JPH10284362A - Method and device for exposing with charged particle beam, and for predicting processing time - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charged particle beam exposing device which can expose charged particle beam to a sample without exposure failure at the shortest exposure time and an exposing method thereof, and to provide a processing time predicting method which predicts processing time in above charged particle beam exposing device and a device thereof. SOLUTION: This beam exposing method determines scanning velocity based on layout data, pattern data and secondary data containing coarseness information of the pattern data, and draw an exposure pattern on a sample. In this case, device information having at least current density information of the charged particle beam is referred prior to exposure processing associated with exposure starting operation, velocity data with velocity distribution based on the layout data, the secondary data and device information is generated, and the sample according to pattern data is irradiated with while moving the sample at variable velocity according to generated velocity data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus using a charged particle beam such as an electron beam or an ion beam and an exposure method therefor. More specifically, the present invention relates to an exposure apparatus and an exposure method for performing exposure while continuously moving a stage on which a sample is placed.

[0002]

2. Description of the Related Art Charged particle beam exposure using an electron beam or the like (hereinafter simply referred to as electron beam exposure) is used to form a fine pattern on an LSI chip or the like. In the electron beam exposure method, an enormous number of fine patterns must be irradiated on a sample such as a wafer, and the throughput is inferior to that of a conventional stepper. In particular, when exposing a fine pattern to a desired position on a sample, the electron beam is deflected to generate a desired pattern, and the electron beam is further deflected to a desired position. However, the range in which the electron beam is deflected is limited, and when exposing to a position on the sample that exceeds the range, it is necessary to move the stage on which the sample is mounted.

However, in the method in which the stage is moved and stopped, and the exposure of the deflection range is performed in that state, it takes a settling time until the stage is stopped after the movement of the stage. Since the movement of the stage involves mechanical movement, the settling time becomes long. Therefore, for example, when the sample is a semiconductor wafer, if there are, for example, 100 deflectable regions in one chip,
The exposure time of one chip is 10 times of the settling time of the stage.
0 times the time is required. As a result, the exposure time for one wafer becomes enormous.

Therefore, instead of repeating the above-described method of moving and stopping the stage, a method of irradiating the sample with an electron beam while continuously moving the stage has been proposed. This method is called a stage scanning method. In this stage scanning method, exposure is performed while moving the stage at a constant scanning speed. Therefore, if the moving speed of the stage is set to be high, the exposure position of the sample deviates from the exposure area before the exposure processing is completed, resulting in exposure failure. Conversely, if the stage moving speed is set to a low speed that does not cause the above-described exposure failure even in the portion where the exposure time is the longest and is necessary because the shot density in the exposure pattern is high, the overall exposure processing time become longer.

[0005] This problem can be solved by an exposure method using a variable speed scan that scans the sample while changing the moving speed of the stage.

[0006]

However, this variable speed scan exposure method has many problems to be solved. The reason is that if the stage movement speed is made as high as possible within the range where exposure failure does not occur and the overall exposure time is shortened, when moving the stage at high speed, it suddenly exposes an area that requires a long exposure time, This is because the deceleration falls outside the exposure range in time. The control of the moving speed of the stage cannot always be simply solved.

As an example of a means for solving this problem, the present applicant has proposed a speed control by feedback as disclosed in, for example, JP-A-7-272995. In this method, an optimum speed in a scanning area is given as an initial value, and whether the exposure is advanced or delayed is always monitored while actually performing exposure, and the moving speed is changed by feedback. However, in this method, it is not possible to decelerate abruptly as described above, and it is expected that poor exposure will occur.

As another solution, it has been proposed to calculate the time required for exposure from pattern data of exposure to obtain the speed distribution of the stage. However, the amount of information of the pattern data itself becomes enormous with the increase in the integration degree of the LSI, and when the exposure time is calculated directly from the pattern data, the calculation time is longer than the exposure time. Further, the characteristics such as the beam current value and the deflection area are different for each exposure apparatus, or the characteristics change with the lapse of time even in the same exposure apparatus, so that the velocity distribution once calculated cannot be used again in many cases.

In the manufacturing process of a semiconductor device, means for estimating the processing time of the device is required for the purpose of, for example, setting up an operation plan of the production line. However, in an electron beam exposure apparatus, it is not easy to predict the processing time because the time required for the exposure processing largely depends on the pattern density, the beam current value, and the like. SUMMARY OF THE INVENTION It is an object of the present invention to provide a charged particle beam exposure apparatus capable of exposing a sample in a shortest exposure time with no exposure failure using a variable speed scan exposure, and an exposure method thereof.

It is another object of the present invention to provide a processing time prediction method and apparatus for predicting the processing time in the above charged particle beam exposure apparatus.

[0011]

The object of the present invention is based on arrangement data including arrangement information of an exposure pattern on a sample, pattern data including the exposure pattern, and secondary data including density information of the pattern data. In the charged particle beam exposure method of determining the scan speed of the sample for drawing by writing and writing the exposure pattern on the sample, the current density information of the charged particle beam is synchronized with the exposure start operation prior to the exposure processing. Generating speed data having a speed distribution in the moving direction of the sample based on the arrangement data, the secondary data, and the device information by referring to the device information having at least: Irradiating a charged particle beam on the sample according to the pattern data while moving the sample at a variable speed according to data It is achieved by the charged particle beam exposure method characterized by having a degree. If the speed data is generated immediately before exposure in this manner, the sample can be exposed at the optimum scan speed without occurrence of exposure failure even when the device state such as the beam current density changes.

[0012] The object of the present invention is to perform drawing based on arrangement data including arrangement information of an exposure pattern on a sample, pattern data including the exposure pattern, and secondary data including density information of the pattern data. In the charged particle beam exposure method of determining the scan speed of the sample and writing the exposure pattern on the sample, for each frame extending in the direction in which the sample is scanned, the minimum writing is performed in a direction orthogonal to the scanning direction. Calculating a drawing time of a band in which units are arranged; arranging the frame in the scanning direction and dividing the frame into a plurality of small block regions including a plurality of bands; included in the small block region In consideration of the position coordinates of the band and the drawing processing time, a scan that can be drawn for each of the small blocks is performed. Calculating the scanning speed, generating speed data based on the scanning speed obtained for each of the small block areas, and moving the sample at a variable speed according to the generated speed data, Irradiating the sample with a charged particle beam according to the above method. If the scan speed is determined in this way, it is possible to accurately determine the scan speed for each small block area, even if there is an overlap between the chips arranged at the time of the sample.

In the above charged particle beam exposure method, when the band has an area where the band overlaps in the frame, the frame is divided so that the boundary of the small block area is not located in the area where the band overlaps. It is desirable. If the small block area is divided in this manner, the calculation of the scan speed can be facilitated.

In the above charged particle beam exposure method, it is preferable that the length of the small block area in the scanning direction is shorter than the length of the drawing area in which the charged particle beam can be deflected in the scanning direction. . By setting the length of the small block area in this manner, an optimum scan speed can be set even when the pattern density difference in the small block area is large. It is also effective in improving the throughput.

[0015] Further, the object is to provide an arrangement data file containing arrangement information of an exposure pattern on a sample, a pattern data file storing pattern data including at least an irradiation pattern and an irradiation position of the exposure pattern,
A secondary data file generated from the pattern data and storing secondary data having at least density information of an exposure pattern for each of a plurality of regions; and deflecting and irradiating a charged particle beam to a predetermined position of the sample in accordance with the pattern data. Exposure means for exposing the sample to an exposure pattern and
A variable particle beam exposure apparatus having a sample movement control unit for continuously moving the sample at a variable speed according to the secondary data, wherein the arrangement data file has information for referring to the pattern data file. Charged particle beam, wherein the pattern data file and the secondary data file are associated with each other such that the secondary data file can be referred to using the information for referencing the pattern data file. This is also achieved by an exposure device. By configuring the charged particle beam exposure apparatus in this way, the secondary data can be directly referred to from the arrangement data file without changing the data format of the arrangement data file. Thus, the operator does not directly handle the secondary file, so that the handling of the exposure apparatus can be simplified.

Further, in the above charged particle beam exposure apparatus, in conjunction with an operation of storing the pattern data in a predetermined memory area, a secondary data generation for generating the secondary file and storing the same in a predetermined memory area is performed. It is desirable to have further means. If the charged particle beam exposure apparatus is configured in this manner, the operator can simply read the pattern data and does not handle the secondary data, so that data management can be simplified.

In the above charged particle beam exposure apparatus, the data file deleting means for deleting the secondary data file corresponding to the pattern data file in conjunction with the operation of deleting the pattern data file from the memory area. It is desirable to have more. By configuring the charged particle beam exposure apparatus in this manner, it is possible to prevent the correspondence between the pattern data file and the secondary data file from being broken.

In the above charged particle beam exposure apparatus, the pattern data constituting the pattern data file and the secondary data constituting the secondary data file are stored in different records of one file. Is desirable. By configuring the charged particle beam exposure apparatus in this way, the correspondence between the pattern data file and the secondary data file can be further strengthened.

Further, the object of the present invention is to provide a processing time prediction method for predicting a processing time in a charged particle beam exposure apparatus for irradiating a sample with a charged particle beam for exposure. Processing time for exposing the exposure pattern on the sample based on secondary data including density information of the data and arrangement data including arrangement information of the exposure pattern on the sample; It is also achieved by the prediction method. By estimating the processing time in this way,
Even in a charged particle beam exposure apparatus, the processing time of a desired product can be calculated in a short time.

Further, in the above processing speed prediction method,
It is preferable that the processing time is estimated by referring to device information including beam current density information from a predetermined memory of the charged particle beam exposure apparatus and taking the device information into consideration. By predicting the processing time in this way, it is possible to calculate the processing time according to the latest device status. Further, the above object is to provide a processing time predicting apparatus for predicting a processing time in a charged particle beam exposure apparatus that irradiates a sample with a charged particle beam for exposure, wherein the pattern data including an exposure pattern and the density of the pattern data are adjusted. Processing time calculation means for calculating a time for exposing the exposure pattern on the sample based on secondary data including information and arrangement data including arrangement information of the exposure pattern on the sample; and the processing time calculation Display means for displaying information on the processing time obtained by the means. By configuring the processing time prediction device in this manner, the time required for the exposure processing of the charged particle beam exposure device can be calculated in a short time.

In the above processing time prediction device,
The processing time predicting means further includes apparatus information reading means for accessing the charged particle beam exposure apparatus and referring to apparatus information including beam current density information from a predetermined memory of the charged particle beam exposure apparatus, It is desirable that the time calculation means estimates the processing time in consideration of the device information. By configuring the processing time prediction device in this way, it is possible to calculate the processing time according to the latest device status.

In the above processing means predicting apparatus,
It is preferable that the processing time calculation means calculates a processing time for each processing content in the exposure process, and the display means displays the processing time for each processing content. By displaying the calculation results in this way, it is possible to accurately estimate how much the performance improvement of the unit that affects the processing time can reduce the processing time in the development of the apparatus / process.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a charged particle beam exposure apparatus, an exposure method, and a processing time prediction method and apparatus according to an embodiment of the present invention will be described with reference to the drawings. However, such an embodiment does not limit the technical scope of the present invention. The present invention can be applied to an exposure apparatus using a charged particle beam. Here, an electron beam exposure apparatus will be described as an example.

[Overall Configuration of Charged Particle Beam Apparatus] FIG.
FIG. 2 is a configuration diagram of a lens barrel portion of the electron beam exposure apparatus. An electron beam generated by an electron gun 14 as an electron beam source is applied to a rectangular aperture 15 via an alignment coil (not shown) for alignment and a lens L1a. The resulting rectangular electron beam passes through the lens L
The light enters a slit deflector (deflector) 17 through 1b. The slit deflector 17 is controlled by a correction deflection signal (not shown) and is used for correcting a minute position.

In order to shape the electron beam into a desired pattern, a transmission mask 20 having a plurality of transmission holes such as a rectangular opening and a block mask having a predetermined pattern is used. The transmission mask 20 is mounted on a mask stage 19 that can move in the horizontal direction. Then, in order to deflect the electron beam to a desired block mask position, the electromagnetic lens L2
a, L2b and the deflectors 21 to 24 are provided above and below the transmission mask 20. The astigmatism corrector 11 and the field curvature corrector 12 are provided above the transmission mask 20.
The irradiation and non-irradiation (on / off) of the electron beam shaped by the transmission pattern in the transmission mask 20 on the wafer 36 by the blanking electrode 25 as described above are controlled. The electron beam turned on by the blanking electrode 25 is
Further, the light passes through the lens L3 and passes through the round aperture 27. The round aperture 27 is a kind of stop, and the degree of its opening can be controlled. This limits the half angle of convergence of the electron beam. And
The beam shape is finally adjusted by the refocal coil 28 and the electromagnetic lens L4. Then, an electron beam is focused on the surface of the wafer 36 as an exposure target surface by a focus coil (not shown) provided near the lens L4, and correction of astigmatism and the like is performed by a Sting coil (not shown).

In the final stage, the electron beam is reduced to an exposure size by the projection lens L5, and is controlled by a main deflector (main deflector) 33 and a sub deflector (sub deflector) 34 controlled by an exposure position determination signal (not shown). , Is irradiated to the correct position on the surface of the wafer 36.
The main deflector 33 is an electromagnetic deflector, and the sub deflector 34 is an electrostatic deflector. Then, the sample wafer 36 is mounted on the continuously movable stage 35. The control of the movement of the stage will be described later in detail.

Actuators such as a deflector, an electromagnetic lens, and a stage in the lens barrel of the above-described electron beam exposure apparatus are driven by control signals from a control unit. FIG. 2 is a schematic configuration diagram of a control unit of the electron beam exposure apparatus. In this figure, control means for a part of the above actuator is shown. The CPU 51 has an arrangement data file 52, a pattern data file 53,
The next data file 54, the device data file 55, the speed data file 56, and the like are connected. The pattern data memory 57 stores, for example, the pattern data file 5.
From 3, the pattern data to be exposed is read by the CPU 51. Then, the pattern generation means 58 generates data on, for example, which pattern in the transmission mask 20 is to be used (irradiated) and which position on the wafer 36 is to be irradiated with the electron beam. Among these data, for example, irradiation pattern data is given to a mask deflection control unit 62 in the actuator control unit 61. Then, the deflection Kudo digital signal generated by the control unit 62 is converted into a drive analog signal by the corresponding digital / analog conversion means and amplifier 63 and supplied to the mask deflectors 21 to 24.

The sequence control section 59 controls the electron beam drawing process sequence in the exposure step. Therefore, it receives irradiation pattern data, irradiation position data, and the like generated by the pattern generation means, and controls the entire drawing process. Specifically, synchronization control between the actuator control unit 61 and the stage control unit 60 is performed. In addition, each deflection position data is given to the main deflection control unit 64, the sub deflection control unit 66, and the like according to the irradiation position data. Main deflection controller 6
4. In the sub-deflection controller 66, a deflection digital signal corresponding to the irradiation position is generated, converted into a deflection analog signal by digital / analog converters and amplifiers 65, 67, and provided to the respective deflectors 33, 34. .

The sequence control unit 59 also provides the stage control unit 60 with data necessary for moving the stage.
For example, data such as the position of a pattern currently being exposed. The stage control unit 60 supplies a drive signal to the stage driving unit 68 and receives data on the current stage position from the stage position detecting unit 69 composed of a laser interferometer or the like.

In this embodiment, the moving speed of the stage is variably controlled. The moving speed is set, for example, according to speed data formed by the CPU 51 based on data in the secondary data file. In this example, CPU 51 is 2
The speed data generated based on the next data file is temporarily stored in the speed data file 56, and the speed data is given to the stage control unit 60 from the file. The stage control unit 60 calculates the actual stage movement speed by servo control based on the speed data, generates an optimum movement control signal, and provides the optimum movement control signal to the stage driving unit 68.

Although not shown in FIG. 2, the actuator control unit 61 includes a mask stage movement control unit, a blanking deflector control unit, and the like, in addition to the above. Various correction values generated in accordance with the exposure pattern data generated by the pattern generation means 58 in the figure are supplied to drive control units (not shown) such as the astigmatism corrector 11, the field curvature corrector 12, and a refocal lens. Given to.

FIG. 3 is a diagram showing a relationship between pattern data, arrangement data, and a frame indicating a scan area on a wafer 36 as a sample. In the pattern data file 53 shown in FIG. 2, for example, pattern data for exposure in a chip 37 area as shown in FIG. 3A is stored. There are various methods for the configuration of this pattern data, and a data configuration generally employed by those skilled in the art can be applied.

FIG. 3B illustrates the arrangement data in the arrangement data file 52 in FIG. That is, the pattern data for each chip shown in FIG. 3A is exposed at a position 38 arranged in the wafer 36 as shown in FIG. 3B. As a result, as shown in FIG. 3C, a plurality of chip regions on the wafer 36 are irradiated with an electron beam having an exposure pattern according to the respective pattern data. That is, a region corresponding to the exposure pattern of the resist layer formed on the surface of the wafer 36 is exposed by the electron beam.

FIG. 3 (c) shows the wafer 36, the chip area 37, and the frame 39 which is the scan area when the wafer 36 is exposed while being continuously moved.
Is shown. That is, the frame region 39 is a band-shaped region obtained by dividing the surface of the wafer 36 into stripes. That is, the deflectable range of the electron beam is, for example, a range of several millimeters.
It is divided into nine. And, for example, a plurality of frame areas 3
9, one chip area 37 is covered. FIG.
In the example of (c), one chip area 37 is covered by three frame areas 39.

FIG. 4 is a diagram showing that the exposure area of the electron beam is scanned by moving the stage on which the wafer is mounted. The movement of the stage is controlled so that the exposure area moves along the frame area 39 described above. And
As shown by the arrow in FIG. 4, when the exposure of one frame area 39 is completed, the exposure area moves in the opposite direction along the adjacent frame area.

FIG. 5 is a diagram showing an example of a deflection area in the frame area. The main deflector shown in FIG. 1 is usually constituted by an electromagnetic deflector and can deflect a relatively large range, for example, a few millimeters. However, the response of the electromagnetic deflector is slow due to its inductance. Further, the sub-deflector is usually constituted by an electrostatic deflector, and can deflect, for example, only in a range of several hundred microns. However, in the case of an electrostatic deflector, the response is fast. Usually, the main deflector 3
The main field that can be deflected by the sub deflector 3
4 is divided into subfields that can be deflected. Then, the electron beam having the pattern shaped by the block mask is deflection controlled to a desired position by a combination of the main deflector 33 and the sub deflector 34.

A part 40 of the frame 39 shown in FIG.
Shows a region that can be deflected by the main deflector (hereinafter, referred to as a deflectable region 40). As shown in FIG. 5, the deflectable area 40 includes a plurality of subfields SF that can be deflected by the sub deflector 34. A plurality of subfields S are arranged in a direction perpendicular to the direction of movement of the wafer along the frame 39.
F are arranged side by side. A region where the subfields SF are arranged in a line is referred to as a band B. In FIG. 5, the moving speed of the stage is controlled so that the exposure process in the band Bi is completed while the band Bi indicated by oblique lines is located in the deflectable region 40, for example. In the figure, bp0
Ｂbpn indicates the boundary of band B.

FIG. 6 is a diagram showing an example of the relationship between the frame in the chip area and the deflectable range of the main deflector. As apparent from FIGS. 3, 4, and 5, in this example, the chip area 37 is covered by three frames, and each frame is divided into a plurality of small block areas 41.
The small block area 41 is composed of a plurality of bands B, and corresponds to, for example, a main field by a main deflector.

[Structure of Data File] FIG. 7 is a diagram showing an example of the data structure of the pattern data in the pattern data file 53. The pattern data includes at least data of a pattern P having a beam shape to be irradiated and a position (x, y) at which the pattern P is irradiated. Specifically, the beam shape is data on which aperture in the transmission mask 20 is used when using the block mask method. When the blanking aperture method is used, the data is pattern number data such as a pattern table prepared separately and recorded in a file.

This pattern data has, for example, data in one chip area. Therefore, as shown in FIG. 6, one chip area has a plurality of main field areas, and each main field area has a plurality of subfield areas. Along with that, the pattern data is also shown in FIG.
, The plurality of main fields MF1 to MF
n. Each main field is divided into a plurality of subfields SF1 to SFm. The pattern data (P1, x1, y1) to be exposed for each subfield SF
(Pk, xi, yj) 〜.

As described above, it is preferable that the pattern data in the pattern data file is divided into the main field and the subfield in the variable speed control of the sample. That is, the situation related to the time required for exposure, such as the density of the exposure pattern in the subfield, differs for each subfield. Accordingly, the time required for exposing one band composed of a plurality of subfields naturally differs. As shown in FIG. 5, when exposing while moving continuously along the frame 39, it is necessary to control the moving speed of each band according to the time required for exposing each band. Alternatively, it is necessary to control the moving speed in that part according to the time required for exposure in units of a plurality of bands.
Therefore, it is important that the pattern data is divided for each subfield which is a component of the band.

FIG. 8 is a diagram showing an example of the data structure of the secondary data in the secondary data file 54. In the present embodiment, the secondary data includes information necessary for calculating the moving speed distribution of the stage. Then, such secondary data is created in advance before exposure. Therefore, the velocity distribution of each frame can be calculated from the secondary data and the arrangement data.

A first example of this secondary data is a pattern P
Of the electron beam irradiation density (shot density). In order to perform exposure by irradiating an electron beam of one pattern, it is necessary to chemically change a resist film on a sample. In addition, as shown in FIG. 1, it is necessary to deflect the electron beam to a desired position in the transmission mask 20 and deflect the electron beam again to a desired position on the sample by the main and sub deflectors 33 and 34. Although there is a slight difference depending on the degree of change of each deflection position, for example, the time required for exposure by irradiating one pattern of the electron beam can be averaged mainly from the exposure time and the like. Therefore, by storing the distribution of the shot density of the frame in the chip in the scan direction as a file in advance as secondary data, the wafer 36
When the arrangement data of the chips in the wafer is determined, the velocity distribution in the scanning direction in the frame of the whole wafer can be easily obtained.

In the example of the secondary data shown in FIG. 8, the data DE of the shot density is divided for each subfield SF. That is, in the subfield SF1 in the main field MF1, data on the number of shots in the subfield is stored as DE11. In this example, since the area is already divided into subfields, the number of shots in that area is substantially equivalent to the shot density. Therefore, the shot density for each band can be easily obtained by using the secondary data. Furthermore, each shot density in the small block area 41 composed of a plurality of bands can be easily obtained.

FIG. 9 shows a second example having shot density data.
FIG. 14 is a diagram illustrating another example of a data configuration of next data. In this example, band B composed of a plurality of subfields SF
Shot density data DE is obtained and stored for each shot.
With this configuration, the time required for exposure for each band can be roughly obtained from the product of the shot density and the average exposure time for one shot. The exposure time required for one shot is
Such data has, for example, a device data file 55 because it has device dependency such as device and resist and process dependency.
Is stored within. It can be obtained by reading these data.

The second example of the secondary data includes, in addition to the number of shots per predetermined area, the number of times the deflection position has been changed (the number of jumps) and the velocity distribution of the amount of change in the deflection position. The deflectors are mainly electrostatic deflectors 21 to 24 for changing the deflection position in the transmission mask 20, an electromagnetic deflector 33 as a main deflector, and an electrostatic deflector 34 as a sub deflector. When the deflection position of the electron beam is changed by the deflector, different deflection signals are given to each deflector. Therefore, when the deflection position is changed, a waiting time for settling at the deflection position is required. In particular, the settling time with the electromagnetic deflector is much longer than with the electrostatic deflector. Also, the electrostatic deflector is relatively short, but the number of times is large, and similarly a settling time is required.

Therefore, by adding the number of times these deflection positions are changed to the above shot density, a more actual distribution of the exposure time can be obtained. Further, when the deflection position is changed, the settling time tends to be longer as the change amount is larger. Therefore, a more accurate settling time can be calculated by including, in the secondary data, the frequency distribution of the amount of change in the deflection position, which is made up of the number of changes (the number of jumps) for each change amount (jump distance).

FIG. 10 is a diagram showing an example of a frequency distribution of the amount of change in the deflection position. In this example, the number of deflection position changes (jumps) in which the amount of change in the deflection position is in the range of 0 to DL1, DL1 to DL2... DL4 to DL5 is N1, N2. This is the frequency distribution. Therefore, the respective settling times t1, t2,.
5 is obtained from the device file data, the total settling time Ts can be obtained as Ts = N1 × t1 +... + N5 × t5.

Therefore, such a frequency distribution is used as a part of the secondary data for each subfield, for each band, or for the unit length of a frame for setting the velocity distribution, for example, for each small block area 41 or each main field. With this, the time required for more accurate exposure can be determined. The frequency distribution is, for example, the electron deflector 3
3, provided to the electrostatic deflectors 21 to 24 and 34, respectively.

FIG. 11 is a diagram showing another example of the frequency distribution of the amount of change in the deflection position. While the example of FIG. 10 has a one-dimensional frequency distribution, the example of FIG. 11 has a two-dimensional frequency distribution. As described in FIG. 1, the main electrostatic deflectors are:
Deflectors 21 to 21 for deflecting an electron beam in the transmission mask 20
24 and a sub deflector 34 for deflecting the light in the wafer 36. Since the settling time of the electromagnetic deflector 33 is very long, even if the change of the deflection position by the electrostatic deflector occurs simultaneously with the change of the deflection position of the electromagnetic deflector, the settling time at that time is the settling time of the electromagnetic deflector. Be bound. However, if the change of the deflection position by the mask deflectors 21 to 24 and the change of the deflection position by the sub deflector 34 occur simultaneously in the main field, the settling time of both is equal, so that the settling time of both is reduced. Duplicate counting requires a longer settling time than the actual settling time. In that case,
It is desirable to count only the longer settling time.

Therefore, in the example of FIG. 11, a two-dimensional frequency distribution having a horizontal axis, which is the amount of change in the deflection position by the sub deflector 34, which is a sub deflector, and a vertical axis, which is the amount of change in the deflection position by the mask deflector. Is adopted. Accordingly, the frequency distribution is represented by a number of times N11 to N5 in a two-dimensional matrix.
5 is obtained. In this example, for example, the number N1
In step 5, the total settling time is calculated mainly in accordance with the settling time by the sub-deflector. In the number of times N51,
The calculation of the total settling time is mainly performed according to the settling time of the mask deflectors 21 to 24. Their settling time is
As described above, it is stored in the device data file 55.

Further, when this concept is expanded, the drive current of the electromagnetic coils is set in consideration of the settling time generated in the electromagnetic coils such as the astigmatism corrector 11 and the field curvature corrector shown in FIG. A more accurate total settling time can be obtained by adding the distribution of the variation and obtaining the N-dimensional frequency distribution in advance. Therefore, the most detailed example of the secondary data is the number of shots, the frequency distribution of the electromagnetic deflector as shown in FIG. 10, and the two-dimensional frequency distribution of the two electrostatic deflectors as shown in FIG. Have. Further, if the computer has a high processing capability, an N-dimensional frequency distribution can be used. FIG. 12 shows each small block area 41 obtained from the secondary data and the arrangement data.
It is a figure showing an example of speed distribution for every. The horizontal axis is frame 3
9, the small block area 41 arranged in the scanning direction
The vertical axis indicates each speed. In this example, the small block area 41 is the same as the main field. As described above, a small block area (MF1
When the speed (V1... Vn + 4...) At... MFn + 4... Is obtained, the speed data is stored in the speed data file 56 shown in FIG. The calculation of the speed data is performed by the CPU 51 based on the data in the arrangement data file 52 and the secondary data file 54. That is, the time required for exposure for each small block area is obtained from both data, and the stage speed in the small block area is obtained from the relationship with the deflectable area 40.

The speed data for each small block area shown here means the maximum speed there. Therefore, moving the stage at a speed higher than the maximum speed may cause exposure failure. Therefore, the stage control unit 6
At 0, the stage movement is controlled so that the speed is within the range of the speed data. Movement control on such a stage
It can be realized by some kind of servo control. As shown in FIG. 2, the stage control unit 60 supplies a drive signal to the stage driving unit 68 and simultaneously monitors the speed of the stage by the stage position detecting unit 69. Therefore, while monitoring the stage speed by the stage control unit 60, the stage speed can be controlled so as to match the speed distribution of FIG. 12 as closely as possible. Servo control involving such feedback control is performed by servo control means obvious to those skilled in servo control.

Since the above-mentioned secondary data has, for example, a shot density for each subfield, it has an extremely small data amount as compared with the pattern data. Further, by providing the secondary data for each band or each small block area, the data amount can be further reduced. Further, the step of calculating the speed data from the secondary data and the arrangement data by calculation is preferably performed before the exposure step, and the speed data is stored in the file 56. However, since the calculation itself is not so complicated, it is also possible to generate speed data at the same time as drive data is generated from pattern data by the pattern generation means.

Since the secondary data depends only on the pattern data, it can be used for different exposure apparatuses and exposure conditions. For specific control of moving the stage using the speed data file 56 generated as described above, for example, a speed control method described in Japanese Patent Application No. 9-922248 by the same applicant may be applied. it can.

[Data File Storage Form] Normally, the layout data file 52 contains the name of the pattern data file to be exposed, but not the name of the secondary data file. It is necessary to specify the file 54 or separately provide a record specifying the secondary data file 54 in the arrangement data file 52.

Although the secondary data creation program and the speed data creation program must be directly executed by the operator, it is necessary to manage these data in addition to the pattern data and the arrangement data. The burden on the operator is significantly increased as compared with the repeat exposure method. In order to solve such a problem, the pattern data file 53 and the secondary data file 54 are stored in association with each other, and the information for referring to the pattern data included in the arrangement data file 52 is used for the secondary data file 54. It is desirable to be able to refer to By associating the secondary data file 54 in this way, the secondary data file 54 can be automatically specified without changing the data format of the arrangement data file 52 at all. As a result, the operator can perform the exposure process by designating only the arrangement data file 52 without directly dealing with the secondary data file 54.

First to associate the secondary data file 54
As a method, the file name of the pattern data file 53 and the file name of the secondary data file 54 are the same, and only a predetermined extension (for example, “.dns”) is added to the secondary data file. It is valid. For example, if the file name of the pattern data file 53 is "aa"
In the case of “a”, the file name of the secondary data file is, for example, “aaa.dns.” In the arrangement data file 52, “aaa” is used as information for referring to the pattern data file 53 and the secondary data file 54. In addition, in consideration of file management, etc., it is desirable that the arrangement data file 52, the pattern data file 53, and the secondary data file 54 be stored in separate directories.

If the file names of the pattern data file 53 and the secondary data file 54 are set in this way, when the operator specifies an arrangement data file 52 to be exposed and executes an exposure command, the arrangement data file 52 The pattern data file name stored in a predetermined record in the file is designated, and the corresponding pattern data file (for example, pattern data file “aaa”)
Can be referred to.

At the same time, the corresponding secondary data file 54 is specified from the information of the pattern data file 53 stored in a predetermined record in the arrangement data file 52,
A corresponding secondary data file (eg, secondary data file “aaa.dns”) can be referenced. The secondary data file 54, which has the same file name as the pattern data file 53 and has only an extension added thereto, can be easily specified on software without manipulating the records of the arrangement data file.

Therefore, when the operator specifies the arrangement data file 52, the secondary data file is automatically specified, so that the operator can perform the exposure processing without directly handling the secondary data file 54. In the above method, an extension is added as the easiest method for associating a data file. However, if a pattern data file 53 and a secondary data file 54 can be associated and referenced from a predetermined record in the arrangement data file 52, Any method may be used.

In conjunction with the operation of storing the pattern data information in the computer for controlling the exposure apparatus, the pattern data information is analyzed to create a secondary data file 54, which is stored in a predetermined memory area with a predetermined file name. Then, when the operator takes in the pattern data information and creates the pattern data file 53, the secondary data file 54 can be created at the same time. In this way, it is possible to prevent the operator from directly handling the secondary data file 54 even in the process of generating the secondary data file 54.

The pattern data file 53 and the secondary data file 54 are stored in the memory of the computer for controlling the exposure apparatus, and it is desirable to program such that the creation and deletion of these files are linked. This is because if only one file is stored in the memory, the correspondence between the pattern data file 53 and the secondary data file 54 may be broken.

FIG. 13 shows one storage form of the data file in the first method for associating the secondary data file 54. In the arrangement data, for example, a pattern data name to be exposed, arrangement information for arranging the pattern data on a wafer, and an exposure amount are described, and are stored in a directory of an exposure apparatus control computer, for example, “/ LYO /”. Store.

In the pattern data, for example, data of a pattern to be exposed is described and stored in a directory of a computer for controlling the exposure apparatus, for example, "/ PTN /". In the secondary data, for example, the position coordinates within the chip of the small block area 41, the number of shots in the small block area 41, and the number of deflector jumps are described. The secondary data is created by analyzing the pattern data stored in the directory “/ PTN /” by a program that operates in conjunction with a command that the apparatus can use, and creates a directory of the exposure apparatus control computer, for example, Stored in "/ DNS /".

The operator enters the directory "/ LYO
When the exposure command is executed by designating, for example, the arrangement data A from /, the pattern data file "aaa" is referred to from the directory "/ PTN /". At the same time, the secondary data file "aaa" is read from the directory "/ DNS /".
a.dns ". After that, using these data files, the speed data file 56 is obtained by the method described above.
And an exposure process can be performed.

When a pattern data file is deleted from the system, the corresponding secondary data file 54 is deleted by a program operating in conjunction with a command for deleting the pattern data file 53 from the system. In addition to these means, there is no particular need to provide a means for the operator to introduce or delete pattern data from the system.

The second linking the secondary data file 54
It is also effective to form the pattern file including the pattern data and the secondary data without dividing the pattern data file 53 and the secondary data file 54. For example, a pattern file having a record corresponding to the contents of the pattern data file 53 and a record corresponding to the contents of the secondary data file is created, and predetermined information for referring to the pattern file name is stored in the arrangement data file 52. Store. For example, if the pattern file name is “aaa”, the arrangement data file 52
Information "aaa" may be stored as information for referring to the pattern file. Further, in consideration of file management and the like, it is desirable to store the arrangement data file 52 and the pattern file in separate directories.

When a pattern file including the contents of the pattern data file 53 and the contents of the secondary data file 54 is prepared, the operator executes the exposure command by specifying the arrangement data file 52 to be exposed. Then, the pattern file name stored in a predetermined record in the arrangement data file 52 is designated, and the corresponding pattern file (for example, the pattern file “aa”) is specified.
a ").

Therefore, if the operator specifies the layout data file 52, the contents corresponding to the pattern data file 53 and the secondary data file 54 can be automatically referred to, so that the operator can directly refer to the secondary data file 5.
Exposure processing can be performed without dealing with Step 4. Also,
The pattern data information is analyzed in conjunction with the operation of converting the pattern data information from the CAD data, and a pattern file having the pattern data and the secondary data is created and stored in a predetermined memory area with a predetermined file name. By doing so, it is possible to eliminate the need for the operator to handle the secondary data. The creation of the pattern file may be performed by a computer for controlling the exposure apparatus, or may be performed by a computer other than the exposure apparatus.

Since the pattern file includes the contents of the pattern data file 53 and the secondary data file 54, the creation / deletion of the data file need only be performed for this file. Therefore, a data file can be handled without breaking the correspondence between the pattern data and the secondary data. The second method for associating the secondary data file 54 is an extremely effective method for maintaining the correspondence between the files.

FIG. 14 illustrates a storage form of the data file in the second method for associating the secondary data file 54. In the arrangement data, for example, a pattern data name to be exposed, arrangement information for arranging the pattern data on a wafer, and an exposure amount are described, and are stored in a directory of an exposure apparatus control computer, for example, “/ LYO /”. Store.

The pattern file includes, for example, data of a pattern to be exposed and a pattern data file (pattern data file 5).
3), the in-chip position coordinates of the small block area 41, the number of shots in the small block area 41, the number of deflector jumps, and the equivalent of a secondary data file. For example, "/ PTN
/ ”.

The operator enters the directory "/ LYO"
When the exposure command is executed by designating, for example, the arrangement data A from /, the pattern file “aaa” is referred to from the directory “/ PTN /”.
Since "aaa" stores information corresponding to the pattern data file 53 and information corresponding to the secondary data file 54, the speed data file 56 is created by the above-described method using the pattern file "aaa". Exposure processing can be performed.

[Formation of Data File Generation] In the charged particle beam exposure method according to the present embodiment, the pattern data is analyzed to create secondary data which is the pattern density data in the chip, and the secondary data and the device data are converted. The scanning speed distribution in the wafer is arranged on the basis of the speed data to create speed data, and scanning is performed at a high speed at a low density and at a low speed at a high density while exposing. According to this method, once created speed data can be reused basically when the same pattern is exposed again.

However, if there is a change in the apparatus state such as the beam current density between the time when the speed data is generated and the time when the exposure processing is performed, the scanning speed is too high to cause exposure failure, or the scanning is performed at a meaninglessly low speed. There is a concern that the throughput may be reduced. In order to solve such a problem, the apparatus status immediately before exposure is taken into an apparatus data file 55, and the apparatus data file 55 is referred to by referring to the arrangement data file 52, the secondary data file 54, and the apparatus data file 55. It is desirable to create the speed data file 56 according to the situation. As described above, by determining the scan speed using the speed data file generated using the state immediately before the exposure of the apparatus, the exposure can be performed at the optimum scan speed. In addition, the possibility of exposure failure can be reduced.

[Cover Area Overlap Correction] In the scan speed calculation method according to the present embodiment, as shown in FIG. 15, the area inside the chip 37 is first divided into small block areas 41 having a frame 39 width. The maximum scan speeds V ₀₀ ... V _NxNy are obtained for each 41 (FIG. _15A ), and the scan speed distribution on the wafer 36 is obtained based on the information of the arrangement data file 52. The maximum scanning speed of the small block area 41 is such that the small block area 41 is further divided into bands B, and the time t ₀ ... T _Nb required for the exposure processing is calculated for each band B (FIG. 15B). , By calculating the scan speed V from these values.

However, the areas of the chips 37 to be exposed on the wafer 36 may overlap each other due to the necessity at the time of exposure, the layout, and the like (FIG. 15C). In such a case, an appropriate scan speed in the overlap region cannot be obtained from the speed V obtained by the above method. Using FIG.
The reason why the optimum scan speed cannot be obtained will be described. FIG. 16 is a partial cross-sectional view for explaining the effect of overlap between chips.

If there is no overlap between the chips 37 as shown in FIG. 16A, the small block area 41a included in the second chip is exposed after exposing the small block area 41a included in the first chip. Expose 41b. FIG.
Even when the overlap region 70 exists as shown in FIG. 6B, exposure is performed in principle in this sequence because control is efficient. However, it is necessary to return the beam deflection position to the lower end of the small block area 41b after exposing to the upper end of the small block area 41a.
If the scan is performed at the scan speed set for 1a, the overlap region may be out of the drawable range during exposure of the small block region 41b, and exposure failure may occur. Although it is possible to forcibly specify a very low scan speed in the overlap portion, this is often not the optimum speed, and furthermore, exposure failure may occur depending on the pattern.

When the areas of the chips 37 to be exposed overlap each other, the following scan speed determination method is effective. FIG. 17 is a diagram for explaining a method of determining a scan speed when the chip 37 areas overlap. First, the inside of the chip 37 is divided into predetermined bands B.

Next, the chips 37 divided into the bands B are arranged on the wafer 36, and are developed on the frame 39 in consideration of the position of each band B (FIG. 17A). Subsequently, the necessary exposure time is calculated for each of all the bands B included in the frame 39 exposed by one scan when the chip 37 is placed on the wafer 36.
In the overlap region 70 of the chip 37, the necessary exposure time is calculated for each of the overlapping bands B.

Subsequently, the frame 39 is divided into a plurality of small block areas 41 arranged in the scanning direction (FIG. 17).
(B)). In order to facilitate the calculation in the scan speed determination area in the post-process, it is desirable to divide the frame 39 so that the boundary of the small block area 41 is not located in the overlap area of the chip 37. Thereafter, the scan speed is determined for each small block area 41.
The scanning speed can be obtained from the required exposure time of the band B included in the small block area 41. Here, the scan speed of the small block area 41 including the overlap area is determined as follows.

That is, including the overlap area 70
The small block area 41c includes the small block area 41c.
Band B₀~ B_NIn addition to the required exposure time
₀~ B_NScan speed considering the position coordinates in the frame
decide. For example, as shown in FIG.
_iAnd band B_{i + 1}If they overlap,
Band B included in lock area 41c₀~ B_NRequired exposure
After finding the fastest scan speed from time, band B_i
Band B after exposure_{i + 1}Exposure to band B _{i + 1}Drawable
Scan as fast as necessary to stay within the image range
You only have to reduce the speed. The rate at which the scan speed decreases
B_iAnd band B_{i + 1}Required exposure time, band position
Overlap length L obtained from coordinates, settling time of deflector
Easily calculated by numerical calculation
can do.

Even when a plurality of bands B overlap each other, the fastest scan speed can be determined by the same method as described above. Thus, the frame 39
If the scan speed of all the small block areas 41 over the entire area is determined, it is possible to determine the optimum speed according to the pattern to be exposed even when the chip includes an area where the chip overlaps.

[Division of Small Block Area] FIG. 18 is a diagram for explaining a problem relating to the length of the small block area 41 in the scanning direction. When the fine patterns are concentrated in a very narrow range A in the small block area 41 as shown in FIG. 18A and there are almost no other patterns, the above-described scan speed distribution data calculation method uses the area A Is determined so that the pattern included in the area A can be drawn within the time in which the pattern remains within the drawable range. Therefore, the area A
Must be scanned at the same speed from the time when drawing of the pattern is finished to the time when the scanning of the small block area 41 is completed, even though there is almost no pattern to be exposed (FIGS. 18B to 18C). . Therefore, when the entire small block area 41 is viewed, the exposure time is unnecessarily consumed, and the set scan speed is not always optimal.

In such a case, the length of the small block area 41 in the scanning direction is smaller than the range in which the electron beam can follow when the position on the sample to be drawn moves by the stage scan (drawable range). It is desirable.
The scanning speed in the small block area 41 is set so that the drawing of the fine area in the small block area 41 can always be performed near the column center position. Therefore, immediately after the exposure of the fine area is completed, an unexposed area exists in the drawing range before the column center position, and even when the stage scan speed is slow, the unexposed area is located at the center of the column. Exposure can be performed without waiting for the position to be reached.

Therefore, if the length of the small block area 41 is approximately half the length of the drawable area, the stage scan speed is affected even if a small exposure area exists in the small block area 41. Thus, the exposure in the small block area 41 can be completed in a short time. On the other hand, considering the case where the electron beam deflection position is near the upper end of the drawable range at the end of drawing the fine area, the unexposed area is exposed to almost the entire drawable range. , The unexposed area in this range can be exposed. Therefore, the small block area 41
Is approximately equal to the length of the drawable range, the exposure time can be reduced without being largely affected by the stage scan speed.

Accordingly, when the entire small block area 41 is viewed, the length of the small block area 41 is set to be smaller than the length of the drawable range, preferably about half the drawable range. Exposure can be performed at an optimum scan speed. By setting the length of the small block area 41 in this manner, even if patterns are densely packed in a narrow area, the next small block area can be created by the time drawing of this dense area is completed. Since the drawing enters the drawing range, the throughput can be improved without unnecessary stage scanning at a low speed.

In a typical electron beam exposure apparatus at present,
Since the drawable range is about 1.6 mm □, the length of the small block area 41 can be set to, for example, about 0.8 mm. Note that the smaller the small block area 41, the longer the time spent for data processing increases. Therefore, it is desirable to make appropriate adjustments according to the pattern data.

[Estimation Method of Exposure Processing Time] In the manufacturing process of a semiconductor device, a means for estimating the processing time of the device is required for the purpose of, for example, making an operation plan of the production line. In a normal exposure apparatus using the step-and-repeat method, the processing time can be relatively easily estimated from the exposure time per chip, the number of chips, the number of wafers, and the like. Since it largely depends on the density, beam current value, etc., it is not easy to predict the processing time.

In particular, in an electron beam exposure apparatus, the apparatus state such as the beam current density may fluctuate. Therefore, even if the processing time is calculated and measured for a certain product, the processing speed also changes due to the change in the apparatus state. Thus, it is difficult to find an appropriate processing time according to the situation. In addition, in the development stage of an exposure apparatus or a manufacturing process, in order to know exactly how effective the performance improvement of a certain unit that affects the processing time is in reducing the processing time, it is necessary to perform complicated calculations. It was necessary to actually perform the exposure processing. The former requires an enormous number of steps and time, and the latter requires an occupation time of the apparatus, which is not preferable.

Therefore, a method of calculating a processing time according to the state of the apparatus in a short time is desired for an electron beam exposure apparatus. By the way, in the above-mentioned electron beam exposure apparatus, in order to obtain the scan speed distribution in the wafer plane, at least the position coordinates in the chip of the small block area 41, the number of shots in the small block area 41, and the number of deflector jumps are determined. The secondary data file 54 is generated.

The secondary data file 54 generally has a significantly smaller amount of information than the pattern data, but contains sufficient information for calculating the processing time. Therefore,
By analyzing the secondary data file 54, the processing time of the electron beam exposure apparatus for an arbitrary product can be calculated in a short time. Further, by providing means for accessing the exposure apparatus control computer and obtaining apparatus information of the exposure apparatus, it is possible to calculate the processing time according to the apparatus state.

Hereinafter, a method and apparatus for estimating the processing time in the above-described electron beam exposure apparatus will be described in detail. FIG.
Is a diagram for explaining the outline of a processing time prediction device, and FIG. 20 is a flowchart for explaining a processing time prediction method. FIG.
Is a graph showing a display example of the processing time in the processing time prediction method. First, the processing time prediction device will be described.

The CPU 51 of the computer for controlling the exposure apparatus includes:
An arrangement data file 52, a pattern data file 53, a secondary data file 54, a device data file 55, a speed data file 56, and the like are connected via a bus.
The CPU 51 performs a series of processes of the electron beam exposure apparatus (see FIG. 2). A processing time calculation computer is provided separately from the exposure apparatus control computer. The CPU 71 of the processing time calculation computer has an arrangement data file 52, a secondary data file 54, an apparatus data file 55, and the like via a bus. Is connected. These data files are desirably configured to be shared with the exposure apparatus control computer. The CPU 71 is further connected to a display means 72 for displaying a calculation result of the processing time.

The CPU 71 operates the arrangement data file 52,
The display unit 72 displays the processing time calculated based on each data read from the secondary data file 54 and the device data file 55. The arrangement data file 52 stores information such as array information for arranging pattern data on a wafer, an exposure amount, and the number of alignment points.

The secondary data file 54 stores information such as the position coordinates within the chip of the small block area 41, the number of shots in the small block area 41, and the number of deflector jumps. The device data file 55 stores information such as electron beam current density and electron beam adjustment frequency.
Since the information stored in the apparatus data file 55 is greatly affected by fluctuations in the characteristics of the electron beam exposure apparatus, it is desirable to store new information frequently. By calculating the processing time using the most recently stored data, it is possible to generate a predicted value that is very close to the current processing time.

The display means is, for example, a CRT display. In FIG. 19, a computer for controlling the electron beam exposure apparatus and a computer for calculating the processing time are separated, but this makes it possible to calculate the processing time even when the electron beam exposure apparatus is performing the exposure processing. To do that.
Therefore, it is not always necessary to use separate computers, and one computer may have both functions. Alternatively, a plurality of processors may be provided in the exposure apparatus control computer.

Next, a processing time prediction method will be described with reference to FIG. The processing time per wafer can be obtained by calculating the processing time for each of the following items and calculating the sum of these. (i) Scan Time The scan time includes, among processing times required for exposing one wafer, a time for actually shooting a sample, a settling time for the main deflector 33, and the like.

The scan time is set in the placement data file 52.
Array information and exposure amount, the position coordinates in the chip of the small block area 41 in the secondary data file 54, the number of shots,
It is calculated based on information such as the number of deflector jumps, the current density in the device data file 55, and the settling time of the polarizer.
In calculating the scan time, the scan speed distribution is calculated in the same manner as the above-described speed distribution calculation algorithm, and the scan time is calculated from this distribution.

Various methods are disclosed in Japanese Patent Application No. 9-922248 for controlling the speed at the time of moving the stage. When this control method is applied, it is desirable to appropriately change the scan time calculation method according to each control method. (ii) Alignment time Alignment time is one of the time required to perform alignment with a base pattern in a certain process during exposure.
This is the sum per wafer.

The alignment time is obtained by (standard alignment time) × (number of alignment points). The number of alignment points means the number of alignments performed in one wafer, and can be obtained by reading the number of alignment points stored in the arrangement data file 52.

The standard alignment time means a standard time required for one alignment, and can be easily obtained by an approximate calculation using a linear expression or the like using empirical values. (iii) Beam Adjustment Time The beam adjustment time is the total time per wafer for adjusting the electron beam in a certain process during exposure. The adjustment of the electron beam is to adjust the electron beam to a predetermined state again using the mark detection function in order to correct the state of the electron beam when the deflection efficiency of the polarizer changes during exposure.

The beam adjustment time is obtained by (standard beam adjustment time) × (number of times of beam adjustment). The number of beam adjustments can be obtained by reading the beam adjustment frequency during the exposure process set in the apparatus from the apparatus data file 55, and calculating the number of beam adjustments from the scan time. The standard beam adjustment time means a standard time required for one beam adjustment, and can be easily obtained by performing an approximate calculation by a linear expression or the like using empirical values.

(Iv) Other Processing Times In order to predict the processing time per lot when processing wafers in lots, it is desirable to consider the following time in addition to the above processing time. By taking these processing times into account, more accurate throughput can be estimated.

A) Wafer Replacement Time In an electron beam exposure apparatus, since exposure processing is performed in a vacuum, there is time to replace a wafer between a main chamber for performing exposure and a sub-chamber for performing wafer replacement. For this reason, when processing a plurality of wafers continuously, it is desirable to consider the wafer replacement time.

As the wafer replacement time, a time empirically obtained in each electron beam exposure apparatus may be used. b) Vacuum evacuation and vacuum leak time When processing one lot, a certain period of time is required from when the first wafer is loaded into the sub-chamber to when a predetermined degree of vacuum is reached. Further, after processing the last wafer, a certain time is required in a vacuum leak process for removing the wafer from the sub-chamber. Therefore, by considering these times, a more accurate throughput can be estimated.

As the vacuum evacuation and vacuum leak time, a time empirically obtained in each electron beam exposure apparatus may be used. The predicted processing time thus obtained can be displayed by the display means 72, for example, as shown in FIG. FIG. 21 shows a case where the processing time is divided into five components and displayed in the four-layer lithography process. In the figure, item a is a stage arrival waiting time associated with the upper limit of the acceleration of the stage driving means in a region where the stage scan speed greatly changes. Item b is the stage arrival waiting time associated with the upper limit of the speed of the stage driving unit. Item c is the settling time of the main deflector 33. Item d is a waiting time for mounting a mask and a wafer. Item e is a shot time. These items can be obtained in the process of calculating the various processing times described above.

By displaying the time required for processing separately for each component in this way, it is possible to see at a glance which component determines the processing time, and it is possible to improve the performance of any unit. It is possible to predict whether the total processing time can be effectively reduced. Therefore, the guideline of the development stage can be obtained without requiring an enormous amount of time and occupation time of the device.

If the processing time per wafer is obtained, the number of wafers that can be processed per unit time can be predicted. Therefore, such data may be displayed.

[0111]

As described above, according to the present invention, based on the arrangement data including the arrangement information of the exposure pattern on the sample, the pattern data including the exposure pattern, and the secondary data including the density information of the pattern data. In a charged particle beam exposure method for determining a scan speed of a sample for writing by drawing and writing an exposure pattern on the sample, at least having current density information of the charged particle beam prior to exposure processing in conjunction with an exposure start operation Generating speed data having a speed distribution in the moving direction of the sample based on the arrangement data, the secondary data, and the device information by referring to the device information; and moving the sample at a variable speed according to the generated speed data. Irradiating the sample with a charged particle beam according to the pattern data while performing the measurement. Even if there is, it is possible to expose the sample at the optimum scanning speed without exposure failure occurs.

Further, the scan speed of the sample for drawing based on the arrangement data including the arrangement information of the exposure pattern on the sample, the pattern data including the exposure pattern, and the secondary data including the density information of the pattern data is set. Determined, in the charged particle beam exposure method for writing the exposure pattern on the sample, for each frame extending in the scanning direction of the sample, the writing time of the band in which the minimum writing unit is arranged in a direction orthogonal to the scanning direction, Calculating, arranging the frames in the scanning direction, dividing the frame into a plurality of small block regions including a plurality of bands, and taking into account the position coordinates of the bands included in the small block regions and the drawing processing time, Calculating the drawable scan speed for each of the And a step of irradiating the sample with a charged particle beam according to the pattern data while moving the sample at a variable speed according to the generated speed data. Even if overlap occurs,
The scanning speed can be accurately determined for each small block area.

When a band has an area where a band overlaps in a frame, the frame is divided so that the boundary of the small block area is not located in the area where the band overlaps, so that the calculation of the scanning speed can be facilitated. In addition, since the length of the small block area in the scanning direction is shorter than the length of the drawing area in which the charged particle beam can be deflected in the scanning direction, the optimum scanning speed is used even when the pattern density difference in the small block area is large. Can be set. It is also effective in improving the throughput.

Further, an arrangement data file containing arrangement information of an exposure pattern on a sample, a pattern data file storing pattern data including at least an irradiation pattern and an irradiation position of the exposure pattern, and at least a plurality of data generated from the pattern data. A secondary data file for storing secondary data having density information of an exposure pattern for each region; an exposure unit for deflecting and irradiating a charged particle beam to a predetermined position of the sample according to the pattern data to expose the sample to the exposure pattern; A variable particle beam exposure apparatus having a sample movement control means for continuously moving the sample at a variable speed according to the secondary data;
Has information for referring to the pattern data file,
The pattern data file and the secondary data file are stored using information for referring to the pattern data file.
Since the charged particle beam exposure apparatus is configured so as to be related to each other so that the next data file can be referred to, secondary data can be directly referred from the arrangement data file without changing the data format of the arrangement data file. can do. Thus, the operator does not directly handle the secondary file, so that the handling of the exposure apparatus can be simplified.

Further, by providing secondary data generating means for generating a secondary file and storing it in the predetermined memory area in conjunction with the operation of storing the pattern data in the predetermined memory area, the operator can save the pattern data. Since the secondary data is not handled just by taking in the data, the management of the data can be simplified. Further, by providing a data file deleting means for deleting a secondary data file corresponding to the pattern data file in conjunction with an operation of deleting the pattern data file from the memory area, the correspondence between the pattern data file and the secondary data file is provided. Can be prevented from collapsing.

If the pattern data forming the pattern data file and the secondary data forming the secondary data file are stored in different records of one file, the correspondence between the pattern data file and the secondary data file can be changed. It can be more robust. Further, a time for exposing the exposure pattern on the sample is calculated based on the pattern data including the exposure pattern, the secondary data including the density information of the pattern data, and the arrangement data including the arrangement information of the exposure pattern on the sample. Thus, the processing time is predicted, so that the charged particle beam exposure apparatus can calculate the processing time of a desired product in a short time.

Further, referring to device information including beam current density information from a predetermined memory of the charged particle beam exposure device,
If the processing time is predicted in consideration of the device information, the processing time according to the latest device status can be calculated. Further, there is provided a processing time predicting apparatus for predicting a processing time in a charged particle beam exposure apparatus for irradiating a sample with a charged particle beam for exposure, wherein a pattern data including an exposure pattern and a secondary Processing time calculating means for calculating the time for exposing the exposure pattern on the sample based on the data and the arrangement data including the arrangement information of the exposure pattern on the sample; and information on the processing time obtained by the processing time calculating means. Since the processing time estimating apparatus is constituted by the display means for displaying, the time required for the exposure processing of the charged particle beam exposure apparatus can be calculated in a short time.

The processing time estimating means further includes apparatus information reading means for accessing the charged particle beam exposure apparatus and referring to apparatus information including beam current density information from a predetermined memory of the charged particle beam exposure apparatus. If the processing time is predicted in consideration of the information, it is possible to calculate the processing time according to the newest device status. In addition, if the processing time is calculated for each processing content in the exposure process, and the processing time is displayed for each processing content by the display means, how much the processing time can be improved in the equipment / process development by improving the performance of the unit affecting the processing time. Can be accurately estimated.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a lens barrel portion of an electron beam exposure apparatus.

FIG. 2 is a schematic configuration diagram of a control unit of the electron beam exposure apparatus.

FIG. 3 is a diagram showing a relationship between pattern data, pattern data, arrangement data, and a frame.

FIG. 4 is a diagram illustrating a method of scanning an electron beam by moving a stage on which a wafer is mounted.

FIG. 5 is a diagram illustrating an example of a deflection area in a frame area.

FIG. 6 is a diagram showing a relationship between a frame in a chip area and a deflectable range of a main deflector.

FIG. 7 is a diagram illustrating an example of a data configuration of pattern data.

FIG. 8 is a diagram illustrating an example of a data configuration of secondary data.

FIG. 9 is a diagram illustrating an example of another data configuration of the secondary data.

FIG. 10 is a diagram showing an example of a frequency distribution of a deflection position change amount.

FIG. 11 is a diagram illustrating another example of the frequency distribution of the amount of deflection position change.

FIG. 12 is a diagram illustrating an example of a speed distribution for each small block area.

FIG. 13 is a diagram illustrating an example of a storage mode of a data file.

FIG. 14 is a diagram showing another example of a storage mode of a data file.

FIG. 15 is a diagram (part 1) for explaining a problem when there is overlap between chips;

FIG. 16 is a diagram (part 2) for explaining a problem when there is overlap between chips;

FIG. 17 is a diagram illustrating a method of determining a speed distribution when there is overlap between chips;

FIG. 18 is a diagram illustrating the effect of the size of a small block area on a scan speed.

FIG. 19 is a diagram schematically illustrating a processing time prediction device.

FIG. 20 is a flowchart illustrating a processing time prediction method.

FIG. 21 is a graph showing a display example of processing time in the processing time prediction method.

[Explanation of symbols]

L1a, L1b, L2a, L2b, L3, L4, L5 ...
Lens 11 astigmatism corrector 12 field curvature corrector 14 electron gun 15 rectangular aperture 17 slit deflector 19 mask stage 20 transmission mask 21 deflector 22 deflector 23 deflector 24 Deflector 25 ... Blanking electrode 27 ... Round aperture 28 ... Refocal coil 33 ... Main deflector 34 ... Sub deflector 35 ... Stage 36 ... Wafer 37 ... Chip 38 ... Position 39 ... Frame 40 ... Deflectable area 41 ... Small block Area 51: CPU 52: Arrangement data file 53: Pattern data file 54: Secondary data file 55: Device data file 56: Speed data file 57: Pattern data memory 58: Pattern generating means 59: Sequence control unit 60: Stage control unit 61 ... actuator control unit 62 ... ma Deflection control unit 63 Digital-to-analog converter and amplifier 64 Main deflection control unit 65 Digital-to-analog converter and amplifier 66 Sub-deflection control unit 67 Digital-to-analog converter and amplifier 68 Stage driving means 69 Stage position detecting means 70: overlap area

Claims (13)

[Claims] 1. An image forming method according to claim 1, further comprising the steps of: placing data including arrangement information of the exposure pattern on the sample; pattern data including the exposure pattern; and secondary data including density information of the pattern data. In a charged particle beam exposure method for determining a scanning speed and writing the exposure pattern on the sample, in conjunction with an exposure start operation, refer to device information having at least current density information of a charged particle beam prior to exposure processing. Generating speed data having a speed distribution in the moving direction of the sample based on the arrangement data, the secondary data, and the device information; and changing the sample at a variable speed according to the generated speed data. Irradiating the sample with a charged particle beam according to the pattern data while moving the sample. The charged particle beam exposure method that. 2. The method according to claim 1, further comprising the steps of: positioning data including arrangement information of the exposure pattern on the sample; pattern data including the exposure pattern; and secondary data including density information of the pattern data. In a charged particle beam exposure method for determining a scanning speed and writing the exposure pattern on the sample, for each frame extending in a direction in which the sample is scanned, a minimum writing unit is arranged in a direction orthogonal to the scanning direction. Calculating the drawing time of the band, dividing the frame into a plurality of small block regions including the plurality of bands, and arranging the frames in the scanning direction; and positioning the bands included in the small block region. Calculating the drawing speed for each of the small blocks in consideration of the coordinates and the drawing processing time. Generating speed data based on the scan speed obtained for each of the small block areas; and moving the sample at a variable speed in accordance with the generated speed data, while moving the sample on the sample in accordance with the pattern data. Irradiating a charged particle beam to a charged particle beam exposure method. 3. The charged particle beam exposure method according to claim 2, wherein when the frame has an area where the band overlaps, the frame is arranged such that a boundary of the small block area is not located in an area where the band overlaps. And a charged particle beam exposure method. 4. The charged particle beam exposure method according to claim 2, wherein a length of the small block region in the scanning direction is longer than a length of the drawing area in which the charged particle beam can be deflected in the scanning direction. A charged particle beam exposure method, characterized in that it is also short. 5. An arrangement data file including arrangement information of an exposure pattern on a sample, a pattern data file storing pattern data including at least an irradiation pattern and an irradiation position of the exposure pattern, and at least a pattern data file generated from the pattern data. A secondary data file storing secondary data having density information of an exposure pattern for each of a plurality of regions; and a charged particle beam deflecting and irradiating a predetermined position of the sample according to the pattern data, thereby turning the sample into an exposure pattern. In a variable particle beam exposure apparatus having an exposure unit for exposing and a sample movement control unit for continuously moving the sample at a variable speed according to the secondary data, the arrangement data file refers to the pattern data file. The pattern data file and the The following data file, a charged particle beam exposure device, characterized in that associated with each other so as to be able to see the secondary data file by using the information for referring to the pattern data file. 6. The charged particle beam exposure apparatus according to claim 5, wherein the secondary file is generated and stored in a predetermined memory area in conjunction with an operation of storing the pattern data in a predetermined memory area. A charged particle beam exposure apparatus, further comprising a next data generation unit. 7. The charged particle beam exposure apparatus according to claim 5, wherein the secondary data file corresponding to the pattern data file is deleted in conjunction with an operation of deleting the pattern data file from a memory area. A charged particle beam exposure apparatus further comprising a data file deleting unit. 8. The charged particle beam exposure apparatus according to claim 5, wherein the pattern data forming the pattern data file and the secondary data forming the secondary data file are:
A charged particle beam exposure apparatus characterized by being stored in different records of one file. 9. A processing time prediction method for predicting a processing time in a charged particle beam exposure apparatus that irradiates a sample with a charged particle beam for exposure, comprising: pattern data including an exposure pattern; and density information of the pattern data. A processing time estimating method for calculating a time for exposing the exposure pattern on the sample based on secondary data including the following and arrangement data including arrangement information of the exposure pattern on the sample. 10. The processing speed prediction method according to claim 9, wherein processing time is predicted in consideration of said apparatus information by referring to apparatus information including beam current density information from a predetermined memory of said charged particle beam exposure apparatus. A processing time prediction method. 11. A processing time predicting apparatus for predicting a processing time in a charged particle beam exposure apparatus that irradiates a sample with a charged particle beam for exposure, comprising: pattern data including an exposure pattern; and density information of the pattern data. Processing time calculation means for calculating a time for exposing the exposure pattern on the sample based on secondary data including the following, and arrangement data including arrangement information of the exposure pattern on the sample, and the processing time calculation means And a display unit for displaying information on the processing time obtained by the method. 12. The processing time estimating apparatus according to claim 11, wherein the processing time estimating means accesses the charged particle beam exposure apparatus and includes beam current density information from a predetermined memory of the charged particle beam exposure apparatus. A processing time prediction device, further comprising device information reading means for referring to device information, wherein the processing time calculation means predicts a processing time in consideration of the device information. 13. The processing means predicting device according to claim 11, wherein said processing time calculating means calculates a processing time for each processing content in an exposure process, and said display means comprises a processing time for each processing content. Is displayed.