JPS63186428A - Method and apparatus for charged beam lithography - Google Patents

Abstract

PURPOSE:To enable the efficient data to be compressed and developed when the irradiation level for correcting approach effect etc., is changed to be written for increasing the writing throughput by a method wherein the irradiation time of unit figure is decided by selecting one irradiation level data out of repeating frequency of writing. CONSTITUTION:The positions Xxi, Nyi of reference point of group pattern, repeating frequency Nxi, Nyi, repeating pitch Pxi, Pyi, number Ni of unit figures belonging to this group pattern as well as storage address PFi of shape data and storage address PDi of irradiation level data are written in an arrangement data group. As for the repeating patterns and writing data corresponding to the repeating patterns, 5 X 5 of group patterns 10 comprising two rectangles 11, 12 are arrayed. In such a constitution, the shape data on one group pattern are used in common for all group patterns so that the level of shape data may be reduced notably to improve the data compression efficiency markedly.

Description

[Detailed Description of the Invention] [Objective of the Invention] (Industrial Field of Application) The present invention relates to a technique for drawing a pattern using a charged beam, and particularly to a method for correcting the dose when drawing a pattern using a charged beam. The present invention relates to a charged beam lithography method and a lithography apparatus.

(Prior art) Conventionally, in an electron beam lithography system using a variable shaped beam, pattern repetition has been used to shorten the time it takes to transfer pattern lithography data from an external storage device to a lithography control circuit. The drawing data is being compressed. For example, as shown in Figure 6(a), two rectangles 61.6
When two group patterns 60 are arranged in a 4×4 array, the drawing data is expressed by a layout data group and a figure data group as shown in FIG. Here, the figure data group is a set of data that describes the irradiation position X IYm% dimensions h and w of the unit figure (shot 1 and shot 2), the irradiation mmI+1 time t, and the like. In addition, the arrangement data group refers to the position X of the reference point of the group pattern.
Y Number of repetitions Nx, (-4), N, (-4)
, xi' yiゝrepetition pitch PP and the group putter X1'
The number of figures N1 for the yl line is a set of data representing the first storage address PF1 of data in which the figure data is stored.

FIG. 7 shows a procedure for expanding and drawing the drawing data compressed in this way. External storage device 71 such as a magnetic disk
The drawing data stored in the drawing buffer memory 7 is passed through the main memory 72 of the computer that controls the system.
Transferred to 3. For one unit figure to be drawn, the system calculates the data X Y N,...
N,, Pxi'yl' Xl y+
Using xi'P and the data X, y in the figure data, the irradiation position calculation circuit 74 calculates N,, N pieces Xi
The irradiation position of yl is calculated according to the following formula.

However, I(1-0,1,..., (Nxl-1)K
2-0.1. ..., (N, -1)Xl Then, the irradiation position control circuit 7 sequentially changes the calculated irradiation position
5 to control the irradiation position. Further, the data tm of the irradiation time in the graphic data is sent N×1×N times to the blanking control circuit 76 to control the irradiation time. Furthermore, the dimension data h and w in the figure data are set to NxlX
Nyi times, the shot shape l1ffl is sent to the control circuit 77 to control the dimensions of the variable shaped beam.

By the way, in the above conventional method, for one of the figures, data t of irradiation time (dose data) and dimension h of the figure are used.
, w and the irradiation position x, y as m
m
One each of m a+representing data (shape data) is defined. On the other hand, if an attempt is made to change the irradiation amount in order to correct the proximity effect, etc., the irradiation time will have a different value depending on the location of the figure even if the shape of the figure is the same. For example, the irradiation time for the unit figure 21 in FIG. 2 is different because the surrounding patterns are different.
This will be different from the irradiation time.

Therefore, when drawing a pattern as shown in Figure 2,
Although the shapes of the figures are the same within the area surrounded by the two-dot chain line in the figure, data compression is only possible in the area within the one-dot chain line due to differences in irradiation time due to proximity effect correction, etc. It turns out.

In other words, there was a problem that data compression was insufficient. Furthermore, since data compression is insufficient, there is a problem in that the data transfer time becomes long, leading to a decrease in the operation rate of the electron beam lithography apparatus, and, in turn, a decrease in the lithography throughput.

(Problems to be Solved by the Invention) Conventionally, when correcting the proximity effect, etc., data compression is insufficient, increasing the time required to transfer drawing data, and reducing the operation rate of electron beam drawing equipment. There was a problem of lowering the

The present invention has been made in consideration of the above circumstances, and its purpose is to enable efficient data compression and expansion even when drawing is performed by changing the dose for proximity effect correction, etc. ,Draw Sloop,.

An object of the present invention is to provide a charged beam lithography method that can improve the performance.

Another object of the present invention is to provide a charged beam lithography apparatus for carrying out the above method.

[Configuration of the Invention (Means for Solving Problems) The gist of the present invention is that when drawing figures of the same shape,
The objective is to provide a mechanism that commonly uses shape data representing height, width, etc., and that allows one to be selected from two or more dose control data when repeatedly drawing figures of the same shape. . This makes it possible to change the irradiation amount depending on the drawing position of the figure while maintaining the same data compression efficiency as before.

That is, the present invention provides a charged beam drawing method in which a charged beam is irradiated onto a sample to draw a desired pattern on the sample. Consisting of radiation dose control data representing the radiation dose for the object and arrangement data representing the arrangement of a group pattern consisting of a set of unit figures, one unit figure to be drawn when repeatedly drawing the group pattern N times on the same sample. The same shape data is used for N repetitions, and the irradiation time of a unit figure is determined by one irradiation amount from among the irradiation amount control data according to the number of repetitions of drawing or the drawing position of the group pattern. In this method, the determination is made by selecting data.

The present invention also provides a charged beam drawing apparatus for carrying out the above method, including a shape data storage memory that stores shape data representing the shape and size of a unit figure, and dose control data for the drawing position of the unit figure. A radiation dose control data storage memory to be stored, a placement data storage memory to store placement data of a group pattern consisting of a set of unit figures, and a shape data storage memory and a radiation dose according to the contents of the placement data storage memory. The apparatus includes means for selecting the contents of the memory for storing control data, and means for controlling the charged beam according to the contents of the memory for storing arrangement data and the selected data.

(Function) The present invention makes it possible to repeatedly use one piece of data for the shape of the unit figure to be drawn, even when unit figures having the same shape and different irradiation doses are repeatedly drawn. For this reason, it is necessary to provide separate data representing shapes for shapes with different irradiances, which was unavoidable in the conventional method.
It becomes possible to eliminate the need for this, improve compression efficiency of drawing data, and shorten data transfer time.

(Example) Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 4 is a diagram showing the optical system configuration of an electron beam lithography apparatus used in an embodiment of the method of the present invention. In the figure, 40 is an electron gun, 41 is various lens systems, 42. ~.

44 is various deflection systems, 45 is a blanking plate, 46° 47
4 is a beam shaping aperture mask, 48 is a backscattered electron detector, and 49 is a target.

The electron beam emitted from the electron gun 40 is turned off by a blanking deflector 42.

By adjusting the irradiation time, this device can
This makes it possible to change the irradiation amount depending on the irradiation position.

The beam that has passed through the blanking plate 45 is transferred to a beam shaping deflector 43 and a beam shaping aperture mask 46.4.
7, the beam is shaped into a rectangular beam, and the dimensions of the rectangle are varied. Then, this shaped beam is deflected and scanned on the target 49 by the scanning deflector 44, and the target 49 is drawn in a desired pattern by this beam scanning. The accelerating voltage of the electron beam in this device is 50 [KV], and the variable shaped beam that can be generated has a maximum size and height of 2 [μ].

It is a rectangular beam with a width of 2 [μ7IL].

FIG. 1 is a schematic diagram showing a repetitive pattern and drawing data in a method according to an embodiment of the present invention.

As shown in FIG. 1(a), it is assumed that a group pattern 10 consisting of two rectangles 11 and 12 is arranged in a 4×4 arrangement. The drawing data for this array is composed of a placement data group, a shape data group, and a dose control data group, as shown in FIG. 1(b).

That is, the figure data group in the conventional method is divided into a shape data group and a dose control data group, and the shape data group includes the irradiation position x, y and size m of the unit figure.
A collection of data that describes the modulus h and w, and the dose control demo m
The Ill-ta group is a set of data that describes the irradiation Qtm of a unit figure. In addition, in the arrangement data group, as in the conventional method, the positions of the reference points of the group pattern X, Y
,,Number of repetitions N N,,x+ of repetitions
yx xi' yt pitch PP
In addition to the number N1 of x1' yi inch unit figures belonging to the group pattern, the starting address PF for storing shape data and the starting address PD for storing dose data are also written.

Next, the repetitive pattern and the drawing data for the same will be explained in more detail with reference to FIGS. 2 and 3. FIG. 2 is an example of a repeating pattern. Group pattern 10 consisting of two rectangles 11 and 12 is 5×5
The patterns within the dashed line in the figure have the same shape and size, and have the same irradiation amount. However, the patterns outside the one-dot chain line have the same figure size and shape, but have different irradiation doses.

FIG. 3 is an example of drawing data describing the pattern within the two-dot chain line in FIG. The 16 group patterns outside the one-dot chain line have the same shape but different irradiation doses, so these are defined as the first to 16th group patterns. Furthermore, since the nine group patterns within the one-dot chain line are the same in shape and dose, they are collectively defined as the seventeenth group pattern. In the conventional method, the dimensions and irradiation positions of unit figures inside the 1st to 17th group patterns are 17
However, in this method, as shown in the figure, the shape of the unit figure for the 1st and 17th group patterns is expressed by one data, and the irradiation amount for the 17th group pattern is also expressed by one data. It is expressed as a single piece of data.

Comparing the above drawing data with the conventional method, the arrangement data is almost the same in both the embodiment and the conventional example, and the amount of information of the dose control data is completely the same in both the embodiment and the conventional example.

However, regarding the shape data, conventionally each of the 1st to 17th group patterns was required independently, but in this embodiment, the shape data for one group pattern is shared by all group patterns. , compared to the conventional example, the information amount of shape data is significantly reduced in the embodiment.

In other words, it is possible to significantly improve data compression efficiency.

FIG. 5 shows a control system for carrying out the method of this embodiment, in which the irradiation position and irradiation shape of a unit figure are determined from the compressed drawing data in the buffer memory.

FIG. 2 is a block diagram of a circuit that determines and controls the irradiation amount.

The buffer memory that stores the drawing data includes a layout data storage memory 51 that stores array data, a shape data storage memory 52 that stores shape data, and a dose control data storage memory 53 that stores dose data. Consists of seed memory.

By separating the shape data memory and the dose data memory, a plurality of dose data can be stored for one shape data.

In the figure, the controller 50a is a memory 51 for storing arrangement data.
is accessed repeatedly, thereby controlling the repetitive drawing of the unit figure in the group pattern, and the control is transferred to the repetitive drawing of the next group pattern by the END signal from the counter 54. By accessing the controller 50a, from the arrangement data storage memory 51, the number of repetitions in the x and y force directions NN, the repetition pitch P,, P
,, glue xi' ylゝ xlyl
The number N of unit figures in the pattern, the storage address of the shape data and the dose data are output. The counter 54 is N
.

The irradiation position calculation circuit 56 calculates Nxi×Nyi irradiation positions for each unit figure in the group pattern, where K□
-0,1,-・, (Nx1-1)1(2-0,1,
. . . (N, , -1), and the calculated irradiation positions are sequentially sent to the irradiation position control circuit 55.

The controller 50b outputs the output (N
,XN,), number of figures in the group pattern x
yl yl N and the shape data storage address are input. The controller 50b stores the shape data storage address in an internal register, sequentially adds a predetermined value to this register value, calculates the storage address of the data on the dimensions and positions of the N unit figures in the group pattern, and calculates the shape data. The storage address of the data storage memory 52 is accessed. The controller 50b repeats this operation (N time i×Nyl) times.

The controller 50C receives as input the output from the multiplier 57 (N x work x N,), the number N1 of figures in the group pattern, and the dose data storage address. The controller 50c stores the dose data storage address in an internal register, sequentially adds a predetermined value to this register value to obtain the dose data storage addresses of N unit figures in the group pattern, and stores the dose control data. The storage address in the storage memory 53 is accessed. The controller 50C performs such operations (N
Repeat 1) times.

The shape data storage memory 52 sends the irradiation position data X t +y1 to the irradiation position calculation circuit 56 and the dimension data h and w of the unit figure to the irradiation shape control circuit 58 when accessed by the controller 50b. The irradiation Q ffi control data storage memory 53 sends the irradiation amount data to the irradiation port control circuit 59 when accessed by the controller 50c.

Then, the irradiation position control circuit 55 determines a deflection signal to be applied to the scanning deflector 44, thereby controlling the beam position on the target 49. Further, the irradiation shape control circuit 58 determines a deflection signal to be applied to the beam shaping deflector 43, thereby controlling the shape and size of the beam. Further, the irradiation amount control circuit 59 determines a blanking signal to be applied to the blanking deflector, thereby controlling the beam irradiation time.

According to this embodiment, the drawing data is divided into three parts: placement data, shape data, and dose control data, so when changing the dose for proximity effect correction, The compression efficiency of drawing data can be greatly improved.

In other words, if the group patterns have the same shape and irradiation ports, the compression efficiency will not change, but if the group patterns have the same shape but different irradiation ports, the shape data for each group pattern, which was previously required, will be reduced. This becomes unnecessary and one shape data can be shared. For this reason, the data transfer time is reduced by 111. It becomes possible to increase the operating rate of the electron beam lithography apparatus.

Note that the present invention is not limited to two consecutive embodiments. Although the electron beam lithography apparatus of the embodiment is a system that can generate only a rectangular variable shaped beam, the present invention can also be applied to a system that generates a triangular variable shaped beam. In that case, this can be implemented, for example, by introducing a code that distinguishes rectangular and triangular shapes into the shape data.

In addition, in the embodiment, the dose control data is stored in a memory separate from the shape data storage memory, but the shape data is stored in the same data format as the conventional dose and paired data format, corresponding to the drawing position. This can also be implemented by reading out the irradiation correction amount for the entire group pattern from the irradiation amount control data and adding it to the irradiation amount for each shot.

Further, the configuration of the electron optical lens barrel is not limited to the same as shown in FIG. 4, but can be changed as appropriate according to specifications. Furthermore, it is also possible to apply the present invention to an ion beam writing apparatus that uses an ion beam instead of an electron beam. In addition, various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] As described in detail above, according to the present invention, the amount of drawing data in which the irradiation amount of each shot is set can be significantly reduced compared to the conventional method.

Therefore, the time for data transfer is shorter than in the conventional method, and the number of samples that can be drawn per unit time by the electron beam drawing device increases, making it possible to improve drawing throughput.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a format of drawing data according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing an example of a pattern to be drawn, and FIG. 3 is a schematic diagram showing an example of a pattern to be drawn. FIG. 4 is a diagram showing the optical system configuration of an electron beam lithography apparatus for carrying out the above embodiment method, and FIG. 5 is a schematic diagram showing the drawing data expressed in the data format of . FIG. 6 is a block diagram showing the control system, FIG. 6 is a schematic diagram showing the data format according to the conventional method, and FIG. 7 is a schematic diagram showing the transfer and expansion of compressed data according to the conventional method. 10... Group pattern, 11. 12... Rectangular figure, 40... Electron gun, 41... Lens system, 42.
~. 44... Q similar system, 46.47... Beam shaping aperture mask, 48... Backscattered electron detector, 49...
Target, 50a, ~, 50c...Controller, 51...Memory for storing arrangement data, 52...Memory for storing shape data, 53...Memory for storing dose control data, 54...Counter, 55... Irradiation position control circuit, 56... Irradiation position calculation circuit, 57... Multiplier, 58... Irradiation shape control circuit, 59... Irradiation amount control circuit.

Claims (3)

[Claims] (1) In a charged beam drawing method in which a charged beam is irradiated onto a sample to draw a desired pattern on the sample, drawing data is used as shape data representing the shape and size of a unit figure, and irradiation on the drawing position of the unit figure. The shape of one unit figure to be drawn when repeatedly drawing the above group pattern N times on the same sample The data is N
The same data is used for the number of repetitions, and the irradiation time of a unit figure is determined by one of the above irradiation control data according to the number of repetitions of drawing or the drawing position of the group pattern. A charged beam drawing method characterized in that the charged beam drawing method is determined by selection. (2) In a charged beam drawing device that irradiates a charged beam onto a sample to draw a desired pattern on the sample, a shape data storage memory that stores shape data representing the shape and size of a unit figure; A dose control data storage memory that stores dose control data for a drawing position, a placement data storage memory that stores placement data of a group pattern consisting of a set of unit figures, and a placement data storage memory that stores dose control data for a drawing position; It comprises means for selecting data in a memory for storing shape data and a memory for storing dose control data, and means for controlling the charged beam according to the contents of the memory for storing arrangement data and each of the selected data. A charged beam lithography device featuring: (3) The means for controlling the charged beam determines the irradiation position of the beam according to the contents of the arrangement data storage memory and the data of the selected shape data storage memory, and controls the selected shape data storage memory. The charged beam drawing apparatus according to claim 2, wherein the shape and dimensions of the beam are determined according to the data, and the irradiation time of the beam is determined according to the data in the memory for storing dose control data. .