JP5631068B2 - Charged particle beam lithography system - Google Patents

Description

  The present invention relates to a charged particle beam drawing apparatus for drawing a graphic pattern on a sample.

  Lithography technology is used to form a desired circuit pattern on a semiconductor device. In lithography technology, a pattern is transferred using an original pattern called a mask (reticle). In order to manufacture a highly accurate reticle, an electron beam (electron beam) drawing technique having excellent resolution is used.

  Such an electron beam drawing apparatus includes a deflection electrode for controlling the trajectory and irradiation position of an electron beam by an electric field when the mask is irradiated with an electron beam generated by an electron beam source (electron gun). Yes. A deflection amplifier for applying a voltage to the deflection electrode is provided (see Patent Document 1).

  An electron beam drawing apparatus is required to increase the drawing speed in order to improve productivity. In order to increase the writing speed, it is required to shorten the establishment time of the beam position on the sample. Further, since shortening the time required for maintenance also contributes to improvement in productivity, improvement in maintenance is also required at the same time.

JP 2007-142100 A

  An object of the present invention is to provide a charged particle beam drawing apparatus in which writing speed is increased and maintenance is improved.

A charged particle beam drawing apparatus according to one embodiment of the present invention includes a vacuum container capable of maintaining an inside in a vacuum atmosphere, a lens barrel that covers the vacuum container, and a charged particle that is provided at one end of the vacuum container and generates charged particles. A radiation source, a deflection electrode provided in the vacuum vessel, for controlling a trajectory of charged particles generated in the charged particle beam source, and provided outside the vacuum vessel, at least a part being in the lens barrel, A circuit board; a shield case that houses the circuit board; a heat dissipation member that is in surface contact with the shield case; detachable from the vacuum vessel; and a deflection amplifier that applies a voltage to the deflection electrode; provided outside the vacuum vessel, a connecting portion for electrically connecting said deflection amplifier and the deflection electrode, and a guide portion for said deflection amplifier supported upon removable to facilitate detachment of the deflection amplifier, wherein Provided outside the cylinder, characterized in that it comprises a cooler in contact with the heat radiating member.

  In the charged particle beam drawing apparatus according to the above aspect, it is desirable that the heat dissipation member is a heat pipe.

  In the charged particle beam drawing apparatus of the above aspect, it is desirable that the connection portion is provided on the side wall of the vacuum vessel, and the deflection amplifier and the deflection electrode are connected outside the vacuum vessel without going through the power cable.

  In the charged particle beam drawing apparatus of the above aspect, the distance between the deflection amplifier and the deflection electrode is desirably 20 cm or less.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the charged particle beam drawing apparatus with which the drawing speed was increased and the maintenance property was improved.

It is a schematic block diagram of the electron beam drawing apparatus of embodiment. It is sectional drawing perpendicular | vertical to the extending | stretching direction of the lens-barrel of the deflector part of embodiment. It is sectional drawing parallel to the expansion | extension direction of the lens-barrel of the deflector part of embodiment. It is detail drawing of the cross section parallel to the extension direction of the lens-barrel of the deflector part of embodiment. It is explanatory drawing of the effect | action and effect of embodiment. It is explanatory drawing of the effect | action and effect of embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. Hereinafter, in the embodiment, a configuration using an electron beam will be described as an example of a charged particle beam. However, the charged particle beam is not limited to the electron beam, and may be a beam using charged particles such as an ion beam. In the embodiment, a variable shaped electron beam drawing apparatus will be described as an example of the electron beam drawing apparatus.

  Further, in the present specification, the “power cable” means a conductive cable, such as a coaxial cable or a copper wire.

  The charged particle beam drawing apparatus according to the embodiment includes a vacuum container capable of maintaining the inside in a vacuum atmosphere, a charged particle beam source that generates charged particles provided at one end of the vacuum container, and a charged container that is provided in the vacuum container. A deflection electrode that controls the trajectory, irradiation position, etc. of charged particles generated by a particle beam source, a deflection amplifier that is provided outside the vacuum vessel, is detachable from the vacuum vessel, and applies a voltage to the deflection electrode, and the outside of the vacuum vessel And a guide part for electrically connecting the deflection electrode and the deflection amplifier, and a guide part for supporting the deflection amplifier when attaching and detaching and facilitating attachment and detachment of the deflection amplifier.

  Hereinafter, an electron beam drawing apparatus will be described as an example of the charged particle beam drawing apparatus as described above. Therefore, the charged particles are electrons, and the charged particle beam source is an electron beam source (electron gun).

  The charged particle beam drawing apparatus according to the present embodiment has the above-described configuration, so that the distance between the deflection electrode and the deflection amplifier can be reduced. Therefore, it is possible to suppress ringing caused by impedance mismatching at both ends of the power cable and shorten the beam position establishment time. In addition, maintenance can be improved by making the deflection amplifier easily detachable. Therefore, the productivity of the charged particle beam drawing apparatus can be improved.

  FIG. 1 is a schematic configuration diagram of an electron beam drawing apparatus according to the present embodiment. The electron beam drawing apparatus 100 is an example of a charged particle beam drawing apparatus. The electron beam drawing apparatus 100 includes a drawing unit 102 and a control unit 104 that controls the drawing operation of the drawing unit 102. The electron beam drawing apparatus 100 draws a predetermined pattern on the sample 110.

  A stage 112 on which the sample 110 is placed is accommodated in the sample chamber 108 of the drawing unit 102. The stage 112 is driven by the control unit 104 in the X direction (left and right direction on the paper surface), the Y direction (front and back direction on the paper surface), and the Z direction. As the sample 110, for example, there is an exposure mask for transferring a pattern to a wafer on which a semiconductor device is formed. Further, this mask includes, for example, mask blanks on which no pattern is formed.

  Above the sample chamber 108, an electron beam optical system is installed in a lens barrel 114. The electron beam optical system includes a vacuum vessel 115 capable of maintaining the inside in a vacuum atmosphere, an electron gun 116 that is provided at one end (upper end in FIG. 1) of the vacuum vessel 115 and generates electrons, for example, various electron lenses configured by exciting coils. 118, 120, 122, 124, 126, blanking deflector 128, beam size variable deflector 130, beam scanning main deflector 132, beam scanning sub deflector 134, and variable shaped beam. For this purpose, the first aperture 136 and the second aperture 138 are formed for beam shaping.

  Each of the blanking deflector 128, the beam size changing deflector 130, the beam scanning main deflector 132, and the beam scanning sub deflector 134 is provided in the vacuum vessel 115, and an electron gun is provided. A deflection electrode is provided for controlling the trajectory, irradiation position, and the like of electrons generated at 116. Further, the electron beam optical system is provided outside the vacuum vessel 115 and is detachable from the vacuum vessel 115. The above-described blanking deflector 128, beam size variable deflector 130, and beam scanning main deflector 132 are provided. Each of the sub-deflectors 134 for beam scanning is provided with deflection amplifiers 228, 230, 232, 234 for applying a voltage.

  The control unit 104 includes, for example, a storage unit that stores drawing data, a shot data generation unit that generates shot data from the drawing data, a control circuit, and the like. The control unit 104 controls the various electronic lenses 118, 120, 122, 124, 126 and the deflection amplifiers 228, 230, 232, 234.

  FIG. 2 is a cross-sectional view perpendicular to the extending direction of the lens barrel of the deflector portion of the present embodiment. Here, the cross section of the main deflector 132 for beam scanning will be described as an example. As shown in FIG. 1, the electron beam drawing apparatus includes eight main deflectors 132 in a vacuum container 115. The main deflector 132 has a deflection electrode 132a. Further, a deflection amplifier 232 corresponding to each main deflector 132 is provided outside the vacuum vessel 115 and at least partially inside the lens barrel 114.

  Further, a connection portion 250 provided outside the vacuum vessel 115 and electrically connecting the deflection electrode 132 a and the deflection amplifier 232 is provided on the side wall of the vacuum vessel 115. In addition, the deflection electrode 132a and the connection portion 250 are connected in the vacuum vessel 115 by, for example, a power cable 132b of a coaxial cable. However, the deflection amplifier 232 and the deflection electrode 132a are connected outside the vacuum vessel 115 without using a power cable.

  As shown in FIG. 2, the deflection amplifier 232 is provided outside the vacuum container 115 and is detachable from the vacuum container 115. For example, the connection unit 250 includes a vacuum vessel side connector 250a provided on the side wall of the vacuum vessel 115 and a deflection amplifier side connector 250b. The electrical connection in the connection portion 250 may be performed by a connector as described above, and for example, a spring pin or the like may be used. In addition, it is desirable that the deflection amplifier be thin and elongated in order to save space in the lens barrel.

  FIG. 3 is a cross-sectional view parallel to the extending direction of the barrel of the deflector portion of the present embodiment. Here, as in FIG. 2, a cross section of the main deflector 132 for beam scanning will be described as an example. FIG. 3A shows a state where the deflection amplifier is attached to the vacuum vessel, and FIG. 3B shows a state where the deflection amplifier is removed from the vacuum vessel.

  As shown in FIG. 3, the electron beam drawing apparatus includes a guide unit 260 that supports the deflection amplifier 232 during attachment and detachment and facilitates attachment / detachment of the deflection amplifier 232. The guide unit 260 is configured to guide the deflection amplifier 232 when the deflection amplifier 232 is attached, and to connect the vacuum vessel side connector 250a and the deflection amplifier side connector 250b only by, for example, pushing the deflection amplifier. This is a so-called slot-in configuration. Even when the deflection amplifier 232 is removed, since the guide portion 260 supports the deflection amplifier 232, the deflection amplifier 232 can be easily pulled out.

  The guide portion 260 may be, for example, a flat plate shape, a rail shape, or other shapes. The material may be a metal or a resin. Further, it may be provided at a desired position such as the bottom surface side, the top surface side, or the side surface side of the deflection amplifier as required. Further, the guide portion 260 may be fixed to the lens barrel 114, fixed to the vacuum vessel 115, or fixed to both.

  The deflection amplifier 232 that can be attached to and detached from the vacuum vessel 115 is connected to the control unit 104 (FIG. 1) by a power cable 270 that is a coaxial cable, for example, and a control signal is input to the deflection amplifier 232 from the power cable 270. Is done.

  FIG. 4 is a detailed view of a cross section parallel to the extending direction of the lens barrel of the deflector portion of the present embodiment. The deflection amplifier 232 includes a circuit board 304 such as a printed board on which an electronic component 302 such as a semiconductor or a diode is mounted. An analog amplifier circuit (amplifier circuit) for amplifying at least a signal to be applied to the deflector 132 is formed on the circuit board 304. A digital analog converter (DAC) circuit in front of the amplifier circuit may be formed on the circuit board 304.

  At least the circuit board 304 part is housed in the shield case 306. The shield case 306 prevents an external electric field or magnetic field from affecting the operation of the deflection amplifier, and is made of, for example, a metal such as Fe, Cu, or Al. On the vacuum container 115 side of the shield case 306, a deflection amplifier side connector 250b is provided. Further, on the opposite side, a take-out portion for the power cable 270 and a front panel 308 are provided.

  As described above, the electron beam drawing apparatus includes the guide unit 260 that supports the deflection amplifier 232 during attachment / detachment, and facilitates attachment / detachment of the deflection amplifier 232. Here, the guide portion 260 is fixed to both the lens barrel 114 and the vacuum vessel 115.

  Further, the deflection amplifier 232 includes a heat radiating member 310 for radiating heat generated by the electronic components on the circuit board 304. The heat radiating member 310 is in direct contact with the circuit board 304 or the shield case directly or indirectly. In order to efficiently conduct heat to the cooler 312 provided outside the lens barrel 114, the heat radiating member 310 is preferably a material having high thermal conductivity in the surface direction, that is, the direction perpendicular to the surface (the horizontal direction in FIG. 4). . For example, a heat pipe, a graphite sheet, or the like can be used. In particular, the heat pipe is preferable because of its high thermal conductivity. Moreover, it is desirable that the heat radiation member 310 has a thin shape in order to save space in the lens barrel.

  The cooler 312 radiates heat transmitted by the heat radiating member 310 by circulating the cooling water. For example, it is preferable to provide a mechanism for improving the adhesion between the cooler 312 and the heat dissipation member 310, for example, a mechanism for pressing the cooler 312 and the heat dissipation member 310 from above and below.

  In FIG. 1 thru | or FIG. 4, in describing embodiment, description is abbreviate | omitted except a required component. Needless to say, the electron beam lithography apparatus may normally include other necessary configurations.

  5 and 6 are explanatory diagrams of the operation and effect of the present embodiment. As shown in FIG. 5, the deflection of the electron beam emitted from the electron gun is controlled by controlling the electric field between the deflection electrodes with a voltage applied to the deflection electrodes by a deflection amplifier. Thereby, the position of the electron beam on the sample is changed to a desired position.

  However, for example, when the position of the electron beam is changed from position 1 to position 2, establishment time is required until the position is stabilized. This establishment time depends on the distance from the deflection amplifier to the deflection electrode.

  FIG. 6 is a diagram for explaining the relationship between the distance from the deflection amplifier to the deflection electrode and the establishment time. FIG. 6A shows a case where the distance from the deflection amplifier to the deflection electrode is relatively long, and FIG. 6B shows a case where the distance from the deflection amplifier to the deflection electrode is relatively short.

  For example, if the deflection amplifier and the deflection electrode are connected by a coaxial cable, reflection occurs at both ends of the coaxial cable due to impedance mismatching, and ringing occurs, as shown in FIG. The establishment time from 1 to position 2 is stabilized. On the other hand, when the length of the coaxial cable is sufficiently short, ringing is suppressed and the establishment time is shortened as shown in FIG.

In order to increase the drawing speed, the establishment time until the position is stabilized is required to be about 10 ns. For example, if the transfer characteristics of the deflection amplifier is a primary delay, settling time t _s, the relationship between the error rate r _e, and rise time t _r,
t _r = 2.2 · t _s / (− ln (r _e )) (Equation 1)
It is represented by

Here, when t _s = 10 ns and r _e = 0.01%, t _r = 2.4 ns. Reflecting the coaxial cable delay time exceeds 1/2 of the rise time t _r is remarkable. Therefore, when a coaxial cable having a wavelength shortening rate of 67% determined by the relative dielectric constant of the insulator of the coaxial cable is used, the allowable length of the coaxial cable is 24 cm or less.

  Therefore, in order to realize the establishment time of about 10 ns, the distance from the deflection amplifier to the deflection electrode is preferably 20 cm or less in consideration of various margins, and more preferably 10 cm or less.

  According to the present embodiment, since the deflection amplifier and the deflection electrode are connected outside the vacuum vessel without going through the power cable, it is easy to reduce the distance from the deflection amplifier to the deflection electrode.

  The distance from the deflection amplifier to the deflection electrode is strictly the distance of the electrical wiring from the output terminal of the amplifier circuit in the deflection amplifier to the end of the deflection electrode.

  In general, in a lens barrel, for example, a large number of components such as an excitation coil of an electronic lens are arranged in contact with a vacuum vessel. For this reason, even if an attempt is made to provide the deflection amplifier in contact with the vacuum vessel in order to shorten the distance between the deflection amplifier and the deflection electrode, it is difficult to provide a sufficient space to easily remove the deflection amplifier for maintenance. . Therefore, every time maintenance is performed, operations such as disassembling the lens barrel and removing and reassembling the components in the lens barrel cause a decrease in productivity. According to this embodiment, for example, by using a slot-in type detachable deflection amplifier, maintenance of the deflection amplifier is facilitated and productivity is improved.

  In this embodiment, a heat radiating member is incorporated in a detachable deflection amplifier. For this reason, good heat dissipation is enabled without depending on the insertion state of the deflection amplifier. When the heat radiating member is not incorporated in the deflection amplifier, heat dissipation is ensured by bringing the inserted deflection amplifier into contact with a cooler or a heat radiating member provided in the lens barrel. However, for example, even when the inserted deflection amplifier is slightly inclined, sufficient surface contact with the cooler and the heat radiating member cannot be ensured.

  In addition, it is difficult to provide a mechanism that ensures thermal conductivity by reliably bringing the deflection amplifier into surface contact with the cooler and the heat radiating member in a state where the deflection amplifier is inserted in a lens barrel having no space. According to the present embodiment, heat is transferred to the outside of the lens barrel by the heat radiating member incorporated in the deflection amplifier, and a reliable surface contact is ensured to contact the cooler outside the lens barrel having a sufficient space. Becomes easier.

  Furthermore, space-saving in the lens barrel can be realized by providing the cooler outside the lens barrel.

  The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples.

  For example, in the embodiment, the deflection amplifier is described as having a heat dissipation member. In order to improve the heat dissipation characteristics as described above, this form is desirable, but even with a configuration in which the heat dissipation member is not incorporated in the deflection amplifier, it is possible to increase the drawing speed and maintainability of the charged particle beam drawing apparatus. Improvements can be realized.

  Further, for example, in the embodiment, it is described that the connection portion is provided on the side wall of the vacuum vessel, and the deflection amplifier and the deflection electrode are connected outside the vacuum vessel without going through the power cable. As described above, this mode is desirable to reduce the distance between the deflection amplifier and the deflection electrode. However, even if the connection portion is separated from the side wall or the power cable is interposed between them, the desired shape can be obtained. If a sufficient distance for realizing the establishment time can be realized, it is possible to increase the drawing speed and maintainability of the charged particle beam drawing apparatus.

  Further, regarding the lens barrel, it is not always necessary to be an integral case, and it may be understood that it simply means the outer shape of a member attached around the vacuum vessel.

  Further, although the mask has been described as an example of the substrate, the present invention can also be applied to a case where a semiconductor wafer is used as a substrate and a pattern is directly drawn on the wafer by an electron beam.

  In addition, although descriptions are omitted for parts and the like that are not directly required for the description of the present invention, such as a device configuration and a control method, a required device configuration and a control method can be appropriately selected and used. In addition, all charged particle beam drawing apparatuses that include the elements of the present invention and whose design can be appropriately changed by those skilled in the art are included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Electron beam drawing apparatus 102 Drawing part 104 Control part 106 Storage part 114 Barrel 115 Vacuum container 116 Electron gun 132 Deflector 132a Deflection electrode 132b Power cable 232 Deflection amplifier 250 Connection part 260 Guide part 270 Power cable

Claims (4)

A vacuum container capable of maintaining the interior in a vacuum atmosphere;
A lens barrel covering the vacuum vessel;
A charged particle beam source provided at one end of the vacuum vessel for generating charged particles;
A deflection electrode provided in the vacuum vessel and controlling the trajectory of charged particles generated by the charged particle beam source;
Provided outside the vacuum vessel, at least part of which is in the lens barrel, and includes a circuit board, a shield case that houses the circuit board, and a heat dissipation member that is in surface contact with the shield case, the vacuum A deflection amplifier that is detachable from the container and applies a voltage to the deflection electrode;
A connection portion provided outside the vacuum vessel, for electrically connecting the deflection electrode and the deflection amplifier;
A guide unit that supports the deflection amplifier at the time of attachment and detachment and facilitates attachment and detachment of the deflection amplifier;
A cooler provided outside the lens barrel and in contact with the heat dissipation member;
A charged particle beam drawing apparatus comprising: A charged particle beam drawing apparatus according to claim 1, wherein the heat dissipation member is a heat pipe. The said connection part is provided in the side wall of the said vacuum vessel, and the said deflection | deviation amplifier and the said deflection | deviation electrode are connected without the power cable outside the said vacuum vessel, The Claim 1 or Claim 2 characterized by the above-mentioned. Charged particle beam lithography system. The charged particle beam drawing apparatus according to any one of claims 1 to 3 , wherein a distance between the deflection amplifier and the deflection electrode is 20 cm or less.

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