JPH06244089A - Method and device for electronic beam pattern generation - Google Patents

Abstract

PURPOSE:To provide an electronic beam pattern generation method and a device thereof which can prevent generation of graphic pattern separation, double exposure data, etc., and enables proper correction processing of proximity effect without lowering through-put even when processing data of a device pattern exceeding capacity of buffer memory. CONSTITUTION:The title device prepares exposure data from design data 1 and carries out exposure based on the exposure data. It is provided with an output means 15 which outputs exposure data by dividing the data into a plurality of exposure data files 5-1 to 5-n not exceeding capacity of a buffer memory 7 provided to the electronic beam pattern generation device after specified conversion processings 11 and 13 are performed for the design data 1.

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 and apparatus, and more particularly, when handling data of a device pattern which exceeds the capacity of a buffer memory, the throughput of the device is not lowered and the figure pattern is not reduced. The present invention relates to an electron beam drawing method and apparatus capable of preventing the occurrence of separation and double exposure data and correctly performing the proximity effect correction process.

The degree of integration of electronic devices is increasing year by year, and a technique for exposing a device having a sub-quarter μm size is required. The electron beam exposure technique is known as an exposure technique having high resolution, but the exposure time becomes extremely long as the number of patterns increases, and the positional accuracy of the pattern must be improved due to the influence of temperature fluctuations and beam drift. It is becoming more difficult to control. 256
In order to perform drawing with high position accuracy on a device pattern having a sub-quarter μm size such as [M bit] DRAM and having an enormous number of patterns, it is essential to suppress the exposure time.

[0003]

2. Description of the Related Art The flow of pattern data when writing a device pattern in a conventional electron beam writing apparatus is described below.
Description will be given according to the flowchart shown in FIG.

Design data 101 created by a CAD (Computer Aided Design) system is used for inversion, enlargement / reduction,
And a graphic processing such as shifting, and a program 201 for dividing into main fields and sub-fields of the electron beam drawing apparatus are converted into exposure data 103, and if necessary, the exposure data 103 is corrected by a proximity effect correction program 203. To be done.

When the exposure is actually performed, the disk 105 for storing the pattern data in the electron beam drawing apparatus.
Is transferred to the buffer memory 107, and further sent to the pattern generation circuit for drawing. Here, the capacity of the buffer memory 107 is usually about 10 million patterns.

When exposing a highly integrated device such as a 16 [Mbit] DRAM or a 64 [Mbit] DRAM, the number of exposure patterns for one chip may exceed the capacity of the buffer memory 107. In such a case, the data transfer from the disk 105 to the buffer memory 107 is performed in units of data for one main field, and data transfer and exposure are performed alternately.

At this time, when the i-th (i = 1 to M) field is to be transferred to the buffer memory 107,
The computer in the electron beam drawing apparatus searches for the i-th field data from the beginning of the exposure data 103 to be exposed, and then performs the search.

That is, as shown in FIG. 7, when the computer issues an exposure command, the i-th field data in the exposure data 105 in the disk 105 is searched (step S212) and transferred to the buffer memory 105. (Step S213), after exposure (step S214), the search, transfer, and exposure are repeated for the (i + 1) th field data. Therefore, the larger the value of i, the larger the interval between the end of transfer and the start of exposure.

Further, the position accuracy of the electron beam drawing apparatus, that is, the requirement for connecting the main field and the sub-field becomes more and more severe as the device line width becomes smaller, and the field size must be set small for both the main field and the sub-field. I'm in a situation where I can't get it. For example, the main field size is 1 [mm] or less and the subfield size is 50 [μm] or less. It should be noted that before, the main field size = 5 [mm],
The requirement for positional accuracy was satisfied even with the subfield size = 100 [μm].

On the contrary, even if the device is highly integrated, the chip size itself does not become small, and as a result, the total number M of main fields tends to increase. For example, when a device pattern with a chip size of 10 × 20 [mm] is directly drawn with a field size of 1 [mm], the number of fields is 200.

An example showing the phenomenon described above is shown in FIG.
In FIG. 8, the horizontal axis represents the field number i (i = 1 to M) in the disk 105, and the vertical axis completes the transfer of the data of the (i−1) th field from the disk 105 to the buffer memory 107. It shows the time required for. During this time, no drawing operation is performed. That is,
The exposure data 103 in the disc 105 is stored in the order of field numbers and is read out sequentially, so that the time required for transfer increases in proportion to the number of field numbers.

Focusing only on this problem, the following method can be considered in order to suppress an increase in the total exposure time including the data transfer time. That is, as shown in FIG. 9, in consideration of the design data 101 from the beginning so as not to exceed the capacity of the buffer memory 107, a plurality of 101 'and 10' are stored in advance.
Exposure data 103 'and 103 "by dividing the data into 1" and performing data conversion in the same manner as the processing flow of FIG.
Is obtained and exposure is performed. By this method, it has been confirmed that the processing that required 180 [minutes] as the total exposure time because the capacity of the buffer memory 107 is exceeded can be reduced to 10 [minutes] by dividing the processing into two.

However, the use of this method causes the following problems. That is, as mentioned above,
In data conversion processing, graphic processing such as dimension shift (2
01) and the proximity effect correction process (203) are necessary, and in that case, the connection information of the pattern is important.

FIG. 10 shows device pattern design data 101 that exceeds the capacity of the buffer memory 107.
As shown in (1), two design data 101 'and 1
When the conversion processing 201 and 203 is performed by dividing the pattern into 01 ", since there is no information that the figure pattern 301 is a figure that extends over both of the divided design data 101 'and 101", the final exposure is performed. When the data 103 ′ and 103 ″ are also viewed together, as a result of performing the negative dimension shift processing as shown in FIG. 10 (2), the figures 301 ′ and 301 ″ may be separated from each other, and FIG. As a result of the positive dimension shift as shown in FIG.
01 ″ may become double exposure data. Also, in the proximity effect correction process (203), since the connection information is not included, correct correction cannot be performed.

[0015]

As described above, in the conventional electron beam writing method and apparatus, when the data of the device pattern which exceeds the capacity of the buffer memory is handled, the design data is designed to speed up the processing time. Is divided into a plurality of design data and subjected to figure processing and proximity effect correction processing to generate exposure data. In this case, when the final plurality of exposure data are viewed together, the figure There is a problem that the pattern is separated and double exposure data is generated. Further, even in the proximity effect correction process, since there is no connection information, correct correction cannot be performed.

The present invention solves the above problems.
Even when handling device pattern data that exceeds the capacity of the buffer memory, it is possible to prevent the separation of graphic patterns and the generation of double exposure data without reducing the throughput, and to perform the proximity effect correction process correctly. An object is to provide a possible electron beam writing method and apparatus.

[0017]

In order to solve the above problems, the electron beam drawing method and apparatus of the first feature of the present invention generate exposure data from design data 1 as shown in FIG. An electron beam drawing apparatus that performs exposure based on the exposure data, which has a capacity equal to or less than a capacity of a buffer memory 7 included in the electron beam drawing apparatus after performing predetermined conversion processes 11 and 13 on the design data 1. It comprises an output means 15 for dividing and outputting to a plurality of exposure data files 5-1 to 5-n (n is an arbitrary positive integer).

The second feature of the electron beam writing method of the present invention is an electron beam writing method for generating exposure data from design data 1 and performing exposure based on the exposure data. Steps 11 and 13 for applying a predetermined conversion process to 1 and the data after the conversion process are
An output step 15 for dividing and outputting to a plurality of exposure data files 5-1 to 5-n having a capacity equal to or less than the capacity of the buffer memory 7 included in the electron beam drawing apparatus is processed.

The electron beam writing apparatus or method according to the third aspect of the present invention is the electron beam writing apparatus or method according to claim 1 or 2, wherein the exposure data is divided in the output means or the output step 15. The processing is performed in units of the main field of the exposure data.

The electron beam writing apparatus or method according to the fourth aspect of the present invention is the electron beam writing apparatus or method according to claim 1, 2 or 3, wherein the exposure is performed in the output means or the output step 15. The data division process is performed in units of subfields of the exposure data.

The electron beam writing apparatus or method according to the fifth aspect of the present invention is the electron beam writing apparatus or method according to claim 3 or 4, wherein the exposure data is divided in the output means or the output step 15. The processing is performed only when the number of main fields of the exposure data exceeds a predetermined value.

Further, an electron beam writing apparatus or method according to a sixth aspect of the present invention is the electron beam writing apparatus or method according to claim 3 or 4, wherein the exposure data is divided in the output means or the output step 15. When the number of main fields of the exposure data is less than or equal to a predetermined value, the process is divided for each given number of main fields.

[0023]

In the electron beam drawing method and apparatus having the first, second and third characteristics of the present invention, as shown in FIG. 1, a predetermined conversion process (for example, a graphic process 11 or a proximity effect) is applied to the design data 1. After performing the correction processing 13 and the like), the output means (output step) 15 divides and outputs to a plurality of exposure data files 5-1 to 5-n having a capacity equal to or less than the capacity of the buffer memory 7 included in the electron beam drawing apparatus. Then, the exposure is performed based on the exposure data.

In particular, in the electron beam writing method and apparatus of the third feature of the present invention, the output means (output step) 15 divides the exposure data in units of the main field of the exposure data. That is,
The number of patterns in the main field is sequentially added from the first main field based on the pattern information of the exposure data 3 in units of the main field.
When the capacity of the data calculated from the pattern data up to the 1st main field exceeds the capacity of the buffer memory 7, the pattern data of the i-1th main field is output as one exposure data file 5-1. This is repeated up to the Mth main field (M is the total number of main fields), and the exposure data file 5
-2, ..., 5-n are output.

Therefore, in the present invention, since the exposure is divided into a plurality of exposure data files 5-1 to 5-n, the exposure processing time can be shortened, and the data conversion processing for the design data 1 can be performed. That is, the exposure data 3 subjected to the graphic processing 11 such as the dimension shift and the proximity effect correction processing 13
Since the division processing is performed for the pattern connection information, the connection information of the pattern, which is important in the graphic processing 11 and the proximity effect correction processing 13, is stored, and the pattern separation and double exposure data are not generated unlike the conventional case. , Proximity effect correction processing 1
Even in No. 3, correct correction can be performed.

In the electron beam writing method and apparatus of the fourth feature of the present invention, the output means or the output step 15 is used.
The division process of the exposure data is performed in units of subfields of the exposure data. That is, in the processing of the output means (output step) 15 in the electron beam writing method and apparatus having the third characteristic, the data capacity calculated from the pattern data up to the i-th main field exceeds the capacity of the buffer memory 7. In this case, further, in the i-th main field,
Based on the pattern information in units of subfields, the number of patterns in a subfield is sequentially added to the total number of patterns from the first subfield to the i-1th main field, and the total is calculated. If the capacity of the data calculated based on the above exceeds the capacity of the buffer memory 7, the pattern data of the i-1th main field and the j-1th subfield of the i-th main field is set to 1 It is output as one exposure data file 5-1. This is repeated up to the Mth main field, and the exposure data files 5-2, ...,
It outputs 5-n.

Therefore, according to the processing method of this embodiment, only the exposure data for the main field is used for the buffer memory 7.
This has the effect of easily supporting future ultra-high-density devices that will exceed the capacity of.

Further, in the electron beam drawing apparatus and method of the fifth feature of the present invention, the division processing of the exposure data in the output means or the output step 15 is performed in the electron beam drawing apparatus and method of the third and fourth features. , Only when the number of main fields of the exposure data exceeds a predetermined value, and in the electron beam drawing apparatus and method of the sixth feature, the division processing of the exposure data in the output means or the output step 15 is performed. When the number of main fields of the exposure data is equal to or less than a predetermined value, the exposure data is divided for each given number of main fields.

As explained in the prior art, the lengthening of the total exposure time becomes remarkable when the number of fields is large, and when the total number of fields is not extremely large, the capacity of the buffer memory 7 is taken into consideration. It is not necessary to perform the divided division.

[0030]

Embodiments of the present invention will now be described with reference to the drawings. First Embodiment FIG. 1 is a diagram for explaining the flow of pattern data in the electron beam drawing apparatus according to the first embodiment of the present invention.

Design data 1 created by the CAD system 200 includes graphic processing such as inversion, enlargement / reduction, and shift,
Also, the exposure data 3 is converted by the graphic processing program 11 for dividing into main fields and sub-fields possessed by the electron beam drawing apparatus, and the exposure data 3 is further corrected by the proximity effect correction program 13 if necessary.

Next, the exposure data output routine 15 divides the obtained exposure data 3 into a plurality of exposure data files 5-1 to 5-n each having a size less than or equal to the capacity of the buffer memory 7 of the electron beam drawing apparatus. Output.

This exposure data output routine 15 is shown in FIG.
It is processed according to the flowchart shown in FIG. The electron beam drawing apparatus is supposed to have M main fields. That is, the exposure data 3 is fetched (step S3
1), after initializing the parameters (step S32),
The number of patterns in the main field is sequentially added from the first main field based on the pattern information of the exposure data 3 in units of the main field (step S34). If the data capacity calculated from the data exceeds the capacity of the buffer memory 7 (step S35), the i-th
The pattern data of the main fields up to the second is output as one exposure data file 5-1 (step S
36). This is repeated up to the Mth main field (determined in step S33), and the exposure data file 5
-2, ..., 5-n are output (steps S36 and S3).
9). For example, two exposure data files 5-1 and 5
When divided into -2, the result is as shown in FIG.

The above-mentioned processing is generally processed by using a large computer, and when actually performing the exposure, for example, the exposure data file 5-1 held on a magnetic tape or the like.
˜5-n is a buffer memory 7 in the electron beam drawing apparatus
And then sent to the pattern generation circuit for drawing. In general, the computer provided in the electron beam drawing apparatus is small and medium-sized, and the buffer memory 7
The capacity is such that pattern data of about 10 million patterns can be handled.

At the time of exposure, the exposure data file 5-
The data transfer from 1 to 5-n to the buffer memory 7 is carried out in units of data for one main field, for example, and data transfer and exposure are performed alternately.

As described above, in this embodiment, since the exposure is divided into a plurality of exposure data files 5-1 to 5-n, the exposure processing time can be shortened. Moreover, since the data conversion process for the design data 1, that is, the division process is performed on the exposure data 3 to which the graphic process 11 such as the dimension shift and the proximity effect correction process 13 are performed, the graphic process 11 and the proximity effect correction process 13 are performed. The connection information of the pattern, which is important in the above, is stored, and correct correction can be performed in the proximity effect correction processing 13 without generating pattern separation and double exposure data as in the conventional case. Second Embodiment This embodiment also has a flow of pattern data as shown in FIG. 1 as in the first embodiment. This embodiment is the first
The difference from the embodiment is the processing in the exposure data output routine 15.

FIG. 4 shows a flowchart of an exposure data output routine in the electron beam drawing apparatus according to the second embodiment. The electron beam drawing apparatus has M main fields and P subfields.

Similar to the first embodiment, after the exposure data 3 is fetched (step S51) and the parameters are initialized (step S52), the main data is stored based on the pattern information in units of the main field of the exposure data 3. The number of patterns in the field is sequentially added from the first main field (step S54).

If the data capacity calculated from the pattern data up to the i-th main field exceeds the capacity of the buffer memory 7 (step S55),
In the i-th main field, the number of patterns in the sub-field is sequentially calculated from the first sub-field based on the pattern information in units of the sub-field.
The sum is added to the total number of patterns (Sh-1) up to the -1st main field (step S57).

When the capacity of the data calculated based on these totals (Sg) exceeds the capacity of the buffer memory 7 (step S58), the main field up to the (i-1) th main field and the j-th main field in the i-th main field. The pattern data of the -1st subfield is output as one exposure data file 5-1 (step S60).
This is repeated up to the Mth main field (determined in step S53), and the exposure data file 5-2,
, -N are output (steps S60 and S63).

In step S60, the j-1.sup.th subfield is output to the exposure data file 5-1 as the i.sup.th main field, but the remaining j.sup.th to P.sup.th subfields are output. Is output as the first main field of the next exposure data file 5-2. That is, in the processing method of this embodiment, the i-th main field of the exposure data file 5-1 and the first main field of the exposure data file 5-2 overlap.

According to the processing method of this embodiment, the future 64
There is also an effect that it is possible to easily cope with a case where there is a possibility that the capacity of the buffer memory 7 will be exceeded only by the exposure data for the main field, such as an ultra-high density device after the [M bit] DRAM. That is, in the conventional electron beam drawing apparatus, in such a case, the disk 10
5 cannot be transferred to the buffer memory 107, and it is necessary to reduce the field size and convert the data again. However, in this embodiment, the main field is automatically divided and processed. Third Embodiment This embodiment also has a pattern data flow as shown in FIG. 1 as in the first embodiment. This embodiment is the first
The difference from the embodiment is the processing in the exposure data output routine 15.

FIG. 5 shows a flowchart of an exposure data output routine in the electron beam drawing apparatus according to the third embodiment. Similar to the first embodiment, the exposure data 3 is fetched (step S31) and the parameters are initialized (step S31).
32) However, next, when the number M of main fields is smaller than the predetermined value α (determined in step S71), the division processing in the first embodiment (steps S32 to S39).
The output process (step S72) is performed without performing.

That is, as described in the prior art (see FIG. 8), the lengthening of the total exposure time becomes remarkable when the number of fields is large. For example, when the total number of fields is several, Even if drawing is performed as in the conventional case, the drawing time does not extremely increase. Therefore, in the flowchart of the exposure data output routine 15 of the first embodiment, step S31 is executed between step S31 and step S32.
In this embodiment, the processes of 71 and S72 are added.

As the output processing in step S72, the data is collectively output to one exposure data file 5-1 or, if the total number of fields is not extremely large (for example, about 10), several data are output. The main fields (for example, two or four) are output as one exposure data file. In this case, the capacity of each exposure data file may exceed the capacity of the buffer memory 7.

The addition of steps S71 and S72 is as follows.
It may be performed for the second embodiment, and it may be considered to be inserted between step S51 and step S52 in the flowchart of FIG.

[0047]

As described above, according to the present invention,
After subjecting the design data to predetermined conversion processing (for example, graphic processing, proximity effect correction processing, etc.), a plurality of exposure data that is less than or equal to the capacity of the buffer memory provided in the electron beam drawing apparatus by the output means (output step) Since it is divided into files and outputted, and the exposure is performed based on the exposure data, the exposure processing time can be shortened by dividing the exposure into a plurality of exposure data files and performing the exposure. Data conversion processing for design data, that is, because division processing is performed on exposure data that has undergone graphic processing such as dimension shifting and proximity effect correction processing, pattern connection information that is important during graphic processing and proximity effect correction processing Is stored, correct correction is performed even in proximity effect correction processing without generating pattern separation or double exposure data. It is possible to provide an electron beam drawing method and apparatus capable of.

Further, according to the present invention, since the division processing of the exposure data in the output means or the output step is performed in units of the main field and / or subfield of the exposure data, only the exposure data for the main field is exposed. Thus, it is possible to provide an electron beam drawing method and apparatus that can easily cope with future ultra-high density devices that will exceed the capacity of the buffer memory 7.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a flow of pattern data in an electron beam drawing apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart of an exposure data output routine in the first embodiment.

3A and 3B are explanatory views when the exposure data is divided into two exposure data files, FIG. 3A shows the contents of the exposure data, and FIG. 3B shows the contents of the exposure data file.

FIG. 4 is a flowchart of an exposure data output routine in the second embodiment.

FIG. 5 is a flowchart of an exposure data output routine in the third embodiment.

FIG. 6 is a diagram illustrating a flow of pattern data in a conventional electron beam writing apparatus.

FIG. 7 is a flowchart of an exposure process in a conventional electron beam drawing apparatus.

FIG. 8 is a characteristic diagram illustrating the time required to transfer the i-th (i = 1 to M) field data in the disc.

FIG. 9 is a diagram for explaining the flow of pattern data in the conventional electron beam drawing apparatus that divides design data.

10 is an explanatory diagram of pattern data in an electron beam drawing apparatus that divides conventional design data, and FIG.
0 (1) is the division of the design data, FIG. 10 (2) is the exposure data subjected to the negative dimension shift, and FIG. 10 (3) is the exposure data subjected to the positive dimension shift.

[Explanation of symbols]

1, 101 ... Design data 101 ', 101 "... Divided design data 3, 103 ... Exposure data 103', 103" ... Divided exposure data 5-1 to 5-n ... Exposure data files 105, 105 ', 105 "... Disk 7, 107 ... Buffer memory 11, 201 ... Graphic processing program 13, 203 ... Proximity effect correction program 15 ... Output means, exposure data output routine (output step) 17, 205 ... Exposure processing program 200 ... CAD system 301 ... Graphic pattern 301 ', 301 "... Divided graphic pattern

Claims (6)

[Claims] 1. An electron beam drawing apparatus for generating exposure data from design data (1) and performing exposure based on the exposure data, wherein a predetermined conversion process (11) is applied to the design data (1). And 13) and then divided into a plurality of exposure data files (5-1 to 5-n; n is any positive integer) which is equal to or less than the capacity of the buffer memory (7) included in the electron beam drawing apparatus. An electron beam drawing apparatus having an output means (15) for outputting. 2. An electron beam drawing method for generating exposure data from design data (1) and performing exposure based on the exposure data, wherein predetermined conversion processing is performed on the design data (1). Steps (11 and 13) and dividing the data after the conversion into a plurality of exposure data files (5-1 to 5-n) having a size less than or equal to the capacity of the buffer memory (7) included in the electron beam drawing apparatus. And an output step (15) of outputting. 3. The electron beam drawing according to claim 1, wherein the division processing of the exposure data in the output means or the output step (15) is performed in units of a main field of the exposure data. Device or method. 4. The division process of the exposure data in the output means or the output step (15) is performed in units of subfields of the exposure data. Electron beam drawing apparatus or method. 5. The division processing of the exposure data in the output means or the output step (15) is performed only when the number of main fields of the exposure data exceeds a predetermined value. Alternatively, the electron beam writing apparatus or method according to Item 4. 6. The division processing of the exposure data in the output means or the output step (15) is performed for each given number of main fields when the number of main fields of the exposure data is equal to or less than a predetermined value. The electron beam drawing apparatus or method according to claim 3 or 4, characterized in that.