JP3834271B2 - Multi-charged beam lens, charged particle beam exposure apparatus and device manufacturing method using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electron optical system used in an exposure apparatus using a charged particle beam such as an electron beam, and more particularly to a multi-charged beam lens in an electron optical system array in which a plurality of electron optical systems are arranged. A charged particle beam (also referred to as a charged beam) is a general term for an electron beam or an ion beam.
[0002]
[Prior art]
In the production of semiconductor devices, electron beam exposure technology has been spotlighted as a promising candidate for lithography that enables fine pattern exposure of 0.1 μm or less, and there are several methods. For example, there is a variable rectangular beam method that draws a pattern by so-called one-stroke drawing. However, this has a low throughput and has many problems as an exposure machine for mass production. In order to improve the throughput, a figure batch exposure method has been proposed in which a pattern formed on a stencil mask is reduced and transferred. This method is advantageous for simple patterns with many repetitions, but random patterns such as a logic wiring layer have many problems in terms of throughput, and greatly impede productivity improvement in practical use.
[0003]
On the other hand, a multi-beam system that simultaneously draws a pattern with a plurality of electron beams without using a mask has been proposed. This multi-beam system eliminates the need for physical mask production and replacement, and has many advantages for practical use. In the multi-beam system, what is important in making the electron beam multi-directional is the number of arrays of electron lenses used for this. This is because the number of beams is determined by the number of arrays of electron lenses that can be arranged inside the electron beam exposure apparatus, which is a major factor in determining the throughput. For this reason, one of the keys to improving the performance of the multi-beam type exposure apparatus is how to reduce the size while improving the performance of the electron lens.
[0004]
Electron lenses include an electromagnetic type and an electrostatic type, and the electrostatic type is easier to configure than the electromagnetic type without the need for a coil core or the like, and is advantageous for downsizing. There are the following documents as main prior art relating to miniaturization of an electrostatic electron lens (electrostatic lens).
[0005]
AD Feinerman et al. (J. Vac. Sci. Technol. A 10 (4), p611, 1992) developed an electrostatic monolithic technique using micromechanics technology using V-grooves fabricated by crystal anisotropic etching of fiber and Si. Disclosed is the formation of a three-dimensional structure consisting of three electrodes as lenses. Si is provided with a membrane frame, a membrane, and an opening through which the electron beam passes. In addition, KY Lee et al. (J. Vac. Sci. Technol. B12 (6), p3425, 1994) have developed a structure in which Si and Pyrex (registered trademark) glass are bonded in a plurality of layers using an anodic bonding method. Disclosed is a microcolumn electron lens that is aligned with high accuracy. Sasaki (J. Vac. Sci. Technol. 19, 963 (1981)) discloses a configuration in which an Einzel lens array is formed by three electrodes having a lens aperture array.
[0006]
[Problems to be solved by the invention]
According to the above conventional example, the electron lens has a structure in which a plurality of electrodes are stacked with an insulator interposed therebetween. However, since the insulator constituting the electron lens in the conventional example is exposed from the electron beam, the insulator is easily charged. That is, an electric field is generated by the electric charge generated on the insulator surface, and there is a big problem of a so-called charge-up problem that the electron beam trajectory becomes unstable due to the electric field, or the aberration is increased and the beam is blurred. As a solution to this problem, there is a method of preventing charge-up by making the insulator invisible from the beam. However, this method is limited to single-beam lenses and uses a semiconductor process. In the multi-charged beam lens produced in this way, the charge-up of the insulator was still a big problem.
[0007]
The present invention starts from recognizing the above-mentioned problems of the prior art, and its main purpose is to improve it.
One of the specific objectives is to provide a multi-charged beam lens that realizes various conditions such as miniaturization and high accuracy at a high level. More specifically, an object of the present invention is to provide an excellent multi-charged beam lens in which the influence on the electron beam due to charge-up is reduced. Furthermore, it aims at providing the highly accurate exposure apparatus using this, the device manufacturing method excellent in productivity, a semiconductor device production factory, etc.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, a multi-charged beam lens according to the present invention comprises the following arrangement. That is,
A multi-charged beam lens configured by laminating a plurality of electrodes having a charged beam passage region provided with a plurality of charged beam openings in an optical axis direction of the charged beam through an insulator,
In each electrode pair sandwiching the insulator,
An opening provided between the charged beam passage region and the insulator on a surface of at least one electrode facing the other electrode;
A conductive shield provided between the charged beam passing region and the insulator is provided, which penetrates into the opening and does not contact at least the electrode having the opening.
[0009]
Moreover, according to the present invention,
A charged particle source emitting a charged particle beam;
A correction electron optical system including the multi-charged beam lens and forming a plurality of intermediate images of the charged particle source;
A projection electron optical system for reducing and projecting the plurality of intermediate images onto a wafer;
There is provided a charged particle beam exposure apparatus comprising a deflector that deflects the plurality of intermediate images projected onto the wafer so as to move on the wafer.
[0010]
Furthermore, according to the present invention, a device manufacturing method using a charged particle beam exposure apparatus is provided.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.
[0012]
[First Embodiment]
<Description of components of electron beam exposure apparatus>
First, an electron beam exposure apparatus to which the multi-charged beam lens of the present invention can be applied will be described.
[0013]
FIG. 10 is a schematic view of the main part of the electron beam exposure apparatus according to the present embodiment. In FIG. 10, reference numeral 1 denotes an electron gun, which includes a cathode 1a, a grid 1b, and an anode 1c. In the electron gun 1, electrons emitted from the cathode 1a form a crossover image between the grid 1b and the anode 1c (hereinafter, this crossover image is referred to as an electron source).
[0014]
The electrons emitted from the electron gun 1 become a substantially parallel electron beam by the condenser lens 2 whose front focal position is at the electron source position. The condenser lens 2 of the present embodiment has two sets (21, 22) of unipotential lenses composed of three aperture electrodes. The substantially parallel electron beam obtained by the condenser lens 2 enters the correction electron optical system 3. The correction electron optical system 3 includes an aperture array, a blanker array, a multi-charged beam lens as one embodiment of the present invention, an element electron optical system array unit, and a stopper array. Details of the correction electron optical system 3 will be described later.
[0015]
The correction electron optical system 3 forms a plurality of intermediate images of the light source, and each intermediate image is reduced and projected by a reduction electron optical system 4 described later to form a light source image on the wafer 5. At this time, the correction electron optical system 3 forms a plurality of intermediate images so that the interval between the light source images on the wafer 5 is an integral multiple of the size of the light source image. Further, the correction electron optical system 3 varies the position of each intermediate image in the optical axis direction according to the field curvature of the reduction electron optical system 4, and each intermediate image is reduced and projected onto the wafer 5 by the reduction electron optical system 4. Aberrations that occur during the correction are corrected in advance.
[0016]
The reduction electron optical system 4 includes two sets of symmetric magnetic tablets, and each symmetric magnetic tablet includes a first projection lens 41 (43) and a second projection lens 42 (44). When the focal length of the first projection lens 41 (43) is f1, and the focal length of the second projection lens 42 (44) is f2, the distance between the two lenses is f1 + f2. The object point on the optical axis AX is at the focal position of the first projection lens 41 (43), and the image point is connected to the focal point of the second projection lens 42 (44). This image is reduced to -f2 / f1. In addition, since the two lens magnetic fields are determined so as to act in opposite directions, theoretically, the five aberrations of spherical aberration, isotropic astigmatism, isotropic coma aberration, field curvature aberration, and axial chromatic aberration are determined. Except for aberrations, other Seidel aberrations and chromatic aberrations related to rotation and magnification are canceled out.
[0017]
A deflector 6 deflects a plurality of electron beams from the correction electron optical system 3 to displace a plurality of light source images on the wafer 5 by substantially the same amount of displacement in the X and Y directions. Although not shown, the deflector 6 includes a main deflector used when the deflection width is wide and a sub-deflector used when the deflection width is narrow. The main deflector is an electromagnetic deflector, and the sub deflector is an electrostatic deflector.
[0018]
Reference numeral 7 denotes a dynamic focus coil, which corrects the focus position shift of the light source image due to deflection aberration generated when the deflector 6 is operated. Reference numeral 8 denotes a dynamic stig coil which, like the dynamic focus coil 7, corrects astigmatism of deflection aberration caused by deflection.
[0019]
Reference numeral 9 denotes a θ-Z stage on which a wafer is placed and can move in the optical axis AX (Z-axis) direction and the rotation direction around the Z-axis. A stage reference plate 10 and a Faraday cup 13 are fixed to the θ-Z stage 9. The Faraday cup 13 detects the charge amount of the light source image formed by the electron beam from the correction electron optical system 3. Reference numeral 11 denotes an XY stage, which is a stage on which the θ-Z stage 9 is mounted and is movable in the XY direction orthogonal to the optical axis AX (Z axis). A reflected electron detector 12 detects reflected electrons generated when the mark on the stage reference plate 10 is irradiated with an electron beam.
[0020]
Next, the correction electron optical system 3 will be described with reference to FIG. FIG. 11A is a view of the correction electron optical system 3 viewed from the electron gun 1 side, and FIG. 11B is a cross-sectional view taken along line AA ′ of FIG.
[0021]
As described above, the correction electron optical system 3 includes the aperture array AA, blanker array BA, multi-charged beam lens ML, element electron optical system array unit LAU (ordered from the electron gun 1 side) along the optical axis AX. LA1 to LA4) and a stopper array SA.
[0022]
The aperture array AA has a plurality of openings formed in a substrate, and divides a substantially parallel electron beam from the condenser lens 2 into a plurality of electron beams. The blanker array BA is formed by forming a plurality of deflecting means for individually deflecting a plurality of electron beams divided by the aperture array AA on a single substrate. The details of one of the deflecting means are shown in FIG. The substrate 31 has an opening AP. A blanking electrode 32 is composed of a pair of electrodes sandwiching the opening AP and has a deflection function. Further, wiring (W) for individually turning on / off the blanking electrode 32 is formed on the substrate 31.
[0023]
Returning to FIG. 11, the multi-charged beam lens ML is used in the correction electron optical system 3 to increase the charged beam convergence effect. The multi-charged beam lens ML of the present embodiment has the above-described charge-up countermeasures, and details of the configuration will be described later.
[0024]
The element electron optical system array unit LAU is an electron lens array formed by two-dimensionally arranging a plurality of electron lenses in the same plane. The first electron optical system array LA1, the second electron optical system array LA2, and the third electron An optical system array LA3 and a fourth electron optical system array LA4 are included.
[0025]
FIG. 13 is a diagram illustrating the first electron optical system array LA1. The first electron lens array LA1 is a multi-electrostatic lens composed of three pieces of an upper electrode UE, an intermediate electrode CE, and a lower electrode LE in which a plurality of openings are arranged, and one upper, middle, and lower electrode arranged in the direction of the optical axis AX. One electron lens EL1, ie, a so-called unipotential lens is formed. All the upper and lower electrodes of each electron optical system are connected at the same potential and set to the same potential (in this embodiment, the acceleration potential of the electron beam is set). The intermediate electrodes of the electron lenses arranged in the y direction are connected by a common wiring (W). As a result, the potentials of the intermediate electrodes of the electron lenses arranged in the y direction can be individually set by the LAU control circuit 112 described later, whereby the optical characteristics of the electron lenses arranged in the y direction are set to be substantially the same. , Optical characteristics (focal lengths) for the respective electron lens groups arranged in the y direction are individually set. In other words, the electronic lenses arranged in the y direction and set to the same optical characteristic (focal length) are grouped together, and the optical characteristics (focal length) of the group arranged in the x direction orthogonal to the y direction are individually set. ing.
[0026]
FIG. 14 is a diagram illustrating the second electron optical system array LA2. The second electron optical system array LA2 differs from the first electron optical system array LA1 in that the intermediate electrodes of the electron lenses arranged in the x direction are connected by a common wiring (W). As a result, the potential of each intermediate electrode of the electron lenses arranged in the x direction can be individually set by the LAU control circuit 112 described later, and the optical characteristics of the electron lenses arranged in the x direction are set to be substantially the same. The optical characteristics (focal length) for each group of electron lenses arranged in the direction are individually set. In other words, the electronic lenses arranged in the x direction and set to the same optical characteristic (focal length) are set as one group, and the optical characteristics (focal length) of the group arranged in the y direction are individually set.
[0027]
Since the third electron optical system array LA3 is the same as the first electron optical system array LA1, and the fourth electron optical system array LA4 is the same as the second electron optical system array LA2, their description is omitted. To do.
[0028]
Next, the effect of the electron beam received by the correction electron optical system 3 described above will be described with reference to FIG.
[0029]
The electron beams EB1 and EB2 divided by the aperture array AA are incident on the element electron optical system array unit LAU via different blanking electrodes. The electron beam EB1 is an electron lens EL11 of the first electron optical system array LA1, an electron lens EL21 of the second electron optical system array LA2, an electron lens EL31 of the third electron optical system array LA3, and an electron lens of the fourth electron optical system array LA4. An intermediate image img1 of the electron source is formed via EL41. On the other hand, the electron beam EB2 includes the electron lens EL12 of the first electron optical system array LA1, the electron lens EL22 of the second electron optical system array LA2, the electron lens EL32 of the third electron optical system array LA3, and the fourth electron optical system array LA4. The intermediate image img2 of the electron source is formed through the electron lens EL42.
[0030]
At this time, as described above, the electron lenses arranged in the x direction of the first and third electron optical system arrays LA1 and LA3 are set to have different focal lengths, and the second and fourth electron optical system arrays LA2 are arranged. The four electron lenses arranged in the x direction are set to have the same focal length. Furthermore, the combined focal length of the electron lens EL11, electron lens EL21, electron lens EL31, and electron lens EL41 through which the electron beam EB1 passes, and the electron lens EL12, electron lens EL22, electron lens EL32, and electron lens EL42 through which the electron beam EB2 passes. The focal lengths of the respective electron lenses are set so that the combined focal lengths are substantially equal. Thereby, the intermediate images img1 and img2 of the electron source are formed at substantially the same magnification. Further, in order to correct the field curvature that occurs when each intermediate image is reduced and projected onto the wafer 5 via the reduction electron optical system 4, the intermediate images img1 and img2 of the electron source according to the field curvature. Are formed in different positions in the optical axis AX direction.
[0031]
Further, when an electric field is applied to the passing blanking electrode, the electron beams EB1 and EB2 change their trajectories as shown by broken lines in the figure, and cannot pass through the openings corresponding to the respective electron beams of the stopper array SA. The beams EB1 and EB2 are blocked.
[0032]
Next, FIG. 16 shows a system configuration diagram of the present embodiment. The BA control circuit 111 is a control circuit that individually controls on / off of the blanking electrodes of the blanker array BA, and the LAU control circuit 112 is a control circuit that controls the electro-optical characteristics (focal length) of the lens array unit LAU. It is.
[0033]
The D_STIG control circuit 113 is a control circuit that controls the astigmatism of the reduction electron optical system 4 by controlling the dynamic stig coil 8. The D_FOCUS control circuit 114 is a control circuit that controls the focus of the reduction electron optical system 4 by controlling the dynamic focus coil 7. The deflection control circuit 115 is a control circuit that controls the deflector 6. The optical characteristic control circuit 116 is a control circuit that adjusts optical characteristics (magnification, distortion, rotational aberration, optical axis, etc.) of the reduction electron optical system 4.
[0034]
The stage drive control circuit 117 is a control circuit that drives and controls the XY stage 11 in cooperation with the laser interferometer LIM that drives and controls the θ-Z stage 9 and detects the position of the XY stage 10.
[0035]
The control system 120 controls each control circuit described above based on data from the memory 121 in which the drawing pattern is stored. The control system 120 is controlled by a CPU 123 that controls the entire electron beam exposure apparatus via an interface 122.
[0036]
<Explanation of exposure operation>
Next, with reference to FIG. 16, the exposure operation of the above-described electron beam exposure apparatus of the present embodiment will be described.
[0037]
The control system 120 commands the deflection control circuit 115 based on the exposure control data from the memory 121, deflects a plurality of electron beams by the deflector 6, and commands the BA control circuit 111 to pattern the wafer 5 to be exposed. In response to this, the blanking electrodes of the blanker array BA are individually turned on / off. At this time, the XY stage 11 continuously moves in the y direction, and the deflector 6 deflects the plurality of electron beams so that the plurality of electron beams follow the movement of the XY stage.
[0038]
Each electron beam scans and exposes a corresponding element exposure area (EF) on the wafer 5 as shown in FIG. Since the element exposure area (EF) of each electron beam is set so as to be adjacent in two dimensions, as a result, a subfield (SF) composed of a plurality of element exposure areas (EF) that are exposed simultaneously is formed. Exposed.
[0039]
The control system 120 instructs the deflection control circuit 115 to expose the next subfield (SF2) after exposing the subfield (SF1), and the deflector 6 causes the direction orthogonal to the stage scanning direction (y direction). A plurality of electron beams are deflected in the (x direction). At this time, the aberration when each electron beam is reduced and projected via the reduction electron optical system 4 also changes due to the change of the subfield due to the deflection. Therefore, the control system 120 instructs the LAU control circuit 112, the D_STIG control circuit 113, and the D_FOCUS control circuit 114 to set the lens array unit LAU, the dynamic stig coil 8, and the dynamic focus coil 7 so as to correct the changed aberration. adjust. Then, as described above, the subfield (SF2) is exposed by exposing the element exposure region (EF) to which each electron beam corresponds. Then, as shown in FIG. 17, the subfields (SF1 to SF6) are sequentially exposed to expose a pattern on the wafer 5. As a result, a main field (MF) composed of subfields (SF1 to SF6) arranged in a direction (x direction) orthogonal to the stage scanning direction (y direction) is exposed on the wafer 5.
[0040]
Further, after exposure of the main field 1 (MF1) shown in FIG. 17, the control system 122 instructs the deflection control circuit 115 to sequentially enter the main fields (MF2, MF3, MF4...) Aligned in the stage scanning direction (y direction). A plurality of electron beams are deflected and exposed. As a result, as shown in FIG. 17, a stripe (STRIPE1) composed of main fields (MF2, MF3, MF4...) Is exposed. Then, the XY stage 10 is stepped in the x direction to expose the next stripe (STRIPE2).
[0041]
<Multiple charged beam lens>
Next, the multi-charged beam lens ML according to the present embodiment will be described with reference to FIGS. FIG. 1 is a plan view of a multi-charged beam lens ML according to the first embodiment. FIG. 2A is a cross-sectional view taken along the line AA in FIG. FIG. 2B is a perspective view of a lens unit (charged beam passage region) located at the center of FIG. FIG. 3 is a BB arrow view of FIG.
[0042]
As shown in FIGS. 1 to 3, the multi-charged beam lens ML is formed by stacking three electrodes 201 a to 201 c via an insulator (optical fiber chip 212). That is, the multi-charged beam lens ML is formed by inserting a short cut optical fiber chip 212 into a fiber groove 213 provided in the upper electrode 212a, the middle electrode 212b, and the lower electrode 212c, and sandwiching it between the three electrodes. ing. The use of the fiber groove 213 increases the assembly accuracy of the lens. 211 is a large opening on the back surface of the electrode, which forms a membrane electrode indicated by 202.
[0043]
Each of the electrodes 201a to 201c is provided with a shield opening 203, and the conductive shield 204 is disposed through the opening without touching each electrode. In the present specification, the term “opening” in the shield opening is a generic term for a through-hole as shown in FIG. 2 and a recess as described later in FIG. As shown in FIG. 2A, the shield 204 is screwed to the clamp 205 (not shown). The clamp 205 supports the shield 204, and sandwiches the upper electrode 201a to the lower electrode 201c directly above and below the fiber 212, thereby assembling a multi-charged beam lens without adhesion or bonding. Since the position where the clamp 205 presses the electrode is directly above (or directly below) the fiber, distortion of each electrode can be suppressed, and assembly accuracy can be improved. In addition, such a mechanical clamp structure eliminates the need for bonding with an organic material such as an adhesive, and can maintain a high degree of vacuum. Usually, the lens action on the electron beam is obtained by setting the upper electrode 201a and the lower electrode 201c to the ground potential and applying a negative (or positive) voltage to the middle electrode 201b.
[0044]
As shown in FIG. 3, the shield 204 is positioned between the beam passage region 202 through which the charged beam passes and the fiber 212, and the fiber 212 is shielded from the charged beam by the shield 204. This prevents or reduces charge-up of the fiber 212, which is an insulator, and even if the insulator is charged up, the influence of the electric field on the charged beam is prevented or reduced, preventing beam blur and beam drift. Is possible.
[0045]
Next, a manufacturing method of the multi-charged beam lens having the above structure will be described with reference to FIG.
[0046]
An SOI substrate having a silicon dioxide layer (SiO2) between two silicon layers Si (1) and Si (2) is used, and a photoresist is applied to Si (1) and then patterned (FIG. 4 ( a)). Next, by Si-deep RIE, a beam opening (202a) through which the charged particle beam passes through the silicon layer Si (1) of the SOI substrate, a shield opening (203) through which the shield passes, and an optical fiber chip are placed between the electrodes. A fiber groove (213) for positioning is formed (FIG. 4B). Similarly, after applying a photoresist on the Si (2) surface, patterning is performed (FIG. 4C), and then by Si-deep RIE, a large electrode back surface opening (211), a shield opening (203), a fiber A groove for use (213) is formed (FIG. 4D). Finally, after etching SiO2 with buffered hydrofluoric acid, Cr is deposited as an adhesion layer, followed by Au for preventing charging (FIG. 4F).
[0047]
Next, assembly of a multi-charged beam lens using three electrodes prepared as described above will be described with reference to FIG.
[0048]
First, the fiber 212 is placed on the fiber groove 212 on the lower electrode 201c created according to FIG. 4 (FIG. 5A). Next, the middle electrode 201b is placed on the fiber groove 213 on the back surface of the middle electrode 201b so that the fiber 201 enters (FIG. 5B). Similarly, the fiber 212 is placed in the fiber groove 213 on the middle electrode 201b, and the upper electrode 201a is assembled (FIG. 5C). The conductive shield 204 is arranged through the upper, middle, and lower electrode shield openings 203 (FIG. 5D). Here, the conductive shield 24 may be a metal plate or a metal film formed on the insulator surface. However, the conductive shield 204 does not contact any of the electrodes 201a to 201c. Finally, the shield 204 is attached to the clamp 205 with screws (not shown), and the upper, middle, and lower electrodes (201a to 201c) are sandwiched and clamped by the clamp 205, thereby completing the assembly of the charged beam lens. (FIG. 5 (e)).
[0049]
In the multi-charged beam lens ML produced as described above, each electrode is produced by a semiconductor process, so that high accuracy and miniaturization are possible. In addition, since there is a conductive shield 204 maintained at the ground potential between the insulator (fiber 212) and the beam passage region 202 (the portion where the plurality of beam openings 202a are provided), the insulator (fiber 212) can be reduced. Even if the insulator is charged up, the conductive shield 204 has an effect of preventing the electric field caused by the charge on the surface of the insulator from affecting the beam. In addition, since mechanical materials such as adhesives are not used due to the mechanical clamp, there is an effect of preventing a discharge by suppressing a decrease in the degree of vacuum.
[0050]
In this embodiment, an optical fiber (SiO2) is used as an insulator, and a fiber groove 213 formed by a photolithography process is used for alignment between electrodes. However, the insulator is not an optical fiber, but other materials (for example, alumina). Ceramics). In addition, the alignment can be performed not only by the fiber and fiber groove described herein but also by checking the alignment between the electrodes using an alignment apparatus. In this case, the shape of the insulator that replaces the fiber between the electrodes can be a plate such as a rectangular parallelepiped. In the present embodiment, the electrostatic lens is configured with three electrodes. However, it is generally possible to configure the lens using n (n ≧ 3) electrodes. In addition, as shown in FIG. 1, the conductive shield 204 is substantially symmetric with respect to the optical axis of the charged particle beam, but the present invention is not limited to this. For example, the conductive shield may exist in all directions around the optical axis of the charged particle beam (for example, the conductive shield is formed in an annular shape).
[0051]
[Second Embodiment]
Next, a second embodiment will be described with reference to FIG. In the first embodiment, the conductive shield 204 that penetrates the shield opening 203 is provided. However, in the second embodiment, the configuration of a multi-charged beam lens in which each electrode is provided with a convex portion that functions as a conductive shield. explain. Note that an electron beam exposure apparatus to which the multi-charged beam lens of the second embodiment can be applied is the same as that of the first embodiment, and thus description thereof is omitted.
[0052]
FIG. 6 is a cross-sectional view of a multi-charged beam lens according to the second embodiment. In the multi-charged beam lens of the second embodiment, six electrodes (upper electrode 301a, first to fourth middle electrodes 301b to 301e, and lower electrode 301f) are used. In the figure, the upper electrode 301a has an opening 303a for a convex portion (shield) provided on the middle electrode 301b. A shield 304b which is a convex portion of the middle electrode 301b enters the opening 303a. Similarly, the middle electrode 301b is provided with a shield 304b and an opening 303b for shielding the middle electrode 301c. The shield 304c of the middle electrode 301c enters the opening 303b.
[0053]
Similarly, the middle electrode 301c is provided with a shield and has an opening for shielding provided in the middle electrode 301d. The shield of the middle electrode 301d enters the opening. The middle electrode 301d is provided with a shield and has an opening for shielding provided in the middle electrode 301e, and the shield of the middle electrode 301e enters the opening. Further, the middle electrode 301e is provided with a shield and has an opening for the shield 304f provided on the lower electrode 301f, and the shield 304f of the lower electrode 301f enters the opening. The lower electrode 301f is provided with a shield 304f. These shields prevent a rectangular parallelepiped insulator disposed between the electrodes from facing the charged beam passage region, that is, all straight paths connecting the charge beam passage region and the insulator are blocked. Therefore, charge-up is prevented or reduced.
[0054]
Next, a method of creating the middle electrode (301b) among the electrodes according to the second embodiment will be described with reference to FIG.
[0055]
An SOI substrate having a silicon dioxide layer (SiO2) between two silicon layers Si (1) and Si (2) is used and manufactured using a silicon semiconductor process. A beam opening 302a through which a charged particle beam passes and a shield opening 303b are respectively formed by dry etching in the silicon layer Si (1) of the SOI substrate (FIG. 7A). Using a similar process, the shield 304b is formed on the silicon layer Si (2) of the SOI substrate by dry etching (FIG. 7B). Subsequently, the silicon dioxide layer is removed by wet etching (FIG. 7C). Finally, a metal film is sputtered over the entire surface in order to provide conductivity (FIG. 7D). Other shaped electrodes can be produced in the same manner as the middle electrode described above.
[0056]
[Third Embodiment]
FIG. 8 is a cross-sectional view showing the configuration of the multi-charged beam lens according to the third embodiment. In the figure, shields 404a and 404c of the upper electrode 401a and the lower electrode 401c are provided as convex portions on the respective electrodes. The shields 404a and 404b shield the insulator 412 from the beam so that the insulator 412 cannot be seen from the charged beam passage region, and are abutted and in contact with each other in the shield opening 403b of the middle electrode 401b. According to this structure, in addition to preventing the charge-up in the insulator of the multi-charged beam lens, there is an effect that the multi-charged beam lens is made stronger and the assembly accuracy is improved.
[0057]
[Fourth Embodiment]
FIG. 9 is a sectional view of a multi-charged beam lens according to the fourth embodiment. The upper electrode 501a has a shield opening 503a into which the shield 504b of the middle electrode 501b enters. The middle electrode 501b is provided with a shield 504b, and a shield opening (concave portion) 503b is provided so as not to contact the shield 504c of the lower electrode 501c. According to this embodiment, it is possible to prevent or reduce the charge-up of the insulator 512 as in the above-described embodiments.
[0058]
[Other Embodiments]
Next, an embodiment of a device production method using the electron beam exposure apparatus described above will be described.
[0059]
FIG. 18 shows a flow of manufacturing a microdevice (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc.). In step 1 (circuit design), a semiconductor device circuit is designed. In step 2 (exposure control data creation), exposure control data for the exposure apparatus is created based on the designed circuit pattern. On the other hand, in step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the above-described charged particle beam exposure apparatus and the wafer to which the prepared exposure control data is input. The next step 5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer produced in step 4, and is a process such as an assembly process (dicing, bonding), a packaging process (chip encapsulation), or the like. including. In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test. Through these steps, the semiconductor device is completed and shipped (step 7).
[0060]
FIG. 19 shows a detailed flow of the wafer process. In step 11 (oxidation), the wafer surface is oxidized. In step 12 (CVD), an insulating film is formed on the wafer surface. In step 13 (electrode formation), an electrode is formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (resist process), a photosensitive agent is applied to the wafer. In step 16 (exposure), the circuit pattern is printed on the wafer by exposure using the above-described charged particle beam exposure apparatus. In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.
[0061]
By using the manufacturing method of the present embodiment, a highly integrated semiconductor device that has been difficult to manufacture can be manufactured at low cost.
[0062]
【The invention's effect】
As described above, according to the present invention, the influence on the electron beam due to the charge-up of the insulator in the multi-charged beam lens is eliminated. Therefore, it is possible to provide a multi-charged beam lens that realizes various conditions such as miniaturization and high accuracy at a high level. Then, it is possible to provide a high-precision exposure apparatus using this, a device manufacturing method with excellent productivity, a semiconductor device production factory, and the like.
[Brief description of the drawings]
FIG. 1 is a plan view of a multi-charged beam lens according to a first embodiment.
2A is a cross-sectional view taken along the line AA in FIG. 1, and FIG. 2B is a perspective view showing details of a charged beam passage region.
FIG. 3 is a view taken along arrow BB in FIG.
FIG. 4 is a diagram illustrating an electrode creation process according to the first embodiment.
FIG. 5 is a diagram illustrating assembly of a multi-charged beam lens according to the first embodiment.
FIG. 6 is a cross-sectional view of a multi-charged beam lens according to a second embodiment.
FIG. 7 is a diagram illustrating an electrode creation process according to a second embodiment.
FIG. 8 is a cross-sectional view of a multi-charged beam lens according to a third embodiment.
FIG. 9 is a cross-sectional view of a multi-charged beam lens according to a fourth embodiment.
FIG. 10 is a diagram illustrating the overall configuration of a multi-charged beam exposure apparatus.
FIG. 11 is a diagram illustrating details of a correction electron optical system.
12 is a diagram for explaining the details of BA of the blanker array shown in FIG.
13 is a diagram illustrating details of the first electron optical system array (LA1) shown in FIG. 11. FIG.
14 is a diagram illustrating details of the second electron optical system array (LA2) shown in FIG. 11. FIG.
FIG. 15 is a diagram for explaining the effect of an electron beam received by the correction electron optical system 3;
FIG. 16 is a diagram illustrating a system configuration of an electron beam exposure apparatus according to an embodiment.
FIG. 17 is a view for explaining an exposure method of the electron beam exposure apparatus according to the embodiment.
FIG. 18 is a diagram illustrating a manufacturing flow of a microdevice.
FIG. 19 is a diagram for explaining the details of the wafer process of FIG. 18;

Claims (14)

A multi-charged beam lens configured by laminating a plurality of electrodes having a charged beam passage region provided with a plurality of charged beam openings in an optical axis direction of the charged beam through an insulator,
In each electrode pair sandwiching the insulator,
An opening provided between the charged beam passage region and the insulator on a surface of at least one electrode facing the other electrode;
A multi-charged beam lens comprising: a conductive shield that penetrates into the opening and does not contact at least an electrode having the opening, and is provided between the charged beam passage region and the insulator. . 2. The multi-charged beam lens according to claim 1, wherein all of the plurality of electrodes have through-holes as the openings, and the conductive shield is provided through the through-holes of all the electrodes. . The multi-charged beam lens according to claim 2, wherein the plurality of electrodes and the insulator provided between the electrodes are integrated by a clamp. 4. The multi-charged beam lens according to claim 3, wherein a position where the clamp sandwiches the plurality of electrodes includes a position where the insulators are arranged in a stacking direction. 5. The multi-charged beam lens according to claim 3 or 4, wherein the conductive shield is fixed to the clamp. The multi-charged beam lens according to claim 1, wherein the conductive shield is made of metal. In at least one electrode pair of the plurality of electrodes, the conductive shield is formed as a convex portion on one electrode, and the conductive shield penetrates into the opening of the other electrode. The multi-charged beam lens according to claim 1, wherein: The plurality of electrodes includes a first electrode having a through-hole as the opening, and two second electrodes having a convex portion as the conductive shield sandwiching the first electrode,
2. The multi-charged beam lens according to claim 1, wherein the convex portion of the second electrode is abutted and brought into contact with each other through the through hole of the first electrode. In the electrode pair, at least one of the electrodes has a convex portion as the conductive shield, and the other electrode has a concave portion as the opening in a region including the closest portion to the convex portion. The multi-charged beam lens according to claim 1. The multi-charged beam lens according to claim 9, wherein the shield exists in all directions around the optical axis of the charged particle beam. The multi-charged beam lens according to claim 9, wherein the shield is axisymmetric with respect to an optical axis of the charged particle beam. The multi-charged beam lens according to claim 9, wherein at least one of the plurality of electrodes has both the convex portion and the opening. A charged particle source emitting a charged particle beam;
A correction electron optical system including the multi-charged beam lens according to claim 1 and forming a plurality of intermediate images of the charged particle source;
A projection electron optical system for reducing and projecting the plurality of intermediate images onto a wafer;
A charged particle beam exposure apparatus comprising: a deflector configured to deflect the plurality of intermediate images projected onto the wafer so as to move on the wafer. A manufacturing apparatus group for various processes including the charged particle beam exposure apparatus according to claim 13 is installed in a semiconductor manufacturing factory, and a semiconductor device is manufactured by a plurality of processes using the manufacturing apparatus group. A device manufacturing method.

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