JP2009278001A - Charged beam lithography system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charged beam lithography system capable of performing precise lithography by uniformizing temperature in a uniform heating plate 19 to suppress a temperature difference depending on a position in a sample 12. <P>SOLUTION: The electron beam lithography system 11 has: an electron-optical barrel 16 for emitting electron beams; a uniform heating unit 17 comprising a uniform heating plate 19 formed at a lower portion of the electron-optical barrel 16, a first cooling pipe 21 disposed along the periphery of the uniform heating plate 19, and a second cooling pipe 21 that is disposed along the first cooling pipe 21 and has a coolant flowing in a direction opposite to that of a coolant flowing in the first cooling pipe; and a casing 14 having the electron-optical barrel 16 at an upper portion and an XY stage 13 for placing the sample 12 inside. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a charged beam drawing apparatus.

  With the miniaturization of semiconductor devices, miniaturization of mask patterns such as LSIs is required. For the formation of this fine mask pattern, an electron beam lithography apparatus having an excellent resolution is used.

  This electron beam writing apparatus mainly includes a stage on which a sample on which a pattern is drawn is placed, a housing having this stage inside, and an electron beam generating device that is provided on the housing and emits an electron beam. A source and an electron optical column having an electron beam control system for forming an electron beam for drawing a desired pattern at a desired position on the sample.

  In the above-described electron beam drawing apparatus, the sample is radiated from the side surface of the chamber of the electron beam drawing apparatus, heat conduction from the stage on which the sample is placed, and the transport process until the sample is placed on the stage. Has a temperature distribution. As a result, the sample is complicatedly deformed due to the difference in thermal expansion.

  On the other hand, the irradiation position of the electron beam by the conventional electron beam drawing apparatus is highly controlled based on the measured value of the laser interferometer. However, this measured value does not detect and control the deformation of the sample due to heat. Therefore, when the sample is deformed by heat as described above, the irradiation position of the electron beam is shifted.

Therefore, a constant temperature container cooled by circulating cooling water inside is installed in the lower part of the electron optical column, and by bringing it close to the sample, the temperature of the constant temperature container is transferred to the sample, and the sample temperature There is known an electron beam lithography apparatus that achieves uniformization (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2003-195476 (paragraph 0020, FIG. 1, etc.)

  However, in contrast to the recent increase in accuracy of electron beam lithography apparatus, there is a problem that it is difficult to make the temperature distribution of the sample uniform with sufficiently high accuracy in the conventional electron beam lithography apparatus having a thermostatic container. is there.

  The above-mentioned problem is not limited to an electron beam lithography apparatus, but also applies to a charged beam lithography apparatus including an electron beam, an ion beam, etc., and it is difficult to make the temperature distribution of the sample uniform with sufficiently high accuracy. is there.

  Accordingly, an object of the present invention is to provide a charged beam drawing apparatus capable of suppressing the deformation of the sample by equalizing the temperature of the soaking plate with higher accuracy and performing drawing with higher accuracy. To do.

  A charged beam drawing apparatus according to the present invention includes a charged particle optical column that emits a charged beam, a heat equalizing plate formed at a lower portion of the charged particle optical column, and a first arranged along the circumference of the heat equalizing plate. A soaking unit, a soaking unit that is disposed along the first cooling pipe, and that has a second cooling pipe that flows in a direction opposite to the refrigerant that flows through the first cooling pipe, and the charged particle optical mirror. And a casing having an XY stage on which a sample is placed.

  In the charged beam drawing apparatus of the present invention, the refrigerant is introduced from the inflow portion of the first cooling pipe to the second cooling pipe through the folded portion, and is discharged from the discharge portion of the second cooling pipe. It is what.

  In the charged beam drawing apparatus of the present invention, it is preferable that the folded portion is provided in the vicinity of the inflow portion or the discharge portion.

  Further, the soaking unit in the charged beam drawing apparatus of the present invention may have a plurality of first cooling pipes and second cooling pipes.

  Here, the soaking plate in the charged beam drawing apparatus of the present invention is preferably formed of copper.

  ADVANTAGE OF THE INVENTION According to this invention, the charged beam drawing apparatus which can suppress the deformation | transformation of a sample by equalizing the temperature of a soaking plate with higher precision, and can perform drawing with higher precision can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. In the present embodiment, an electron beam drawing apparatus will be described as an example of a charged beam drawing apparatus.

  First, the electron beam drawing apparatus of this embodiment will be described with reference to FIG.

  FIG. 1 is a structural cross-sectional view schematically showing a configuration of an electron beam drawing apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the electron beam lithography apparatus 11 according to the present embodiment includes a housing 14 having an XY stage 13 on which a sample 12 is placed, and an upper portion of the housing 14. It has a gun (not shown) and an electron optical column 16 having an electron beam control system for forming an electron beam, and a heat equalizing unit 17 formed below the electron optical column 16. Here, the electron beam control system includes, for example, a coiled electromagnetic lens 15, first and second apertures (not shown) having a square opening or a keyhole-shaped opening.

  FIG. 2 is a perspective view showing the soaking unit 17. As shown in FIG. 2, the soaking unit 17 includes a soaking plate 19 in which an opening 18 through which an electron beam passes is formed in the center, and a small-diameter portion 20 formed along the circumference of the soaking plate 19. The large-diameter portion 22 is formed on the small-diameter portion 20 and has a cooling pipe 21 inside. Here, large diameter and small diameter mean large and small outer diameters. The large diameter portion 22 is provided with an inlet 23 and an outlet 24 for injecting and discharging a refrigerant for cooling the soaking plate into the soaking unit 17.

  FIG. 3 is a cross-sectional view of the large diameter portion 22 of the soaking unit 17 shown in FIG. As shown in FIG. 3, a refrigerant inlet 23 and a refrigerant outlet 24 are formed through the side wall 22 a of the large diameter portion 22. The cooling pipe 21 is formed by a single pipe having a folded portion 21 ′, and the inflow portion 21 in and the discharge portion 21 out at both ends are connected to the inflow port 23 and the discharge port 24, respectively. Here, the folded portion 21 ′ of the cooling pipe 21 refers to a place where the flow direction of the refrigerant flowing inside the cooling pipe 21 is reversed. Such a cooling pipe 21 is formed such that the folded portion 21 ′ is disposed in the vicinity of the discharge portion 21 out. That is, most of the cooling pipes 21 are arranged in a double manner along the large diameter portion 22, and are arranged in a single manner between the inflow portion 21in and the discharge portion 21out.

  In such an electron beam drawing apparatus 11, an electron beam emitted from an electron gun (not shown) formed above the electron optical column 16 is caused by a magnetic field generated by passing a current through the electromagnetic lens 15. The first and second apertures (not shown) are formed to have a desired shape by being deflected and passed to desired positions of the openings of the first and second apertures, and further controlled to be irradiated to the desired position of the sample 12. The Such electron beam irradiation is performed by measuring the position of the sample 12 with a laser interferometer (not shown) and moving the XY stage 13 based on the measured value, thereby forming a desired pattern.

  Here, the soaking unit 17 included in the electron beam lithography apparatus 11 of the present embodiment transfers the temperature of the soaking plate 19 to the sample 12 by causing the soaking plate 19 to be adjacent to the sample 12. The soaking plate 19 is made of, for example, copper or a metal containing copper. However, the soaking plate 19 is not limited to these, and any material having high thermal conductivity may be used. At this time, the refrigerant flows in from the inflow portion 21in of the cooling pipe 21 connected to the inlet 23 provided in the soaking plate 19, circulates in the cooling pipe 21, and is discharged from the discharge portion 21out. This refrigerant is, for example, water.

  The temperature of the refrigerant circulating through the cooling pipe 21 arranged in the soaking unit 17 increases as it circulates through the soaking plate 19 in the direction indicated by the arrow in FIG. For example, the refrigerant temperatures at eight locations (21a, 21b, 21c, 21d, 21e, 21f, 21g, 21h) shown in FIG. 20.143 ° C., 20.286 ° C., 20.429 ° C., 20.571 ° C., 20.714 ° C., 20.857 ° C., 21.000 ° C., and the temperature of the refrigerant at the position 21 a near the inflow portion 21 in; A difference of about 1.000 ° C. occurs with the temperature of the refrigerant at the position 21 h in the vicinity of the discharge portion 21 out.

  However, since the cooling pipe 21 is arranged so that the refrigerant makes one round along the circumference of the heat equalizing plate 19 and then turns back at the turn-back portion 21 ′ and makes one round in the opposite direction, each position of the heat equalizing plate 19 The average temperature of the refrigerant is about 20.500 ° C., which is almost the same. Furthermore, since the cooling pipe 21 is also arranged in a single manner between the inlet 23 and the outlet 24, the region between the inlet 23 and the outlet 24 in the soaking plate 19 is also cooled. Therefore, since the temperature of the soaking plate 19 is kept substantially the same, the sample 12 has almost the same temperature regardless of the position. Accordingly, since deformation of the sample 12 can be suppressed, it is possible to suppress deterioration in drawing accuracy due to deformation of the sample 12.

  Although the electron beam drawing apparatus 11 of the present embodiment has been described above, in the present invention, the cooling pipe 21 may be formed of a set of pipes in which the refrigerant circulating inside flows in opposite directions. It can be deformed.

  FIG. 4 shows a modification of the arrangement of the cooling pipes. As shown in FIG. 4, the cooling pipes 31 and 32 are composed of two pipes, and the cooling pipe 31 is arranged on the inner circumference along the large diameter portion 22, and the cooling pipe 32 is arranged on the outer circumference thereof. Yes. Further, inflow portions 31in and 32in and discharge portions 31out and 32out are formed at both ends of the two cooling pipes 31 and 32, respectively, and are connected to the inflow ports 33 and 33 ′ and the discharge ports 34 and 34 ′, respectively. . At this time, as indicated by the arrows in the figure, the same effects as described above can be obtained if the flow directions of the refrigerants flowing through the two cooling pipes 31 are opposite to each other. Further, although not shown, the cooling pipe shown in FIG. 3 or 4 may have a configuration in which a plurality of sets of pipes in which the refrigerant circulating inside flows in opposite directions are formed. Needless to say, the same effect as described above can be obtained even if the positions where the inlet and outlet of the cooling pipe are formed are opposite to each other.

  Moreover, although the refrigerant | coolant was water in the above-mentioned embodiment, the other fluid from which the endothermic effect is acquired may be sufficient, and the kind of refrigerant | coolant is not limited.

The electron beam drawing apparatus according to the present invention has been described above. However, the present invention is not limited to the above-described electron beam drawing apparatus, and can be variously applied without departing from the spirit of the present invention. For example, the present invention can be applied to an ion beam drawing apparatus that performs drawing by irradiating a mask substrate with an ion beam and a charged particle optical column included in a charged beam drawing apparatus including the ion beam drawing apparatus. . Here, the charged particle optical column corresponds to the electron optical column included in the electron beam drawing apparatus described above, and a charged particle generation source and a charged beam control system for controlling the charged beam are provided inside the column. It is what you have.

It is a structure sectional view showing the electron beam drawing apparatus of this embodiment. It is a perspective view which shows the soaking | uniform-heating unit which concerns on this embodiment. It is sectional drawing which shows the large diameter part of the soaking | uniform-heating unit shown in FIG. It is sectional drawing which shows the large diameter part of the soaking | uniform-heating unit which shows the modification of arrangement | positioning of a cooling pipe.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Electron beam drawing apparatus, 12 ... Sample, 13 ... XY stage, 14 ... Housing, 15 ... Electromagnetic lens, 16 ... Electro-optic lens barrel, 17 ... Uniformity Heat unit, 18 ... opening, 19 ... soaking plate, 20 ... small diameter part of soaking unit, 21, 31, 32 ... cooling pipe, 21 '... folding part of cooling pipe , 21in, 31in, 32in ... inflow part, 21out, 31out, 32out ... discharge part, 21a to 21h ... each position of the cooling pipe, 22 ... large diameter part of the soaking unit, 22a ... large diameter part Side walls, 23, 33, 33 '... inlet, 24, 34, 34' ... outlet.

Claims (5)

A charged particle optical column that emits a charged beam;
A soaking plate formed in a lower portion of the charged particle optical column; a first cooling pipe arranged along the circumference of the soaking plate; and a first cooling pipe arranged along the first cooling pipe. A soaking unit having a second cooling pipe in which the refrigerant flows in a direction opposite to the refrigerant flowing in the cooling pipe;
A housing having an XY stage for placing the sample therein, the charged particle optical column at the top;
A charged beam drawing apparatus comprising:   The said refrigerant | coolant is introduce | transduced into the said 2nd cooling pipe through the return part from the inflow part of the said 1st cooling pipe, and is discharged | emitted from the discharge part of the said 2nd cooling pipe. Charged beam lithography system.   The charged beam drawing apparatus according to claim 2, wherein the folding portion is provided in proximity to the inflow portion or the discharge portion.   4. The charged beam drawing apparatus according to claim 1, wherein the soaking unit includes a plurality of the first cooling pipes and the second cooling pipes. 5.   The charged beam drawing apparatus according to claim 1, wherein the soaking plate is made of copper.

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