

  With the configuration as described above, the electron beam drawing apparatus 101 of this embodiment can suppress fluctuations in drawing accuracy due to atmospheric pressure or the like. That is, as described above, in the electron beam drawing apparatus 101, the stage 302 is disposed not on the bottom of the drawing chamber 300 but on the hanging member 404, and the hanging member 404 is attached to the electron optical column 301. It is connected.

  According to the above structure, when the drawing chamber 300 is slightly deformed due to the atmospheric pressure and the electron optical column 301 is inclined, the suspension member 404 is also inclined following the electron optical column 301. For this reason, the relative positional relationship between the electron optical column 301 and the stage 302 is maintained before and after the tilt occurs, and the positional relationship of the electron optical column 301 with respect to the sample 102 is also maintained. Therefore, even when the drawing chamber 300 is deformed, the irradiation position of the electron beam B can be suppressed from being shifted from the adjusted position. That is, for the electron beam B whose irradiation position on the aperture is adjusted so as to have a desired shape and size, and whose irradiation position on the sample 102 is adjusted so as to be drawn at a desired position, It is possible to minimize the deviation of the irradiation position from each adjustment position.

  FIG. 3 is a cross-sectional view illustrating the configuration of the drawing chamber 300 in the electron beam drawing apparatus 101 of the present embodiment shown in FIG. As shown in FIG. 3, the drawing chamber 300 has a structure in which a stage 302 is disposed in a chamber 300a in which an opening 318 is formed in a ceiling portion.

  As shown in FIG. 3, the electron beam drawing apparatus 101 according to the present embodiment includes an electron optical column 301 attached to the ceiling of the chamber 300 a and a suspension member 404 connected to the electron optical column 301. . The electron beam B emitted from the electron optical column 301 enters the drawing chamber 300 through the opening 318 of the chamber 300a, and is irradiated to the sample 102 placed on the stage 302.

  The suspension member (stage placement portion) 404 includes a rectangular lower plate 405 on which the stage 302 is placed, support members 406 disposed at the four corners of the lower plate 405, support members 406, and the electron optical column 301. And a mounting member 407 for mounting the laser interferometer 402. The connection member 510 connects the support member 406 and the electron optical barrel 301 through the opening of the electron optical barrel 301. The lower plate 405, the support member 406, the connection member 510, and the attachment member 407 can be connected to each other by, for example, screws.

  The strut member 406, the connection member 510, and the attachment member 407 can also be configured as a single unit. In this case, if the support member 406, the connection member 510, and the attachment member 407, which are integrally formed, are the second members, the second member is disposed on the lower plate 405 as the first member, Connect to the opening of the electron optical column 301. Laser interferometer 402 is attached to the second member. Note that the lower plate 405, the support member 406, the connection member 510, and the attachment member 407 can be configured integrally.

  With the above configuration, in the electron beam lithography apparatus 101 of the present embodiment, the hanging member 404 is connected to the electron optical column 301 independently from the chamber 300 a, and the stage 302 is placed inside the chamber 300 a by the hanging member 404. It becomes a structure that can be suspended. As described above, the stage 302 is suspended from the electron optical column 301 independently of the chamber 300a, thereby minimizing the influence on the stage 302 even if the chamber 300a is deformed due to a change in atmospheric pressure or temperature. can do. Accordingly, the relative position of the electron optical barrel 301 with respect to the sample 102 and the relative position of the mirror 302a with respect to the laser interferometer 402 can be prevented from being shifted, and a reduction in drawing accuracy can be suppressed.

  The stage 302 includes an XY stage 315, a Z stage 316 that is disposed on the XY stage 315 and is movable in the Z direction, a pedestal 317 disposed on the Z stage 316, and a pin (not shown) fixed on the pedestal 317. have. The pedestal 317 is provided with a mirror 302a. The back surface of the sample 102 is supported by the above pins.

  A drive rod 320 inserted from an opening 322 formed on the side wall of the chamber 300 a is attached to the XY stage 315 via a coupling 323. The drive rod 320 is connected to a drive unit 321 provided so as to close the opening 322. By controlling the driving of the driving rod 320 by the driving unit 321, the XY stage 315 can be moved in the X direction and the Y direction orthogonal to each other. The coupling 323 has a function of absorbing the amount of deformation when minute deformation occurs in the chamber 300a due to a change in atmospheric pressure or the like. Therefore, it is possible to prevent a minute deformation generated in the chamber 300a from being transmitted to the XY stage 315, and to suppress a decrease in traveling accuracy and drawing accuracy of the XY stage 315.

  FIG. 4 is an upper cross-sectional view for explaining the configuration of the drawing chamber 300 in the electron beam drawing apparatus 101 of the present embodiment shown in FIG. As shown in FIG. 4, four support members 406 a to 406 d are attached to the four corners of the lower plate 405 in the drawing chamber 300. The stage 302 is disposed on the lower plate 405, so that the stage 302 is suspended in the drawing chamber 300.

  In FIG. 4, the shape of the attachment member 407 can be, for example, a rectangular flat plate shape. In this case, the drive rod 320 is driven in the gap between the attachment member 407 and the lower plate 405. One end of the attachment member 407 is connected to the support member 406a, and the other end of the attachment member 407 is connected to the support member 406b. A laser interferometer 402 is attached to the attachment member 407. Although the illustration of the configuration of the laser interferometer 402 is omitted, the laser interferometer 402 includes a laser head that is a light source and an optical system that receives light that has been emitted from the light source and then reflected by the mirror 302a and returned. The mirror 302a may be one of the components of the laser interferometer 402, and the mirror 302a may be referred to as the laser interferometer 402.

  1, 3, and 4, there is only one laser interferometer 402, but a laser interferometer that measures the position of the stage 302 in the X direction and a laser that measures the position of the stage 302 in the Y direction. There may be an interferometer. Therefore, the position and number of the attachment member 407 and the mirror 302a in the hanging member 404 are appropriately determined according to the position and number of the laser interferometer. Further, the shape of the attachment member 407 is such that the laser interferometer 402 is attached to the suspension member 404, the light emitted from the laser interferometer 402 is reflected by the mirror 302a, and the reflected light can be received by the laser interferometer 402. If it is what makes it, it will not be limited to the above. For example, a planar wall may be provided between the support members 406a and 406b, 406b and 406c, 406c and 406d, and 406d and 406a, and the laser interferometer 402 may be attached to the walls. The drive rod 320 can be driven by providing an opening in the wall.

  Next, the structure of the connection portion between the electron optical column 301 and the suspension member 404 in the electron beam drawing apparatus 101 of the present embodiment will be described. FIG. 5 is an enlarged cross-sectional view for explaining a portion A surrounded by a dotted line shown in FIG. 3, that is, a connection portion between the electron optical barrel 301 and the suspension member 404.

  At the lower part of the electron optical column 301, a flange 401 is formed to face outward in the radial direction of the opening 318 of the chamber 300a. A seal is formed by an O-ring 409 at the edge 319 of the chamber 300a between the flange 401 and the chamber 300a. Thereby, the atmosphere inside and outside the chamber 300a is separated.

  In the electron beam drawing apparatus 101 according to the present embodiment, the connection member 510 is screwed to the electron optical column 301 so that the electron optical column 301 and the suspension member 404 are connected.

  As shown in FIG. 5, in the connection member 510, a screw hole 400b is formed on the side opposite to the side connected to the column member 406 (FIG. 3). In addition, a female screw 400a is formed in the electron optical column 301, and the screw member 415 is screwed into the screw hole 400b and the female screw 400a from the inside of the chamber 300a, whereby the suspension member 404 is attached to the electron optical column 301. Connected.

  With the connection method by screwing, the suspension member 404 should be fixed to the electron optical column 301 with sufficient strength even if the materials of the electron optical column 301 and the connection member 510 are different. Is possible. In the present embodiment, the electron optical column 301 is made of, for example, stainless steel or iron. On the other hand, a low thermal expansion material such as invar is used for the suspension member 404 as described later.

  Here, as a prior art related to the suspension member, there is one described in Japanese Utility Model Publication No. 53-13070. This publication discloses an electron beam microfabrication apparatus in which a lower end of an electron column including a lens assembly is supported by a flange facing inward in the radial direction of a hole in a ring. In this device, the base plate extends parallel to the face of the ring and with the column and is freely held in the chamber formed by the lid, wall and base. The stage holds a mirror support that holds a plane mirror, and the stage is held by a base plate. Furthermore, the interferometer head is supported on the ring by a rigid support.

  However, in the above apparatus, the member for holding the stage is not connected to the electron column independently from the vacuum chamber. For this reason, when the vacuum chamber is deformed due to fluctuations in atmospheric pressure, the stage is affected, and the relative position of the electron column with respect to the substrate (sample) and the relative position of the plane mirror with respect to the interferometer head are shifted and drawn. May reduce accuracy.

  Furthermore, the conventional electron beam drawing apparatus may be deformed due to factors other than fluctuations in atmospheric pressure. Specifically, when the electron optical column or the drawing chamber undergoes thermal expansion due to heat generated by guide friction or motor electromotive force accompanying the stage operation, minute deformation occurs in the electron beam drawing apparatus. Then, the relative position of the electron optical column with respect to the sample and the relative position of the mirror with respect to the laser interferometer are shifted, leading to a decrease in drawing accuracy.

  In Japanese Utility Model Laid-Open No. 53-13070, there is a problem of distortion generated in the cover, wall or base of the vacuum chamber during or after exhausting the vacuum chamber, and there is no description regarding deformation due to thermal expansion. Further, since there is only a description that the ring is a rigid member, when the ring is thermally deformed, the relative position of the base plate with respect to the ring is changed, and the irradiation position of the electron beam is inevitably shifted. .

Therefore, in the electron beam drawing apparatus 101 of the present embodiment, a low thermal expansion material is used for the chamber 300a and the suspension member 404. Specifically, the chamber 300a and the suspension member 404 are preferably made of a material having a linear expansion coefficient of about 2 × 10 ⁻⁶ / K or less near room temperature. Note that the linear expansion coefficients of the chamber 300a and the suspension member 404 may be the same or different.

  Since the low thermal expansion material is not easily deformed by heat, it is not easily affected by heat generated by the friction of the guide accompanying the operation of the stage 302 or the electromotive force of the motor. Therefore, by forming the chamber 300a and the suspension member 404 using such a material, deformation of the charged particle beam drawing apparatus 101 with respect to a temperature change can be suppressed. Then, coupled with the configuration in which the stage 302 is placed on the suspension member 404, the stability of the drawing accuracy can be further improved.

As the low thermal expansion material, for example, invar (Fe-36% Ni) which is a low expansion coefficient alloy can be used. The linear expansion coefficient of Invar is about 1.2 × 10 ⁻⁶ / K near room temperature, which is about 1/10 that of iron or nickel. For this reason, in this Embodiment, it is preferable to comprise the chamber 300a and the suspension member 404 using an invar material. However, in the present invention, the low thermal expansion material is not limited to Invar.

  The chamber 300a is required to have a vacuum holding function for preventing leakage between the atmosphere side and the vacuum side. Here, the low-purity low-thermal-expansion material may contain defects such as bubbles inside. In such a case, if the chamber 300a is processed so as to form a groove for providing the O-ring 409, defects may appear on the surface and a good sealing surface cannot be formed, and the desired vacuum holding function may not be exhibited. Therefore, it is preferable to use a high-purity low thermal expansion material for the chamber 300a.

  It is also possible to configure the chamber 300a only from high-purity invar. However, high-purity products are not readily available and expensive because they require more manufacturing steps than low-purity products. Therefore, in the present embodiment, it is preferable to use high-purity invar only for the seal portion of the chamber 300a and use low-purity invar for portions other than the seal portion. Thereby, the manufacturing time of the electron beam drawing apparatus 101 can be shortened and the manufacturing cost can be reduced.

  For example, the portion where the seal is formed by the O-ring 409 is configured with high-purity invar, while the other portions are configured with low-purity invar. In this case, the seal portion is a groove portion where the O-ring 409 is provided and the vicinity thereof, and in the chamber 300a, the seal portion is a region represented by reference numeral 511 in FIG. On the other hand, a region denoted by reference numeral 512 in FIG. 5 is a non-sealed portion, which is a portion that can be configured by low-purity invar.

  In the present embodiment, the purity of Invar can be expressed by the concentrations of phosphorus (P) and sulfur (S). Specifically, the higher the concentration of phosphorus (P) and sulfur (S), the lower the purity of Invar. In the present embodiment, phosphorus (P) and sulfur (S) both having a predetermined concentration or less can be defined as “high purity invar”. For example, phosphorus (P) and sulfur (S) that are each 0.001% by mass or less can be designated as “high purity invar”. In this case, one in which either phosphorus (P) or sulfur (S) exceeds 0.001% by mass is “low-purity invar”.

  In the present embodiment, the concentration of phosphorus (P) and sulfur (S) in the seal part 511 is set to be 1/10 or less of the concentration of phosphorus (P) and sulfur (S) in the non-seal part 512. Is preferred.

  In FIG. 5, the seal part 511 and the non-seal part 512 are joined by welding. The invars constituting them can be welded because the constituent materials are the same even if the purity is different.

  In the present embodiment, even when a low thermal expansion material other than Invar is used for the chamber 300a or the suspension member 404, the same effect can be obtained by considering the purity.

  The seal portion is not limited to between the flange 401 of the electron optical column 301 and the chamber 300a. In the present embodiment, as shown in FIG. 4, the drive rod 320 is inserted into the chamber 300a through the opening 322 formed in the side wall of the chamber 300a. For this reason, a gap is formed between the opening 322 and the drive rod 320. In the present embodiment, this portion of the chamber 300a is also preferably made of a high-purity low thermal expansion material. Furthermore, for example, when a window that can be seen from the outside is provided in the chamber 300a, the periphery of the window becomes a seal portion. Therefore, the chamber 300a in this portion is also preferably made of a high-purity low thermal expansion material.

  It is also possible to provide a gap between the opening 322 and the drive rod 320 so that the gap between them is not used as a seal portion. In this case, as shown in FIG. 6, a configuration in which a vacuum cover 324 that covers the driving unit 321 in an airtight manner is provided in the chamber 300 a can be employed. In such a configuration, the space between the vacuum cover 324 and the outer wall of the chamber 300a is a seal portion. Therefore, when the configuration shown in FIG. 6 is adopted, it is preferable that the chamber 300a in this portion is also composed of a high-purity low thermal expansion material. In FIG. 6, an O-ring 325 is provided in a groove formed in the vacuum cover 324, and the atmosphere inside and outside the chamber 300a is separated.

  Moreover, the part comprised with a highly purified low thermal expansion material is not restricted to a seal | sticker part. For example, when the chamber 300a is not configured as a single unit but is configured from a plurality of components, the components are joined together by welding. At this time, if each component is made of, for example, low-purity Invar, leakage due to internal defects may occur at the joint. Although relatively large internal defects can be found in advance by X-ray inspection or the like, it is preferable to use high-purity invar at the joint in that the internal defects can be avoided from the beginning. This makes it difficult for internal defects to occur and reduces the occurrence of leaks at the junction. It should be noted that invars having different purities are used for the joining part and the non-joining part, respectively, but these are easily joined by welding since they only differ in purity.

  The same applies to the case where the suspension member 404 is not integrally formed. For example, when the lower plate 405, the support member 406, the connection member 510, and the attachment member 407 are joined to each other by welding to form the suspension member 404, low purity invar can be used for each joint portion of these members. . Further, when the column member 406, the connection member 510, and the attachment member 407 are integrally formed as a second member, the joint between the second member and the lower plate 405 as the first member is also low. Purity invar can be used.

  In this embodiment, the laser interferometer 402 is attached to the suspension member 404. However, the present invention is not limited to this, and the laser interferometer 402 may be provided outside the chamber 300a. In this case, a reference mirror is provided in the laser interferometer 402 to correct a relative positional shift of the mirror 302a with respect to the laser interferometer 402 caused by deformation of the chamber 300a. For example, laser light emitted from a laser head is divided into reference light and measurement light by a beam splitter and then incident on an interferometer. The interferometer has a semi-transparent mirror inside, and divides the light incident by the semi-transparent mirror into two different optical paths. Then, one of the reference lights is incident on the reference mirror, and one of the measurement lights is incident on the mirror 302 a attached to the stage 302. Next, by observing the reflected light reflected by these mirrors, the exact position of the stage 302 can be grasped.

  As another configuration example for grasping the position of the stage 302, in addition to the laser interferometer 402 or in place of the laser interferometer 402, a linear scale composed of a mark row and a linear sensor facing the linear scale And those mounted on the XY stage 315. In this case, each mark row is detected by the linear sensor, and the position of the stage 302 is grasped.

  As described above, according to the electron beam drawing apparatus of the present embodiment, it is possible to suppress a reduction in drawing accuracy due to a change in atmospheric pressure or a temperature change. Further, by configuring the chamber with a low thermal expansion material, it is possible to further suppress a decrease in drawing accuracy. In addition, by using a high-purity low thermal expansion material only for the seal portion, the manufacturing cost of the electron beam drawing apparatus can be reduced and the manufacturing time can be shortened.

  7 and 13 are conceptual diagrams for explaining a state in which the electron beam drawing apparatus is deformed under the influence of atmospheric pressure fluctuation or temperature change. FIG. 7 shows an electron beam drawing apparatus 101 according to this embodiment. On the other hand, FIG. 13 shows a conventional charged particle beam drawing apparatus 1001 in which a stage 1021 on which a mask 1022 is placed is attached to the bottom of a drawing chamber 1011 and a laser interferometer 1023 is fixed to a side wall of the drawing chamber 1011. . In FIG. 7, the illustration of the drive rod 320, the drive unit 321 and the opening 322 shown in FIG. 3 is omitted. The same applies to FIG.

  In FIG. 7, the central axis L of the electron optical column 301, the horizontal plane M of the stage 302, and the laser interferometer 402 in a state where the electron beam drawing apparatus 101 is slightly deformed due to the influence of atmospheric pressure fluctuation or temperature change. The incident direction N of the laser beam from each is indicated by a broken line.

  In FIG. 7, dotted lines indicate the state of the laser beam from the central axis of the electron optical column 301, the horizontal plane of the stage 302, and the laser interferometer 402 in a state where the electron beam drawing apparatus 101 is not deformed, that is, in an initial state. The incident direction is shown.

  In the initial state of the electron beam drawing apparatus 101, the central axis of the electron optical column 301 and the horizontal plane intersect perpendicularly, and the horizontal plane and the incident direction are parallel. Here, in order to realize high drawing accuracy, it is required that the relative position of the electron optical barrel 301 with respect to the sample 102 and the relative position of the mirror 302 a with respect to the laser interferometer 402 do not deviate. That is, the relative position is required to be maintained even if the electron beam lithography apparatus 101 changes minutely under the influence of atmospheric pressure fluctuation or temperature change.

  Also in FIG. 13, the central axis L of the electron optical column 1031, the horizontal plane M of the stage 1021, and the laser interferometer in a state where the electron beam drawing apparatus 1001 is slightly deformed due to the influence of atmospheric pressure fluctuation or temperature change. The incident direction N of the laser beam from 1023 is indicated by a broken line. On the other hand, the dotted line indicates the incident direction of the laser beam from the central axis of the electron optical column 1031, the horizontal plane of the stage 1021, and the laser interferometer 1023 in a state where the electron beam drawing apparatus 1001 is not deformed, that is, in an initial state. ing.

  In the conventional electron beam drawing apparatus 1001 shown in FIG. 13, as a result of the electron beam drawing apparatus 1001 being slightly deformed by the influence of atmospheric pressure fluctuation or temperature change, the central axis L of the electron optical column 1031 is the central axis in the initial state. Tilt against. Further, the horizontal plane M of the stage 1021 is inclined with respect to the horizontal plane in the initial state. Furthermore, the incident direction N of the laser light from the laser interferometer 1023 is also inclined with respect to the incident direction in the initial state. These inclination angles are expected to be different from each other, and it is difficult to predict the relative displacement amount of the electron optical barrel 1031 with respect to the mask 1022 and the relative displacement amount of the mirror 1024 with respect to the laser interferometer 1023. It is.

  On the other hand, in the electron beam drawing apparatus 101 according to the present embodiment shown in FIG. 7, the stage 302 has a structure that is suspended by a suspension member 404 connected to the electron optical column 301. For this reason, when the central axis L of the electron optical barrel 301 is tilted under the influence of atmospheric pressure fluctuation or temperature change, the suspension member 404 is also tilted. Since the electron optical column 301 and the suspension member 404 are physically connected, their inclination angles are the same. Therefore, the horizontal surface M of the stage 302 above the suspension member 404 is also inclined with the same inclination angle. That is, since the electron optical column 301 and the stage 302 are inclined with the same inclination angle with respect to the central axis indicated by the dotted line and the horizontal plane, the relative position of the electron optical column 301 with respect to the sample 102 is maintained. Is done.

  In the charged particle beam drawing apparatus 101 of the present embodiment shown in FIG. 7, the laser interferometer 402 is attached to the suspension member 404 by the attachment member 407. For this reason, when the central axis L of the electron optical column 301 and the horizontal plane M of the stage 302 are inclined due to the influence of atmospheric pressure fluctuation or temperature change, the laser light from the laser interferometer 402 is transmitted via the suspension member 404. The incident direction N is also inclined with the same inclination angle. That is, since the incident direction of the laser light from the laser interferometer 402 is inclined with the same inclination angle as the central axis of the electron optical column 301 (indicated by a dotted line) and the horizontal plane of the stage 302, the laser interferometer 402 The relative position of the mirror 302a with respect to is maintained.

  Furthermore, in the electron beam drawing apparatus 101 of the present embodiment, the chamber 300a and the suspension member 404 are made of a high-purity low thermal expansion material. Thereby, the deformation | transformation of the electron beam drawing apparatus 101 with respect to a temperature change can be suppressed. At this time, if only the seal part and the joint part of the chamber 300a and the suspension member 404 are made of a high-purity low thermal expansion material and the other parts are made of a low-purity low thermal expansion material, all of them Compared with the case where is made of a high-purity low thermal expansion material, the cost of manufacturing the electron beam lithography apparatus 101 can be reduced, and the manufacturing time can be shortened.

  In other words, the charged particle beam drawing apparatus of the present embodiment described above can be expressed as follows. That is, the charged particle beam drawing apparatus includes a chamber having an opening, a stage placement unit provided in the chamber, a stage placed on the stage placement unit, a mirror provided on the stage, and a stage placement A drawing chamber provided with a laser interferometer that receives light incident on and reflected from the mirror and measures the position of the stage, a convex portion that fits into the opening of the chamber, An optical column having a built-in beam irradiating means for irradiating a charged particle beam from the opening provided at the end of the convex portion toward the stage, provided with a flange that is provided around and forming a seal portion with the chamber The stage mounting portion is connected to the optical barrel independently from the chamber, and the chamber and the stage mounting portion are made of a low thermal expansion material such as Invar.

Embodiment 2. FIG.
FIG. 8 is a cross-sectional view of the drawing chamber in the electron beam drawing apparatus of the present embodiment. In addition, it has shown that the part which attached | subjected the same code | symbol as FIG. 3 is the same.

  The electron beam drawing apparatus 501 includes a drawing room and an electron optical column (also referred to as a column) 301 provided on the ceiling of the drawing room. The drawing chamber includes a chamber 300a having an opening 318, a stage 302 disposed in the chamber 300a, and a mirror 302a provided in the stage 302. The electron optical column 301 has a convex portion 331 that fits into the opening 318 of the chamber 300a. An opening is provided at the end of the convex portion 331, and an electron beam is irradiated from the opening toward the stage 302. A flange 401 is provided around the convex portion 331.

  An electron beam irradiation means (not shown) for irradiating an electron beam toward the stage 302 is provided inside the electron optical column 301. This electron beam irradiation means is the same as that of the first embodiment, and is an electron gun, illumination lens, blanking deflector, blanking aperture, first shaping aperture, projection lens, shaping deflector, second shaping aperture, main deflection. And an objective lens and a sub deflector.

  As shown in FIG. 8, the electron beam drawing apparatus 501 of the present embodiment also has a suspension member (stage mounting portion) 504. The suspension member 504 includes a lower plate 405 on which the stage 302 is placed, support members 406 disposed at the four corners of the lower plate 405, a connection member 412 that connects the support member 406 and the electron optical column 301, and a laser. And an attachment member 407 for attaching the interferometer 402. With this configuration, the electron beam drawing apparatus 501 of this embodiment has a structure in which the stage 302 is suspended by the suspension member 504.

  The present embodiment is different from the first embodiment in that the connection member 412 is also connected to the chamber 300a. Specifically, the connection member 412 is connected to the edge 319 of the opening 318 of the chamber 300a. That is, the flange 401 of the electron optical column 301 and the edge 319 of the chamber 300a are on the same plane, and the connection member 412 is connected to this surface, whereby the connection member 412 is connected to the electron optical column 301 and the chamber 300a. Are connected.

  The lower plate 405, the support member 406, the connection member 412 and the attachment member 407 can be connected to each other by welding, for example, but may be configured as a single unit. For example, the support member 406, the connection member 412, and the attachment member 407 can be configured as a single unit. In this case, if the support member 406, the connection member 412 and the attachment member 407, which are configured as a single body, are the second members, the second member is disposed on the lower plate 405 as the first member, The opening 318 of the electron optical column 301 is connected to the chamber 300a. Laser interferometer 402 is attached to the second member. Note that the lower plate 405, the support member 406, the connection member 412, and the attachment member 407 can be configured integrally.

  A connection portion between the electron optical barrel 301 and the suspension member 504 will be described in more detail with reference to FIG.

  FIG. 9 is an enlarged cross-sectional view of a portion C surrounded by a dotted line shown in FIG. 8, that is, a connection portion between the electron optical barrel 301 and the suspension member 504.

  The connection member 412 constituting the suspension member 504 has a ring shape having an opening corresponding to the edge 319 of the chamber 300a. Seals are formed between the flange 401 and the connection member 412, and between the chamber 300a and the connection member 412 by O-rings 513 and 514, respectively. Thereby, the atmosphere inside and outside the chamber 300a is separated.

  In FIG. 9, the first seal portion 404 a formed on the connection member 412 corresponds to a groove portion where the O-ring 514 is provided and a region in the vicinity thereof. On the other hand, the second seal portion 404b formed in the connection member 412 corresponds to a groove portion where the O-ring 513 is provided and a region in the vicinity thereof. Airtightness between the flange 401 and the connection member 412 is maintained by the first seal portion 404 a and the seal portion 414 provided on the flange 401. Similarly, the airtightness between the chamber 300a and the connection member 412 is maintained by the second seal portion 404b and the seal portion 413 provided in the chamber 300a.

  As shown in FIG. 10, the groove may not be provided in the chamber 300 a or the flange 401, but the groove may be provided only in the connection member 412, and the seal may be formed by the O-rings 513 and 514. In this case, the seal portion 416 provided in the chamber 300a and the seal portion 417 provided in the flange 401 are formed on a plane, and this plane portion contacts the first seal portion 404a and the second seal portion 404b, and the chamber The atmosphere inside and outside of 300a is separated.

  The chamber 300a is made of a low thermal expansion material or stainless steel. On the other hand, each member constituting the suspension member 504, that is, the connection member 412, the support member 406, the attachment member 407, and the lower plate 405 are each configured using a low thermal expansion material.

  In particular, the connection member 412 is required to have a vacuum holding function for preventing leakage between the atmosphere side and the vacuum side. For this reason, it is preferable that the connecting member 412 is made of a high-purity low thermal expansion material. On the other hand, the support member 406, the attachment member 407, and the lower plate 405 can be made of a low-purity low thermal expansion material.

  By doing as described above, the cost of manufacturing the electron beam drawing apparatus 501 can be reduced and the manufacturing time can be shortened as compared with the case where all the suspension members 504 are made of a high-purity low thermal expansion material. become able to.

  In the said structure, each member which comprises the suspension member 504 can be mutually connected, for example with a screw | thread.

  Further, the connection member 412 may be partially made of a high-purity low thermal expansion material without being made of a high-purity low thermal expansion material. Specifically, the first seal portion 404a and the second seal portion 404b that are in contact with the chamber 300a and the flange 401 are made of a high-purity low thermal expansion material, and the other regions are made of a low-purity low thermal expansion material. be able to. By doing in this way, the cost which manufactures the electron beam drawing apparatus 501 can further be reduced, and manufacturing time can further be shortened.

  FIG. 11 is a cross-sectional view for explaining another configuration example of the electron beam drawing apparatus.

  As shown in FIG. 11, the electron beam drawing apparatus 601 includes a chamber 300a to which the flange 401 of the electron optical barrel 301 is connected, a connection member 412 to be connected to the edge 319 of the chamber 300a, and a column to be connected to the connection member 412. A member 406, a lower plate 405 attached to the column member 406, and a stage 302 disposed on the lower plate 405 are provided. That is, in the electron beam drawing apparatus 601 shown in FIG. 11, the edge 319 of the chamber 300a is sandwiched between the flange 401 of the electron optical column 301 and the connection member 412.

  The support members 406 are disposed at the four corners of the lower plate 405. A common attachment member 407 is connected to the two adjacent strut members 406, and the laser interferometer 402 is attached to the attachment member 407. Although the illustration of the configuration of the laser interferometer 402 is omitted, the laser interferometer 402 includes a laser head that is a light source and an optical system that receives light that has been emitted from the light source and then reflected by the mirror 302a and returned. The mirror 302a may be one of the components of the laser interferometer 402.

  The electron beam drawing apparatus 601 is different from the electron beam drawing apparatus 501 (shown in FIGS. 8 and 9) in that the connecting member 412 is connected to the inner surface of the chamber 300a. More specifically, the connection member 412 is connected to the inner surface of the chamber 300a, and the flange 401 of the electron optical column 301 is formed on the outer surface of the chamber 300a, that is, the atmosphere-side surface. With this configuration, the atmosphere inside and outside the chamber 300a is separated.

  The outer surface of the chamber 300a and the flange 401 of the electron optical column 301 are connected via an O-ring (not shown) provided in a groove (not shown), whereby the chamber 300a and the flange 401 are connected. Airtightness between them is maintained. In FIG. 11, a seal portion 515 is a groove portion where an O-ring is provided and a region in the vicinity thereof.

  The connection member 412, the column member 406 connected to the connection member 412, the lower plate 405 connected to the column member 406, and the attachment member 407 to which the laser interferometer 402 is attached are preferably made of a low thermal expansion material.

  The chamber 300a can be made of stainless steel, but the seal portion 515 is preferably made of a low thermal expansion material, in particular, a high purity low thermal expansion material. In this case, the connection member 412 is connected to the stainless steel chamber 300a by screws. Further, the entire chamber 300a can be made of a low thermal expansion material.

  As described above, the seal portion 515 between the chamber 300a and the electron optical column 301, the connection member 412 on which the stage 302 is suspended, the support member 406, the lower plate 405, and the attachment member 407 to which the laser interferometer 402 is attached. By using a low thermal expansion material, even if the electron optical column 301 or the drawing chamber is thermally expanded and deformed due to heat generated by the operation of the stage 302, the relative position of the electron optical column 301 with respect to the sample 102 or laser interference It is possible to prevent the relative accuracy of the mirror 302a from shifting with respect to the total 402 and to prevent a reduction in drawing accuracy.

  As described above, according to the first and second embodiments, an electron beam drawing apparatus capable of suppressing a reduction in drawing accuracy caused by a change in pressure or temperature is provided.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, in each of the above embodiments, an electron beam is used, but the present invention can also be applied to cases where other charged particle beams such as an ion beam are used.
The invention described in the scope of claims at the beginning of the present application will be appended.
[C1]
A chamber having an opening on the top surface;
A drawing room comprising a stage provided in the chamber;
An optical barrel containing a beam irradiation means for irradiating a charged particle beam toward the stage through the opening;
The optical lens barrel has a convex portion that fits into the opening of the chamber;
A flange provided around the convex portion and forming a seal portion with the chamber;
The charged particle beam drawing apparatus, wherein the seal portion of the chamber is made of a material having lower phosphorus and sulfur concentrations than other portions.
[C2]
The charged particle beam drawing apparatus according to [C1], wherein the chamber is made of a material having a linear expansion coefficient of 2 × 10 −6 / K or less at room temperature.
[C3]
The chamber is configured by joining a plurality of members,
Each of the joint portions of the plurality of members is made of a material having a lower phosphorus and sulfur concentration than the other portions. The charged particle beam drawing apparatus according to [C1] or [C2].

B Electron beam 5 pattern 51 Stripe 52 Subfield 53 Graphic 101, 501, 601, 1001 Electron beam drawing apparatus 102 Sample 300, 1011 Drawing chamber 300a Chamber 301, 1031 Electro-optical column 302, 1021 Stage 302a, 1024 Mirror 303, 1032 Electron gun 304 Illumination lens 305 Blanking deflector 306 Blanking aperture 307 First shaping aperture 308 Projection lens 309 Molding deflector 310 Second shaping aperture 311 Main deflector 312 Objective lens 313 Sub deflector 315 XY stage 316 Z stage 317 base 318 Opening 319 Edge 320 Drive rod 321, 1025 Drive part 322 Opening 323 Coupling 324 Vacuum cover 325, 409, 513 14 O-ring 330, 331 Convex part 400a Female screw 400b Screw hole 401 Flange 402, 1023 Laser interferometer 404, 504 Hanging member 404a First seal part 404b Second seal part 405 Lower plate 406, 406a to 406d Strut member 407 Mounting member 412, 510 connection member 413, 414, 416, 417, 511, 515 Seal part 415 Screw 512 Non-seal part 1022 Mask 1033, 1035 Deflector 1034 Aperture

Claims (15)

A chamber having an opening in the top surface, a drawing chamber and a stage provided in the prior Symbol chamber,
An optical column having a built- in beam irradiation means for irradiating a charged particle beam toward the stage through the opening and having a flange formed outwardly in the radial direction of the opening of the chamber ;
A seal portion formed between the flange and the chamber and having a groove portion provided with an O-ring;
An O-ring provided in the groove portion of the seal portion and forming a seal;
Have
At least the groove and its vicinity of the front Symbol seal portion, the concentration of Li emissions and sulfur is formed by high-purity low thermal expansion material is below any predetermined concentration,
The chamber is configured by a low-purity low-thermal-expansion material in which either one of phosphorus or sulfur concentration exceeds the predetermined concentration .
Load conductive particle beam writing apparatus. The charged particle beam drawing apparatus according to claim 1, wherein the predetermined concentration is 0.001 mass percent. The concentration of phosphorus and sulfur of the high purity low thermal expansion material of the seal portion is 1/10 or less of the concentration of phosphorus and sulfur of the low purity low thermal expansion material of the chamber. Charged particle beam lithography system. The low thermal expansion material, a charged particle beam drawing apparatus according to any one of claims 1, characterized in that it is made of a material having a linear expansion coefficient of 2 × 10 -6 ^{/ K} or less at room temperature for 3 . The charged particle beam drawing apparatus according to any one of claims 1 to 4, wherein the low thermal expansion material is an iron alloy containing at least nickel. The chamber is configured by joining a plurality of members , or has a seal part with other members ,
2. The charged particle beam drawing apparatus according to claim 1, wherein each joint portion of the plurality of members of the chamber or a seal portion with the other member is made of the high purity low thermal expansion material. . The optical barrel further includes a convex portion that fits into the opening of the chamber and has an opening at the end for irradiating the charged particle beam toward the stage,
The charged particle beam drawing apparatus further includes a hanging portion on the inside of the chamber, on which the stage is mounted and connected to the convex portion of the optical barrel independently of the chamber. The charged particle beam drawing apparatus according to claim 1. The charged particle beam drawing apparatus according to claim 7, wherein at least a joining portion of members constituting the suspension portion is made of the low-purity low thermal expansion material. A chamber having an opening on the top surface;
A drawing room comprising a stage provided in the chamber ;
An optical column having a built-in beam irradiation means for irradiating a charged particle beam toward the stage through the opening and having a flange formed outwardly in the radial direction of the opening of the chamber ;
A first seal portion having a first groove portion facing the flange, provided with an O-ring, and a second seal portion having a second groove portion facing the chamber, provided with another O-ring. A connecting member comprising:
Two O-rings provided in the first groove portion and the second groove portion of the connection member, each forming a seal;
Have
At least the first seal part and the second seal part of the connection member are made of a high-purity low thermal expansion material in which the concentrations of phosphorus and sulfur are both equal to or lower than a predetermined concentration,
The chamber is configured by a low-purity low-thermal-expansion material in which either one of phosphorus or sulfur concentration exceeds the predetermined concentration.
Charged particle beam lithography system. 10. The charged particle according to claim 9, wherein a portion other than the first seal portion and the second seal portion of the connection member is configured by the high purity low thermal expansion material or the low purity low thermal expansion material. Beam drawing device. The charged particle beam drawing apparatus according to claim 9, wherein the predetermined concentration is 0.001 mass percent. The phosphorus and sulfur concentrations of the high purity low thermal expansion material of the first seal portion and the second seal portion are 1/10 of the phosphorus and sulfur concentrations of the low purity low thermal expansion material of the chamber. The charged particle beam drawing apparatus according to claim 9, wherein: The charged particle beam drawing apparatus according to any one of claims 9 to 12, wherein the low thermal expansion material is an iron alloy containing at least nickel. The charged particle beam drawing apparatus according to claim 9, further comprising a suspending unit that is placed on the stage and is suspended from and connected to the connection member, inside the chamber. . The charged particle beam drawing apparatus according to claim 14, wherein at least a joining portion of members constituting the hanging portion is made of the low-purity low thermal expansion material.

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