JP3357927B2 - Charged particle beam exposure apparatus and charged particle beam exposure method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an exposure apparatus and an exposure method for transferring a pattern formed on a mask by a charged particle beam onto a photosensitive substrate such as a semiconductor wafer.

[0002]

2. Description of the Related Art As an apparatus of this type, a scatterer 3 is disposed on a thin film 2 of a mask 1 as shown in FIG.
The entire amount of the charged particle beam B1 passing through the gap between the first lens 4 and the second lens 6
And deflects it in the direction orthogonal to the photosensitive substrate 7, while guiding only a part of the charged particle beam B2 scattered by passing through the scatterer 3 from the through-hole 5 a to the second lens 6 and deflects it. There is a type in which a contrast is generated on the photosensitive substrate 7 to expose a pattern corresponding to the arrangement of the scatterers 3.

In the above-described exposure apparatus, the mask 1 is divided into one or more areas called a main field of view MF as shown in FIG. 12, for example, in response to the enlargement of the photosensitive substrate 7 and the miniaturization of the circuit pattern. After dividing the main field of view MF into a plurality of areas called sub-fields of view SF, exposure to the photosensitive substrate 7 may be repeated while adjusting the exposure conditions for each sub-field of view SF. When performing such field division, a beam-shaped boundary member 8 having a very small width is arranged at the boundary of the sub-field SF (the position indicated by the dotted line in FIG. 12), as shown in FIG. The boundary member 8 is formed of a material that does not substantially pass through the charged particle beam, for example, silicon that is sufficiently thick. When the charged particle beam is irradiated to one sub-field SF, the charged particle beam is transmitted to the adjacent sub-field SF. Each sub-field of view SF is divided so as not to leak. At the time of exposure, as shown by arrows Fm and Fw in FIG.
And the photosensitive substrate 7 are continuously moved in opposite directions. At this time, the irradiation position of the charged particle beam on the mask 1 is changed stepwise by one deflector SF in a direction orthogonal to the direction of relative movement between the mask 1 and the photosensitive substrate 7 by a deflector (not shown). You. Therefore, if the mask 1 in FIG. 12 moves in the direction of the arrow Fm in FIG. 12, each sub-field of view SF is irradiated with a charged particle beam in the order indicated by the arrow E in FIG. Transcribed.

[0004]

By the way, in the lithography process of a semiconductor wafer, as shown in FIG. 14B, an island-shaped non-exposed portion NE whose entire periphery is entirely surrounded by an exposed portion EP is formed on the photosensitive substrate 7. May form on top. in this case,
In the above-described exposure apparatus, as shown in FIG. 14A, the entire periphery of the scatterer 3 for forming the island-shaped non-exposed part NE is a transmission part G of the charged particle beam, and the scatterer 3 is used as the sub-field SF. It is necessary to float in the air, so to speak. For this reason,
When an island-shaped non-exposed portion is formed with a single mask, the thin film 2 supporting the scatterer 3 has been indispensable.

However, since the thin film 2 is extremely thin, about 500 angstroms, it is difficult to make it and it is easy to break. Also,
The scatterer 3 supported by the thin film 2 needs to be thin (50
The material is limited to heavy metals. Therefore, the heat capacity of the scatterer 3 becomes small, and relatively large thermal expansion occurs due to the irradiation of the charged particle beam, so that the position of the pattern transferred to the photosensitive substrate 7 shifts, and the exposure accuracy deteriorates. Moreover, since the thin film 2 and the scatterer 3 are made of different materials, it is necessary to always examine the influence of a solvent or a cleaning agent used for removing or correcting defects on the mask 1 on both the thin film 2 and the scatterer 3. (1) The restrictions on maintenance management are also large.

Further, since the charged particle beam is somewhat scattered when passing through the thin film 2, the charged particle beam B 1 passing through the gap between the scatterers 3 also passes through the through hole 5 a of the filter 5. Some are blocked. For example, filter 5
Is 1 mrad., The transmittance of the filter 5 for the charged particle beam B1 decreases to about 50%. On the other hand, the aberration of the charged particle beam lens system is large at 1 mrad.
It needs to be adjusted to about 4 mrad. In this region, the transmittance of the filter 5 drops to about 10%. If the transmittance of the filter 5 is low, the beam current reaching the photosensitive substrate 7 becomes small, and the throughput is significantly reduced. If the beam current from the emission source of the charged particle beam is increased to compensate for this, the beam blur due to the space charge effect becomes remarkable, and the exposure accuracy decreases.

In order to avoid such inconveniences, an island-shaped non-exposed portion may be formed using two masks 1. In this case, a part of the transmitting part of the charged particle beam corresponding to the exposed part around the island-shaped non-exposed part is formed on one mask, and the remaining part of the transmitting part is formed on the other mask, and the exposure images of both masks are formed. It is transferred to the same region on the photosensitive substrate to form an island-shaped non-exposed portion. According to such a method, it is not necessary to provide a scatterer floating in the air in the mask, so that a thin film is not required.
However, since a mask needs to be replaced during the exposure of one photosensitive substrate, the number of man-hours for the setup operation increases, and the exposure time is simply doubled, so that the throughput is reduced to almost half.

An object of the present invention is to provide a charged particle beam exposure apparatus and a charged particle beam exposure method in which an island-shaped non-exposed portion can be formed by a single mask and a thin film supporting a scatterer is not required. is there.

[0009]

According to an embodiment of the present invention, one or more main fields of view MF are provided on a mask 10 irradiated with a charged particle beam. Is set, the main field of view MF is divided into a plurality of sub-fields of view SF ,
The present invention is applied to a charged particle beam exposure apparatus that exposes the entire main field MF by repeatedly exposing the photosensitive substrate 7 for each divided sub-field SF. The object described above is to form a scatterer 120 that scatters the charged particle beam irradiated on the mask 10 to form the island-shaped non-exposed portions NE1 to NE4 on the photosensitive substrate 7 .
This is achieved by supporting the sub-field SF on the boundary member 11 provided at the boundary.

[0010] In the present invention of claim 2, a charged particle beam exposure apparatus according to claim 1, wherein the subfield SF _D corresponding to the island-like non-exposed portion NE5 to be formed on the photosensitive substrate 7, for example, in FIG As shown, a plurality of sub-field-of-view components SF _D1 , S _D2 are divided on a single mask 10, and the plurality of sub-field-of-view components S _D1 , S _D2 are surrounded by an island-shaped non-exposed portion NE 5. Charged particle beam transmitting portion 13 for forming the exposed portion EP
a, 13b are divided and formed, and patterns corresponding to the transmission portions 13a, 13b formed in the divided sub-field-of-view constituting portions SF _D1 , SF _D2 are transferred to the same region on the photosensitive substrate 7 and transferred to the corresponding region. An island-shaped non-exposed portion NE5 is formed.

For example, as shown in FIG. 8, when it is assumed that the image is not divided into sub-fields of view, the length L and the width W
Scatterer 22 whose ratio L / W is larger than a predetermined allowable value
May be divided into sub-field components SF21 and SF22. In this case, thermal displacement of the scatterer 22 due to irradiation of the charged particle beam is suppressed, and the exposure accuracy is improved. Further, the sub-field of view SF3 in which the pattern filling rate is larger than a predetermined allowable value when the division into the sub-field-of-view constituent units is not performed may be divided into the sub-field-of-view constituent units SF31 and SF32. In this case, the beam current that reaches the photosensitive substrate when transferring the pattern of the sub-field-of-view constituent portions SF31 and SF32 is reduced, and beam blur due to the space charge effect is prevented. The pattern filling rate refers to the total area A of the charged particle beam transmitting portions 214 and 215 included in the single sub-field of view SF3.
The value A1 / A0 obtained by dividing 1 by the area A0 of the sub-field of view SF3.
Say. According to a fifth aspect of the present invention, at least one main field of view is set on a mask irradiated with a charged particle beam, the main field of view is divided into a plurality of sub-fields of view, and each divided sub-field of view is transferred to a photosensitive substrate. Is applied to the charged particle beam exposure method for exposing the entire main field of view by repeating the exposure. Then, island-shaped or peninsula-shaped non-exposed portions included in the main field of view are detected, and the transmission portion of the charged particle beam for forming an exposed portion around these non-exposed portions is arranged to span at least two sub-fields. Then, the position or size of the sub-field of view is set, and the sub-field of view in which an island-shaped or peninsula-shaped non-exposed portion remains even if such a setting is made, as shown in FIG. Divided into the sub-field-of-view constituent units SF _D1 and SF _D2, and divided into two sub-field-of-view constituent units S
F _D1, SF _D2 the formed transparent portion 13a, by multiple exposure to transfer a pattern corresponding to 13b in the same area on the photosensitive substrate 7 to perform the exposure.

[0012]

According to the first aspect of the present invention, the island-shaped non-exposed portions NE1 to NE1 are provided.
Since the scatterers 120 for forming NE4 are supported by the boundary member 11, a thin film supporting these scatterers 120 becomes unnecessary. The transmission part 13 of the charged particle beam to be formed around the scatterer 120 can be divided into a plurality of sub-fields of view SF adjacent to each other with the boundary member 11 interposed therebetween.

[0013] claimed in the invention of claim 2, claim subfields SF _D only a plurality of sub-field configuration unit SF _D 1 corresponding to a plurality of sub-field SF island unexposed portion NE5 which could not be divided into the invention of 1 , SF _D2 , so that the number of sub-fields SF for performing multiple exposure can be minimized.

According to the third aspect of the present invention, the island-shaped non-exposed portion NE is provided.
Are formed on the single mask 20 by dividing into a plurality of sub-field forming portions SF11 and SF12, so that the sub-field forming portions SF11 and SF12 are divided. In each of the above, it is not necessary to support the scatterer 22 for forming the island-shaped non-exposed portion NE in a suspended state. Therefore, a thin film supporting the scatterer 22 is not required. The sub-field-of-view configuration SF11, SF is formed on a single mask 20.
Since 12 is formed, it is not necessary to use a plurality of masks for one photosensitive substrate.

In the means and means for solving the above-mentioned problems which explain the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0016]

【Example】

First Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. The exposure apparatus of this embodiment is characterized by the structure of the mask portion, and the configuration of the lens system is the same as that shown in FIG. Therefore, the structure of the mask will be mainly described below.

FIG. 1 shows the main field of view MF of the mask 10 of this embodiment.
And the sub-field of view SF and the island-shaped non-exposed portion NE1 of the photosensitive substrate
3 shows the positional relationship with the NE5. As is clear from the drawing, in this embodiment, four island-shaped non-exposed portions NE1 to NE4 to be formed on the photosensitive substrate extend over at least two sub-fields SF beyond the boundary of the sub-field SF (the position indicated by the dotted line). The position and size in the x and y directions of the sub-field of view SF are determined so as to span. One of the x direction and the y direction corresponds to a direction of relative movement between the mask 10 and the photosensitive substrate, and the other corresponds to a direction of deflecting the charged particle beam.

FIG. 2 and FIG. 3A show details of the mask 10 in a portion II (a portion corresponding to the non-exposed portion 12) in FIG. As is apparent from these figures, in the mask 10 of the present embodiment, a scatterer 12 for scattering a charged particle beam is integrally provided at the lower end portion of a grid-like boundary member 11 corresponding to the boundary of the sub-field of view SF. At the same time, a slit 13 for passing the charged particle beam is formed so as to penetrate the scatterer 12 in the thickness direction. In FIG. 2, the scatterers 12 of a pair of adjacent sub-fields of view SF are indicated by hatched areas.
The pattern according to the shape and arrangement of the scatterers 12 and the slits 13 is transferred to the photosensitive substrate 7.

Among the scatterers 12, the scatterers 12 for forming the island-shaped non-exposed portions NE2 (see FIG. 1) on the photosensitive substrate 7 are formed.
0 is a pair of sub-fields of view SF adjacent via the boundary member 11
Are formed to protrude equally to both sides.

In this embodiment, as shown in FIG. 3B, the exposure range is adjusted so that the areas inside the boundary member 11 of each sub-field of view SF are in contact with each other on the photosensitive substrate 7. Therefore, by exposing a pair of adjacent sub-fields of view SF, the non-exposed portions NE2 _L and NE2 _R corresponding to the scatterers 120 are connected to form an island-shaped non-exposed portion NE2 on the photosensitive substrate 7. .

As is clear from the above, in this embodiment, the scatterer 120 for forming the island-shaped exposed portion NE is integrated with the boundary member 11, so that a thin film supporting the scatterer 120 is not required. Become. As a result, all the labor for manufacturing and maintaining the thin film is eliminated. In addition, since it is not necessary to make the scatterer 120 thin in preparation for supporting with a thin film, the scatterer 120
Is replaced by a light atomic material having a large heat capacity, for example, silicon (S
i), silicon nitride (SiN) and silica (SiO ₂ ) can be formed sufficiently thick (2 to 3 μm). For this reason, the heat capacity of the scatterers 12 and 120 is increased, so that thermal expansion during exposure is suppressed, and exposure accuracy is improved. By the way, when the scatterer 120 having a thickness of 2 to 3 μm is formed from the above materials,
The heat capacity becomes about 50 times and the thermal expansion becomes about 1/50.
Further, by forming the scatterers 12 and 120 thickly, the rigidity thereof is also improved. Since there is no thin film supporting the scatterer 12, the scattering of the charged particle beam passing through the slit 13 is eliminated, the transmittance at the filter 5 becomes 100%, the beam current reaching the photosensitive substrate 7 increases, and high throughput is achieved. Can be expected. Since the boundary member 11 and the scatterer 12 are formed of the same material, the labor required for maintenance and management of the mask 10 is reduced, for example, restrictions on the cleaning liquid for the mask 10 are reduced.

Here, by merely adjusting the boundary position and size of the sub-field SF, all the island-shaped non-exposed portions NE to be formed on the photosensitive substrate 7 are arranged so as to be in contact with the boundary of the sub-field SF. can not, for example, as in the subfield SF _D and unexposed portions NE5 in figure 1, there is a case where part entire island unexposed portions NE in a single subfield SF is encompassed remain. In this case, performing multiple exposure by dividing only the sub-field SF _D. An example will be described with reference to FIG.

[0023] In the example of FIG. 4, is divided into subfield SF _D has two subfield configuration unit SF _D1, SF _D2. FIG. 4 (a)
As shown in FIG. 5, a slit 13a corresponding to a part EP ₁ of the exposed portion EP surrounding the non-exposed portion NE5 (see FIG. 2B) is formed in the first sub-field-of-view constituting portion SF _D1 . ,
The second sub-field component SF _D2, slits 13b corresponding to the remainder EP ₂ exposure portion EP surrounding unexposed portion NE5
Is formed. In the second sub-field-of-view component SF _D2 , a region corresponding to the slit 13 a formed in the first sub-field-of-view component SF _D1 is formed of the scatterer 12, and this portion forms the non-exposed portion NE 5. The scatterer 120 is supported. A boundary member 11 is provided on the boundary between the sub visual field forming units SF _D1 and SF _D2 .

In the example of FIG. 4, first, the first sub-field-of-view component SF _D1 is irradiated with a charged particle beam, and an exposure portion corresponding to the slit 13a is formed on the photosensitive substrate. Next, the charged particle beam is irradiated to the second sub-field-of-view component SF _D2 to form an exposed portion corresponding to the slit 13b in the same region on the photosensitive substrate. As a result, as shown in FIG. 4B, the exposed portions EP ₁ and EP ₂ corresponding to the slits 13a and 13b are connected to form an island-shaped non-exposed portion NE5. In addition,
Sub-field-of-view component S formed at different positions on mask 10
In order to form the exposure images of F _D1 and SF _D2 on the same area on the photosensitive substrate, the optical path of the charged particle beam may be adjusted by a deflector (not shown). The sub-field-of-view components SF _D1 , SF _D2 do not necessarily have to be adjacent to each other on the mask 10, and the sub-field-of-view component SF _D1 , SF _D2 may be formed at completely different positions on the mask 10.

Here, the above-mentioned island-shaped non-exposed portions NE1 to NE1
NE5 is rarely present except in special cases such as exposing a contact hole with a negative resist. Even if NE5 is present, it can be almost eliminated by adjusting the position and size of the sub-field of view SF described above. Therefore, the actual throughput hardly decreases even if the specific sub-field of view SFD is _subjected to multiple exposure as shown in FIG. If the number of island-shaped non-exposed portions is extremely small, all the island-shaped non-exposed portions may be subjected to multiple exposure as shown in FIG.

In the example shown in FIGS. 1 to 3, the island-shaped non-exposed portion NE1
To NE4, the scatterer 120 is projected into the two sub-fields of view SF, but as shown in FIG.
The scatterer 120 may be protruded only at F, and only the slit 13 may be formed at the other sub-field of view SF. In addition, the scatterer 120 extends over three or more sub-fields of view SF.
May be arranged. The scatterer 120 is not necessarily the boundary member 1
It is not necessary to manufacture it integrally with 1, and it may be detachable from the boundary member 11.

Second Embodiment A second embodiment of the present invention will be described with reference to FIGS. Note that the exposure apparatus of the present embodiment also has a feature in the structure of the mask portion as in the first embodiment, and the configuration of the lens system is the same as that shown in FIG. Therefore, the structure of the mask will be mainly described below.

FIG. 6 shows one main field of view MF of the mask 20 according to the present embodiment. The main field of view MF is also divided into a plurality of sub-fields SF at dotted line positions in the drawing, similarly to the first embodiment. Have been. The hatched area in the figure is the charged particle beam transmitting portion 21 in each sub-field of view SF, and the portion other than the transmitting portion 21 is formed of a scatterer 22 that scatters the charged particle beam. A boundary member (not shown) is provided at the boundary of the sub-field of view SF. Here, in the present embodiment, four sub-fields of view SF1 to SF4
Are two sub-field-of-view constituent parts SFn1, S adjacent in the y direction in the figure.
Fn2 (n = 1, 2, 3, 4). The sub-fields of view SF1 and SFn2 are divided into sub-fields SF1-S
It has the same size as the other sub-fields of view SF other than F4. Regions R1, R2, and R3 extending in the x direction along with the sub-field forming portion SFn2 of the mask 20 are spare regions of the mask 20 where the transmission portion 21 is not formed at all. In the present embodiment, these spare regions R1 are provided. Using R3, sub-field of view SF1
SF4 is divided.

FIGS. 7 to 10 show the respective sub-field components SFn1 and SFn2 of the sub-fields SF1 to SF4 and the sub-fields SF1 and SFn2.
7A to 7F show the relationship with the exposure pattern of the photosensitive substrate corresponding to SF4.
(B) shows the exposure pattern of the photosensitive substrate. As shown in FIG. 7A, the sub-field-of-view component SF1 constituting the sub-field of view SF1 is provided.
1, SF12 includes an island-shaped non-exposed portion NE shown in FIG.
Are formed, and U-shaped transmission portions 210 and 211 corresponding to half of the exposed portion EP1 around are formed. Further, as shown in FIG. 8A, the sub-view component SF constituting the sub-view SF2 is formed.
21 and SF22, a hook-shaped exposure unit EP2 shown in FIG.
21 corresponding to the shape obtained by dividing the line by the PP line in FIG.
2, 213 are formed. Further, as shown in FIG. 9A, the sub-view component SF31,
SF32 includes a rectangular exposure portion EP3 occupying almost the entire surface of an exposure region (portion surrounded by a two-dot chain line) corresponding to the sub-field of view SF3 on the photosensitive substrate as shown in FIG. The transparent portion 214 corresponding to the shape divided along
215 are formed. Then, as shown in FIG. 10A, the sub-field-of-view constituent parts SF41, SF41,
In the SF 42, transmission portions 216 and 217 corresponding to the shape obtained by dividing the exposure portion EP4 in a meandering pattern shape shown in FIG.

In the exposure apparatus of this embodiment, the mask 20 is continuously moved in the y direction in FIG. 6 by a mask moving mechanism (not shown), and the photosensitive substrate is moved in the direction opposite to the y direction by a substrate moving mechanism (not shown). Continuously moved to In synchronization with these movements, the irradiation position of the charged particle beam is changed stepwise at a predetermined timing by the deflector (not shown) in the x direction at a predetermined pitch of the sub-field SF. From the column C1 to the lower columns C2, C3,
Exposure is performed sequentially toward C4. At this time, similarly to the first embodiment described above, the exposure position is adjusted such that portions inside the boundary members of the sub-fields of view SF are in contact with each other on the photosensitive substrate.

In particular, at the time of exposure of the sub-fields SF1 to SF4, the sub-field constituting part SFn1 is first irradiated with a charged particle beam, and a pattern corresponding to these transmission parts 210, 212, 214, 216 is formed on the photosensitive substrate. Field of view SF1-SF4
Is transferred to the exposure area corresponding to. Subsequently, the irradiation position of the charged particle beam is deflected in the y direction in the figure, and
n2 is irradiated with a charged particle beam, and
Patterns corresponding to 13, 215, and 217 are transferred to exposure regions corresponding to the sub-fields of view SF1 to SF4 on the photosensitive substrate. As described above, in the area corresponding to the sub-fields of view SF1 to SF4 on the photosensitive substrate, the patterns corresponding to the sub-field-of-view constituent parts SFn1 and SFn2 are connected, and the exposure units EP1 to EP4 shown in FIGS. Each is formed.

In the present embodiment, only the sub-fields SF1 to SF4 are 2
Since exposure is performed one by one, the moving speed of the mask 20 and the photosensitive substrate needs to be set to be slower by the number of sub-fields SF1 to SF4 than in a normal case where multiple exposure is not performed. However, since the number of sub-fields requiring division is small, there is almost no decrease in throughput due to a decrease in moving speed, and the throughput is maintained much higher than in the conventional example using two masks. Since a thin film supporting the scatterer 22 is not required, the same effect as in the first embodiment can be obtained.

In the present embodiment, the sub-field-of-view constituent parts SFn1, SFn2
Are formed adjacent to the feed direction of the mask 20, and if the irradiation position of the charged particle beam is provided so as to be able to deflect about three sub-fields SF in the y direction, the mask 20 is exposed when the sub-fields SF1 to SF4 are exposed. It is not necessary to switch the moving direction of the photosensitive substrate or the photosensitive substrate, and it is only necessary to reduce the feed speed of the mask 20 and the photosensitive substrate by the overlap of the sub-fields of view SF1 to SF4 as described above. In this regard, if the sub-field-of-view constituent parts SFn1 and SFn2 are provided at positions far apart from each other by deflection of the charged particle beam, it is necessary to adjust the position of the mask 20 and the photosensitive substrate only at the position where multiple exposure is performed. In addition, the movement of the mask 20 and the photosensitive substrate becomes complicated. However, the sub-view component SF
Even if n1 and SFn2 are separated from each other, there is no change in the necessity of replacing the mask, and the improvement of the throughput can be expected.

In the present embodiment, the sub-fields SF2 to SF4 other than the sub-field SF1 corresponding to the island-shaped non-exposed portion are also divided, for the following reason. (1) Sub-field of view SF2, SF4 Assuming that the sub-field of view SF2 is not divided into sub-fields of view SF21, SF22, the transmission part of the sub-field of view SF2 is shown in FIG.
Has a similar shape to the exposed portion EP2 shown in FIG. In this case, it is necessary to provide a scatterer similar in shape to the non-exposure portion NE20 sandwiched between the pair of exposure portions EP2 in the sub-field of view SF2, and the ratio L / W of the total length L and the width W of the scatterer is not exposed. It is equal to the ratio L '/ W' of the total length L 'to the width W' of the portion NE20. An elongated scatterer having a ratio L / W of a certain value or more is supported by other scatterers only at both ends or one end thereof, and a large thermal displacement occurs at an intermediate portion and a free end due to a temperature rise due to irradiation of a charged particle beam. However, the exposure accuracy is greatly reduced due to the thermal displacement. FIG.
In the example of (b), the largest displacement occurs in the corner portion K of the non-exposed portion NE20. Therefore, the sub-field of view SF2 is changed as shown in FIG.
The scatterer is divided as shown in FIG.
W was restricted to within a certain value. The same applies to the sub-field of view SF4.

(2) Sub-field SF3 Assuming that the sub-field SF3 is not divided into sub-field components SF31 and SF32, the transmission part of the sub-field SF3 is shown in FIG.
Has a similar shape to the exposure part EP3 shown in FIG.
The pattern filling ratio of 3, that is, the ratio A1 / A0 of the area A1 of the transmitting portion and the area A0 of the sub-field of view SF3 approaches 100%. Assuming that the beam current of the charged particle beam applied to the sub-field of view SF is constant, the beam current reaching the photosensitive substrate increases as the pattern filling rate increases. When the beam current increases, the focal position of the charged particle beam moves to a distant position due to the space charge effect, and the blur of the beam on the photosensitive substrate becomes so large that it cannot be ignored. In order to avoid this, it is necessary to reduce the beam current from the electron gun so that the beam blur is negligibly small even in the subfield of view where the pattern filling rate is the maximum, but in this case, the pattern filling rate is the smallest. The beam current that reaches the photosensitive substrate during the exposure of the sub-field of view becomes extremely low, and the exposure time is prolonged, thereby greatly reducing the throughput. Therefore, in this embodiment, in order to perform the exposure with a large beam current while suppressing the variation in the pattern filling rate for each sub-field, the sub-field SF3 in which the pattern filling rate is particularly large is connected to the sub-field forming sections SF31 and SF.
The pattern filling rate of the sub-field of view SF3 after division into 32 parts was limited to 50% or less.

In this embodiment, the island-shaped non-exposed portion is dealt with only by dividing the sub-field of view SF. However, it is needless to say that the present embodiment may be combined with the first embodiment in which the island-shaped scatterer is supported by the boundary member. It is. The shape of the transmission section 21 shown in FIG. 6 is merely an example, and does not show an actual LSI circuit pattern.

[0037]

As described above, according to the first aspect of the present invention, since the scatterer for forming the island-shaped non-exposed portion is supported by the boundary member, a thin film for supporting the scatterer is unnecessary. Eliminates the labor of manufacturing and maintaining thin films. Since it is not necessary to make the scatterer thin in preparation for supporting it with a thin film, the scatterer can be formed sufficiently thick from a light atomic material with a large heat capacity to suppress thermal expansion during exposure and improve exposure accuracy. In addition to this, the rigidity of the scatterer can be improved. Since the thin film supporting the scatterers can be omitted, the scattering of the charged particle beam passing through the gap between the scatterers is eliminated,
The beam current reaching the photosensitive substrate increases, and high throughput can be expected. By forming the boundary member and the scatterer with the same material, the labor required for maintenance and management of the mask can be reduced.

According to the second aspect of the present invention, the number of sub-fields for performing multiple exposure is minimized, and the throughput is further improved.

According to the third aspect of the invention, the ratio L of the length L to the width W is L
It is possible to improve the exposure accuracy by excluding scatterers having a large / W from the mask. According to the fourth aspect of the present invention, it is possible to prevent the occurrence of a sub-field having a high pattern filling rate in which the beam blur due to the space charge effect becomes so large that it cannot be ignored.
Exposure accuracy and throughput can be improved. According to the fifth aspect, the sub-field in which the island-shaped or peninsula-shaped non-exposed portion remains is divided into two sub-field components, so that the transmission portion for forming the non-exposed portion is divided into each sub-field component. By forming the scatterers, it is possible to prevent the generation of scatterers floating in the air.

[Brief description of the drawings]

FIG. 1 is a diagram showing a positional relationship between a field-of-view division position of a mask and an island-shaped non-exposed portion formed on a photosensitive substrate in a first embodiment of the present invention.

FIG. 2 is a plan view of a mask in a part II in FIG. 1;

3A is a cross-sectional view of the mask shown in FIG. 2 along the line III-III, and FIG. 3B is a view showing a corresponding exposure shape of a photosensitive substrate.

Shows [4] in a state where the subfield SF _D shown in FIG. 1 was divided into a plurality of subfields constituting unit (a), the exposure shape of the corresponding photosensitive substrate and (b).

FIG. 5 is a view showing a modification of FIG. 2;

FIG. 6 is a diagram showing a main field of view of a mask according to a second embodiment of the present invention.

FIG. 7 is a view showing a state (a) in which the sub-field of view SF1 shown in FIG. 6 is divided into a plurality of sub-field-of-view components, and a corresponding exposure shape (b) of the photosensitive substrate.

FIG. 8 is a view showing a state (a) in which the sub-field of view SF2 shown in FIG. 6 is divided into a plurality of sub-field-of-view components, and a corresponding exposure shape (b) of the photosensitive substrate.

9 is a view showing a state (a) in which the sub-field of view SF3 shown in FIG. 6 is divided into a plurality of sub-field-of-view components, and a corresponding exposure shape (b) of the photosensitive substrate.

FIG. 10 is a diagram showing a state (a) in which the sub-field of view SF4 shown in FIG. 6 is divided into a plurality of sub-field-of-view components, and a corresponding exposure shape (b) of the photosensitive substrate.

FIG. 11 is a view schematically showing a charged particle beam exposure apparatus.

FIG. 12 is a diagram showing an example of field division of a mask.

FIG. 13 is a view showing movement of a mask and a photosensitive substrate during exposure.

FIG. 14 is a diagram showing an island-shaped non-exposed portion formed on a photosensitive substrate and a corresponding subfield of view of a mask.

DESCRIPTION OF SYMBOLS 10, 20 Mask 11 Boundary member 12, 22 Scattering body 13, 13a, 13b Slit for transmitting charged particle beam 21 Transmission part of charged particle beam 120 Scattering body for forming island-shaped non-exposed part EP, EP1 Exposure portion around island-shaped non-exposed portion MF Main field of view NE, NE1, NE2, NE3, NE4, NE5 Island-shaped non-exposed portion SF Sub-field of view SF _D , SF1 Corresponds to island-shaped non-exposed portion Sub field of view SF _D1 , SF _D2 , SF11, SF12 Sub field of view

Claims (5)

(57) [Claims] 1. A method according to claim 1, wherein one or more main fields of view are set on a mask irradiated with a charged particle beam, and the main field of view is divided into a plurality of sub-fields of view. In a charged particle beam exposure apparatus that repeatedly exposes the entire main field of view, a scatterer that scatters a charged particle beam applied to the mask to form an island-shaped non-exposed portion on the photosensitive substrate is formed by using the auxiliary A charged particle beam exposure apparatus characterized by being supported by a boundary member provided at a boundary of a visual field. 2. The charged particle beam exposure apparatus according to claim 1, wherein a plurality of sub-fields corresponding to island-shaped non-exposed portions to be formed on the photosensitive substrate are formed on a single mask. The plurality of sub-field-of-view component parts are formed by dividing and transmitting a charged particle beam transmission part for forming an exposed part around the island-shaped non-exposure part. A charged particle beam exposure apparatus, wherein a pattern corresponding to the transmissive portion formed on the photosensitive substrate is transferred to the same region on the photosensitive substrate to form an island-shaped non-exposed portion in the region. 3. The method according to claim 1, wherein the mask is irradiated with a charged particle beam.
Set the upper main field of view and divide this main field of view into multiple sub-fields of view
The exposure is repeated for each of the divided sub-fields of view, and the
In a charged particle beam exposure apparatus that exposes the entire field of view, In the sub-field of view, the ratio L / W of the length L to the width W is within a predetermined range.
A single field of view is created where the scatterers that are larger than
Divide into multiple sub-field components on the disc, and
To the transmission part of the charged particle beam formed in
Transfer the corresponding pattern to the same area on the photosensitive substrate
A charged particle beam exposure apparatus characterized in that: 4. The method according to claim 1, wherein one or more masks are irradiated with the charged particle beam.
Set the upper main field of view and divide this main field of view into multiple sub-fields of view
The exposure is repeated for each of the divided sub-fields of view, and the
In a charged particle beam exposure apparatus that exposes the entire field of view, If the sub-view is not divided into sub-view constituents,
Pattern filling rate is greater than the specified tolerance
Multiple sub-field components on a single mask
Divided into a plurality of divided sub-field-of-view components
The pattern corresponding to the transmission part of the charged particle beam is formed on the photosensitive substrate.
Charged particle beam exposure characterized by being transferred to the same area above
Light device. 5. The method according to claim 1, wherein the mask is irradiated with a charged particle beam.
Set the upper main field of view and divide this main field of view into multiple sub-fields of view
And exposure to the photosensitive substrate is repeated for each of the divided sub-fields of view.
Charged particle beam exposure method for exposing the entire main field of view
At Island-shaped or peninsula-shaped non-exposed portions included in the main field of view
To detect and form exposed areas around these unexposed areas.
Of the charged particle beam for at least two sub-fields
Set the position or size of the sub field of view so that
However, even if the above setting is made, non-exposed portions in the form of islands or
For the remaining sub-fields, the sub-fields are divided into two sub-fields
Divided into components and formed into the two sub-field-of-view components
The pattern corresponding to the transparent part
The exposure is performed by multiple exposure to transfer to the area.
Charged particle beam exposure method.