JPH10223506A - Charged beam lithography system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an aperture mask compsn. which does not change the shape or position of a beam due to thermal expansion, thereby improving the drawing accuracy. SOLUTION: This electron beam lithography system is provided an aperture mask having an aperture for passing an electron beam through, thereby shaping the beam which is then irradiated on a wafer to form a desired pattern. The aperture mask has 4 aperture plates 21, each having one reference side straight line. The plates 21 are combined to form a rectangular aperture defined by the reference side lines thereof. One end 23 of the reference side of each aperture plate 21 is fixed to a mask holder 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged beam drawing apparatus using a beam of electrons, ions, and the like, and more particularly to a charged beam drawing apparatus for improving an aperture mask for forming a desired beam shape.

[0002]

2. Description of the Related Art In recent years, with the increase in the density of integrated circuits, photolithography, which has become the mainstream of fine pattern formation technology, has been pointed out by its limitations. ing.

In an electron beam lithography apparatus for performing lithography using an electron beam, an aperture mask is used to obtain a desired beam shape for forming a fine pattern. Since this aperture mask needs to accurately form an aperture serving as a beam passage hole,
Recently, aperture processing has been performed using semiconductor process technology.

Usually, an aperture mask has an aperture of about 1 cm square. There are various methods of holding the aperture mask. To determine the position of the aperture with high accuracy, for example, as shown in FIGS. 10A to 10D, at least one side or at least two points outside the aperture mask are used. Must be fixed or supported.
In FIGS. 10A and 10B, the position of the aperture mask 101 is determined by the support pins 102. FIG. 10 (c)
In (d), the position of the aperture mask 101 is determined by the support block 103.

Incidentally, in recent electron beam writing apparatuses, further miniaturization and processing capability (throughput) are required.
For improvement, high acceleration and large current exist as one flow. That is, the energy of the electron beam tends to increase, and the aperture mask directly exposed to the beam becomes hot. The hot aperture mask expands thermally. For this reason, as shown in FIGS. 11A and 11B, the aperture moves to a position shifted from a predetermined position or the aperture shape changes.

For example, in the two-point support shown in FIG. 11A and the three-point support shown in FIG. 11B, the aperture mask 111 is indicated by a broken line 115 with the side determined by the support pin 112 as a fulcrum. To expand. This displacement or deformation (enlargement in the case of FIG. 11) causes deterioration of the drawing accuracy. The effect of the shape deformation is relatively small when the size of the aperture (aperture) of the aperture mask is small. However, since the positional deviation depends on the size of the aperture mask, even a small temperature rise has a great effect on the writing accuracy.

In order to solve such a problem, it is conceivable to provide a mechanism for keeping the aperture mask at a constant temperature. However, the mechanism for keeping the aperture mask at a constant temperature complicates the device structure. Also, since the aperture mask is placed in a vacuum, it has a large thermal resistance, and it is extremely difficult to keep it at a constant temperature with a fast response time and high accuracy.

[0008] The problem of thermal expansion which causes the above-mentioned aperture deformation is not limited to the aperture mask for beam shaping but also occurs in the aperture mask for blanking. The mechanism by which thermal expansion occurs in these aperture masks will be described.

FIG. 12 is an enlarged view showing a mounting portion of the aperture mask. In this example, the aperture mask 121 is held by the holding portion 1
23. The mask holding section 123 is mounted on a ceramic ring 125 fixed to the lens barrel main body 124, and its direction can be changed by a rotation driving mechanism (not shown).

Here, heat conduction between the aperture mask 121 and the mask holding portion 123 is performed by the pressing spring 122 and the contact portions 127 and 128. However, the force of the pressing spring 122 is at most about 100 g, and therefore, the contact portion 1 between the pressing spring 122 and the aperture mask 121 is different.
27, aperture mask 121 and mask holding unit 123
There are many gaps in the contact portion 128 with the micro. Therefore, the heat conduction at the contact portions 127 and 128 is much smaller than the bulk heat conduction.

When an electron beam is applied to an aperture mask for beam shaping or an aperture mask for blanking, the energy is almost converted into thermal energy.
Therefore, the temperature of these aperture masks rises to a considerable extent. In this case, the temperature of the aperture mask greatly increases, and the size and shape of the electron beam formed by the aperture mask change due to thermal expansion accompanying the temperature. For example, assuming that an aperture mask made of silicon having a thickness of 0.6 mm and 10 mm square is irradiated with an electron beam of 50 keV and 1 μA, if there is no heat conduction and only radiation to both sides is considered, the emissivity is set to 0.7. If the temperature reaches 100 ° C. or more.

Aperture mask 121 and mask holding unit 1
The heat conduction with 23 is, for example, with a gap of 10 μm.
Assuming that the connection portion is only supported by three protrusions having a diameter of about 6 μm, the thermal conductivity coefficient of Si is 0.84
Assuming that J / cm / sec / K, the amount of heat flowing in by the electron beam is 50 mW, and the temperature is 20 ° C. using the mask holding unit 123 as a heat sink, the temperature of the aperture mask 121 reaches 90 ° C. or more.

The linear expansion coefficient of silicon is 2.4 × 10 ^-6 / K
Since the characteristic length is 500 μm,
Deformation due to thermal expansion is on the order of 0.8 μm. Assuming that the reduction ratio between the aperture mask 121 and the wafer is 1/40, this means that the dimensional fluctuation on the wafer reaches 20 nm or more, which is a value that cannot be ignored. Although not as large as the aperture mask 121, the mask holding unit 123
Also the temperature rises. The thermal expansion accompanying the temperature rise of the mask holding section 123 cannot be ignored. Further, since the beam current applied to the blanking aperture mask is large, the blanking aperture mask may be melted in some cases.

On the other hand, for example, it is conceivable to secure heat conduction by fixing the aperture mask to the mask holding portion with a conductive adhesive. In that case, however, the aperture mask is fixed and the mask position is fixed. It is not practical because there is a problem that it becomes difficult to correct the problem.

[0015]

As described above, in the conventional electron beam writing apparatus, the aperture mask is thermally expanded by the irradiation of the electron beam. This phenomenon is a major factor that hinders future increase in drawing accuracy in the trend of higher beam acceleration and higher current.

The present invention has been made in consideration of the above circumstances, and has as its object to realize a configuration of an aperture mask that does not change the beam shape or position due to thermal expansion, and to achieve a higher writing accuracy. An object of the present invention is to provide a charged beam writing apparatus which can be improved.

Another object of the present invention is to provide a charged beam writing apparatus capable of suppressing an increase in the temperature of an aperture mask, reducing thermal expansion of the mask and improving writing accuracy. .

[0018]

[Means for Solving the Problems]

(Structure) In order to solve the above problem, the present invention employs the following structure. (1) In a charged beam drawing apparatus which includes an aperture mask having an aperture of a predetermined shape for passing a charged beam and irradiates a beam formed by the aperture mask onto a sample to form a desired pattern, the aperture mask is At least one reference side composed of straight lines
A plurality of aperture plates are combined to form the aperture with the reference side, and one end of both ends of the reference side of each aperture plate or a portion on an extension of the reference side is fixed. It is characterized by becoming. (1-1) The charged beam shall be an electron beam or an ion beam. (1-2) The aperture plate has a strip shape. (1-3) The aperture mask is a beam shaping aperture mask that determines the beam shape. (1-4) In addition to the aperture mask for beam shaping, an aperture mask for peripheral cutting for blocking peripheral beams is provided. (2) An aperture mask having an aperture for allowing a charged beam to pass therethrough is set on a mask holding unit, and the beam passing through the aperture is irradiated onto a sample to form a desired pattern. A liquid, a gel, a metal thin film, a low-melting-point metal, or an elastic body is sandwiched at least in part of the contact portion with the part. (2-1) The liquid to be sandwiched is conductive. (2-2) The liquid to be sandwiched is liquid metal. (2-3) The sandwiched metal thin film is not harder than the aperture mask or mask holding part. (2-4) The metal thin film to be sandwiched is gold. (2-5) The low melting point metal to be sandwiched is gallium. (2-6) The low melting point metal to be sandwiched is indium. (2-7) The low melting point metal to be sandwiched is easy fusion metal. (2-8) Means for confirming electrical continuity between the aperture mask and the charged beam optical column must be provided. (Operation) As in the present invention, by fixing one end of the reference side of the aperture plate constituting the aperture mask or a part of the extension of the reference side, the aperture mask is temporarily expanded by beam irradiation. However, the aperture shape and position hardly change. For this reason, it is possible to prevent the beam shape and the beam position from being changed due to the thermal expansion of the aperture mask, and it is possible to perform highly accurate writing.

Further, by interposing a liquid, a gel, a metal thin film, a low-melting-point metal, or an elastic body at least in a part of a contact portion between the aperture mask and the mask holding portion, heat conduction between the aperture mask and the mask holding portion is achieved. Characteristics can be enhanced. This makes it possible to suppress a rise in the temperature of the aperture mask and to suppress thermal deformation of the aperture mask.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a diagram showing a basic configuration of an electron beam writing apparatus according to a first embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a sample chamber, in which a sample table 3 on which a wafer (sample) 2 is placed is accommodated. Reference numeral 10 denotes an electron optical column. The electron optical column 10 includes an electron gun 11, various lens systems 12a to 12e, various deflection systems 13 to 16, an aperture mask 17 for blanking, first and second beams. Aperture masks 18 and 19 are formed.

The electron beam emitted from the electron gun 11 is
Irradiation is performed on the first beam shaping aperture mask 18 by the lenses 12a and 12b to be shaped into a rectangular beam, and an image of the shaped aperture (first aperture image) is formed by the projection lens 12c for the second beam shaping. An image is irradiated on the aperture mask 19. Here, by adjusting the degree of overlap between the first aperture image and the opening (second aperture) of the second aperture mask 19 by the shaping deflector 14, a beam having an arbitrary dimension can be obtained. And
The wafer 2 is projected by the projection lens 12d and the objective lens 12e.
It is shrunk up and illuminated. At this time, the objective deflector 1
A desired position on the wafer 2 is radiated by 5 and 16.

In order not to irradiate the wafer 2 with an electron beam, the beam is deflected by a blanking deflection system 13 and the beam is blanked by blocking the beam by a blanking aperture mask 17.

The basic structure of the above-described electron beam writing apparatus is the same as that of the prior art, but this embodiment is characterized by the structure of an aperture mask described below. FIG. 2 is a diagram showing a specific configuration of the aperture mask used in the present embodiment. (A) shows one of the aperture plates constituting the aperture mask, (b) shows a state where the aperture mask is set on the mask holding portion, and (c) shows a state where the aperture mask is expanded.

In this embodiment, an aperture mask having a rectangular aperture is formed by combining four aperture plates. That is, as shown in FIG. 21A, the aperture plate 21 has a shape having a straight line serving as a reference side and an arc. Each of the aperture plates 21 has one end (hatched portion surrounded by a broken line) 23 of both ends of the reference side fixed to the mask holding unit. Specifically, as shown in FIG. 2B, one end 23 of each of the aperture plates 21 is fixed by a fixing plate 24 in a state where the two aperture plates 21 are separated from each other so that the reference sides face each other. 24 is fixed on the mask holder 22. Further, another two aperture plates 21 are similarly fixed by the fixing plate 24, and are fixed on the mask holding portion 22 in an arrangement orthogonal to the previous two aperture plates 21.

As described above, the four aperture plates 21 are overlapped, and the aperture fixing plate 24 is attached to the aperture holder 22.
Is fixed to form an aperture capable of forming a square beam. This aperture mask may be used for beam shaping or for blanking.

In this apparatus using such an aperture mask, when the temperature of the aperture mask rises due to beam irradiation, the aperture mask expands as shown at 25 in FIG. In this case, as shown in the figure,
Each aperture plate 21 is fixed at one end of the straight line, and therefore expands with the fixed point as a fulcrum. However, since the sides involved in beam shaping have the same direction of expansion and side direction, the beam shape or beam position is not deformed.

Therefore, even if the thermal expansion of the aperture mask occurs, the shape and position of the aperture do not change. Therefore, it is possible to prevent a decrease in drawing accuracy due to the thermal expansion of the aperture mask, and to improve the drawing accuracy. This effect is particularly effective in a flow of increasing the beam acceleration and increasing the current. (Second Embodiment) FIG. 3 is a view showing an aperture mask portion of an electron beam writing apparatus according to a second embodiment of the present invention. (A) shows the relationship between the aperture mask and the beam size, (b) shows the state where the aperture mask is set on the mask holding unit, and (c) shows the state where the aperture mask is expanded.

In this embodiment, an aperture plate 31 having the same shape as that of the first embodiment is used. However, FIG.
Since the area of the aperture is smaller than the size of the beam as indicated by 36 in FIG. 3A, as shown in FIG. 3B, an auxiliary aperture mask, that is, for blocking the peripheral portion of the beam is used. A peripheral cut aperture mask 37 is provided.

The fixing method of the peripheral cut aperture mask 37 is arbitrary. However, as shown in FIG. 3C, it is necessary to determine the hole diameter of the aperture in consideration of the effect of expansion. That is, it is necessary to prevent interference between the shape 35 of the aperture mask 37 after thermal expansion and the formed beam 38. As can be seen from the figure, in this example, the aperture mask 37 expands with the aperture fixing plate 34 as a fulcrum. However, since the portion that actually determines the beam shape has the same structure as in the first embodiment, No change appears in the shape and position due to thermal expansion.

In the present embodiment, the peripheral cut aperture mask 37 for blocking the peripheral beam is provided below the aperture plate 31 which determines the beam shape, but this aperture mask 37 is provided above the aperture plate 31. I don't care. In this case, since the aperture mask 37 blocks most of the beam, there is an advantage that the temperature rise of the aperture plate 31 is reduced. (Third Embodiment) FIG. 4 is a diagram showing an aperture mask portion of an electron beam writing apparatus according to a third embodiment of the present invention. (A) shows one of the aperture plates constituting the aperture mask, and (b) and (c) show a state where the aperture mask is set on the mask holding unit.

In this embodiment, the shape of the aperture plate 41 used in the first embodiment is changed to a strip shape. Further, as shown in FIGS. 4B and 4C, several fixing methods are conceivable. In the case of (b), since the aperture plate 41 is fixed by the aperture fixing plate 44, it becomes as shown by a broken line 45 after thermal expansion. However, in this case, there is no change in the shape and position of the hatched portion.

Next, the case where the fixing is performed as shown in FIG. In this case, the aperture plate 41 is indicated by a broken line 46.
It is thought to expand like. In the case of the present embodiment, as can be seen from the figure, a slight deformation occurs in the beam shape (in this case, reduction of the rectangle). However, the beam position does not move.

When considering the actual configuration, the aperture plate 4
In many cases, the beam shape is sufficiently small compared to the size of 1. At this time, the influence of the deformation of the aperture due to thermal expansion is small, and the main factor that degrades the drawing accuracy is the movement of the position of the opening of the aperture mask. For this reason, even if the fixing method as in the present embodiment is used, an effect of remarkably improving accuracy can be obtained as compared with the conventional example. (Fourth Embodiment) FIG. 5 is a view showing an aperture mask portion of an electron beam writing apparatus according to a fourth embodiment of the present invention. (A) shows one of the aperture plates forming the aperture mask, and (b) shows a state in which the aperture mask is formed by combining the aperture plates.

In this embodiment, although the shape of the aperture plate 51 is more complicated than in the previous embodiments,
There is a fixed point 54 of the aperture on the extension of the side that determines the aperture shape. In this case, it is considered that the fixed point 54 expands in a similar manner with the fulcrum as a fulcrum like 55, and as a result, the aperture shape or position is not affected. (Fifth Embodiment) FIG. 6 is a view showing an aperture mask portion of an electron beam writing apparatus according to a fifth embodiment of the present invention. (A) shows one of the aperture plates forming the aperture mask, and (b) shows a state in which the aperture mask is formed by combining the aperture plates.

In this embodiment, a square aperture shape is formed by stacking two U-shaped aperture plates 61 as shown in FIG. 6A, as shown in FIG. 6B.
By setting the position of the aperture fixing plate 64 in FIG. 6A, it is substantially the same as fixing the ends of the two rectangular aperture plates as shown in FIG. 4C. Therefore, the deformation of the aperture plate 61 due to the thermal expansion is shown in FIG.
It becomes like 66 in (b).

In the case of this embodiment, although there is a possibility that the aperture shape slightly changes as in the embodiment shown in FIG. 4C, the influence of the expansion does not appear on the beam position. (Sixth Embodiment) FIG. 7 is a view showing an aperture mask portion of an electron beam writing apparatus according to a sixth embodiment of the present invention. (A) shows one of the aperture plates forming the aperture mask, and (b) shows a state in which the aperture mask is formed by combining the aperture plates.

In this embodiment, a square aperture shape is formed by stacking two square-shaped aperture plates 71 as shown in FIG. 7A, as shown in FIG. 7B.
The position of the aperture fixing plate 74 is substantially the same as that in the sixth embodiment, and the deformation of the aperture plate 71 due to thermal expansion is as shown in FIG. 7B.

In the case of this embodiment as well, there is a possibility that the shape may slightly change as in the embodiment shown in FIG. 4C, but the influence of the expansion does not appear on the beam position. In this way, it is also possible to determine the shape of the aperture plate according to the purpose and obtain the target accuracy. (Seventh Embodiment) FIG. 8 is a view showing an aperture mask portion of an electron beam lithography apparatus according to a seventh embodiment of the present invention. (A) shows a state in which an aperture mask is formed by combining aperture plates, and (b) shows a state of beam forming using the aperture mask.

In the present embodiment, eight aperture plates 81 similar to those in the embodiment of FIG. 4 are used, and these are combined to form an octagonal aperture shape different from the previous embodiments. The method of using this aperture mask is as follows.

That is, in the electron beam writing apparatus shown in FIG. 1, the aperture mask shown in FIG. 8A is used as the second beam shaping aperture mask 19, and the aperture shape of the first beam shaping aperture mask 18 is square. Suppose there is. Then, as shown in FIG. 8B, an aperture image 86 of the first beam shaping aperture mask is formed on the second beam shaping aperture mask 19. As a result, as shown by hatching in the figure, a beam of a square 87, a rectangle 88, and a triangle 89 having an arbitrary size can be formed.

Also in the case of the present embodiment, the aperture fixing plate 8
By devising the fixed position of the aperture plate 81 by 4, the structure is not affected by the thermal expansion of the aperture mask.

In the above-described first to seventh embodiments, the material of the aperture plate and the manufacturing method are not particularly described. However, the material is not particularly limited as long as the material satisfies processing accuracy, strength, and the like. Absent. For example, in the case of using a charged beam such as an electron beam, the material is required not to be charged in addition to the above. In such a case, a material that satisfies the requirements can be selected by a method such as selecting a conductive material or coating a conductive film on the surface of an insulating material. Since the purpose of the present invention is to eliminate the influence of expansion, it goes without saying that a material having an expansion coefficient as small as possible is suitable.

Next, an embodiment for eliminating the thermal expansion itself, not the influence of the thermal expansion of the aperture mask, will be described. (Eighth Embodiment) FIG. 9 is a view showing an aperture mask portion of an electron beam writing apparatus according to an eighth embodiment of the present invention.

The aperture mask 91 is fixed to the mask holding section 93 by a pressing spring 92. The mask holding section 93 is mounted on a ceramic ring 95 fixed to a lens barrel main body 94, and its direction can be changed by a rotation driving mechanism (not shown).

The configuration up to this point is the same as that of the conventional one, but in this embodiment, in addition, the connection part 96 between the aperture mask 91 and the mask holding part 93 is filled with a liquid having a low vapor pressure. Also, a connection part 97 between the mask holding part 93 and the lens barrel body 94 and a connection part 98 between the mask holding part 93 and the lens barrel body 94 via the ceramic 95 are filled with a liquid having a low vapor pressure. ing. Note that a hole or a concave portion may be provided in the connection portion in order to sufficiently fill the connection portion with the liquid.

As the liquid having a low vapor pressure, for example, fomblin oil may be used. If there is a risk of dripping with a liquid, a gel-like material such as vacuum grease can be used. Since the volume of the connection is very small, only a small amount of liquid or gel needs to be filled.
For example, if a small hole is formed in the mask holding unit 93 and the liquid is filled therein, the liquid can be held by the surface tension.

Assuming that the thermal conductivity of the filling is about olive oil and 1.7 × 10 ⁻³ J / sec / K / cm, the contact area is 10 cm under the conditions described in the prior art.
When ^2, the temperature rise against heat inflow 50 mW 0.
About 03K, and the resulting thermal expansion is at most 0.4 nm.
And the dimensional fluctuation on the wafer can be ignored.

Further, for the liquid or gel which has protruded,
For example, it can be removed by ashing treatment using oxygen radicals. Further, when the aperture mask 91 is in an electrically floating state, it may be charged with the inflow of the electron beam. In order to prevent this, in the present embodiment, the lead wire 99 is drawn out from the presser spring 92, and conduction can be confirmed by measuring the electric resistance between the lead wire 99 and the lens barrel body 94.

Further, a conductive material can be used as the liquid. As the conductive material, for example, a liquid metal such as mercury can be used. If the filling is conductive, the problem of charging does not occur, so that the incineration treatment is unnecessary.

Also, a thin film of a soft metal such as gold can be interposed. Since gold is softer than silicon as a mask material or a material such as a mask holding portion, for example, beryllium copper, it has a function of closing a gap between the aperture mask 91 and the mask holding portion 93 by a pressure when the aperture mask 91 is attached. Thereby, heat conduction can be increased.

Further, a low melting point metal can be interposed. In this case, the following advantages are newly obtained as compared with the case where the liquid is used. Now, in FIG. 9, it is assumed that gallium is put in the contact portion 96 between the aperture mask 91 and the mask holding portion 93. Since gallium is a soft metal, the heat conduction is considerably increased only by the pressure at the time of attaching the aperture mask 91. However, if the electron beam is irradiated, the temperature of the aperture mask 91 rises and the melting point of the aperture mask 91 increases.
When the temperature exceeds 8 ° C., the liquid becomes liquid, and closes the gap between the aperture mask 91 and the mask holding section 93. Thereafter, when the beam is cut off and the temperature of the aperture mask 91 decreases, the connection portion 9 is cut.
6 will be filled with gallium without gaps,
The heat conduction efficiency becomes extremely high. In addition, as the low melting point metal, an easy fusion metal such as indium having a melting point of 156.6 ° C., a Newton alloy having a melting point of 95 ° C., and a wood alloy having a melting point of 70 ° C. can be used.

For example, the thermal conductivity of gold is 3.1 J / cm /
Since sec / K, gallium, indium and mercury are 0.41, 0.25 and 0.09 J / cm / sec / K, respectively, the effects are much larger than those of the above oil and the effects are obvious. .

An elastic body such as synthetic rubber may be used. Rubber is about 1.3 × 10 ⁻³ J / cm / sec / K, so the same effect as oil can be obtained. As described above, according to the present embodiment, the contact portion 96 between the aperture mask 91 and the mask holding portion 93 and the contact portions 97 and 98 between the mask holding portion 93 and the lens barrel body 94 are provided with liquid, gel, and metal thin films. By sandwiching the low-melting point metal or the elastic body, the heat conduction characteristics from the aperture mask 91 to the lens barrel main body 94 can be enhanced, and the heat radiation of the aperture mask 91 can be effectively performed.

As a result, the temperature rise of the aperture mask 91 can be suppressed, and the thermal deformation of the aperture mask 91 can be suppressed. That is, unlike the first to seventh embodiments, the effect of the thermal expansion of the aperture mask 91 is not eliminated, but the thermal expansion itself can be eliminated. As a result, it is possible to contribute to the improvement of the drawing accuracy. .

The present invention is not limited to the embodiments described above. Although the embodiment has been described by taking an electron beam lithography apparatus as an example, the present invention is not limited to the electron beam lithography apparatus, but can be applied to an ion beam lithography apparatus. Further, the present invention is not necessarily limited to the drawing apparatus, and the present invention can be applied to any beam apparatus that forms a beam using an aperture mask. Further, the shape of the aperture plate, the method of use, and the like are not limited to the embodiment, and for example, an aperture plate having another shape may be used. In addition, various modifications can be made without departing from the scope of the present invention.

[0057]

As described above in detail, according to the present invention, it is possible to prevent the aperture shape or the aperture position from changing even by thermal expansion, that is, to prevent the beam shape and the beam position from changing. As a result, a highly accurate charged beam drawing apparatus can be configured.

As is apparent from the above description, according to the present invention, the temperature rise of the aperture mask is suppressed, so that the thermal deformation of the mask is suppressed, whereby the accuracy of the size and shape of the beam can be maintained. Becomes

[Brief description of the drawings]

FIG. 1 is a diagram showing a basic configuration of an electron beam writing apparatus according to a first embodiment.

FIG. 2 is a diagram showing a specific configuration of an aperture mask used in the first embodiment.

FIG. 3 is a diagram showing a specific configuration of an aperture mask used in a second embodiment.

FIG. 4 is a diagram showing a specific configuration of an aperture mask used in the third embodiment.

FIG. 5 is a diagram showing a specific configuration of an aperture mask used in a fourth embodiment.

FIG. 6 is a diagram showing a specific configuration of an aperture mask used in the fifth embodiment.

FIG. 7 is a diagram showing a specific configuration of an aperture mask used in a sixth embodiment.

FIG. 8 is a diagram showing a specific configuration of an aperture mask used in the seventh embodiment.

FIG. 9 is a diagram showing a configuration of an aperture mask portion of an electron beam writing apparatus according to an eighth embodiment.

FIG. 10 is a diagram showing a conventional method of fixing an aperture mask.

FIG. 11 is a diagram showing an influence of expansion of an aperture mask.

FIG. 12 is a diagram showing a mounting portion of a conventional aperture mask.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Electron gun 12a-12e ... Electron lens 13-16 ... Deflection system 17-19 ... Aperture mask 21,31,41,51,61,71,81 ... Aperture plate 22,93 ... Mask holding part 23 ... Reference side One end 24, 34, 44, 64, 74, 84… Aperture fixing plate 25, 35, 43, 45, 46, 55, 66, 76… The inflated position of the aperture mask 34, 84, 85, 86… Molding beam 36… Electron beam 37 ... Aperture mask for peripheral cutting 38,87-89 ... Shaped beam 54 ... Fixed point 86 ... First aperture image 91 ... Aperture mask 92 ... Holding spring 94 ... Barrel body 95 ... Ceramic ring 96-98 ... Connecting part 99 ... Lead wire

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Naoji Shimomura 1 Tokoba, Komukai Toshiba-cho, Saiwai-ku, Kawasaki-shi, Kanagawa

Claims (1)

[Claims] 1. A charged beam drawing apparatus, comprising: an aperture mask having an aperture of a predetermined shape for allowing a charged beam to pass therethrough; and irradiating a beam formed by the aperture mask onto a sample to form a desired pattern. Is formed such that a plurality of aperture plates having at least one reference side formed of a straight line are combined to constitute the aperture with the reference side, and one end of both ends of the reference side of each aperture plate.
Alternatively, a charged beam drawing apparatus characterized by fixing a part on an extension of the reference side.