JP2019176001A - Aperture member and multi charged particle beam lithography apparatus - Google Patents

Abstract

To reduce temperature drop at an opening during cooling for prevent thermal expansion, thereby preventing contamination from occurring.SOLUTION: An aperture member 10 according to the present embodiment includes: a substrate 11 provided with an opening 12 therein; and a high thermal resistance area 14 provided on the substrate 11 so as to surround the opening 12 and including a material 16 having a higher thermal resistance than a material of the substrate 11. The high thermal resistance area 14 includes the high thermal resistance material 16 embedded in a recess 15 formed in the substrate 11. The substrate 11 may be provided with a plurality of the openings 12. Each of the openings 12 includes a first opening 12a and a second opening 12b communicating with the first opening 12a and having a smaller diameter than the first opening 12a. The depth of the recess 15 is substantially the same as the depth of the first opening 12a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an aperture member and a multi charged particle beam drawing apparatus.

  As LSIs are highly integrated, circuit line widths required for semiconductor devices have been reduced year by year. In order to form a desired circuit pattern on a semiconductor device, a reduction projection type exposure apparatus is used to form a high-precision original pattern pattern formed on quartz (a mask, or a pattern used particularly in a stepper or scanner is also called a reticle). )) Is reduced and transferred onto the wafer. A high-precision original pattern is drawn by an electron beam drawing apparatus, and so-called electron beam lithography technology is used.

  Since a drawing apparatus using a multi-beam can irradiate many beams at a time as compared with the case of drawing with one electron beam, the throughput can be greatly improved. In a multi-beam drawing apparatus using a blanking aperture array, which is one form of the multi-beam drawing apparatus, for example, an electron beam emitted from one electron gun is passed through a shaped aperture array having a plurality of apertures to form a multi-beam ( A plurality of electron beams). The multi-beams pass through corresponding blankers of the blanking aperture array.

  The blanking aperture array has an electrode pair for individually deflecting the beam, and an opening for passing the beam between them. One of the electrode pair (blanker) is fixed at the ground potential, and the other is ground potential and the other. By switching to this potential, blanking deflection of the passing electron beam is performed individually. The electron beam deflected by the blanker is shielded, and the electron beam not deflected is irradiated onto the sample.

  The temperature of the shaped aperture array increases with beam irradiation, and the opening pitch changes due to thermal expansion. When the aperture pitch of the shaped aperture array changes, the beam pitch of the multi-beam changes, and a beam that does not pass through the aperture of the blanking aperture array is generated, and a part of the beam array to be imaged on the sample surface is lost. There was a problem.

  Although it is conceivable to cool the molded aperture array by providing a cooling mechanism, in the conventional molded aperture array, the opening is also cooled, and contamination easily grows in the opening at a low temperature, and the opening shape changes. There was a problem that the opening was closed.

JP 2017-199610 A Japanese Patent Laying-Open No. 2006-76489 JP 2012-182078 A JP 2014-175573 A JP-A-2006-197531

  The present invention has been made in view of the above-described conventional situation, and an aperture member and a multi-charge that can suppress a decrease in temperature of an opening during cooling for preventing thermal expansion and prevent occurrence of contamination. It is an object to provide a particle beam drawing apparatus.

  An aperture member according to an aspect of the present invention is an aperture member of a charged particle beam lithography apparatus, and is provided on the substrate so as to surround the opening, and has a thermal resistance higher than that of the material of the substrate. And a high heat resistance region including a high heat resistance material.

  In the aperture member according to an aspect of the present invention, the high thermal resistance material is embedded in a recess formed in the substrate.

  In the aperture member according to one aspect of the present invention, the substrate is provided with a plurality of openings, each opening being in communication with the first opening and the first opening, and having a diameter larger than that of the first opening. And the depth of the recess is the same as the depth of the first opening.

  In the aperture member according to one aspect of the present invention, the high thermal resistance material is embedded in a through hole formed in the substrate.

  A multi-charged particle beam drawing apparatus according to an aspect of the present invention includes an emission unit that emits a charged particle beam and a substrate on which a plurality of first openings are formed, and the region including the plurality of first openings A shaping aperture array that receives irradiation of a charged particle beam and forms a multi-beam by passing a part of the charged particle beam through the plurality of first openings, and a multi-beam that has passed through the plurality of first openings. Among them, a plurality of second openings through which the corresponding beams pass are formed, and a blanking aperture array provided with a blanker for deflecting the blanking of the beam in each second opening, and an end of the shaping aperture array are in contact with each other And a cooling section for cooling the molding aperture array, and the substrate of the molding aperture array surrounds the plurality of first openings. As described above, in which high heat resistance regions including a high thermal resistance material is provided than the material of the substrate.

  ADVANTAGE OF THE INVENTION According to this invention, the temperature fall of the opening part at the time of cooling for preventing thermal expansion can be suppressed, and generation | occurrence | production of contamination can be prevented.

1 is a schematic view of a multi-charged particle beam drawing apparatus according to an embodiment of the present invention. It is a top view of a shaping | molding aperture array. It is sectional drawing in the III-III line of FIG. (A) (b) is process sectional drawing explaining the manufacturing method of a high thermal resistance area | region. It is sectional drawing of a shaping | molding aperture array. It is a graph which shows the temperature distribution of a shaping | molding aperture array. It is a top view of the shaping | molding aperture array by a modification. (A)-(d) is a top view of the shaping | molding aperture array by a modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the embodiment, a structure 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 an ion beam or the like.

  FIG. 1 is a schematic configuration diagram of a drawing apparatus according to an embodiment. A drawing apparatus 100 shown in FIG. 1 is an example of a multi-charged particle beam drawing apparatus. The drawing apparatus 100 includes an electron column 102 and a drawing chamber 103. An electron gun 111, an illumination lens 112, a shaping aperture array 10, a cooling unit 20, a blanking aperture array 30, a reduction lens 115, a limiting aperture member 116, an objective lens 117, and a deflector 118 are arranged in the electron barrel 102. Yes.

  The blanking aperture array 30 is mounted (mounted) on the mounting substrate 40. An opening 42 through which an electron beam (multi-beam 130M) passes is formed at the center of the mounting substrate 40.

  An XY stage 105 is disposed in the drawing chamber 103. On the XY stage 105, a drawing target substrate 101 is arranged at the time of drawing. The substrate 101 may be an exposure mask for manufacturing a semiconductor device, or a semiconductor substrate (silicon wafer) on which the semiconductor device is manufactured. Further, the substrate 101 may be a mask blank coated with a resist and on which nothing is drawn yet.

  As shown in FIG. 2, openings (first openings) 12 in a vertical m row × n horizontal row (m, n ≧ 2) are formed in the molded aperture array 10 at a predetermined arrangement pitch. Each opening 12 is formed of a rectangle having the same size and shape. The shape of the opening 12 may be circular.

  The electron beam 130 emitted from the electron gun 111 (emission unit) illuminates the entire shaped aperture array 10 almost vertically by the illumination lens 112. The electron beam 130 passes through the plurality of openings 12 of the shaped aperture array 10 to form a plurality of electron beams (multi-beam 130M).

  The blanking aperture array 30 is provided below the molding aperture array 10, and a passage hole (second opening) 32 is formed in accordance with the arrangement position of each opening 12 of the molding aperture array 10. In each passage hole 32, a blanker made up of a pair of two electrodes is arranged. One of the blankers is fixed at the ground potential, and the other is switched to a potential different from the ground potential. The electron beam that passes through each passage hole 32 is independently deflected by a voltage applied to the blanker. In this way, the plurality of blankers perform blanking deflection of the corresponding beam among the multi-beams 130M that have passed through the plurality of openings 12 of the shaping aperture array 10.

  The multi-beam 130M that has passed through the blanking aperture array 30 is reduced by the reduction lens 115 and travels toward the hole in the center of the limiting aperture member 116. Here, the electron beam deflected by the blanker of the blanking aperture array 30 is displaced from the central hole of the limiting aperture member 116 and is blocked by the limiting aperture member 116. On the other hand, the electron beam that has not been deflected by the blanker passes through the hole in the center of the limiting aperture member 116. Blanking control is performed by turning on / off the blanker, and on / off of the beam is controlled.

  The limiting aperture member 116 shields each beam deflected to be in a beam-off state by a plurality of blankers. A beam of one shot is formed by the beam that has passed through the limiting aperture member 116 formed from when the beam is turned on to when the beam is turned off.

  The multi-beams that have passed through the limiting aperture member 116 are focused by the objective lens 117 and become a pattern image with a desired reduction ratio. The entire multi-beam is deflected together in the same direction by the deflector 118, and is irradiated to each irradiation position on the substrate 101 of each beam. When the XY stage 105 is continuously moving, the beam irradiation position is controlled by the deflector 118 so as to follow the movement of the XY stage 105.

  The multi-beams irradiated at a time are ideally arranged at a pitch obtained by multiplying the arrangement pitch of the plurality of openings 12 of the shaping aperture array 10 by the desired reduction ratio described above. The drawing apparatus 100 performs a drawing operation by a raster scan method in which shot beams are continuously irradiated in order, and when drawing a desired pattern, unnecessary beams are controlled to be beam-off by blanking control.

  When the multi-beam 130M is formed, the shaping aperture array 10 may generate heat and thermally expand to block most of the electron beam 130. Therefore, the cooling unit 20 cools the molding aperture array 10.

  For example, the cooling unit 20 includes a cooling plate 22 that is in contact with an end (peripheral portion) of the molded aperture array 10, a cooling plate 24 that has flowed cooling water, and a heat transfer cable 26 that connects the cooling plate 22 and the cooling plate 24. Have The cooling unit 20 may use a Peltier element.

  2 is a plan view of the molded aperture array 10, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. As shown in FIGS. 2 and 3, the molded aperture array 10 has a substrate 11, and a plurality of openings 12 are provided in the central portion of the substrate 11. The substrate 11 is a silicon substrate, for example.

  The substrate 11 is provided with a high thermal resistance region 14 made of a material having a higher thermal resistance than the material of the substrate 11 so as to surround the region where the opening 12 is formed. For example, as shown in FIGS. 4A and 4B, the high thermal resistance region 14 is formed by forming a groove (concave portion) 15 in the substrate 11 and embedding a low thermal conductive material (high thermal resistance material) 16 in the groove 15. it can.

For the low thermal conductive material 16, for example, a material having a low thermal conductivity such as a metal such as titanium, a fluororesin, or a ceramic such as zirconia can be used. Silicon dioxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC), or the like may be used. Further, a configuration in which nothing is provided in the groove 15 may be employed.

  The opening 12 provided in the shaping aperture array 10 needs to have a small diameter in order to form the multi-beam 130M. However, the substrate 11 needs to have a certain thickness, and it is difficult to process a hole with a uniform diameter because of the aspect ratio. Therefore, as shown in FIG. 5, the opening 12 communicates with the opening 12a formed from one surface of the substrate 11 and the opening 12a, penetrates to the other surface of the substrate 11, and is more than the opening 12a. It is comprised with the opening part 12b with a small diameter.

  For example, the opening 12 a is formed from one surface of the substrate 11. Subsequently, the opening 12b is formed from the other surface of the substrate 11 so as to communicate with the opening 12a in accordance with the position of the opening 12a.

  When forming the opening 12a, it is preferable to form a groove 15 for the high thermal resistance region 14 as well. The depth of the opening 12a and the depth of the groove 15 are (substantially) the same.

  When the cooling plate 22 is brought into contact with the peripheral portion of the molded aperture array 10 provided with the high thermal resistance region 14 so as to surround the opening 12 to cool the molded aperture array 10, as shown in FIG. On the outer side (outer peripheral side), the temperature of the molding aperture array 10 can be kept low. Therefore, the thermal expansion of the shaping aperture array 10 can be prevented. Moreover, when components, such as a circuit element, are attached to the area | region outside the high thermal resistance area | region 14, the damage by the heat | fever to this component can be suppressed.

  On the inner side (center side) of the high thermal resistance region 14, the molding aperture array 10 has a high temperature, and generation and growth of contamination at the opening 12 can be prevented.

  On the other hand, when the high thermal resistance region 14 is not provided, the temperature of the region where the opening 12 is formed is lowered, and contamination is likely to occur.

  As described above, according to the present embodiment, when the molding aperture array 10 is cooled from the peripheral portion thereof in order to prevent thermal expansion of the molding aperture array 10, the temperature drop in the central portion where the opening 12 is formed is suppressed. The occurrence of contamination can be prevented.

  In the above embodiment, the example in which the high heat resistance region 14 is formed in a rectangular ring shape so as to surround the opening formation region has been described. However, as shown in FIG. 7, an annular high heat resistance region 14R may be formed.

  In the above embodiment, the example in which the high thermal resistance region is formed by embedding the low thermal conductivity material in the groove 15 formed in the substrate 11 has been described. However, the high thermal resistance region is embedded by embedding the low thermal conductivity material in the through hole penetrating the substrate 11. May be formed. It is good also as a structure which does not embed anything in a through-hole.

  In this case, for example, as shown in FIG. 8A, the four linear high thermal resistance regions 14A may be arranged so as to be one side of a rectangle. Further, as shown in FIGS. 8B to 8D, a plurality of small-sized high heat resistance regions 14 </ b> B to 14 </ b> D may be arranged at intervals in a rectangular ring shape or an annular shape.

  In the above-described embodiment, an example in which the high thermal resistance region 14 is provided in the shaping aperture array for forming a multi-beam has been described. However, the present invention can also be applied to an aperture installed in a single-beam drawing apparatus. Further, the present invention can be applied not only to a drawing apparatus but also to an aperture installed in an inspection apparatus using a charged particle beam.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

DESCRIPTION OF SYMBOLS 10 Molding aperture array 11 Board | substrate 12 Opening 14 High heat resistance area | region 20 Cooling part 30 Blanking aperture array

Claims (5)

An aperture member of a charged particle beam drawing apparatus,
A substrate provided with an opening;
A high thermal resistance region including a high thermal resistance material provided on the substrate so as to surround the opening and having a higher thermal resistance than the material of the substrate;
An aperture member comprising:   The aperture member according to claim 1, wherein the high thermal resistance material is embedded in a recess formed in the substrate. The substrate is provided with a plurality of openings,
Each opening has a first opening and a second opening communicating with the first opening and having a smaller diameter than the first opening,
The aperture member according to claim 2, wherein a depth of the recess is the same as a depth of the first opening.   The aperture member according to claim 1, wherein the high thermal resistance material is embedded in a through hole formed in the substrate. An emission part for emitting a charged particle beam;
A substrate having a plurality of first openings is formed, a region including the plurality of first openings is irradiated with the charged particle beam, and a part of the charged particle beam is provided to each of the plurality of first openings. A shaped aperture array that forms a multi-beam by passing through;
Of the multi-beams that have passed through the plurality of first openings, a plurality of second openings through which the corresponding beams pass are formed, and a blanking aperture in which a blanker for deflecting beam blanking is provided in each second opening. An array,
A cooling unit that contacts an end of the molded aperture array and cools the molded aperture array;
With
A multi-heat resistance region including a high thermal resistance material having a higher thermal resistance than the material of the substrate is provided on the substrate of the molded aperture array so as to surround the plurality of first openings. Charged particle beam lithography system.

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