JPH0775218B2 - Electron beam exposure system - Google Patents

Description

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 in which deflection of an electron beam used is accurately corrected. Is.

[Prior Art] FIG. 3 is a schematic configuration diagram showing a main part of a conventional electron beam exposure apparatus as disclosed in, for example, Japanese Patent Laid-Open No. 52-113168. In FIG. 3, the data line (1) for the electron beam position data (N bits) in the X-axis direction is X.
The side adder (2) is coupled to the X side main deflection coil (4) via the X side addition output data line (7) and the X side DA converter (3). Further, the data line (10) for electron beam position data (N bits) in the Y-axis direction is connected to the Y-side adder (1
1) is coupled to the Y side main deflection coil (13) via the Y side addition output data line (14) and the Y side DA converter (12). The data lines (1) and (10) described above are both connected to a predetermined pattern data storage device or pattern data generation device (neither shown). Reference numeral (15) is a correction data storage device in which data necessary for correcting the deflection distortion of the electron beam is written as follows. That is, the deflection area of the target electron beam is 2 ⁿ (n is a positive integer) in each of the X and Y axis directions.
Equally divided into (2 ⁿ +1) x (2+
1 ⁿ ) grid points are used as correction data set points, and a predetermined measurement is performed for each. From the correction data obtained by this measurement, use n-bit address data for the 2 ⁿ x2 ⁿ correction data selected by removing any one line from the X and Y axis sides. Then, the data is written in the required storage location. Here, the X side address / data line (5) branches from the X side data line (1), and the Y side address / data line (8) branches from the Y side data line (10). The X-side correction data output line (6) connects the correction data storage device (15) and the X-side adder (2), and the Y-side correction data output line (9) is the correction data storage device (15). The storage device (15) and the Y-side adder (11) are connected.

FIG. 4 is a view showing an example of the operation in the above conventional example. In FIG. 4, the resolution of the electron beam position data and the resolution of the corresponding correction data both correspond to N bits, and the number of bits of the DA converter used is small, so the scanning speed of the electron beam. The number of dots corresponding to is set to 25.

Further, FIG. 5 shows that in the above-mentioned conventional example, the number of bits of the DA converter is increased, and the resolution of the electron beam position data and the resolution of the corresponding correction data correspond to N bits. Similar to the case of the figure, the corresponding number of dots is set to 81.

Next, the operation of the above conventional example will be described. The correction data storage device (15) uses the upper n bits of the electron beam position data (N bits) sent to the X and Y side data lines (1) and (10) as an address, and makes a corresponding correction. The data is output to the X and Y side correction data lines (6) and (9).
Here, taking the flow of data on the X side as an example, the X side adder (2) shows that the electronic bit position data on the X side data line (1) and the correction data from the X side correction data line (6) And are added, and the addition result is output to the X-side addition output data line (7). And X side DA converter (3)
Performs DA conversion on the output data, performs current amplification processing as necessary, and outputs the X-side deflection scanning signal to the X-side deflection coil (4). The same operation is performed for the data flow on the Y side, and a further description will be omitted.

In this conventional example, as the number of address lines for the correction data storage device, it is not necessary to use the number corresponding to all the bits forming the electron beam position data but the number corresponding to the upper n bits. It is intended to simplify the entire configuration by keeping the correction accuracy that conforms to the above, and minimizing the memory capacity required for the correction.

In such a conventional electron beam exposure apparatus, as mentioned in FIG. 5, an error in the electron beam position data due to the resolution of the X, Y side DA converters (3), (12) used. The number of bits may be increased in order to reduce the number of scan lines. However, at this time, the scanning line spacing becomes finer, and when scanning is performed at the same clock frequency as before, scanning (drawing ) The time required for scanning is significantly increased such that the time is quadrupled.

[Problems to be Solved by the Invention] Since the conventional electron beam exposure apparatus has the above-described configuration and operation, the number of bits is increased in order to reduce the position error caused by the resolution of the DA converter used. And let
There has been a problem that the scanning (drawing) time significantly increases as the number of bits of the target data increases when the scanning line interval becomes fine and the clock frequency for scanning is not changed.

The present invention has been made to solve the above-mentioned problems, and the accuracy of electron beam position data is always maintained within a minimum error, and the scanning of the electron beam is performed at high speed. It is an object of the present invention to obtain an electron beam exposure apparatus which is surely made.

[Means for Solving the Problems] In the electron beam exposure apparatus according to the present invention, the position data line to which position data corresponding to the irradiation position of the electron beam on the sample is added, and the correspondence in the address of the upper predetermined number of bits of the position data Correction data storage device that outputs correction data having a larger number of bits than the position data, an adder that adds the position data and the corresponding correction data, and outputs the resulting addition data, and the addition data that corresponds to the corresponding analog data. An electron beam exposure apparatus equipped with a DA converter that converts data into data and a main deflection coil that receives analog data from the DA converter and performs a predetermined deflection correction for distortion of the irradiation position of the electron beam. Then, the number of bits of the correction data is set so that the resolution of the correction data is higher than the resolution of the position data.

[Operation] According to the present invention, the N-bit position data corresponding to the irradiation position of the electron beam on the sample is converted into the M-bit correction data from the correction data storage device at the upper n-bit address of the position data. The addition data is added by the adder, and the resulting M-bit addition data is output to correct the distortion of the irradiation position of the electron beam.

[Embodiment] Next, the present invention will be described based on an embodiment shown in the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing an electron beam exposure apparatus which is an embodiment of the present invention. Although the apparent configuration is the same as that of the conventional example apparatus described above, the X, Y side Higher precision DA converters (3A) and (12A) are used, X and Y side correction data lines (6A) and (9A) and X and Y side addition output data lines (7A) , (14A) has an M-bit capacity, while the electron beam position data lines (1) and (10) have an N-bit (M> N) capacity. There is a difference.

FIG. 2 is used based on the idea of the above embodiment.
It is an illustration figure of operation | movement when increasing the number of bits of a DA converter. In FIG. 2, the resolution of the electron beam position data corresponds to N bits, and the resolution of the corresponding correction data corresponds to M bits. The number of corresponding dots is 25.

A DA converter as used here is typically ± (1 /
2) Has LSB error. Therefore, in order to improve the accuracy of the corresponding electron beam position data, it is essential to increase the number of bits, that is, increase the resolution. In addition, the resolution of the corresponding correction data is
Matching the resolution of the converter allows the maximum performance of the DA converter to be utilized for the desired correction.

Also, by setting the number of bits of the corresponding electron beam position data to an appropriate value within the number of bits in the DA converter, it is possible to rationally suppress the increase in the time required for scanning. That is, as understood from FIG. 2, with the same scanning time as in the case of FIG. 4 in the conventional example,
The accuracy of the correction can be doubled.

The number of bits n for addressing the correction data storage device is specified depending on the degree of distortion of the deflection system before correction. The bit number M of the correction data from the correction data storage device is fixed based on the resolution of the corresponding correction data. The number of bits N of the electron beam position data used is defined based on the scanning speed and the average interval of the position data. (For example, n = 8
Bits, N = 14 bits, M = 16 bits and so on. However, in some cases, n = N = M can be set.

Although the above embodiment has been described with respect to the electron beam exposure apparatus, another charged beam apparatus may be used and the same effect as that of the above embodiment can be obtained.

[Advantages of the Invention] As described above, the electron beam exposure apparatus according to the present invention includes a position data line for adding position data corresponding to the irradiation position of the electron beam on the sample, and a predetermined number of upper bits of the position data. A correction data storage device that outputs correction data having a larger number of bits than the corresponding position data at the address, an adder that adds the position data and the corresponding correction data, and outputs the resulting addition data, and an addition data Electron beam exposure equipped with a DA converter that converts corresponding analog data, and a main deflection coil that accepts analog data from the DA converter and performs predetermined deflection correction for distortion of the irradiation position of the electron beam In the device, the number of bits of the correction data is set so that the resolution of the correction data is higher than the resolution of the position data. The accuracy of the position data is always kept within the minimum error, and the scanning of the electron beam becomes fast, so that a reasonable device can be obtained in terms of performance and price with respect to the required accuracy and speed. The effect is produced.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an electron beam exposure apparatus which is an embodiment of the present invention, FIG. 2 is an illustration of the operation in the above embodiment, and FIG. 3 is a schematic configuration of a conventional electron beam exposure apparatus. FIG. 4, FIG. 5 and FIG. 5 are illustrations of the operation in the above conventional example. (2) and (11) are X and Y side adders, (3A) and (12A) are X and Y side DA converters, (4) and (13) are X and Y side main deflection coils, (15) Is a correction data storage device. The same reference numerals in the drawings denote the same or corresponding parts.

Claims (1)

[Claims] 1. A position data line for adding position data corresponding to an irradiation position of an electron beam on a sample, and correction data having a larger number of bits than the corresponding position data at an address of a predetermined number of upper bits of the position data are output. Correction data storage device, an adder for adding the position data and the corresponding correction data and outputting the resulting addition data, and a DA for converting the addition data into corresponding analog data.
An electron beam exposure apparatus comprising: a converter; and a main deflection coil that receives analog data from the DA converter and performs a predetermined deflection correction on a distortion of an irradiation position of the electron beam, An electron beam exposure apparatus, wherein the number of bits of data is set so that the resolution of the correction data is higher than the resolution of the position data.