JP3097907B2 - Electron beam drawing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam lithography system for irradiating an object to be drawn with an electron beam to form a pattern in a semiconductor device or the like.

[0002]

2. Description of the Related Art The configuration of a conventional electron beam drawing apparatus will be described with reference to the drawings. In FIG. 2, drawing data creation means 11
The pattern data created by the
2, the image is divided into a hierarchical coordinate system by the structure of the electron gun, and data such as the coordinates of the electron beam to be drawn, its size, and the amount of exposure are attached to the lowermost basic region. Is the unit of activation.

First, an exposure amount map for calculating the degree of pattern congestion by accumulatively adding the area value of the data indicating the size of the electron beam or the like to a mesh in which a center point is entered from the data, that is, to a memory corresponding to the center point. The memory is created by the exposure map creating means 13.

Next, a value near the address corresponding to the drawing data is read out from the exposure map memory, and the exposure is controlled so as to be in inverse proportion to the degree of pattern congestion. The data is input to the drawing means 14 to create a corrected drawing.

[0005]

However, in the above-mentioned conventional method, the division position of the pattern data and the position of the mesh are determined.
Since it is determined completely independently of the
The area value cumulatively added to the memory corrects the pattern position.
May not be reflected. Figure 3 shows patterns and meshes
This is a diagram showing the positional relationship with the mesh.
Lines and patterns are indicated by solid lines, and pattern dividing lines are indicated by broken lines.
Also, the center point of each divided pattern (specifically,
The center of gravity) is indicated by a dot. In the conventional method, the divided
In the memory of the mesh where the center point of each pattern is located,
The area values of the individual patterns are added. Therefore, FIG.
As shown in the map formation result diagram, each mesh
Each area value is stored in the memory corresponding to the mesh
Is done. Here, as shown in the upper diagram of FIG.
The actual pattern on the left is divided into six parts,
The center of the two divided patterns is both divided
Exist in one mesh that spans the pattern
You. The area value of the two divided patterns is one
It is added to the mesh. However, these two split patterns
Some of the mesh is also present in the mesh surrounding this mesh.
Despite that, the area value of the divided pattern is
It is not added to the surrounding mesh, only one mesh
They are not added. Therefore, the lower map shape in FIG.
As shown in the result, the center of the division pattern
Area value of the pattern only in the memory corresponding to the mesh
Memory corresponding to a mesh that has been added and has no center
Is not added with the area value. In this way,
In the formula, the position of the pattern can be accurately reflected in the exposure map.
Pattern position and its exposure when writing.
Positional deviation occurs between the exposure unevenness is generated as a result
There was a problem that would .

As means for preventing this, it is possible to reduce the error by using a smaller mesh size. However, this has the drawback that the amount of memory required for the exposure map memory is enormous, and the reliability is thereby reduced.

An object of the present invention is to provide an electron beam lithography system in which the data of an exposure map memory for optimizing the exposure of a pattern to be drawn is as close as possible to the original pattern data.

[0008]

The gist of the present invention to achieve the above object is as follows.

[1] Drawing data creating means for creating a drawing pattern, drawing data creating means for converting it into drawable data having a plurality of hierarchical coordinate systems, and a basic unit for storing as an exposure map Corresponds to the minimum accessible unit of the memory element, and a data decomposer for decomposing the data into a plurality of sizes of meshes, and cumulatively calculates an area value from output data such as coordinates, size (length × width), etc. In the electron beam lithography apparatus provided with an exposure map creating unit capable of observing a pattern distribution, the first data created by the exposure map creating unit and the graphic data from the drawing data creating unit are extracted. Second data for creating an expected value of the pattern shape by using the first data and the second data.
Comparing means for comparing the data provided to detect the base area of the coordinate system of the lowermost comparison error is large compared data by said comparing means, and wherein the kite <br/> to reduce the mesh size of the area Electron beam drawing equipment.

[2] The self-diagnosis by holding the first data created by the exposure map creating means as an expected value of the pattern shape and comparing it with newly created data at an arbitrary time. Electron beam drawing equipment.

(3) The electron beam lithography apparatus is provided with a means for binarizing the first data and the second data.

[4] A file creating means for converting the exposure map created by the exposure map creating means into a file based on the graphic data from the drawing data creating means, and a graphic pattern extracted by extracting the graphic data from the drawing data creating means. with an expected value generation means for generating a period <br/> waiting value of the shape, a comparison means for comparing the expected data pattern, wherein the file creating means file data and the expected value creating unit created created An electron beam lithography apparatus, wherein the comparison means detects a basic processing area having a large error by comparison and assigns a smaller mesh size to this area.

That is, according to the above, the data of the exposure map memory for optimizing the exposure of the pattern to be drawn is made as close as possible to the original pattern data to reduce the error.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of an electron beam lithography apparatus according to an embodiment of the present invention.
An expected value creating means 21 for extracting only a graphic from the drawing data created by the drawing data creating means 11 to create an expected value file, comparing the result files of the file creating means 20 and the expected value creating means 21 and comparing the differences. Comparison means 2 for detecting
2 is provided.

First, an exposure map is created by the exposure map creating means 13 with a relatively large mesh size. The created data is filed by the map file creating means 20. This data is stored in the drawing data creation unit 11.
Is compared with the expected value file created by the expected value creating means 21 by the comparing means 22.

Here, a basic processing region having a large difference is detected. When the map creation is performed again, when the map creation of the basic processing area is started, by reducing the mesh size, data closer to the actual pattern can be obtained.

One embodiment of an electron beam lithography apparatus of a semiconductor manufacturing apparatus, which is one of the products to which the present invention is applied, will be described with reference to FIG.

The electron beam drawing apparatus irradiates a silicon wafer directly with an electron beam to form a wiring pattern. At this time,
Depending on the degree of crowding around the pattern to be drawn, exposure unevenness called a proximity effect may occur.

As means for preventing this, a pseudo map indicating the degree of congestion of the pattern is created by cumulatively adding the area values of the pattern data to a two-dimensionally developed memory called an exposure amount map, thereby obtaining an electron beam. A method is adopted in which the exposure value is corrected in inverse proportion to the degree of congestion by reading the area value near the memory address indicated by the pattern data at the time of drawing.

The wiring pattern data is hierarchically composed of a first coordinate system, a second coordinate system, and the position, size, and exposure amount of an electron beam in the system in the structure of the electron gun. The data created by the means 11 is
2 and decomposed into the above configuration. The activation of the hardware at the time of creating the exposure map and at the time of drawing is performed in units of the second coordinate system.

In the exposure map memory, one address is composed of four pixels, and one pixel performs a cumulative operation by matching pattern data with a basic unit when divided by a certain mesh size. When the map creation is started, the area value of the data is cumulatively added by the exposure map creation means 13 to the memory address containing the center point of the decomposed electron beam data.

At this time, as shown in FIG. 3, the pattern is stored in the memory corresponding to the mesh where the pattern originally exists.
The area value of the pattern is not added, and the
A displacement occurs between them. To prevent this, make the mesh size smaller, and
If the displacement between the position and the boundary of the mesh is reduced , it is possible to create an exposure map close to the original drawing pattern data.

However, for example, when the mesh size is reduced to half, the memory capacity is required to be four times. In particular, when a large-capacity pattern is drawn, a device having a huge memory capacity is required, the reliability is reduced to 1/4 or less, and the device becomes expensive, which is not a good idea.

In the present invention, one data is assigned to one pixel of the exposure map memory by the file creation unit 20 from the exposure map created by the exposure map creation unit 13.
Create a pattern file.

Next, when designing by the user, an expected value file having the same format as that of the file creating means 20 is created by the expected value creating means 21 from the created two-dimensional pattern data. By comparing and verifying this pattern file with the expected value file, a basic processing region having a large error is specified, and the calculation is executed again with a smaller mesh size in these processing regions, thereby achieving higher accuracy. Map creation becomes possible.

Further, means for creating a map file include:
By adding the binarization filter 31, the above processing can be performed at a small size and at a high speed. That is,
By passing through a binarization filter, for example, compared to the case where data of one pixel is allocated to one byte, by allocating it to one bit, it is reduced to 1/8, and one-dimensionally
/ 64 can be compressed.

When the threshold value of the binarizing filter 31 is "0", the contour of the pattern figure is obtained (however, not only the contour). Also, from the drawing data creating means 11,
If graphic data is extracted through the expected value creating means 21,
Since the contour data is obtained, if these are compared by the comparing means 22, a basic processing unit having a large difference is specified, and the same processing can be performed.

FIG. 4 is a block diagram of an electron beam drawing apparatus according to a second embodiment of the present invention. The feature of this device is that an expected value storage means 23 is added.

By storing the map created in the same manner as described above in the expected value storage means 23 and comparing it with the map file created at an arbitrary time, it is possible to perform self-diagnosis of the device and increase the reliability. Become.

[0031]

According to the present invention, the drawing accuracy can be improved without increasing the memory capacity by optimizing the allocation of the exposure map memory to the pattern data.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an electron beam drawing apparatus showing one embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional electron beam writing apparatus.

FIG. 3 is an explanatory diagram of functions of a conventional electron beam drawing apparatus.

FIG. 4 is a configuration diagram of an electron beam lithography apparatus showing another embodiment of the present invention.

[Explanation of symbols]

11: drawing data creation means, 12: data decomposition means, 1
3 Exposure map creation means, 14 Drawing means, 20 File creation means, 21 Expected value creation means, 22 Comparison means, 23 Expected value creation means, 31 Binary filter.

────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-9-45600 (JP, A) JP-A-7-78737 (JP, A) JP-A-4-258111 (JP, A) JP-A-9-45 186058 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/027 G03F 7/20

Claims (4)

(57) [Claims] 1. A drawing data creating means for creating a drawing pattern, a drawing data creating means for converting the drawing pattern into drawable data having a coordinate system having a plurality of hierarchical structures, and a basic unit for storing as an exposure map. A data decomposer for decomposing into a plurality of sizes of meshes corresponding to the minimum accessible unit of the memory element, and an area value is cumulatively calculated from output data such as coordinates, size (length × width) of the data decomposer. An electron beam lithography apparatus provided with an exposure map creating means capable of observing a pattern distribution, wherein: the first data created by the exposure map creating means;
Pas extracts Figure elephants data from the drawing data generation means
Second data for generating an expected value of the turn shape;
Characteristics of the data and providing a comparison means for comparing the second data, detects the base area of the coordinate system of the lowermost comparison error is large compared data by said comparing means, and a kite to reduce the mesh size of the area Electron beam drawing apparatus. 2. The self-diagnosis according to claim 1, wherein the first data created by the exposure map creating means is held as an expected value of a pattern shape and is compared with newly created data at an arbitrary time. Electron beam drawing equipment. 3. The electron beam lithography apparatus according to claim 1, further comprising a binarizing means for binarizing the first data and the second data. 4. A file creating means for converting the exposure map created by the exposure map creating means into a file based on the graphical data from the drawing data creating means, and extracting the graphic data from the drawing data creating means to form a pattern shape. preparedness expected value generation means for generating expected value, a comparator means for comparing the expected data pattern, wherein the file creating means file data and the expected value creating unit created created, the comparison means An electron beam lithography apparatus wherein a basic processing area having a large error is detected by comparison, and a smaller mesh size is assigned to this area.