JPH06267831A - Step and repeat system electron beam lithography - Google Patents

Abstract

PURPOSE:To realize an electron beam lithography capable of accurately executing in a short time a ghost method as the proximity effect countermeasure of an electron beam. CONSTITUTION:Pattern data stored in a storage device 21 are supplied to a standard conversion unit 23 in a data conversion unit 22 and subjected to standard conversion. The pattern data are also supplied to a black-and-white conversion unit 24 and subjected to black-and-white conversion. The pattern data subjected to the black-and-white conversion are supplied to a resize unit 25 and subjected to magnification resize. In an adding unit 26, the pattern data converted by the standard conversion unit 23 and the pattern data converted by the black-and-white conversion unit 24 and the resize unit 25 are added and supplied to a field division unit 27. The data subjected to field division are transferred to a pattern data memory 12 and stored. Image drawing is executed on the basis of the data stored in the pattern data memory 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step-and-repeat type electron beam writing method for writing a predetermined pattern on a material using an electron beam.

[0002]

2. Description of the Related Art Generally, electron beams are widely used for manufacturing various masks for manufacturing semiconductor devices and for directly drawing patterns on a wafer. Further, in the drawing using the electron beam, the step-and-repeat method is adopted in order to perform the drawing with high accuracy over a wide range of the material to be drawn with little influence of the deflection distortion of the electron beam.
In this step-and-repeat electron beam drawing, the drawing data is divided into a range (field) in which drawing is performed only by deflection of the electron beam, and the material is intermittently moved for each field, and the material is stopped. Sometimes, the pattern included in each field is drawn.

By the way, when an electron beam is applied to draw a pattern on a glass plate coated with chromium and coated with a resist or a semiconductor material coated with a resist, for example, silicon or gallium arsenide, the electron beam is irradiated with the resist or chromium. , Scattered inside glass, silicon, etc., and the scattered electron beam sensitizes the resist,
The pattern accuracy is deteriorated. This phenomenon is widely known as the influence of the proximity effect, and various proposals have been made for this countermeasure, but a complete countermeasure technique has not yet been established.

[0004]

A ghost method has been proposed as one of the countermeasures. In this method, a black-and-white inversion pattern of a drawing pattern is created, and this black-and-white inversion pattern is drawn after drawing a regular pattern. When the black-and-white inversion pattern is drawn, electron beam irradiation conditions are changed. That is, the electron beam is set in a defocused state, and the dose amount of the electron beam at the time of writing is set to, for example, 1/4.

However, the disadvantage of this method is that the drawing of the predetermined pattern must be performed twice, that is, the drawing of the regular pattern and the drawing of the black-and-white inverted pattern,
The stage on which the material to be drawn is placed must be moved each time, and the total drawing time becomes extremely long. In addition, the focusing lens system is adjusted to defocus the electron beam when the black-and-white inverted pattern is drawn, but with this, the irradiation position of the electron beam is deviated, or the lens system is changed to be stable. Problems such as taking time to occur also occur.

The present invention has been made in view of the above circumstances, and an object thereof is a step-and-repeat type electron which can effectively perform a ghost method as a countermeasure for the proximity effect of an electron beam in a short time. It is to realize the beam drawing method.

[0007]

A step-and-repeat type electron beam drawing method based on the present invention intermittently moves a material to be drawn field by field so that a predetermined field on the material can be moved when the material is stopped. In the step-and-repeat electron beam writing method that draws a pattern with an electron beam, create a black and white inverted pattern data of regular pattern data for each field, enlarge and resize the black and white inverted pattern data, and In addition to performing the drawing based on the regular pattern data and the pattern data subjected to the enlargement and resize processing, the dose amount of the electron beam is lowered at the time of writing based on the pattern data subjected to the enlargement and resize processing. .

[0008]

In the step-and-repeat type electron beam drawing method according to the present invention, the regular pattern data for each field and the pattern data obtained by inverting the regular pattern data in black and white and further enlarging and resizing the created pattern data are created. Drawing is executed based on the regular pattern data and the pattern data subjected to the enlargement and resize processing for each of them.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows an example of a variable area electron beam writing apparatus for carrying out the present invention. An electron gun 1 generates an electron beam EB, and the electron beam EB generated from the electron gun 1 is applied to a first shaping aperture 3 via an illumination lens 2. The aperture image of the first shaping aperture is imaged on the second shaping aperture 6 by the shaping lens 4, and the position of the image formation can be changed by the shaping deflector 5. The image formed by the second forming aperture 6 is projected onto the drawing material 10 via the reduction lens 7 and the objective lens 8. The irradiation position on the drawing material 10 is
It can be changed by the positioning deflector 9.

Reference numeral 11 denotes a computer, and the computer 11 transfers the pattern data from the pattern data memory 12 to the pattern transfer circuit 13. The pattern data from the pattern transfer circuit 13 is supplied to the shot divider 14 and divided into shots. A signal according to the drawing data from the shot divider 14 performs a blanking control of the shaping deflector 5, a deflection control circuit 15 for controlling the positioning deflector 9, and a blanking of the electron beam generated from the electron gun 1. It is supplied to a blanking control circuit 18 which controls the blanking electrode 17. Further, the computer 11 controls the drive mechanism 20 of the stage 19 on which the material is placed in order to move the material for each field.

Next, the conversion of the pattern data stored in the pattern data memory 12 will be described with reference to FIG. Reference numeral 21 in FIG. 2 is a memory such as a magnetic disk memory, in which data created by an arbitrary CAD is stored. This CAD data must be converted for use on the electron beam drawing apparatus. The data in the memory 21 is sequentially read and supplied to the data conversion unit 22. The data conversion unit 22 includes a standard conversion unit 23, a black and white reversing unit 24, a resizing unit 25, an adding unit 26, and a field dividing unit 27.

The data in the memory 21 is supplied to the standard conversion unit 23 and the black-and-white reversing unit 24, and the data black-and-white inverted in the black-and-white inversion unit 24 is subjected to enlargement resizing processing in the resizing unit 25. The data subjected to the standard conversion in the standard conversion unit 23 and the data subjected to the enlarged resize processing in the resizing unit 25 are added in the adding unit 26. The added data is supplied to the field division unit 27 and divided into fields. The field-divided data is supplied to and stored in the pattern data memory 12. The data conversion in this data conversion unit 22 is shown in FIG.
Although described as hardware, it is usually executed by software using the computer 11 of FIG. 1 or another computer for data conversion. The operation of the electron beam writing apparatus having the configuration shown in FIGS. 1 and 2 is as follows.

First, a general drawing operation in the electron beam drawing apparatus of FIG. 1 will be described. The pattern data stored in the pattern data memory 12 is sequentially read and supplied to the shot divider 14 via the data transfer circuit 13. The deflection control circuit 15 controls the shaping deflector 5 based on the data divided by the shot divider 14, and the control circuit 16 controls the positioning deflector 9.

As a result, based on each of the divided pattern data, the shaping deflector 5 shapes the cross section of the electron beam into a unit pattern shape, and the unit patterns are sequentially shot on the material to form a pattern of a desired shape. Drawing is done. At this time, the blanking control circuit 18
From the blanking electrode to the blanking electrode 17, blanking of the electron beam is performed in synchronization with the shot of the electron beam on the material 10.

Next, the drawing operation for the pattern data shown in FIG. 3 will be described. In the pattern shown in FIG. 3, the pattern P1 exists in a single field F1, and this pattern data is created by CAD.
It is stored in the memory 21. The pattern data stored in the memory 21 is supplied to the standard conversion unit 23 in the data conversion unit 22 and standard-converted.
FIG. 4 shows the standard-converted pattern data, and the pattern P1 is converted into two pattern data a and b. The pattern data of FIG. 4 is supplied to the addition unit 26.

The pattern data shown in FIG. 3 is also supplied to the black and white reversing unit 24 and black and white reversal is performed. Further, the black-and-white inverted pattern data is supplied to the resizing unit 25, which enlarges and resizes it.
FIG. 5 shows the pattern data that has been subjected to black-and-white inversion and further enlarged and resized, and the dotted line is the original pattern data before black-and-white inversion. The data in FIG. 5 is converted into five pattern data c to g as shown in FIG. 6 and supplied to the addition unit 26. The addition unit 26 adds the pattern data converted by the standard conversion unit 23 and the pattern data converted by the black / white inversion unit 24 and the resizing unit 25, and supplies it to the field division unit 27.

FIG. 7 shows an example of the added pattern data, which includes the standard-converted pattern data a and b and the black-and-white inverted and resized pattern data c to g. The standard-converted pattern data a,
The symbol "α" indicating the standard conversion is attached to b, and the symbol "β" indicating that the black-and-white inversion and the resizing processing are performed is attached to the pattern data c to g. In the example of FIG. 3, since it is pattern data of a single field, the pattern data added by the addition unit 26 is transferred to the pattern data memory 12 and stored as it is.

Next, the drawing operation based on the pattern data of FIG. 7 will be described. The pattern data stored in the pattern data memory 12 is read out, and the data transfer circuit 13 is read.
And is supplied to the shot divider 14. The shot divider 14 sequentially divides the pattern data a to g into unit patterns. The deflection control circuit 15 controls the shaping deflector 5 based on the divided data, and
The control circuit 16 controls the positioning deflector 9.

As a result, based on each of the divided pattern data, the shaping deflector 5 shapes the cross section of the electron beam into a unit pattern shape, and the unit patterns are sequentially shot on the material to form a pattern of a desired shape. Drawing is done. At this time, the blanking control circuit 18
From the blanking electrode to the blanking electrode 17, blanking of the electron beam is performed in synchronization with the shot of the electron beam on the material 10. In this case, when the code of the pattern to be shot is “α”, the blanking of the electron beam is performed so that the shot time of the unit pattern is the time required to expose the resist coated on the material 10. Be seen.

On the other hand, when the code of the pattern to be shot is “β”, the shot time of the unit pattern is set to 1/4 of the time required to expose the resist coated on the material 10 by the electron beam. Blanking is performed. That is, the patterns a and b are irradiated with the electron beam at a dose amount so that the exposure amount becomes the specified amount, and the patterns c to g are drawn by the electron beam at 1/4 of the specified dose amount. .

As a result, the same effect can be obtained by defocusing the electron beam and irradiating the black-and-white reversal pattern, which is considered to eliminate the influence of the conventional proximity effect. In this embodiment, since both the regular pattern and the black-and-white reversal pattern are performed under the same electron beam optical system conditions, the time for adjusting the electron beam optical system can be omitted,
Further, it is possible to avoid the problem of axis deviation caused by changing the conditions of the optical system. Further, since both the regular pattern and the black-and-white inverted pattern are drawn by one drawing operation in the same field, the method is remarkably different from the conventional method of drawing two types of patterns in two times. The drawing time can be shortened.

FIG. 8 shows CAD pattern data for explaining another embodiment of the method according to the present invention. In the pattern shown in FIG. 8, a pattern P2 exists across two fields F1 and F2, and this pattern data is created by CAD and stored in the memory 21. The pattern data stored in the memory 21 is supplied to the standard conversion unit 23 in the data conversion unit 22 and standard-converted. The standard-converted pattern data is supplied to the addition unit 26.

The pattern data shown in FIG. 8 is also supplied to the black and white reversing unit 24 and black and white reversal is performed. Then, the black-and-white inverted pattern data is supplied to the resizing unit 25, which enlarges and resizes it. FIG. 9 shows the pattern data which has been subjected to black-and-white inversion and further enlarged and resized, and the dotted line is the original pattern data before black-and-white inversion. The data shown in FIG. 10 is supplied to the addition unit 26. The addition unit 26 adds the pattern data converted by the standard conversion unit 23 and the pattern data converted by the black / white inversion unit 24 and the resizing unit 25, and the field division unit 27
Supply to.

FIG. 10 shows the pattern data that has been standard-converted and field-divided. The pattern data of FIG. 8 includes the pattern a-1 included in the field F1 and
It has been converted into the pattern a-2 included in the field F2. FIG. 11 shows pattern data that is field-divided after black and white inversion, enlarged resize, and the pattern data of FIG. 9 is the pattern b− included in the field F1.
1, c, e-1 and patterns b-2, d, e-2 included in the field F2.

FIG. 12 shows the pattern data of FIG. 10 and FIG. 11 which have been subjected to addition processing and field division.
0 (a) is the pattern data of the field F1, FIG.
(B) is the pattern data of the field F2. Note that the standard-converted pattern data a-1 and a-2 are provided with a symbol "α" indicating standard conversion, and the pattern data b-1, b-2, c, d, and e. -1,
The sign "β" indicating that black-and-white inversion and resizing processing has been performed is attached to e-2.

Next, the drawing operation based on the pattern data of FIG. 12 will be described. First, the pattern data memory 12
The pattern data of the field F1 stored in (1) is read out and supplied to the shot divider 14 via the data transfer circuit 13. The shot divider 14 sequentially performs shot division for each pattern data a-1, b-1, c, e-1 into unit patterns. The deflection control circuit 15 controls the shaping deflector 5 and the control circuit 16 controls the positioning deflector 9 based on the divided data.

As a result, based on each of the divided pattern data, the shaping deflector 5 shapes the cross section of the electron beam into a unit pattern shape, and the unit patterns are sequentially shot on the material to form a pattern of a desired shape. Drawing is done. At this time, the pattern of the pattern to be shot is “α”, and the blanking of the electron beam is performed so that the shot time of the unit pattern is the time required to expose the resist coated on the material 10. Done.
On the other hand, in the pattern in which the code of the shot pattern is “β”, the blanking of the electron beam is performed so that the shot time of the unit pattern is ¼ of the time required to expose the resist coated on the material 10. Done.

After all the patterns included in the field F1 have been drawn, the computer 12 controls the drive mechanism 20 to move the stage 19 so that the field F2 is arranged below the electron beam optical axis. Then, the field F is subjected to the same steps as the drawing of the field F1.
Drawing of patterns a-2, b-2, d, e-2 in 2 is executed.

Although the embodiment of the present invention has been described above, the present invention is not limited to this embodiment. For example, although the variable area type electron beam writing apparatus has been described as an example, the present invention can be applied to an ion beam writing apparatus.

[0030]

As described above, in the step-and-repeat electron beam drawing method according to the present invention, the regular pattern data for each field and the pattern obtained by inverting the regular pattern data in black and white and further enlarging and resizing the pattern data are obtained. Data is created, and drawing is executed based on the regular pattern data and the pattern data that has been enlarged and resized for each field, so the ghost method as a countermeasure for the electron beam proximity effect can be used in a short time. Can be done accurately.

That is, since both the regular pattern and the black-and-white reversal pattern are performed under the same electron beam optical system conditions, the time for adjusting the electron beam optical system can be omitted, and the optical system conditions can be changed. It is possible to avoid the problem of misalignment. Further, since both the regular pattern and the black-and-white inverted pattern are drawn by one drawing operation in the same field, the method is significantly different from the conventional method of drawing two types of patterns. The drawing time can be shortened.

[Brief description of drawings]

FIG. 1 shows an example of an electron beam writing system for carrying out the method according to the invention.

FIG. 2 is a diagram showing a configuration of a data conversion part.

FIG. 3 is a diagram showing a CAD pattern.

FIG. 4 is a diagram showing standard-converted pattern data.

FIG. 5 is a diagram showing a pattern that has undergone black-and-white inversion and enlargement resizing processing.

6 is a diagram showing converted pattern data of the pattern of FIG.

FIG. 7 is a diagram showing pattern data obtained by adding the pattern data of FIGS. 4 and 6;

FIG. 8 is a diagram showing a CAD pattern.

FIG. 9 is a diagram showing a pattern that has undergone black-and-white inversion and enlargement resizing processing.

10 is a diagram showing conversion pattern data of the pattern of FIG.

11 is a diagram showing conversion pattern data of the pattern of FIG.

FIG. 12 is a diagram showing pattern data that has been subjected to addition processing and divided into fields.

[Explanation of symbols]

 1 electron gun 2 illumination lens 3,6 shaping aperture 4 shaping lens 5,9 deflector 7 reduction lens 8 objective lens 10 material 11 computer 12 memory 13 data transfer circuit 14 shot divider 15 shaping deflector control circuit 16 positioning deflector control Circuit 17 Blanking electrode 18 Blanking control circuit 19 Stage 20 Drive mechanism

Claims (1)

[Claims] 1. A step-and-repeat type electron beam drawing method in which a material to be drawn is intermittently moved field by field and a pattern of a predetermined field on the material is drawn by an electron beam when the material is stopped. In, create a black / white inverted pattern data of regular pattern data for each field, enlarge / resize the black / white inverted pattern data, and draw based on the regular pattern data and the enlarged / resized pattern data for each field And a step-and-repeat type electron beam writing method in which the dose amount of the electron beam is lowered at the time of writing based on the pattern data subjected to the enlargement and resizing.