JP2001358053A - Method for electron beam lithography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve precision in overwriting by eliminating deteriorated dimensional precision by the shifted positional error considered to be caused by the blurred electron beam in a overwriting method for improving a connecting accuracy in a batch graphic illuminating method. SOLUTION: A method for the electron beam lithography comprises the steps of cutting out a different batch graphic form from a pattern, deviating fulcra of a plurality of batch graphic forms, and overwriting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam writing apparatus, and more particularly, to a high-speed and high-accuracy electron beam writing method.

[0002]

2. Description of the Related Art Electron beam lithography systems have utilized the pattern generation function to contribute to the manufacture of LSIs. Conventional drawing apparatuses have drawn a pattern by decomposing the pattern into a point beam or a rectangular beam. As a new method
J. Vac. Sci. Technol. B9 (6), Nov / Dec 1991, pp.2940-
As described by Hayada et al. In 2943., an attempt called a collective pattern irradiation method for improving the throughput by forming an electron beam having a complicated shape has been made. In these drawing methods, in order to reduce a pattern connection error, a method called overlay drawing is used as described by Ima et al. In JP-A-10-256129.

[0003]

However, in the overlay drawing method, the positional error is transferred to the blur of the electron beam, so that the dimensional accuracy may be degraded. L with smaller period than figure
There is a problem that the application is limited to the SI pattern. SUMMARY OF THE INVENTION It is an object of the present invention to improve the accuracy when applying overlapping drawing to pattern drawing on a sample.

[0004]

A first feature of the present invention is as follows.
There is a method of cutting out a collective figure from a drawing pattern. That is, different collective figures are cut out from the drawing pattern, and they are superimposed and drawn. In other words, a plurality of collective figures can be drawn by shifting the fulcrum, or a second collective figure can be drawn so as to overlap with a plurality of first collective figures, or a first collective figure can be drawn. And the second collective figure are drawn by overlapping at different connection points on the drawing pattern. As an application of this, there is also a method of decomposing and drawing by a different decomposing method into a plurality of collective figures when decomposing a drawing pattern into collective figures. Then, each of the collective figures is drawn so as to overlap with other collective figures.

[0005] The maximum size of a collective figure on a sample is limited by the apparatus. The batch patterning of a part of the LSI pattern can contribute to the improvement of the throughput as the pattern has more repetitions. However, the size of a frequently repeated pattern is not always sufficiently smaller than the maximum size of the device. If the repetition cycle is equal to or more than １ ／ of the maximum size, one batch figure can include only one repetition pattern and cannot be staggered. In this case, by shifting the fulcrum of the drawing of the collective figure and extracting two or more different collective figures, the collective figure beam can be superimposed and drawn by superimposing the collective figure beams, thereby making it possible to perform the overlapped drawing with a substantial shift. . If the repetition cycle is larger than the maximum size, it is possible to apply the batch figure drawing method by decomposing it into multiple batch figures, but if you prepare a batch figure decomposed by multiple decomposition methods, the same Overlay drawing is possible by the principle. This method is also effective when performing simultaneous drawing of a collective figure on a large pattern without repetition.
As a plurality of decomposition methods, it is conceivable to shift the fulcrum of decomposition by an amount smaller than the size of the collective figure of the first decomposition.

A second feature of the present invention is that the shift amount and the direction of the overlay drawing are changed according to the shape of the collective figure. In many cases, the collective figure has a complicated shape, and the amount and direction of shifting the drawing is limited. This is possible if the drawing apparatus is provided with an input system or storage system for information on the type of the collective figure or its symmetry.

[0007] A third feature of the present invention is to perform overwriting using an electron beam of 60 kV or more. this is,
This is realized by a device having both an acceleration electron gun of 60 kV or more and a data controller for multiple drawing. Higher acceleration is effective not only in the batch pattern irradiation method but also in the variable molding method in order to reduce the aberration and Coulomb effect of the electron beam. In particular, in overlay drawing, since positional accuracy is passed on to the blur of the electron beam, there is a concern that dimensional accuracy will be adversely affected. Therefore, it is effective to reduce the influence of substantial blurring as a result of the overwriting by reducing the aberration of the electron beam in advance.

Although there are several possible ways to reduce aberrations, reducing the aberration coefficient of a lens makes lens design considerably more difficult. A possible approach is to accelerate the electron beam. The problem of high speed is heat generation of the sample substrate. However, since overlaying works in a direction to alleviate this effect, the combination of high acceleration and overlaying is very compatible. More specifically, in the overlapping drawing, the amount of electrons to be irradiated at one time is small, so that the temperature rise is small, and the temperature is lowered until the next irradiation, so that the problem of heat generation is greatly reduced.
Although this method is effective for all electron beam writing methods, the collective pattern irradiation method tends to use a particularly large current to simultaneously irradiate a plurality of patterns, and the electron beam blur due to the Coulomb effect is overwritten. Will reduce the allowable amount of blur. From this point of view, a combination of the collective graphic method, the overlay drawing, and the acceleration voltage of 60 kV or more is effective.

A fourth feature of the present invention is that the amount of exposure is made different when performing overlapping drawing using a collective figure.
This is particularly effective when performing exposure with different exposure amounts depending on the pattern shape in consideration of the proximity effect. For example, in the first drawing, uniform drawing is performed, a proximity effect correction calculation is performed in the meantime, and exposure is adjusted in the second and subsequent drawing to perform drawing. It is also conceivable to set the first exposure to a large value in order to finish the calculation during drawing.

A fifth feature of the present invention relates to optical proximity correction (hereinafter referred to as OPC) pattern drawing. O
Since the shape of the PC pattern is also affected by the peripheral pattern, it is difficult to standardize the shape, and there is a contrivance for applying a collective figure. However, in the case of a memory cell, the peripheral pattern is the same except for the outermost periphery and can be used effectively. In particular, since the collective figure of the hole pattern having the OPC pattern is a pattern having a large number of shots in the variable molding, it is more effective. Further OP
When overwriting the pattern C multiple times, use OPC
A method of performing multiple drawing without changing the pattern dividing method is preferable. The OPC pattern forms a fine pattern on the reticle that does not resolve when the reticle is transferred onto the wafer, and thereby controls the shape of the pattern of the main body. For this reason, the pattern has a smaller size than ever before, and a method of dividing the pattern more finely at the time of multiple writing is not preferable because the load on the apparatus is large. Therefore, when performing multiple writing, it is preferable that the OPC pattern is written in the same place by one type of irradiation pattern. In a hole pattern with a small number of connections, the requirement for reducing the error in the connection portion is loose, and the collective pattern irradiation method is particularly effective. Although a single method of dividing the OPC pattern is effective for both the variable molding method and the collective figure irradiation method, the collective irradiation method has an advantage that the number of collective figure patterns can be reduced.

A sixth feature of the present invention resides in that a collective figure beam used for superposition drawing is formed by at least three masks. For example, the maximum irradiable area of the collective figure is defined by the first and third masks, and the collective figure on the second mask is selectively cut out. Then, a plurality of collective figures are cut out and overlaid and drawn. The apparatus is characterized by having a deflector for deflecting each mask and a data controller for multiple writing. This allows the first
When cutting out a collective figure such as the feature described above from the drawing pattern by a different method, the method can be performed in the apparatus. These features may be applied alone or in combination.

That is, in the electron beam writing method according to the present invention, the step of cutting out the electron beam from the electron source by the opening provided in the first mask, the step of dividing the pattern to be drawn into a plurality of patterns, Irradiating the cut-out electron beam to a second mask having a first opening corresponding to the divided pattern and a second opening corresponding to the pattern straddling the divided pattern;
Exposing the substrate on the sample table to the electron beam that has passed through the second mask.

This electron beam writing method can include a step of changing the shift amount and direction of the overlay writing according to the shape of the opening of the second mask. In addition, it is preferable that the electron beam is accelerated at a voltage of 60 kV or more and the second mask is used to perform overwriting. One aspect of the electron beam lithography method according to the present invention is characterized in that, when performing the overwriting using a collective figure, there is a drawing in which the exposure amount at the time of the overwriting is different.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. [Embodiment 1] FIG. 1 shows an example of the configuration of an electron beam writing apparatus used in the electron beam writing method of the present invention. Electron source 1
The electron beam emitted from 2 is accelerated to 50 kV and irradiates a first mask 14 having a rectangular opening 13. The electron source 12 has a potential of −50 kV and the anode 20
3 is a ground potential, during which electrons are accelerated. The region from the electron source to the anode is an electron gun region, and further includes a Wehnelt electrode and the like. The first mask image is formed on the second mask 20 by the two transfer lenses 16 and 18. The figure selection deflectors 15 and 17 are provided between the two masks to control the position of the first mask image on the second mask 20. The figure selecting deflector is constituted by a two-stage deflector.

The electron beam that has passed through the second mask passes through reduction lenses 22 and 23 and objective lenses 24 and 25 onto a sample (a wafer 27 or a reticle substrate) on a stage, for example, for one beam.
/ 25 is reduced. The apparatus has a data controller 204 for multiplex drawing, generates deflection data from the drawing data, and controls the deflector 25 in the objective lens through a control signal line 205.
And the figure selecting deflector 15 are controlled. Although not shown, an analog circuit for controlling the deflector is provided at the end of the control line.

FIG. 2 shows the opening shape of the second mask. Second
The mask 20 has a rectangular opening in the center, which is used for forming a variable shaped beam. An opening 30 of the collective irradiation method is disposed around the periphery. In the present embodiment, an oblique collective figure opening is prepared for drawing an oblique wiring layer reticle. This opening has translation symmetry in the longitudinal direction in accordance with the translation symmetry direction of the drawing pattern.

FIG. 20 shows the drawing procedure. First, the upper L
The SI data is converted into the drawing data (S11). Next, the drawing data is converted into data for multiple drawing (S1).
2). The data is transferred to the apparatus body (S13), and drawing is started (S14). There are various methods for the overlay drawing method. A collective figure is selected and the overlay drawing is performed while shifting each shot (S15a). In the minimum field, data is first drawn by a normal method, and then data obtained by slightly shifting the minimum field is stored. (S15b), a method of selecting a collective figure and performing overlapping drawing for each maximum field (S15c). The method of performing overlapping drawing for each maximum field has an advantage that the number of times of data switching is small. Further, according to the method of performing the overlapping drawing for each minimum field, there is a feature that high accuracy is easily obtained.

FIG. 3 shows a shot on a reticle at the time of writing in this embodiment. The drawing pattern is an oblique line and a space. The second shot overlaps a plurality of first shots with respect to the first shot, and connection accuracy is improved. In the present embodiment, drawing is performed three times while shifting by one third of the length of the collective figure. In order to make the total exposure time uniform, when shifting by 1 / N, N overlapping exposures are effective. Batch figure is 10μ width
m is an oblique pattern and the reduction ratio of the optical system is 1/25, so that the line width is 0.4 μm on the reticle. 4
If a double reticle is used, the line width on the wafer is 0.1 μm. The longitudinal direction used was 2 μm on the reticle. It is effective to shift in the longitudinal direction in this way. The dimensional accuracy of the pattern connecting portion was 20 nm in the conventional variable molding, 15 nm in a single drawing by batch irradiation, and 10 nm in a double overlap drawing by batch writing, and the present invention was the highest accuracy.

Next, the hole pattern of the memory cell was drawn by replacing the second mask shown in FIG. In this example, 16 holes are drawn at once. This mask is shown in FIG.
As shown in FIG. The shifting method is equivalent to two holes in the X direction. That is, the drawing is performed twice while shifting the length of the collective figure by half. FIG. 5 illustrates some other overlay drawing methods. FIG. 5B shows that 2
An overlapping drawing method in which the image is shifted by two pieces in the Y direction is shown. FIG. 5C shows an overlapping drawing method in which the image is shifted by one image in the X direction (thus, drawing four times). According to the overlay drawing, an effect of averaging the transfer distortion of the collective beam can be expected even in a pattern having no connection such as a hole pattern. In particular, in batch irradiation, irradiation of a large area is performed at once, so that the influence of transfer distortion is important. The hole pattern in this example is 0.15 μm on the reticle and the pitch is 0.4 μm. In FIG. 5, each shot is made one shot in order to make the drawing easy to see, but actually, the pattern is irradiated so as to spread the pattern at a constant pitch.

As is apparent from the above, when performing overlapping drawing with a collective figure, it is an important method to change the shift amount depending on the collective figure. In the variable molding method, the shape of the rectangular shot can be changed according to the shift amount, so the shift amount is independent of the figure, which is a great difference when using a collective figure. In order to process this efficiently, the apparatus configuration shown in FIG. 6 was adopted. A control unit (WS2) for generating drawing data to be sent to the drawing apparatus main body is provided with a memory unit for storing information on the shift amount. Then, the size or shift amount 37 of the collective figure is added to the data to give information to the drawing apparatus, or only the identification number of the collective figure is sent to determine the size or shift amount 36 of the collective figure stored in the apparatus in advance. By calling, the shift amount can be controlled. If the shift amount is known in advance, a plurality of drawing data in which the reference point of the field is shifted by the method of cutting out the drawing data from the LSI pattern is prepared, and the data is stored, and the overlay drawing is performed. Is also effective.

The drawing apparatus is generally controlled by a deflection field having a hierarchical structure as shown in FIG. Shifted overlapping drawing can be realized by changing the fulcrum of this field. Therefore, this can be realized by drawing the shot pattern data by changing the fulcrum of the field in accordance with the information of the collective figure and decomposing the shot, or by creating a plurality of data in which the drawing position of the collective figure is shifted.

In the present embodiment, the position accuracy of the hole pattern is 30 nm in one drawing, 20 nm in the overlapping drawing method of FIG. 5A, 18 nm in FIG. 5B, and 1 nm in FIG. 5C.
At 5 nm, the effect of overlapping drawing was confirmed. Furthermore,
Using the mask of FIG. 8 for the pattern drawing of FIG. 9, the method of overlay drawing of a collective figure according to the present invention was applied. This pattern is a kind of the OPC pattern. A protrusion called a serif is formed at a rectangular corner of a hole pattern of a memory cell, and a line pattern called an outrigger is formed outside each side. Since the shape of the OPC pattern is affected by the peripheral pattern, it is difficult to standardize the shape, and there is some contrivance for applying a collective figure. However, in the case of a memory cell, the peripheral pattern is the same except for the outermost periphery and can be used effectively. In particular, since the collective figure of the hole pattern having the OPC pattern is a pattern having a large number of shots in the variable molding, it is more effective. This is effective for both the throughput and the accuracy without performing the overwriting. By adding the OPC pattern, a reticle corresponding to a 0.1 μm hole on the wafer could be formed. Since the OPC pattern is smaller than the main body, if the OPC pattern is further divided and overwritten, the accuracy of the mask may be deteriorated in producing the mask. Therefore, when performing the overwriting on the OPC pattern, it is desirable not to separate the OPC pattern as in the present embodiment.

Although a 20-μm-thick silicon mask is used for the collective mask, when a small pattern such as an OPC pattern is formed, emphasis is placed on the workability of the mask.
It is also possible to use a material having a thickness of about 10 μm to about 10 μm and draw with a scattering contrast.

[Embodiment 2] Two collective figure masks shown in FIG. 10 are used in combination. Drawing pattern is shown in FIG.
The pattern is as shown in FIG. For example, assuming that the maximum batch size in the system of the present embodiment is 2 μm and the cycle of the drawing pattern is 2 μm on the reticle, the cycle of the drawing pattern is larger than の of the maximum batch size, so that a plurality of repetitions are performed. It is difficult to apply a pattern to a collective figure. Therefore, the one-time pattern is included in the collective figure. However, it is not possible to perform overlapping drawing with the pattern shifted only by this. Therefore, two collective figures 40 and 41 having different ways of extracting figures are used. By performing drawing as shown in FIG. 11 using this, the shots overlap each other with a plurality of other shots, and the connection accuracy can be improved.

In FIG. 11, first, the pattern of the collective figure 40 is drawn in a predetermined area (for example, the minimum deflection field), and then the pattern of the collective figure 41 is drawn across the pattern 40 of the collective figure. As another method, the patterns 40 and 41 may be alternately drawn, and as a result, the patterns may be drawn over each other. Furthermore, pattern 4
Either of 0 and 41 may be drawn first. For example, if the collective figure 40 is defined as a parent opening and the collective figure 41 is defined as a child opening,
The parent opening may be drawn over the parent opening after the parent opening is drawn in the determined area, or the parent opening may be drawn after the child opening is drawn. This method uses a highly periodic SRA
Application to M is particularly effective.

FIG. 21 shows the drawing procedure. First, the upper L
The SI data is converted into the drawing data (S21). Next, the drawing data is converted into data for multiple drawing (S2
2). The data is transferred to the apparatus main body (S23), and drawing is started (S24). There are various methods for the overlay drawing method. In the present embodiment, in order to reduce waste due to the batch figure selection time, one collective figure is selected and drawn in the minimum field, and then another collective figure is selected. Was selected and overlaid.

As an application of this embodiment, there is an isolated gate pattern. In this case, there is no periodicity in the adjacent patterns, which is further complicated. As shown in the mask of FIG.
Separate into sets of 4-47. If these are drawn as shown in FIG. 13, it is possible to improve the connection accuracy by changing the position of the connection part of the collective figure even in a pattern having no periodicity. In addition, the dimensional accuracy of the line width is higher than that of the variable molding because the fixed opening is used. The dimensional accuracy of the pattern width was improved to 10 nm as compared with 20 nm of the variable molding.

Further, application to a case where the period of the periodic pattern is long will be described. The eight collective figures 44 to 51 of the mask of FIG.
Use This is obtained by further dividing the large periodic pattern shown in FIG. 15 into four parts by shifting the fulcrum. Creating a collective figure by a plurality of different division methods for a pattern in this way is also effective for a pattern having periodicity.

An example similar to the first example but applied to an oblique pattern will be described. In order to increase the circuit density of the LSI, the pattern does not necessarily have to be parallel to the XY directions of the wafer or the reticle. In some cases, an oblique line is optimal as shown in FIG. In this case, the collective figure is also formed from the oblique opening as shown in FIG. The oblique pattern is a pattern in which the batch figure method is extremely effective because the shot becomes small and a huge drawing time is required in the variable rectangle method. Further, if only rectangles in the XY directions alone are used, they can be easily overlapped in the XY directions but cannot be overlapped in an oblique direction. The present invention is indispensable when performing overlapping drawing on an oblique pattern.

[Embodiment 3] LSI of 70 nm rule
A 4-fold reticle was prepared for The same optical system and mask as in Embodiment 2 were used, but the acceleration voltage was 70 kV.
That is, -70 kV is applied to the high voltage power supply 999 to accelerate electrons to 70 kV between the electron source and the anode. The reason for 70 kV is to reduce the chromatic aberration and the forward scattering to increase the resolution. Substantial blurring of the electron beam when performing double writing with this apparatus increases by 30 nm. Deterioration of dimensional accuracy due to blurring of the electron beam becomes more pronounced as the dimensions become smaller. In the present embodiment, since a pattern as small as 280 nm is drawn on the reticle, dimensional accuracy other than the pattern connecting portion may be degraded due to overlapping drawing. In particular, blurring of the electron beam degrades dimensional accuracy through the proximity effect. By increasing the acceleration voltage as compared with the case of the second embodiment, blurring of the electron beam can be reduced, thereby making it possible to reduce the influence of the proximity effect on the dimensional accuracy. However, a problem is a heating effect of the substrate.

Roughly speaking, the resist sensitivity is inversely proportional to the acceleration voltage, and the heating of the glass substrate is proportional to the acceleration voltage. Therefore, in order to exert the same photosensitive action on the resist, the temperature rise during the shot is approximately doubled from 70 kV to 50 kV. Therefore, when drawing is attempted by one irradiation, the resist is heated and the dimensional accuracy is deteriorated. The amount of irradiation at a time can be reduced to 1 / N by performing the overwriting.

FIG. 16 shows the relationship between the acceleration voltage, the chromatic aberration, and the temperature rise. The current density of the electron beam is 10 A /
cm ² , and the resist sensitivity is 10 μC / cm ² . 560 nm on reticle corresponding to 140 nm pitch on wafer
From the upper limit of chromatic aberration and temperature rise required to obtain dimensional accuracy of 10 nm with a fine pattern of pitch,
It can be seen that multiple drawing is necessary. But another 80k
If it exceeds V, the effect of the temperature of the reticle slowly increasing and expanding during drawing on the entire surface of the reticle becomes remarkable, so that the positional accuracy deteriorates. Therefore, 60 kV or more,
Overlay drawing at 80 kV or less is effective. In the present embodiment, a hole pattern of 280 nm
It was formed at a pitch of 60 nm. The resulting dimensional accuracy is 8n
m. When a resist with lower sensitivity is used, the irradiation time becomes longer, so that it is effective to further increase the number of multiplexing in order to promote a further decrease in temperature rise.

As can be seen from this embodiment,
If the dimensional rule is loose, it can be used at a low accelerating voltage. The low acceleration voltage has an advantage in that point because the resist sensitivity is improved. Therefore, changing the accelerating voltage of the apparatus according to the dimensional rule of the reticle to be drawn is an effective pattern forming method. The device preferably has a function of setting an acceleration voltage based on pattern information. If two or more drawing devices are installed, one acceleration voltage is set to an acceleration voltage lower than 60 kV, and the other is set to a high acceleration voltage of 60 kV or more. The use of drawing and drawing with strict dimensional rules using a device with a higher acceleration voltage will be effective.

[Embodiment 4] FIG. 23 shows a drawing pattern. Since the location corresponds to the edge of the circuit pattern, it is necessary to increase the exposure amount at the edge pattern. In the present embodiment, drawing is performed twice. In the first drawing, uniform drawing is performed, and during that time, the proximity effect correction calculation is performed by the correction calculation unit 99.
The processing was performed in step 7, and the exposure was adjusted in the second and subsequent drawing steps to perform the overlapping drawing. Since the proximity effect differs depending on the position and shape of the drawing pattern, it is necessary to change the exposure amount according to the pattern. The exposure time is controlled by a blanker 998. This makes it possible to hide the proximity effect correction time when performing the overexposure. This effect can be obtained with or without shifting the overlay exposure. FIG. 24 shows the distribution of the exposure amount. It can be seen that the second exposure amount is larger toward the end. The dimensional accuracy was improved from 20 nm to 10 nm by using the proximity effect correction together.

[Embodiment 5] Using the optical system shown in FIG. Using three masks, a first mask 101 image is formed on the second mask 102 and a second mask image is formed on the third mask 103, and a collective figure beam is formed by combining these three masks. In the drawing, a state in which a multiple drawing data control device 204 is provided and the objective deflector 206, the first deflector 113, and the second deflector 114 are connected by a control line is simply illustrated.

FIG. 18 shows an opening of the mask. The projected image of the rectangular opening 200 of the first mask on the virtual third mask (the projected image on the third mask assuming that the electron beam transmitted through the first mask is not blocked by the second mask) and the 3
The shape of the collective figure beam is defined by the position on the second mask of the virtual rectangular opening formed by overlapping with the mask rectangular opening 200. On the second mask, a part of the large collective figure 201 of the drawing pattern is formed larger than the maximum size of the collective figure that can be irradiated at one time. As a result, as shown in FIG.
02 enables decomposition into various collective figures. However, there are drawbacks such as the optical system becoming complicated, and the position and size of the virtual rectangular opening on the second mask directly affecting the connection accuracy of the collective figure. Is advantageously provided independently. This embodiment has an effect that the total area of the openings can be reduced because the openings are used in an overlapping manner. Note that errors in the virtual rectangular opening position and size can be reduced by increasing the number of times of overlapping drawing.

FIG. 22 shows the drawing procedure. First, the upper L
The SI data is converted into the drawing data (S31). Next, the drawing data is converted into data for multiple drawing (S3
2). The data is transferred to the apparatus body (S33), and drawing is started (S34). Also in the present embodiment, in order to reduce waste due to the time of forming a collective figure, one collective figure is formed, then the minimum figure is drawn with the collective figure, and then another collective figure is formed. Was overlaid and drawn.

[0038]

As described above, according to the present invention, it is possible to improve the connection accuracy of collective figures in an electron beam lithography apparatus capable of performing the collective figure irradiation method, thereby contributing to an improvement in the yield of semiconductor elements and the like. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an electron beam drawing apparatus.

FIG. 2 is a diagram illustrating an example of a second mask.

FIG. 3 is an explanatory diagram showing an example of a drawing pattern.

FIG. 4 is a diagram showing another example of the second mask.

FIG. 5 is an explanatory diagram showing another example of a drawing pattern.

FIG. 6 is a schematic diagram of a data control system.

FIG. 7 is an explanatory diagram of a field structure.

FIG. 8 is a view showing another example of the second mask.

FIG. 9 is an explanatory diagram showing another example of a drawing pattern.

FIG. 10 is a diagram showing another example of the second mask.

FIG. 11 is an explanatory diagram showing another example of a drawing pattern.

FIG. 12 is a view showing another example of the second mask.

FIG. 13 is an explanatory diagram showing another example of a drawing pattern.

FIG. 14 is a view showing another example of the second mask.

FIG. 15 is an explanatory diagram showing another example of a drawing pattern.

FIG. 16 is a view for explaining acceleration voltage dependence of chromatic aberration and temperature.

FIG. 17 is a schematic view showing another example of the electron beam drawing apparatus.

FIG. 18 is an explanatory diagram of a mask.

FIG. 19 is an explanatory diagram of a mask.

FIG. 20 is an explanatory diagram of a drawing procedure.

FIG. 21 is an explanatory diagram of a drawing procedure.

FIG. 22 is an explanatory diagram of a drawing procedure.

FIG. 23 is an explanatory diagram of a drawing pattern.

FIG. 24 is an explanatory diagram of an exposure amount.

FIG. 25 is a view showing another example of the second mask.

FIG. 26 is an explanatory diagram showing another example of a drawing pattern.

[Explanation of symbols]

12: electron source, 13: rectangular opening, 14: first mask, 1
5 figure selection deflector, 16 first transfer lens, 17 variable shaping deflector, 18 second transfer lens, 19 collective aperture, 20 second mask, 21 rectangular opening, 22 first reduction lens , 23: second reduction lens, 24: first objective lens, 25: objective deflector, 26: second objective lens, 27 ...
Wafer, 28 ... aperture group, 29 ... first mask image, 30 ... collective figure aperture, 31 ... first irradiation, 32 ... second irradiation, 33 ... third irradiation, 34 ... fourth irradiation, 35 ...
Drawing data, 36: a memory unit for storing information relating to a shift amount; 37, LSI design data having information relating to a collective figure or information relating to a shift amount; 38, a main deflection field; 39, a sub-deflection field; 41: collective opening 2, 42: connecting part of collective figure 1, 4
3. Connection part of collective figure 2, 44 ... collective figure 1a, 45 ...
Collective figures 1b, 46 ... Collective figures 2a, 47 ... Collective figures 2
b, 48 ... collective figure 1c, 49 ... collective figure 1d, 50 ...
Collective figures 2c, 51: Collective figures 2d, 52: First decomposition grid, 53: Second decomposition grid, 54: Drawing pattern, 1
00: electron source, 101: first mask, 102: second mask, 103: third mask, 104: first transfer lens, 1
05: second transfer lens, 106: third transfer lens, 10
7: fourth transfer lens, 108: first reduction lens, 109
... first objective lens, 110 ... sample, 111 ... stage,
113: first deflector, 114: second deflector, 115: crossover, 116: mask image trajectory, 120: data control system, 121: analog circuit, 140: collective figure 4, 1
41 ... collective figure 3, 142 ... connection part of collective figure 4, 14
3. Connection part of collective figure 3, 200 rectangular opening, 201
Large collective figure aperture, 202: virtual rectangular aperture image, 203
... Anode, 204 ... Multiple drawing data controller, 20
5 Control signal line, 206 Objective deflector, 999 High voltage power supply, 998 Blanker, 997 Proximity effect correction exposure amount calculation unit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuko Goto 1-280 Higashi-Koigakubo, Kokubunji-shi, Tokyo F-term in Central Research Laboratory, Hitachi, Ltd. 2H097 AA12 BB01 CA16 LA10 5C034 BB05 BB10 5F056 CA05 CC09 CD16

Claims (4)

[Claims] 1. A step of cutting out an electron beam from an electron source by an opening provided in a first mask, dividing a pattern to be drawn into a plurality of patterns, and a step corresponding to the plurality of divided patterns. Irradiating the cut-out electron beam to a second mask having a first opening and a second opening corresponding to a pattern straddling the divided pattern; and an electron passing through the second mask. A step of exposing a substrate on a sample stage to a beam. 2. The electron beam lithography method according to claim 1, further comprising a step of changing a shift amount and a direction of the overlay lithography according to the shape of the opening of the second mask. 3. An electron beam drawing method according to claim 1, wherein the electron beam is accelerated at an acceleration voltage of 60 kV or more and the second mask is used to perform overwriting. 4. The electron beam writing method according to claim 2, wherein when performing the overwriting using the collective figure, there is a drawing with a different exposure amount at the time of the overwriting.