JP2002222759A - Electron beam writing method - Google Patents

Abstract

(57) [Problem] To provide an electron beam writing method capable of performing a calculation for obtaining proximity effect correction data at high speed. When rendering a field F5,
The control CPU sends the proximity effect correction data transfer circuit not only the electron beam irradiation data to the field F5 but also the eight fields (F1 to F1) adjacent to the field F5.
4, F6 to F9) electron beam irradiation data are supplied,
It is stored in the internal data memory. The proximity effect correction operation circuit in the data transfer circuit converts the irradiation data of the field F5 to the irradiation data of the field F5 and the field F5 of the eight fields adjacent to the field F5 from the electron beam irradiation data of the nine fields stored in the data memory. Remove the electron beam irradiation data compartment f _n adjacent, on the basis of these data, determined proximity correction data during rendering of each compartment in the field F5 (correction map) by calculation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam drawing method for deflecting an electron beam applied to a material to be drawn to draw a desired pattern, and more particularly to performing a proximity effect correction operation in a short time. The present invention relates to an electron beam lithography method that can perform the method.

[0002]

2. Description of the Related Art In an electron beam lithography system, there is a limited area in which an electron beam can be deflected with high accuracy. When the deflection angle is large, deflection distortion cannot be neglected, and the drawing accuracy deteriorates. In a vector scan type drawing apparatus, an area where deflection distortion can be ignored is called a field.

In general, since the chip size is larger than the field size, pattern data to be drawn is divided into fields of a predetermined size before drawing, and data is collected for each field. At the time of drawing, the stage is moved for each field, and the center of the field is made coincident with the optical axis of the electron beam to draw a pattern in the field.

The above-mentioned field size must be determined at the stage of preparing data before drawing. The size of the field size is determined depending on the purpose of drawing, and usually includes the following cases.

The first case is when the drawing accuracy is more important than the drawing time, and when it is desired to minimize the influence of deflection distortion in a small field. The drawing data is divided into fields smaller than the maximum field of the drawing apparatus. You.

The second case is a case where the tolerance of the drawing accuracy is large and the drawing speed is to be increased instead.
It is divided by the maximum field of the drawing device.

As described above, the size of the field is determined in accordance with the purpose of drawing. Even if the same drawing data is divided into fields in consideration of a specific case, but is drawn in another case, Each time, the first raw drawing data must be divided into fields according to the case, which is extremely troublesome.

For this reason, in the prior application, Japanese Patent No. 2744833, when drawing data is divided into drawing fields and drawing is performed, the length of one side is set to be an integral number of the maximum field length of the drawing apparatus. Depending on the drawing purpose at the time of pattern drawing, draw a field using the above-mentioned section data as one unit, or draw a field as a unit by combining a plurality of section data. I have.

[0009]

In the electron beam writing apparatus of the prior application, when writing in each field, the proximity effect correction is performed on the field. The proximity effect correction data is obtained by calculation based on the electron beam irradiation data of the field and the electron beam irradiation data of eight fields adjacent to the field.

FIG. 1 shows this state. When the proximity effect correction data of the field F5 is obtained by calculation, not only the electron beam irradiation data on the field F5 but also the electrons of the adjacent fields F1 to F4 and F6 to F9. Beam irradiation data is also used. In this case, the length of one side of the field is usually about 1000 μm, and its area is 1000 × 1000.
μm ² . Therefore, this operation requires a considerable amount of time.

The present invention has been made in view of the above points, and an object of the present invention is to realize an electron beam drawing method capable of performing a calculation for obtaining proximity effect correction data at a high speed.

[0012]

According to a first aspect of the present invention, there is provided an electron beam drawing method, wherein when drawing data is divided into drawing fields and drawn, the length of one side is equal to the length of the maximum field of the drawing apparatus. A section made to be 1 / integer is made, and a field is drawn using the section data as one unit, or a field is set as one unit by combining a plurality of section data, depending on the drawing purpose at the time of pattern drawing. In performing the proximity effect correction calculation for a specific field, in the electron beam writing method configured to perform writing of the electron beam, the electron beam irradiation data for the specific field and the field adjacent to the specific field are adjacent to the specific field. From the electron beam irradiation data of the section to be obtained, the proximity effect correction data of the specific field is obtained,
It is characterized in that the proximity effect correction of the drawing in the specific field is performed based on the obtained data.

According to the first aspect of the present invention, when performing the proximity effect correction calculation for a specific field, of the electron beam irradiation data for the specific field and the section adjacent to the specific field among the fields adjacent to the specific field. Since the proximity effect correction data of the specific field is obtained from the electron beam irradiation data, the arithmetic processing can be performed in a short time.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 shows an example of a variable area electron beam writing apparatus for carrying out the present invention. Reference numeral 1 denotes an electron gun for generating an electron beam EB. The electron beam EB generated from the electron gun 1 is irradiated onto a first shaping aperture 3 via an irradiation lens 2.

The aperture image of the first shaping aperture is formed on the second shaping aperture 5 by the shaping lens 4.
The position of the image can be changed by the shaping deflector 6. The image formed by the second shaping aperture 5 is irradiated onto a drawing material 9 via a reduction lens 7 and an objective lens 8. The irradiation position on the drawing material 9 is determined by the positioning deflector 10.
Can be changed by

Reference numeral 11 denotes a control CPU.
Transfers pattern data from a pattern data memory 12 such as a magnetic disk to a drawing data transfer circuit 13 and a proximity effect correction data transfer circuit 14.

The pattern data from the data transfer circuit 13 is supplied to a control circuit 15 for controlling the shaping deflector 6, a control circuit 16 for controlling the positioning deflector 10, and a control circuit 17 for controlling excitation of the objective lens 8. .

A blanking control signal from the proximity effect correction data transfer circuit 14 is used to control a blanker (blanking electrode) 18 for blanking an electron beam generated from the electron gun 1.
Supplied to

Further, the control CPU 11 moves the stage 2 on which the material 9 is placed in order to move the material 9 for each field.
0 drive circuit 21 is controlled. The operation of such a configuration will now be described.

First, a basic drawing operation will be described. The pattern data stored in the pattern data memory 12 is sequentially read out and supplied to the data transfer circuit 13. Based on the data from the data transfer circuit 13,
The deflection control circuit 15 controls the shaping deflector 6, and the control circuit 16 controls the positioning deflector 10.

As a result, the cross section of the electron beam is shaped into a unit pattern shape by the shaping deflector 6 based on each pattern data, and the unit patterns are sequentially shot on the material 9 to draw a pattern of a desired shape. Done. At this time, the blanking of the electron beam is executed in synchronization with the shot of the electron beam on the material 9 by the blanking signal from the blanking control circuit 19 to the blanker 18.

Further, at the time of drawing in different areas on the material 9, the stage 20 is moved by a predetermined distance in accordance with a command from the control CPU 11 to the stage drive circuit 21. Although not shown, the moving distance of the stage 20 is monitored by a laser measuring device, and the position of the stage is accurately controlled based on the measurement result from the measuring device.

Now, the data transfer circuit 13 shown in FIG.
Has a configuration as shown in FIG. That is, it has an adder circuit 23 to which the pattern data from the control CPU 11 is supplied, a register 24 to store the position coordinates from the field of each section, and a data memory 25 to store the addition result of the adder circuit 23. .

Next, a plurality of sections (f1) as shown in FIG.
To f4) are collectively described as one field F. The register 24 stores the reference coordinate position (the upper left coordinate position of the section) of each section as shown in FIG. When the data of the section f1 is transferred from the control CPU 11, the adding circuit 21 adds the reference coordinate position to the position coordinates of the data. Section f1 reference coordinate position (X ₀ , Y ₀ )
Is the same as the origin of the field F, there is no change in the data addition result.

Next, when the data of the section f2 is transferred,
The adder circuit 23 stores the coordinates f2 shown in FIG.
(X ₀ , Y ₁ ) are added. The data of the added section f2 is sent to and stored in the data memory 25. Similarly, the data of the sections f3 and f4 are also added to the respective coordinate positions in the adder circuit 23, sent to the data memory 25 and stored.

In this manner, data obtained by combining the four partitions is stored in the data memory 25. The data of the field F stored in the data memory 25 is read, and controls the deflection controller 14 and the positioning deflector 10.

Next, the proximity effect correction operation will be described. The proximity effect correction data transfer circuit 14 has a data memory and a proximity effect correction operation circuit therein. Now, when drawing a specific field F5 shown in FIG. 6, the control CPU 11 sends the proximity effect correction data transfer circuit 14 not only the electron beam irradiation data to the field F5 but also the 8 adjacent to the field F5. Electron beam irradiation data of two fields (F1 to F4, F6 to F9) are supplied and stored in an internal data memory.

The proximity effect correction operation circuit in the data transfer circuit 14 calculates the irradiation data of the field F5 and the irradiation data of the eight fields adjacent to the field F5 from the electron beam irradiation data of the nine fields stored in the data memory. , taken out electron beam irradiation data compartment f _n adjacent field F5, based on those data, obtaining proximity correction data during rendering of each compartment in the field F5 (correction map) by calculation.

That is, the range affected by the proximity effect is at most 15 μm when the acceleration voltage of the electron beam is 50 kV.
Since it is about m, it is not necessary to use the data of all adjacent fields. If the length of one side of the section is 100 μm, it is sufficient to use only the data of one adjacent column.

The proximity effect is corrected based on the obtained proximity effect correction data (correction map). In the present embodiment, the irradiation time of the electron beam is adjusted based on the correction data. For this reason, the correction data in each section is supplied to the blanker control circuit 19, and the blanker control circuit 19 controls the blanker 18 for adjusting the shot time of the electron beam.

As described above, in the embodiment of the present invention described with reference to FIGS. 2 and 6, when correcting the proximity effect at the time of electron beam writing in the specific field F5, the irradiation data of the entire adjacent field is used. However, since a part of the data is used, the calculation of the proximity effect correction data can be performed in a short time.

For example, in the conventional operation shown in FIG.
Against 00 × of 3000μm had sought proximity effect correction data using electron beam irradiation data ² area, in the case of FIG. 6, because of the use of electron beam radiation data area of 1200 × 1200 [mu] m ^2, The proximity effect correction calculation can be performed at an area ratio of about 1.44 / 9.

Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment. For example, when performing the proximity effect correction calculation, the electron beam irradiation data of one column in a field adjacent to a specific field is used. However, depending on the size of the partition, for example, data of two columns or three columns is used. May be used.

[0034]

As described above, according to the present invention, when performing the proximity effect correction calculation for a specific field, the electron beam irradiation data for the specific field and the field of the specific field among the fields adjacent to the specific field are used. Since the proximity effect correction data of the specific field is obtained from the electron beam irradiation data of the section adjacent to the section, arithmetic processing can be performed in a short time, and as a result, the throughput of drawing is improved.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a conventional proximity effect correction calculation.

FIG. 2 is a diagram showing an example of an electron beam writing apparatus for carrying out the present invention.

FIG. 3 is a diagram illustrating a specific example of a data transfer circuit.

FIG. 4 is a diagram showing a field F and sections f1 to f4.

FIG. 5 is a diagram showing the contents of a register.

FIG. 6 is a diagram for explaining a proximity effect correction calculation based on the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electron gun 2 Irradiation lens 3 1st aperture 4 Molding lens 5 2nd aperture 6 Molding deflector 7 Reduction lens 8 Objective lens 9 Drawing material 10 Positioning deflector 11 Control CPU 12 Pattern data memory 13 Drawing data transfer circuit 14 Proximity Effect correction data transfer circuit 15 Molding deflector control circuit 16 Positioning deflector control circuit 17 Objective lens control circuit 18 Blanker 19 Blanking control circuit 20 Stage 21 Stage drive circuit

Claims (1)

[Claims] When a pattern is drawn by dividing drawing data into drawing fields, a section having a length of one side equal to an integral number of the length of a maximum field of the drawing apparatus is created. In accordance with the above, in the electron beam drawing method in which the field data is drawn as one unit or the field data is drawn as one unit by combining a plurality of partition data, In performing the proximity effect correction calculation, the electron beam irradiation data for the specific field and the electron beam irradiation data for the section adjacent to the specific field among the fields adjacent to the specific field, the proximity effect correction data for the specific field Based on the obtained data, and perform the proximity effect correction of the drawing in the specific field. Electron beam drawing method.