JP3967546B2 - Charged particle beam writing method - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to a charged particle beam writing method for drawing a desired pattern by deflecting charged particles such as an electron beam irradiated on a drawing material.
[0002]
[Prior art]
In the electron beam drawing apparatus, there is a limit to the region where the electron beam can be deflected with high accuracy, and when the deflection angle becomes large, the deflection distortion cannot be ignored, and the drawing accuracy deteriorates. In a vector scanning type drawing apparatus, an area where deflection distortion can be ignored is called a field.
[0003]
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 the data is collected for each field. At the time of drawing, the stage is moved for each field, and the pattern in the field is drawn by matching the center of the field with the electron beam optical axis.
[0004]
The above field size must be determined at the stage of preparing data before drawing. The size of this field size is determined by the purpose of drawing, and there are usually the following cases.
[0005]
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.
[0006]
The second case is a case where the tolerance of the drawing accuracy is large and instead it is desired to increase the drawing speed. In order to reduce the number of stage movements, the drawing data is divided by the maximum field of the drawing apparatus.
[0007]
In this way, the size of the field is determined according to the purpose of drawing, and even if the same drawing data is divided into fields with a specific case in mind, when drawing in other cases, each time, The first raw drawing data must be divided into fields according to the case, which is troublesome.
[0008]
For this reason, in Japanese Patent No. 2744833 of the prior application, when drawing data is divided into drawing fields and drawn, a section in which the length of one side is an integral number of the length of the maximum field of the drawing device is created. In addition, according to the drawing purpose at the time of pattern drawing, the field is drawn with the partition data as a unit, or the field is drawn as a unit by combining a plurality of partition data.
[0009]
[Problems to be solved by the invention]
In the charged particle beam drawing apparatus of the prior application, a dead time occurs when combining a plurality of section data, resulting in a reduction in drawing throughput. That is, the pattern data is stored after being stored in the data memory in the drawing data transfer circuit from the magnetic disk before drawing. The pattern data on the magnetic disk is divided into sections of a certain size, and is expressed as position coordinates at the upper left of each section and a graphic position with the upper left of the section as the origin.
[0010]
A group of these partitions is drawn as a field. At this time, the data is conventionally stored in the data memory in the same form as the magnetic disk, that is, stored in units of partitions and given the position in the field as an offset when drawing. Had gone. The control CPU sets the offset in the drawing field of the section, performs section drawing, and moves the stage when this is completed for one field.
[0011]
In this way, conventionally, since the position of each section is obtained by performing a software operation at the time of drawing, there is a disadvantage that the time required for total drawing becomes long.
The present invention has been made in view of the above-described points, and an object thereof is to realize a charged particle beam writing method capable of drawing a field without performing complicated software calculation.
[0012]
[Means for Solving the Problems]
In the charged particle beam drawing method according to the present invention, when drawing data is divided into drawing fields and drawing is performed, a section in which the length of one side is an integer of the length of the maximum field of the drawing apparatus is created. Depending on the drawing purpose at the time of pattern drawing, a charged particle beam drawing that draws a field with the section data as one unit or combines a plurality of section data into a unit In the method, when drawing a field as a unit by combining a plurality of partition data, in the process of transferring each partition data to the data memory, the position of each partition data and the position in the field of each partition by the adder The added data is stored in the data memory, and the desired drawing is made based on the field data stored in the data memory. It is characterized in that to perform the.
[0013]
In the present invention, when drawing a field as a unit by combining a plurality of partition data, in the process of transferring each partition data to the data memory, the position of each partition data and the position in the field of each partition by the adder And the added data is stored in the data memory. Therefore, it is not necessary to combine partition data by complicated software, and the drawing throughput can be improved.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of a variable area electron beam lithography apparatus for carrying out the present invention. Reference numeral 1 denotes an electron gun that generates an electron beam EB. The electron beam EB generated from the electron gun 1 is irradiated onto the first shaping aperture 3 through the irradiation lens 2.
[0015]
The aperture image of the first shaping aperture is formed on the second shaping aperture 5 by the shaping lens 4, and the position of the image formation can be changed by the shaping deflector 6. The image formed by the second shaping aperture 5 is irradiated onto the drawing material 9 through the reduction lens 7 and the objective lens 8. The irradiation position on the drawing material 9 can be changed by the positioning deflector 10.
[0016]
Reference numeral 11 denotes a control CPU. The control CPU 11 transfers pattern data from the pattern data memory 12 such as a magnetic disk to the data transfer circuit 13. Pattern data from the data transfer circuit 13 is generated from a control circuit 14 for controlling the shaping deflector 6, a control circuit 15 for controlling the positioning deflector 10, a control circuit 16 for controlling excitation of the objective lens 8, and the electron gun 1. It is supplied to a blanking control circuit 18 that controls a blanker (blanking electrode) 17 that performs blanking of the electron beam.
[0017]
Further, the control CPU 11 controls the drive circuit 21 of the stage 20 on which the material 9 is placed in order to move the material 9 for each field. The operation of such a configuration will be described next.
[0018]
First, a basic drawing operation will be described. The pattern data stored in the pattern data memory 12 is sequentially read and supplied to the data transfer circuit 13. Based on the data from the data transfer circuit 13, the deflection control circuit 14 controls the shaping deflector 6, and the control circuit 15 controls the positioning deflector 10.
[0019]
As a result, the cross section of the electron beam is formed into a unit pattern shape by the shaping deflector 6 based on each pattern data, and the unit pattern is sequentially shot on the material 9 to perform pattern drawing of a desired shape. At this time, blanking of the electron beam is executed in synchronization with a shot of the electron beam on the material 9 by a blanking signal from the blanking control circuit 18 to the blanker 17.
[0020]
Further, when drawing on different regions on the material 9, the stage 20 is moved by a predetermined distance according to a command from the control CPU 11 to the stage drive circuit 21. Although the movement distance of the stage 20 is not shown, it is monitored by a laser length measuring device, and the position of the stage is accurately controlled based on the length measurement result from the length measuring device.
[0021]
The data transfer circuit 13 shown in FIG. 1 specifically has a configuration as shown in FIG. That is, it has an addition circuit 23 to which pattern data from the control CPU 11 is supplied, a register 24 in which position coordinates from the fields of each section are stored, and a data memory 25 in which the addition result of the addition circuit 23 is stored. .
[0022]
Next, a description will be given of a case where a plurality of sections (f1 to f4) as shown in FIG. The register 24 stores the reference coordinate positions (upper left coordinate positions) of the sections 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 data position coordinate. Since the 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.
[0023]
Next, when the data of the section f2 is transferred, the adding circuit 23 adds the coordinate position (X ₀ , Y ₁ ) of the section f2 shown in FIG. 4 to the coordinate position of the data. The added data of the section f2 is sent to the data memory 25 and stored therein. Similarly, the data of the sections f3 and f4 are also added to the respective coordinate positions in the adder circuit 23 and sent to the data memory 25 for storage. In this way, data in which the four partitions are combined is stored in the data memory 25. The data of the field F stored in the data memory 25 is read, and the deflection controller 14 and the positioning deflector 10 are controlled.
[0024]
Although one embodiment of the present invention has been described above, the present invention is not limited to this embodiment. For example, although a field composed of four sections has been described as an example, the number of sections can be arbitrarily selected. Further, although the variable area type electron beam drawing apparatus has been described as an example, the present invention can also be applied to an electron beam drawing apparatus that irradiates a thin electron beam on a drawing material. The present invention can also be applied to a drawing apparatus that uses a charged particle beam.
[0025]
【The invention's effect】
As described above, in the present invention, when drawing a field as a unit by combining a plurality of partition data, in the process of transferring each partition data to the data memory, the position of each partition data and each The position in the field of the division is added and the added data is stored in the data memory. Therefore, it is not necessary to combine partition data by complicated software, and the drawing throughput can be improved.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of an electron beam drawing apparatus for carrying out the present invention.
FIG. 2 is a diagram illustrating a specific example of a data transfer circuit.
FIG. 3 is a diagram showing a field F and sections f1 to f4.
FIG. 4 is a diagram illustrating the contents of a register.
[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 data transfer circuit 14 shaping deflector control circuit 15 positioning deflector control circuit 16 objective lens control circuit 17 blanker 18 blanking control circuit 19 shot time correction memory 20 stage 21 stage drive circuit 23 addition circuit 24 register 25 data memory

Claims (1)

When drawing the drawing data by dividing the drawing data into drawing fields, a section in which the length of one side is set to 1 / integer of the length of the maximum field of the drawing device is created. In a charged particle beam drawing method in which a field is drawn with one piece of section data or a field is drawn with a combination of a plurality of pieces of data, a combination of a plurality of pieces of section data is combined. When drawing the field as a unit, in the process of transferring each partition data to the data memory, the adder adds the position of each partition data and the position in the field of each partition, and the added data is stored in the data memory. A charged particle beam drawing method for performing desired drawing based on field data stored in a data memory.

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