JPH11329928A - Electron beam exposure equipment - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To realize a low-cost multi-column electron beam exposure apparatus capable of performing high-precision exposure. SOLUTION: An electron beam generator 9 and an electron beam deflecting means 1 for deflecting an electron beam generated by the electron beam generator.
Stage 1 for placing and moving samples 3, 14, 16 and samples 50a, 50b
An electron beam exposure apparatus comprising: a plurality of columns 8a and 8b having a plurality of columns 7a and 17b; and a control unit 60 for controlling the plurality of columns.
Common process 73 that controls the same process in common in 8a and 8b
And a plurality of processes 71 and 72 for controlling the processing of each column.
Adjust the gap when performing a process common to multiple columns
73 so that they can be synchronized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electron beam exposure apparatus, and more particularly to a multi-column electron beam exposure apparatus provided with a plurality of columns each including an electron beam exposure system and a stage for improving throughput. Semiconductor integrated circuits tend to be more highly integrated with advances in microfabrication technology, and the performance required for microfabrication technology is becoming increasingly severe. Especially in the exposure technology,
The limitations of the photolithography technology (photolithography) used for conventionally used steppers and the like are expected. Electron beam exposure technology is a technology that is likely to be the next generation of microfabrication in place of light exposure technology, and is attracting attention as a next-generation exposure technology.

[0002]

2. Description of the Related Art FIG. 1 is a diagram showing a configuration of an electron beam exposure apparatus. In FIG. 1, reference numeral 1 denotes a processor, 2 denotes a magnetic disk, 3 denotes a magnetic tape device,
These devices are connected to each other via a bus 4 and to a data memory 6 and a stage control circuit 7 via a bus 4 and an interface circuit 5, respectively.

[0003] On the other hand, reference numeral 8 denotes a housing (column) in which an electron gun 9, a lens 10, a blanking electrode 11, and a lens 1 are provided.
2, feedback coil 13, sub deflector coil 14, lens 15, main deflector coil 16,
The stage 17 and the sample 50 are arranged. Sample 50
Is mounted on a stage 17, and the movement of the stage 17 is controlled in the X and Y directions by an output signal of the stage control circuit 7.

The data read from the data memory 6 is supplied to a pattern correction circuit 20 through a pattern generation circuit 19. The pattern correction circuit 20 applies a blanking signal to the blanking electrode 11 via the amplifier 21, and outputs a blanking signal to each DA converter (DAC) 2.
Signals are applied to the coils 13, 14 and 16 via 2, 24 and 26 and amplifiers 23, 25 and 27.

[0005] The electron beam emitted by the electron gun 9 is
After passing through the lens 10 and being transmitted or cut off by the blanking electrode 11 and further shaped into, for example, a parallel rectangular beam having an arbitrary shot size of 3 μm or less, the feedback coil 13, the sub-deflector coil 14, and the main deflector coil While being deflected by 16, it is further converged on the sample surface through the projection lens 15. Feedback coil 13, sub deflector coil 14
And the deflectable area of the main deflector coil 16 is:
It increases in this order. In order to obtain a large deflectable area, it is necessary to increase the number of turns of the coil accordingly, and the response speed of each coil decreases in the reverse order to the above. In other words, the settling wait time of the feedback coil 13 is the shortest, and is longer in the order of the sub deflector coil 14 and the main deflector coil 16.

Although the above description has been made with respect to a system in which exposure is performed using a rectangular beam, there are other various systems such as a block exposure system and a blanking aperture array system. Is the same. An electron beam exposure apparatus has a feature that resolution is better than that of a photolithography apparatus, but has a problem that throughput is lower than that of a photolithography apparatus. Therefore, it is conceivable to improve the throughput by providing a plurality of columns each including an electron beam exposure system and a stage. An electron beam exposure apparatus provided with a plurality of such columns is called a multi-column electron beam exposure apparatus. Simply increasing the number of columns has a space advantage compared to arranging multiple electron beam exposure devices in close proximity, but it cannot be said that there is a sufficient advantage. By exposing the same pattern to a plurality of columns, the configuration of the control unit can be simplified.

[0007]

However, it has been found that there are various problems when actually realizing a multi-column electron beam exposure apparatus. When a multi-column electron beam exposure apparatus is manufactured, each column is manufactured so as to be as identical as possible. However, characteristics such as an electrostatic lens, a coil, and a stage differ for each column due to manufacturing variations.
If there is such a difference between columns, if the same signal is supplied to each column to expose the same pattern in each column, there is a problem that a shift occurs between the columns and a normal exposure cannot be performed. Occurs. For this reason, for example, in a conventional multi-column electron beam exposure apparatus having two columns, even if the control unit is shared,
As shown in the figure, the control unit 60 controls the first column 8a to be controlled.
And a second control unit 61b for controlling the column 8b. In order to realize such a control unit, it is necessary to use, as a CPU constituting the control unit 60, a CPU having a processing capacity of about twice that in the case of controlling a single column. In addition, if the CPU has the same processing capacity as that for controlling a single column, there is a problem that the speed of the exposure processing is reduced to about half.

In an electron beam exposure apparatus, the proportion of the weight of the stage 17 on which a wafer is mounted and moved is considerably large. Therefore, there is a problem that the column is distorted when the stage 17 moves. Of course, the column has sufficient rigidity to minimize the distortion caused by the movement of the stage 17, but it is impossible to completely prevent the distortion from occurring. Influence. The electron beam exposure apparatus exposes a very fine pattern, and the accuracy of the exposure position of the electron beam is required to be 20 nm or less, and the displacement of the exposure position due to distortion cannot be ignored. Therefore, in a conventional electron beam exposure apparatus having one column, a change in the exposure position due to the movement of the stage 17 is measured in advance, and correction is performed so that exposure can be performed at a predetermined position. Similar correction needs to be performed in a multi-column electron beam exposure apparatus having a plurality of columns. However, since the multi-column electron beam exposure apparatus has as many stages as the number of columns, the effect is complicated, and there arises a problem that the correction must be complicated.

As described above, the throughput can be improved by providing a plurality of columns. However, at present, it is difficult to manufacture a multi-column electron beam exposure apparatus capable of performing highly accurate exposure at low cost. An object of the present invention is to solve such a problem and realize a low-cost multi-column electron beam exposure apparatus capable of performing highly accurate exposure.

[0010]

In order to achieve the above object, in a multi-column electron beam exposure apparatus according to a first aspect of the present invention, a control operation is divided into a common process between columns and a process for each column. The process for each column performs the necessary synchronous processing to perform the common process synchronously.

That is, the electron beam exposure apparatus according to the first aspect of the present invention comprises an electron beam generator, electron beam deflecting means for deflecting the electron beam generated by the electron beam generator, and a stage for mounting and moving the sample. An electron beam exposure apparatus comprising: a plurality of columns having: and one control unit that controls the plurality of columns, wherein the control unit comprises:
It has a common process that controls the same process in multiple columns in common, and a plurality of processes that controls the process in each column. The multiple processes adjust the shift when performing the common process in each column. It is characterized in that control is performed so that a common process can be performed synchronously in a plurality of columns.

In order to achieve the above object, in a multi-column electron beam exposure apparatus according to a second aspect of the present invention, a plurality of columns are arranged symmetrically with respect to a central axis of the apparatus. That is, the electron beam exposure apparatus according to the second aspect of the present invention has an electron beam generator, electron beam deflecting means for deflecting the electron beam generated by the electron beam generator, and a stage for mounting and moving the sample. An electron beam exposure apparatus including a plurality of columns and one control unit for controlling the plurality of columns, wherein the plurality of columns are arranged symmetrically with respect to a central axis, and movement of a stage in each column is , With respect to the central axis.

In the electron beam exposure apparatus according to the first aspect of the present invention, each value such as setting of a value corresponding to a characteristic value of each column used in calculating a value of an applied signal to each section according to an exposure position is set. For a process different for each column, a process is provided for each column. Processing that can be performed in common, such as calculation based on exposure data, is a common process. As a result, the common process portion can be shared, and the processing amount is reduced accordingly. In actual arithmetic processing, the common processes that can be shared occupy a large proportion, and thus have a great effect in reducing the processing amount.

Since the characteristic values are different in each column, there is a possibility that even if the common process is started synchronously, a difference occurs during the execution and the synchronized operation cannot be maintained. The process for each column monitors a shift during execution of the common process, and when the shift becomes unacceptable, performs processing to restore synchronization. In the electron beam exposure apparatus according to the second aspect of the present invention, the plurality of columns are arranged symmetrically with respect to the central axis, and the movement of the stage in each column is symmetrical with respect to the central axis. Column tend to be symmetrical with respect to the central axis. For this reason, since the displacement of the exposure position due to the distortion due to the movement of the stage also occurs symmetrically with respect to the central axis, it is easy to perform the correction.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described by taking a multi-column electron beam exposure apparatus having two columns as an example. FIG. 3 is a block diagram showing a configuration of the multi-column electron beam exposure apparatus according to the embodiment of the present invention. Each column 8 of the multi-column electron beam exposure apparatus of the embodiment
Each of a and 8b has the configuration already described with reference to FIG. 1 and is connected to a chamber (vacuum chamber) and the like.
However, the chambers need not necessarily be connected, and may be separated. The columns 8a and 8b are provided with wafer boxes 80a and 80b for supplying a wafer to be exposed and collecting the exposed wafer.

The columns 8a and 8b are controlled by a common control unit 60. The control unit 60 includes a first process 71 for performing a unique process in the column 8a, a second process 72 for performing a unique process in the column 8b, and columns 8a and 8b.
The first process 71 and the second process 72 can communicate with each other to synchronize processing steps with each other. The control contents of the common process 73 are transmitted to the columns 8 a and 8 via the first process 71 and the second process 72.
b. First process 71 and second process 72
When the control by the common process 73 is performed, the common process 73 in each column
It is monitored whether or not a deviation exceeding a predetermined amount has occurred in the process. If the deviation exceeds a predetermined amount, the process cannot be continued as it is, and the fact is notified to the processes of other columns and the common process 73. At the same time, a process for synchronizing with a shift is performed. In response, the common process 73 suspends the supply of the control signal, and the processes in the other columns perform correction according to the stop of the control signal. Then, when the processing in the column where the deviation has increased is completed, the processing of the common process is restarted again. The control unit 60 is configured as shown in FIG.
A first process 71, a second process 72, and a computer such as a PU1, a magnetic disk 2, and a magnetic tape 3;
The common process 73 is realized by software.

FIG. 4 is a top view of the multi-column electron beam exposure apparatus of the embodiment. The columns 8a and 8b are designed to be symmetric about the central axis 100 of the device.
Therefore, when the stage 17a on which the wafer 50a is placed in the left column 8a moves in the lower left direction, the right column 8a
The stage 17b on which the wafer 50b is placed at b moves rightward. Therefore, even when the stage moves, the center of gravity of the two stages 17a and 17b is always on the central axis of the apparatus.

On the other hand, for example, since the apparatus is preferably accessed from one side, the columns 8a and 8b
Are arranged symmetrically with respect to the left and right center planes of the apparatus, when the stage stages 17a and 17b move back and forth (vertically in FIG. 4) with respect to the front of FIG. 3, the stage stages 17a and 17b Moving to one side of the device will cause significant distortion. Therefore, the arrangement of this embodiment shown in FIG. 4 is preferable.

FIG. 5 is a diagram for explaining the mutual relationship in the progress of the processing of the first process 71, the second process 72, and the common process 73. The apparatus of the embodiment is composed of columns 8a and 8
Although b is made to have the same configuration, it is impossible to make the characteristics and arrangement of the electrostatic lens and the magnetic field lens completely identical, and the control coefficient of each part differs. There is also a difference between the stages 17a and 17b. In the data settings 90a and 90b of FIG. 5, the first process 71 and the second process
A unique data setting for the process 72 is performed. During this time,
The common process 72 performs exposure data processing 91.

When the data setting of each process and the exposure data processing 91 are completed and the exposure can be started, synchronization processing 92a, 92b, 93 is performed between the processes, and the common process 73 executes the exposure processing 95. First process 7
A signal for exposure is output to the first and second processes 72.
In response to this, the first process 71 and the second process 72 apply the signals to the respective sections of the columns 8a and 8b and the stages 17a and 17b, and monitor the synchronization state. as mentioned above,
Since there are differences in the control coefficients and the like of the respective parts, even if the same exposure signal is exposed, a difference gradually occurs between columns. As described above, since the columns 8a and 8b are formed so as to have the same configuration, the difference is not so large but is not zero, and the displacement may increase as the exposure progresses.

As described above, the deflection means of the electron beam exposure apparatus are hierarchized. A deflector having a large deflection range has a slow response, and a deflector having a fast response speed has a narrow deflection range. Therefore, when performing exposure while moving the stage, first, the amount of deflection of the deflector having a large deflection range is fixed, and exposure is performed while changing the amount of deflection of the deflector having a small deflection range. When the deflection range of the small deflector exceeds the deflection range, the deflection amount of the deflector having the large deflection range is changed, and after stepwise moving to the next block, the deflection amount of the deflector having the small deflection range is similarly changed after the settling process. The process of performing exposure while repeating is repeated. If there is a difference in the control coefficient of each part for each column, there will be a difference in the timing and the settling time exceeding the deflection range of the small deflector in the exposure processing in each column, and one column will exceed the deflection range of the small deflector. In the other column, the range has not yet exceeded the range, or after changing the deflection position of the deflector having a large deflection range, the setting is completed in one column but the other is not completed. In such a case, even if the common process 73 outputs the exposure signal, the process cannot be performed.

Therefore, the first process 71 and the second process 72 perform the processes required to apply the exposure signal of the common process 73 to each part of the column in the exposure processes 94a and 94b, respectively. Monitor
When synchronization is lost, the process of the other column and the common process 73 are notified that synchronization has been lost. In response, the common process 73 stops outputting the exposure signal, and the process in the other column performs necessary processing such as resetting. Necessary processes such as re-setting are also performed at the same time on the process of the column out of synchronization, and the common process 73 resumes the output of the exposure signal in the synchronized state. Such processing is repeated until the exposure processing ends. The return route in FIG. 5 shows such processing.

When the exposure processing is completed, the stages 17a and 17b are placed on the stage 50a and 50b,
Returning to steps a and 80b, the top to be exposed next is placed, and the above processing is repeated.

[0024]

As described above, according to the present invention,
By providing a plurality of columns, throughput can be improved, and a part of the control unit is shared, so that the configuration can be simplified accordingly, and it is not necessary to use a high-performance CPU for the control unit. Cost can be reduced. Further, since the columns are arranged symmetrically with respect to the central axis, the occurrence of distortion of the column housing due to the movement of the stage can be reduced, and the exposure position can be made highly accurate.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a conventional example of an electron beam exposure apparatus.

FIG. 2 is a diagram illustrating an example of a conventionally conceivable configuration when a control unit is shared by a multi-column having two columns.

FIG. 3 is a diagram illustrating a configuration of an electron beam exposure apparatus according to a first embodiment of the present invention.

FIG. 4 is a top view showing a column arrangement in the first embodiment.

FIG. 5 is a diagram showing the interrelationship of each process as the exposure operation proceeds in the first embodiment.

[Explanation of symbols]

 Reference Signs List 8 housing (column) 8a first column 8b second column 9 electron gun 10, 12, 15 lens 11 blanking electrode 13 feedback coil 14 sub deflector 16 main deflector 17 stage 28 Electronic detector 60 Control unit 71 First process 72 Second process 73 Common process

Claims (3)

[Claims] A plurality of columns having an electron beam generator, electron beam deflecting means for deflecting an electron beam generated by the electron beam generator, and a stage for mounting and moving a sample; An electron beam exposure apparatus including one control unit for controlling, the control unit comprising: a common process for commonly controlling the same process in the plurality of columns; and a plurality of processes for controlling a process for each column. Electron beam exposure, wherein the plurality of processes are controlled so that the common process can be performed synchronously in the plurality of columns by adjusting a shift when the common process is performed in each column. apparatus. 2. The electron beam exposure apparatus according to claim 1, wherein the plurality of columns are arranged symmetrically with respect to a central axis, and the movement of the stage in each column moves with respect to the central axis. An electron beam exposure device that is symmetrical with respect to it. 3. A plurality of columns each having an electron beam generator, electron beam deflecting means for deflecting the electron beam generated by the electron beam generator, and a stage for mounting and moving a sample. An electron beam exposure apparatus including one control unit for controlling, wherein the plurality of columns are arranged symmetrically with respect to a central axis, and movement of the stage in each column is relative to the central axis. An electron beam exposure apparatus having symmetry.