JPH09162101A - Pattern exposing method and electron beam exposure system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the total exposing time by determining the split transfer number for X and Y sorting directions and arranging the field along the direction where the split transfer number is lower thereby correcting the block transfer number. SOLUTION: The split transfer number (BTN) is calculated for X and Y sorting (S) directions and the direction of a smaller number is designated as 3 correction. Exposure data(ED) is then decomposed and a field is arranged in the designated direction. Subsequently, the quantity of ED is compared with the capacity of the memory (KM) in an electron beam exposure system and when KM>=ED, all ED is transferred at once in the designated direction S and all data is exposed thus ending the operation. When KM<ED, a split ED for one time is transferred to the KM along the direction of the lower BTN and a decision is made whether a predetermined BTN has finished at the end of exposure. If it is not finished, the next split ED is transferred and exposed and all exposure is ended when the predetermined BTN is finished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern exposure method and an electron beam exposure apparatus, and more particularly to a reticle exposure for producing a reticle using the electron beam exposure apparatus, a mask exposure for producing a full size mask, or a semiconductor. The present invention relates to a pattern exposure method and an electron beam exposure apparatus for forming a pattern at high speed and with high accuracy in direct exposure for directly drawing on a wafer.

[0002]

2. Description of the Related Art Conventionally, in the manufacture of semiconductor devices, it has been required to form fine dimensions with high reproducibility and high accuracy. Reticles for manufacturing such semiconductor devices, or An exposure mask such as a full size mask is drawn by using an electron beam, and in some cases, an electron beam resist coated on a semiconductor wafer is directly drawn by an electron beam.

For example, taking reticle exposure as an example,
If there are many repeating patterns such as memory type,
The entire exposure pattern is divided into a plurality of fields, for example, 100 × 100 = 10 ⁴ according to the performance of the electron beam exposure apparatus.
The pattern exposure data is divided into an exposure pattern portion (SP) that can be arranged independently and an exposure pattern portion (MP) that can be arranged in a matrix.

Regarding the exposure pattern portion (MP) in which such a matrix can be arranged, one pattern is represented by one pattern data, and when the same repeated pattern is continuously drawn, one pattern is formed. Only the data is transferred, and the exposure of the pattern data is repeated, thereby reducing the amount of data to be transferred, that is, compressing the amount of data.

An exposure procedure in the conventional electron beam exposure apparatus system will be described with reference to FIG. First, in the step of checking the sorting direction, the exposure program automatically recognizes the stage moving direction, that is, the sorting direction, which is uniquely determined in advance in the electron beam exposure system. In this case, the moving direction of the stage is only the X direction or the Y direction, but in the past, regardless of the exposure target, some direction from the beginning,
For example, the X direction is determined, and the X direction is recognized here.

Next, in the process of disassembling the exposure data, the exposure data is logically judged, and the number of fields in the entire field, the number of patterns in the field, or the total number of patterns, and the pattern generation code are confirmed. That is,
The compressed exposure data is decompressed. In this case,
The exposure data is created using a compression function so that the data amount is minimized.

Next, the exposure data arranged regardless of the actual exposure order is rearranged in field units along the sorting direction confirmed by the exposure program.

Next, in the electron beam exposure apparatus system, the storage memory capacity and the exposure data amount in the electron beam exposure apparatus are confirmed.

As a result of the confirmation, if the storage memory capacity ≧ exposure data amount (YES in the figure), there is no problem. Therefore, the exposure data are sorted in the storage memory in the electron beam exposure apparatus in the order sorted. All the exposure steps are completed when the data is transferred as it is, the exposure is started based on the transferred exposure data, and the exposure is performed with all the exposure data.

As described above, when the data compression technique is used in the early days, the storage memory capacity in the electron beam exposure apparatus is sufficiently larger than the exposure data amount, and such a procedure does not cause any problems. It was

However, due to recent changes in the device structure, for example, the advent of a device in which a memory and a logic are integrated, or the improvement of the degree of integration, the exposure data amount is larger than the storage memory capacity in the electron beam exposure apparatus. Becomes
A division transfer method has been adopted in which all exposure data is divided and transferred several times.

That is, in confirming the storage memory capacity and the exposure data amount in the electron beam exposure apparatus, the storage memory capacity <
In the case of the amount of exposure data (NO in the figure), first, the number of division transfer for division transfer is calculated.

Then, the divided exposure data for one time is transferred to the storage memory in the electron beam exposure apparatus in the sorted order, the exposure is started based on the transferred exposure data, and all the exposure data for the transferred data is transferred. When the exposure based on the above is completed, it is judged whether or not the preliminarily calculated number of transfers is finished, and when it is not finished, the next divided exposure data is transferred / exposed, and the preliminarily calculated number of transfers is finished. In this case, all exposure steps are completed.

[0014]

However, when the division transfer method is used, the transfer time of the exposure data to the storage memory is included in the total exposure time, which is accompanied by the high integration of the device. As the number of transfers increases, the ratio of the transfer time included in the total exposure time dramatically increases, the total exposure time itself increases, and the throughput decreases.

Further, since the data compression technique uses the exposure data (MP) that can be arranged in a matrix, the number of pixels to be matrixed naturally changes depending on the sorting direction, and accordingly, the number of divided transfers differs, which is a problem of the device. As the degree of integration is improved, there is a problem that the difference in the number of divided transfers depending on the sorting direction cannot be ignored.

This situation will be described with reference to FIG. As shown in FIG. 5A, the reticle 21 is divided into a plurality of fields 22, and the same exposure pattern (MP) is applied to the central field 22 in which memory cells and the like are arranged.
23 will be arranged. In addition, reference numeral 2 in the drawing
Reference numeral 4 is an exposure pattern (SP) that can be arranged independently, and reference numeral 25 is an exposure start point.

Here, when the sorting direction 26 is the X direction, the same exposure pattern (MP) 23 is many in the X direction, so that the effect of data compression is great and a large number of fields 22 are obtained by one division transfer data. Can be exposed, thus reducing the number of divided transfers.

On the other hand, in the case of sorting in the Y direction, since the same exposure pattern (MP) 23 is small in the Y direction, the data compression cannot be effectively used, and therefore one division transfer is performed. Since the number of fields 22 that can be exposed by data does not increase, the number of divided transfers increases.

However, in the conventional division transfer system,
Since the sorting direction 26 is uniquely determined in advance regardless of the item and type of the semiconductor device, for example,
Since all were decided in the X direction, the same exposure pattern (M
There was no problem when P) 23 was large in the X direction, but there was a problem that the total exposure time was long when it was small.

Therefore, it is an object of the present invention to optimize the number of divided transfers and shorten the total exposure time in pattern exposure using an electron beam exposure apparatus.

[0021]

FIG. 1 is an explanatory view of the principle configuration of the present invention, and means for solving the problems in the present invention will be described with reference to FIG. See FIG. 1. (1) In the pattern exposure method using the electron beam exposure apparatus, the present invention obtains the number of divided transfers in the case where the sorting direction is the X direction and the Y direction, and calculates the number of divided transfers in the sorting direction. It is characterized by arranging fields along a few sorting directions.

As described above, the number of divided transfers is calculated when the sorting direction is the X direction and the Y direction, and the fields are arranged along the sorting direction having the smallest number of divided transfers among the sorting directions. Regardless of the element layout, reduce the number of divided transfers,
The total exposure time can be greatly reduced.

(2) Further, according to the present invention, in the electron beam exposure apparatus, means for obtaining the number of divided transfers when the sorting direction is the X direction and the Y direction, and the number of divided transfers in the sorting direction is small. It is characterized by having a means for arranging fields along the sorting direction.

As described above, by incorporating a means for determining the number of divided transfers in the case where the sorting direction is the X direction and the Y direction in the electron beam exposure apparatus, the sorting direction with a small number of divided transfers is automatically generated by the built-in program. Therefore, the exposure operation becomes easy.

[0025]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described with reference to FIGS. 2 is an explanatory diagram of a specific pattern dividing method in the embodiment of the present invention, and FIG. 3 is an explanatory diagram of an exposure procedure of the embodiment of the present invention.

Referring to FIG. 2A, in the case of the 64M DRAM according to the embodiment of the present invention, the × 5 reticle 11 having an effective exposure area of 150 mm □ is provided (X,
Y) = (0.2 mm, 1.5 mm) elongated rectangular field 12, that is, it is divided into 7.5 × 10 ⁴ fields, and the inner field 12 corresponding to the memory cell portion of this field 12 is divided. That is, the shaded field 12 in the figure is (X, Y) = (0.2 mm, 0.
The exposure pattern (MP) 13 that can be arranged in a matrix having a size of 07 mm) is repeated.

See FIG. 2B. FIG. 2B is an enlarged view of a part of the MP 13 in FIG. 2A. In this case, the wiring patterns 14 to 16 are used.
And the like, each of the wiring patterns 14 to 16 and the like has about 120 large and small rectangular patterns 17 (in the drawing, a leader line is formed in each of the large and small rectangular patterns). It is divided into.

In this case, 1232 wiring patterns 14 to 16 and the like are arranged in one field 12, and the total number of rectangular patterns 17 in one field 12 is about 147840 ( = 1232
× 120), that is, about 1.5 × 10 ⁵ .

Assuming that the total number of rectangular patterns 17 in all fields 12 is approximately 1.5 × 10 ⁵ , the total number of rectangular patterns in reticle 11 is approximately 1 × 10 ¹⁰ [(1.5 × 10 5 ⁵ ) x (7.5 x 10 ⁴ fields)], but approximately 2 x 10 ⁸ using the compression function.
The number (201,800,000). That is, the exposure data amount can be reduced to about 1/50 by using the compression function.

However, in the formation of the wiring layer of 64M DRAM
Number of rectangular patterns required, about 2 x 10 ⁸Pieces are ordinary electronic
About 9,000,0 of the storage memory capacity in the beam exposure apparatus
00 pattern number, that is, 9 × 10⁶About 20 times as many
Therefore, the divided exposure is inevitably started.

Referring to FIG. 3, first, the number of divided transfers is calculated for sorting in the X direction and for sorting in the Y direction, the direction with the smallest number of divided transfers is designated as the sorting direction, and the exposure data is decomposed. And arrange the fields along the specified sorting direction.

For example, vertically long, that is, 64M long in the Y direction.
In the case of DRAM, the number of divided transfers in the case of X sorting is calculated to be 138, and the number of divided transfers in the case of Y sorting is calculated to be 4. Therefore, the Y direction is designated as the sorting direction, and the Y direction is specified. And arrange the fields.

Next, the exposure data amount and the storage memory capacity in the electron beam exposure apparatus are confirmed, and when the storage memory capacity ≧ the exposure data amount (in the case of YES in the figure), that is, when the number of patterns with a small degree of integration is determined. In the case of a small number of semiconductor devices, all the exposure data is transferred once in the specified sorting direction where the amount of exposure data to be transferred is small, and the exposure is started. finish.

However, 64M long in the Y direction as an example
In the case of a DRAM, naturally, the storage memory capacity is smaller than the exposure data amount (in the case of NO in the figure), so the first divided exposure data, that is, the total exposure data, is taken along the Y direction in which the number of divided transfers is small. Of about 1/4 of the exposure data is transferred to the storage memory.

Next, when the exposure is started based on the transferred exposure data and the exposure based on all of the transferred exposure data is completed, it is judged whether or not the number of times of transfer calculated in advance is completed, and the completion is completed. If not, the next division exposure data is transferred and exposed, and when the number of times of transfer calculated in advance is completed, all the exposure steps are completed.

The total exposure time in this case is about 7.5 hours, which is less than 1/3 of the total exposure time of about 24 hours when the X direction is the sorting direction. , The throughput could be greatly improved.

On the other hand, in the case of Y-sorting, one division exposure time is longer than that in X-sorting because the number of exposure fields for the repetition is large, and the total exposure time is significantly large. The reason for this is that the number of times of division transfer decreases, and in the case of division transfer of 138 times as in X-sorting, the transfer time becomes significantly longer than the actual exposure time, and the transfer takes up the total exposure time. This is because the ratio of time is significantly increased.

In the above embodiment, 64M
Although the method of manufacturing a × 5 reticle for DRAM has been described, the technical idea of the present invention is not limited to such a form, and the method of manufacturing a reticle for another device or a full-scale mask can be used. It is applied, and is also applied in a direct writing process on a semiconductor wafer.

The method of dividing the field may be appropriately changed according to the element arrangement of each device, and is guaranteed by the current electron beam exposure apparatus.
It is sufficient to make it an appropriate size within a range not exceeding mm □.

Further, how many rectangular patterns each wiring pattern or the like is divided into is also a design problem.
It may be appropriately divided according to the idea of the data designer.

[0041]

According to the present invention, in the first step, the number of divided transfers in each sorting direction is obtained, the direction with the smallest number of divided transfers is designated as the sorting direction, and the designated sorting direction is automatically set by the exposure program. The subsequent division, rearrangement, transfer, etc. of the exposure data are performed, and the division transfer exposure time can be optimized for a semiconductor device having any arrangement pattern, and the throughput is improved. It greatly contributes to.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a principle configuration of the present invention.

FIG. 2 is an explanatory diagram of a specific pattern division method according to the embodiment of the present invention.

FIG. 3 is an explanatory diagram of an exposure procedure according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram of a conventional electron beam exposure procedure.

FIG. 5 is an explanatory diagram of sorting direction dependence in a conventional electron beam exposure process.

[Explanation of symbols]

 11 reticle 12 field 13 MP 14 wiring pattern 15 wiring pattern 16 wiring pattern 17 rectangular pattern 21 reticle 22 field 23 MP 24 SP 25 exposure start point 26 sorting direction

Claims (2)

[Claims] 1. A pattern exposure method using an electron beam exposure apparatus, wherein the sorting direction is the X direction and the Y direction is the Y direction.
The pattern exposure method is characterized in that the number of divided transfers in the case of the direction is obtained, and the fields are arranged along the sorting direction having the smallest number of divided transfers in the sorting direction. 2. A means for determining the number of divided transfers when the sorting direction is the X direction and the Y direction, and means for arranging fields along the sorting direction having the smallest number of divided transfers among the sorting directions. And an electron beam exposure apparatus.