JPH06291025A - Electron-beam aligner - Google Patents

Abstract

PURPOSE:To obtain an aligner wherein the same exposure as a character projection system can be performed without using a character aperture and a throughtput can be enhanced more than that of the character projection system. CONSTITUTION:In an electron-beam aligner by which a desired pattern is exposed on an object to be exposed, a plurality of electron-beam sources which can control electron beams independently so as to be turned on an off are arranged two-dimensionally. The aligner is provided with an electron-beam generation substrate 10 which drives the electron-beam sources selectively and which emits a shaping beam in a desired pattern, with electro-optical structures 22, 23, 24 which control the acceleration, the convergence and the deflection of the shaping beam emitted from the electron-beam generation substrate 10 and with a specimen stand by which an object 26, to be exposed, which is exposed by the shaping beam through the electro-optical structures 22, 23, 24 is moved inside a plane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam exposure apparatus, and more particularly to an electron beam exposure apparatus that exposes an object to be exposed by using a shaped beam having a desired pattern.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of semiconductor element patterns, an electron beam exposure apparatus as a lithographic apparatus has become indispensable. This electron beam exposure system
Although it has a feature that the resolution is higher than that of the optical stepper, the throughput is low because batch exposure cannot be performed unlike the optical stepper. Therefore, how to increase the throughput becomes an important issue.

In order to improve the throughput in an electron beam exposure apparatus, there has been proposed a method in which multiple independently controllable electron beam sources are operated in parallel to expose a plurality of regions simultaneously (Japanese Patent Laid-Open No. 63-269522). No. 57/76837
Issue). In addition, a large number of apertures according to the exposure pattern are made in advance, and a beam generated from an electron beam source is selectively applied from among these to shape the beam,
A method of exposing an object to be exposed using this beam (character projection method) has also been proposed.

However, this type of device has the following problems. That is, in the apparatus for exposing by operating the multi-electron beam source, the beams from the multi-electron beam source are simultaneously deflected by the electron optical structure in order to simultaneously perform beam scanning on a plurality of exposure regions (for example, chip regions). ing. In this case, it is extremely difficult to uniformly control the magnetic field by the electron lens and the deflection system in a wide range, and the deflection amount of the beam is deviated between the central portion and the peripheral portion of the electron optical structure, so that highly accurate exposure can be performed. Absent. Further, in order to emit a beam to a range corresponding to a plurality of chips and control the deflection, the electron lens surrounding these regions must be increased in size, which in turn causes the size of the electron optical structure to be increased.

On the other hand, in the character projection method, the throughput can be improved by using the conventional electro-optical structure, but the number of apertures that are preliminarily formed and put in the structure is limited, so that there is a limit in improving the throughput. is there.

[0006]

As described above, in the conventional apparatus that simultaneously operates a multi-electron beam source to expose a plurality of regions, the deflection amount of the beam is deviated between the central portion and the peripheral portion of the electron optical structure. May cause deterioration of exposure accuracy,
There has been a problem that the electro-optical structure is upsized. Further, in the character projection method, there is a limit to the improvement in throughput because the number of apertures that can be put in the electro-optical structure is limited.

The present invention has been made in consideration of the above circumstances, and an object thereof is to use a multi-electron beam source for a character without deteriorating the exposure accuracy and increasing the size of the electron optical structure. An object of the present invention is to provide an electron beam exposure apparatus that can perform the same exposure as the projection method and can improve the throughput as compared with the character projection method.

Another object of the present invention is to provide an electron beam exposure apparatus capable of performing batch exposure using an electron beam and achieving a throughput comparable to that of an optical stepper.

[0009]

SUMMARY OF THE INVENTION The gist of the present invention is to form a shaped beam having a desired shape by using an electron beam generating substrate in which an electron beam source is two-dimensionally arranged, without using a character aperture. .

That is, according to the present invention (claim 1), in an electron beam exposure apparatus for exposing a desired pattern on an object to be exposed, a plurality of electron beam sources capable of independently controlling ON / OFF of the electron beam are two-dimensionally arranged. An electron beam generating substrate which is arranged and selectively drives these electron beam sources to emit a shaped beam of a desired pattern, and an shaped beam emitted from the electron beam generating substrate such as acceleration, convergence and deflection. It is characterized by comprising an electro-optical structure for controlling, and means for moving an object to be exposed, which is exposed by a shaped beam passing through the electro-optical structure, in a plane.

The present invention (claim 2) is an electron beam exposure apparatus for exposing a desired pattern onto an object to be exposed.
A mask on which a pattern necessary for exposing an object to be exposed is formed, an optical lens for reducing a light beam obtained by irradiating the mask with light, and a position where the pattern of the mask is imaged by the optical lens. A photoelectric conversion unit that is provided and has a photoelectric conversion material surface that emits electrons when exposed to light, and generates an electron beam having a pattern shape according to the pattern of the light beam, and an electron beam emitted from this photoelectric conversion unit And a means for moving an object to be exposed, which is exposed by the shaped beam passing through the electron optical structure, in a plane. Characterize. Here, the following are preferred embodiments of the present invention.

(1) A small number of electrons are emitted from all electron beam sources in the electron beam generating substrate, and more electrons are emitted from the electron beam source corresponding to a desired shape. Forming a shaped beam with a contrast in the intensity distribution. (2) To expose the exposed object while moving the exposed object.

(3) Different desired patterns are formed in a plurality of regions on the mask, and one of the regions of the mask is selected and irradiated with light to generate a light beam having a pattern in the region.

[0014]

According to the present invention (Claim 1), an electron beam having an arbitrary shape can be obtained from the electron beam generating substrate, and this beam is controlled by the conventional reduction deflection electron optical lens or the like, which is a great technical difficulty. Similarly to the character projection method, it is possible to perform exposure with a shaped beam having a desired pattern. Moreover, unlike the character projection method, it is not necessary to replace the aperture even if the number of pattern types to be formed increases, so that the throughput can be improved. In addition, since the beam from the multi-electron beam source is not simultaneously scanned in a plurality of exposure areas to form a shaped beam for shot exposure, the exposure accuracy is reduced and the size of the electron optical structure is increased. Will not invite.

Further, according to the present invention (claim 2), a mask conventionally used in an optical stepper is selectively irradiated with light to form a light beam having a desired pattern shape, and this is used as an optical lens. The photoelectric conversion material surface that emits electrons when irradiated with light is irradiated with light to form an electron beam having a desired pattern shape, and the electron beam is controlled to converge, reduce, or deflect using an electron optical structure. The object to be exposed that is moving or stopped is shot exposed. In such an apparatus, an electron beam having pattern information of a large area can be easily obtained, so a conventional multi-beam exposure apparatus that parallels spot beams and performs simultaneous exposure, or a character beam is used to perform shots for each cell. Throughput can be remarkably improved as compared with the conventional character projection type exposure apparatus.

[0016]

The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a diagram showing a schematic configuration of an electron beam exposure apparatus according to the first embodiment of the present invention, and FIG. 2 is a diagram showing a specific configuration of an electron beam generating substrate.

In the electron beam generating substrate 10, a multi-electron beam source 12 is arranged in a matrix on a base 11, and the base 1 is further provided.
1, the extraction electrode 13 and the acceleration electrode 14 are arranged to face each other. More specifically, for example, the publication (Japanese Patent Laid-Open No. 54-
111272, JP-A-56-15529, JP-A-3-225721) and the like, a substrate of glass, semiconductor or the like is used, and the electron beam source 12 uses semiconductor manufacturing process technology at a pitch of about 2 μm in the substrate. Then, each electron beam source 12 is manufactured including a voltage application wiring that can be independently controlled. Then, each electron beam source 12 in the electron beam generating substrate 10 is
It is selectively driven by the selective drive circuit 21.

FIG. 3 schematically shows the principle of forming beam generation by the electron beam generating substrate 10. As shown in FIG. 3A, it is assumed that the electron beam sources 12 are arranged in a matrix, and the selection drive circuit 21 selectively drives the electron beam sources 12 to turn on the electron beam sources 12 according to a desired pattern. To do. In FIG. 3B, a circle indicates an electron beam source that is on, and a cross indicates an electron beam source that is off. As a result, a shaped beam having a pattern as shown in FIG. 3C is obtained from the electron beam generating substrate 10.

The shaped beam emitted from the electron beam generating substrate 10 has first and second beam converging lenses 22 and 2.
It is converged and reduced by 3 and is irradiated onto the exposure target substrate 26 placed on a sample table (not shown) movable in the X and Y directions. The exposed body 26 is, for example, a semiconductor wafer coated with an electron beam resist. A two-dimensional deflector 24 including deflection electrodes 24a and 24b for deflecting the shaped beam in the X and Y directions is provided between the second converging lens 23 and the exposed substrate 26. The selective drive circuit 21, the lenses 22 and 23, the deflector 24, the sample stage and the like are controlled and managed by the computer 20.

In the apparatus having such a configuration, the selective driving circuit 21 emits a shaped beam corresponding to the sequential exposure pattern from the electron beam generating substrate 10. The emitted shaped beam is converged and reduced by the first and second beam converging devices 22 and 23, is further deflected by the two-dimensional deflector 24, and is irradiated onto the exposed object 26 which is two-dimensionally raster-moved. As a result, a desired pattern is exposed on the entire surface of the exposed body 26.

Since the electron beam formed on the electron beam generating substrate 10 is emitted from a matrix dot beam source having a pitch of 2 μm, for example, the first and second focusing devices 2 are provided.
If the reduction ratio of 2 and 23 is small, dot-shaped unevenness is generated in the intensity distribution of the shaped beam. Therefore, in forming a fine pattern, it is necessary to secure a reduction ratio that does not cause the dot-shaped unevenness. At least 1 in an electron beam apparatus that requires a pattern exposure function of 0.1 μm width or less
Reduction by more than one digit is required.

The emission characteristics of the electron beam emitted from each electron beam source 12 of the electron beam generating substrate 10 are generally as shown in FIG. That is, as the applied voltage E increases, the beam current I also increases.

By the way, the above-mentioned publication (Japanese Patent Laid-Open No. 54-1112).
72, JP-A-56-15529, JP-A-3-225721) and the like, it is extremely difficult to control on / off of electron emission from each beam source. Specifically, even if the beam current 0 is changed from the off state to the on state, the beam current does not instantaneously change to the on state, but it takes time to stabilize the beam current in the on state.

In order to solve this, in this embodiment, a bias exposure method by applying a bias voltage is applied. That is, the initial voltage A is applied to the total electron beam source 12 in advance so that a small number of electrons are emitted. On the other hand, when a desired exposure pattern is exposed, the voltage B is further applied by the selection drive circuit 13 only to the electron beam source 12 at a required position so that the exposure target 20 is provided with contrast in the beam intensity distribution. Allow the pattern to be formed. When the exposed object is exposed using a beam having such an intensity distribution, it also serves as a good measure against the proximity effect, which is a problem peculiar to the electron beam exposure apparatus.

If alignment with the previously formed three-dimensional structure on the object to be exposed is required, an electron beam emitted from one electron beam source is applied to the alignment mark on the object to be exposed. It is sufficient to take signals and superimpose them. In addition, the coordinate position of the entire electron beam source 12 on the electron beam generating substrate 10 is obtained by irradiating a single mark on the substrate to be exposed by moving the sample stage without deflecting each beam to obtain the same signal. It is possible to easily determine the mark position at the time of reading by using a laser interferometer, for example.

The electron beam source 12 in this embodiment is also used.
The position of each beam from is in a very narrow range, and there is almost no influence of distortion of the optical system. However, in order to perform exposure with higher accuracy, the formation position of the electron beam source 12 may be displaced from the accurate matrix position by the amount of the distortion in consideration of the influence of the distortion of the optical system.

As described above, according to this embodiment, an electron beam having an arbitrary shape can be obtained from the electron beam generating substrate 10, and the beam is converged by the converging lenses 22 and 23 to be irradiated on the exposure target 26. Therefore, as in the conventional character projection method, it is possible to collectively expose a specific pattern. In this case, the electro-optical structure does not need to be changed from the conventional configuration and can be realized without great technical difficulty, and further, the exposure accuracy may be reduced or the optical structure may be increased in size. Absent. Also, unlike the normal character projection method, it does not require a character aperture, so there is no need to replace the aperture even if the number of pattern types to be formed increases, which can improve the throughput over the normal character projection method. it can.

FIG. 5 is a view showing the schematic arrangement of an electron beam exposure apparatus according to the second embodiment of the present invention. 31 in the figure
Is a reticle mask, and at least one exposure pattern 33 necessary for exposing the exposure target 32 is formed on the surface thereof. Here, as shown in FIG. 6, the reticle mask 31 has a pattern of one chip for four layers (33a, 3a).
3b, 33c, 33d) are formed. The method for producing the reticle mask 31 is exactly the same as the method for producing the reticle mask used in the optical stepper. The reticle mask 31 is mounted on a support base 44 so as to be freely movable in the X and Y planes with respect to the light source 34. The movement of the reticle mask 31 causes the exposure patterns 33a, 33b, 33c, Select 33d.

Above the reticle mask 31, a light source 34 that emits, for example, ultraviolet rays is installed via a shutter 45. Below the reticle mask 31, there is an optical lens group 35 that reduces ultraviolet rays, and ultraviolet rays 36 that pass through the reticle mask 31 and have pattern information are transmitted through the optical lens group 3.
The photoelectric conversion unit 38 reduced in size by 5 and placed in the vacuum container 37 is irradiated through an opening 40 sealed with, for example, quartz glass 39. The photoelectric conversion unit 38 is formed by forming a photoelectric conversion material surface on a transparent substrate, for example, and emits electrons when exposed to light. Therefore, the photoelectron conversion unit 3 irradiated with the ultraviolet ray 36 having the pattern information
From 8, an electron beam 41 corresponding to the shape of the ultraviolet ray 36 is emitted.

The electron beam 41 is converged, reduced and deflected by the electron optical structure 42, and is irradiated onto the exposed object 32 placed on the sample stage 43 which is movable in the X and Y directions. The position of the sample table 43 in the X and Y directions is accurately measured by, for example, a laser interferometer.

The operation of the electron beam exposure apparatus configured as described above will be described. Move the support base 44 to move the light source 3
A desired exposure pattern, for example, 33a, is installed directly below 4. The shutter 45 is opened for a certain period of time to irradiate the ultraviolet ray to the reticle mask 33a, and the ultraviolet ray 36 having the reduced pattern information is made through the optical lens group 35, and the ultraviolet ray 36 is made to the photoelectron conversion section 38 installed in the vacuum container 37. Hit An electron beam 41 is emitted from the surface of the photoelectron conversion unit 38 according to the pattern information of the ultraviolet rays 36. The emitted electron beam 41 is converged, reduced, and deflected by the electron optical structure 42, and is irradiated onto a predetermined position of the exposed body 32 placed on the sample stage 43. When the exposure is completed, the sample stage 43 moves, the exposed body 32 is carried to the next exposure position, and the next exposure is executed. In this way, the exposure is performed on the entire surface of the exposed body 32.

Next, overlay exposure between the exposure patterns 33a, 33b, 33c and 33d on the reticle mask 31 will be described. Exposure patterns 33a, 33b, 33
Alignment marks 46 (46
(q, 46b, 46c, 46d) are inserted. The alignment mark 46 is formed by forming a cross mark 48 on each of four sides of each exposure pattern 13.

First, the exposure pattern 33a is the exposed object 32.
The resist applied on the surface is exposed, and the resist is used as a mask to form a pattern on the exposure target 32, and the alignment mark 46 is simultaneously formed. The operation of superposing the exposure pattern 33b on the exposure target 32 on which the alignment mark 46 is formed will be described below.

Support base 4 on which reticle mask 31 is placed
4 is moved to arrange the exposure pattern 33b directly below the light source 34. The exposure pattern 33b includes the exposure pattern 33
An alignment mark 46b is provided at the same position as the alignment mark position of a. Only the alignment mark 46b area of the exposure pattern 33b is illuminated by opening a part of the shutter 45. As a result, the exposure pattern 33a
A light beam having the same shape as the alignment mark 46a can be obtained.

This light beam is reduced by the optical lens group 35, and a photoelectron conversion unit 38 installed in the vacuum container 37.
Then, an electron beam having the same shape as the alignment mark 46a is emitted. This electron beam is focused, reduced, and deflected by the electron optical structure 42, and is irradiated onto the alignment mark 46a previously formed on the exposure target 32.

The backscattered electrons generated at this time are detected by a backscattered electron detector (not shown) provided inside the electro-optical structure 42, for example, and are detected by the laser interferometer with the alignment mark position 46a. The amount of deviation is detected from the relationship,
The deviation amount is given to the electron optical structure 42 as a correction signal, and the alignment error is kept within an allowable value. In this state, the shutter 45 is opened over the entire surface, and the exposure pattern 43b is radiated over the exposure pattern 33a on the exposure target 32.
This operation is repeated over the entire surface of the exposed object 32 to expose the entire surface.

As described above, in this embodiment, a reticle mask conventionally used in an optical stepper is selectively irradiated with light to form a light beam having a desired pattern shape, which is reduced by using an optical lens. , The surface of the photoelectric conversion material that emits electrons when exposed to light is formed, an electron beam having a desired pattern shape is formed, and the electron beam is converged, reduced, or deflected by an electron optical structure to move or move. The object to be exposed that is stopped is shot exposed.

Therefore, since an electron beam having a large area of pattern information can be easily obtained in such an apparatus, a cell can be obtained by using a conventional multi-beam exposure apparatus for parallel exposure of spot beams or a character beam. Throughput can be remarkably improved as compared with a character projection type exposure apparatus that shots every time.

The present invention is not limited to the above embodiment. In FIG. 5, whether or not the desired electron beam is generated is configured by opening and closing the shutter and moving the reticle mask. For example, a polygon mirror is used to scan the light so that the desired electron beam is obtained. Of course, it is okay. Furthermore, since the amount of electrons emitted from the photo-electron conversion material decreases with time, it is possible to extend the life by allowing it to move in a vacuum container and changing the part exposed to light when the amount of emission falls below an allowable value. Of course. In addition, various modifications can be made without departing from the scope of the present invention.

[0040]

As described above, the present invention (Claim 1).
According to the above, an electron beam having an arbitrary shape can be obtained from the electron beam generating substrate, and this beam is controlled using a conventional reduction deflection electron optical lens, so that it is possible to perform the same exposure as the character projection method, Moreover, the exposure throughput can be remarkably improved without great technical difficulty.

Further, according to the present invention (claim 2), the mask conventionally used in the optical stepper is selectively irradiated with light to form a light beam having a desired pattern shape, which is reduced in size. Since the electron beam having a desired pattern shape is formed by irradiating the photoelectric conversion portion, an electron beam having a large area of pattern information can be easily obtained. For this reason, the throughput can be significantly improved as compared with a conventional multi-beam exposure apparatus in which spot beams are arranged in parallel for simultaneous exposure and a character projection type exposure apparatus in which shots are performed for each cell using a character beam. It will be possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an electron beam exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a specific configuration of an electron beam generating substrate used in the first embodiment.

FIG. 3 is a diagram for explaining a principle of generating a shaped beam by an electron beam generating substrate.

FIG. 4 is a diagram showing emission characteristics of electron beams emitted from each electron beam source of the electron beam generating substrate.

FIG. 5 is a diagram showing a schematic configuration of an electron beam exposure apparatus according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a reticle mask used in a second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Electron beam generating substrate 11 ... Base 12 ... Electron beam source 13 ... Extraction electrode 14 ... Accelerating electrode 20 ... Calculator 21 ... Selection drive circuit 22, 23 ... Beam converging lens 24 ... Deflection electrode 26 ... Exposed body 31 ... Reticle Mask 32 ... Exposed object 33 ... Exposure pattern 34 ... Light source 35 ... Optical lens group 36 ... UV ray 37 ... Vacuum container 38 ... Photoelectric conversion part 39 ... Quartz glass 40 ... Opening 41 ... Electron beam 42 ... Electro-optical structure 43 ... Sample Table 44 ... Support table 45 ... Shutter 46 ... Alignment mark 48 ... Cross mark

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Jun Takamatsu 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Prefectural Research & Development Center, Toshiba Corporation (72) Inventor Toshiyuki Magoshi Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa No. 33 Incorporated company Toshiba Production Engineering Laboratory

Claims (2)

[Claims] 1. An electron beam in which a plurality of electron beam sources capable of independently controlling ON / OFF of the electron beam are two-dimensionally arranged and these electron beam sources are selectively driven to emit a shaped beam having a desired pattern. Generation substrate, electron optical structure for controlling acceleration, convergence and deflection of the shaped beam emitted from the electron beam generation substrate, and an object to be exposed by the shaped beam passing through the electron optical structure An electron beam exposure apparatus comprising: a means for moving the substrate in a plane. 2. A mask on which a pattern necessary for exposing an object to be exposed is formed, an optical lens for reducing a light beam obtained by irradiating the mask with light, and the pattern of the mask is connected by the optical lens. A photoelectric conversion unit which is provided at a position to be imaged, has a photoelectric conversion material surface which emits electrons when exposed to light, and generates an electron beam having a pattern shape corresponding to the pattern of the light beam, and the photoelectric conversion unit. An electron optical structure for controlling the converging, reducing, and deflecting of the electron beam emitted from the electron beam; and a means for moving an object to be exposed by the shaped beam passing through the electron optical structure in a plane. An electron beam exposure apparatus, which comprises: