JPH11317341A - Electron beam exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a mask from distorting under heat, even if a non-pattern part of the mask is irradiated with an electron beam. SOLUTION: A mask 2 comprising a plurality of pattern parts, where at least a circuit pattern is formed and a pattern part other than a non-pattern part, an irradiating device 1 for emitting electron beam to the mask 2, and an electron beam focusing device 3 for projecting the electron beam transmitting the mask 2 to a substrate are provided. Here, a shielding member 5 which shields a part of the electron beam us provided at least between the irradiating device 1 and the mask 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electron beam optical system,
The present invention relates to an electron beam exposure apparatus for transferring a circuit pattern on a mask (or reticle) onto a sensitive substrate such as a wafer.

[0002]

2. Description of the Related Art A projection exposure apparatus for manufacturing a semiconductor projects and transfers a circuit pattern formed on a mask surface as an object surface onto a substrate such as a wafer via an imaging device. A resist is applied to the substrate, and the resist is exposed to light in a pattern by exposing to obtain a resist pattern.

In the electron beam exposure for forming a pattern using an electron beam, since the electron beam can be reduced to several Å,
A major feature is that a fine pattern of μm or less can be produced. In the conventional direct writing type electron beam exposure method, a fine pattern is drawn by scanning an electron beam converged on a minute area smaller than the line width of the pattern to be drawn. However, this method has a long drawing time and cannot achieve high throughput. On the other hand, in the case of electron beam exposure for projecting and transferring a circuit pattern formed on a mask surface, a characteristic is that a higher throughput can be obtained than in a conventional direct-drawing electron beam exposure system.

FIG. 4 shows the configuration of a conventional electron beam exposure apparatus. The apparatus includes at least a mask 2, an irradiation device 1 for irradiating the mask 2 with an electron beam 11, and an electron beam imaging device 3 for projecting an electron beam 12 transmitted through the mask 2 onto a substrate 4. You. The electron beam 11 emitted from the illumination device 1 enters the mask 2, and the electron beam 12 transmitted through the mask 2 irradiates the substrate 4 via the electron beam imaging device 3. The substrate 4 is, for example, a silicon wafer coated with a resist.
The electron beam incident on the resist exposes the resist. The electron beam imaging device 3 projects the circuit pattern of the mask 2 in a reduced size. As a result, the resist can be exposed in a fine circuit pattern.

[0005] Further, the electron beam imaging device can obtain a high resolution only in a minute area of, for example, about 1 mm square due to its optical restrictions. On the other hand, since the size of a semiconductor chip is 20 mm square or more, one chip cannot be exposed at a time. Therefore, the conventional electron beam exposure apparatus exposes a desired exposure area by irradiating a part of the mask with the electron beam 11 and further scanning the electron beam. The scanning may be performed not only by the electron beam but also by a mask. In this case, the mask may be scanned by the scanning stage. For example, when the electron beam and the mask are scanned in one direction and the respective scanning directions are orthogonal, a wide field of view can be exposed. Such an apparatus is disclosed in, for example,
8-64522.

FIG. 5 is an enlarged view of a mask 2 for electron beam exposure. The mask is composed of at least a self-supporting thin film member 21 (hereinafter, referred to as a membrane). On one mask, a circuit pattern of one chip or a certain area of one chip is divided and divided into pattern portions 23. And
Each pattern portion 23 is irradiated with an electron beam to form each pattern on the wafer. Incidentally, on the wafer, each pattern portion 2
The three images are stitched together. As the mask pattern, for example, a pattern in which through holes are formed in a pattern in a membrane is used. FIG. 6 shows a cross section of the mask. The electron beam 14 going to the through hole passes through the through hole, but the electron beam 15 going to other parts is scattered or absorbed by the membrane. The electron beam transmitted through the through-hole forms an image on the substrate by the electron beam imaging device 3 to form a circuit pattern.

[0007]

When an electron beam incident on the mask 2 other than the through hole out of the electron beam incident on the mask 2, a part of the electron beam is absorbed and heat is generated. Then, since the mask is thermally expanded and distorted, there is a problem that the shape of the exposed pattern is also distorted. Therefore, in the mask of the conventional electron beam exposure apparatus, the membrane is thinned to 10 μm or less so that the electron beam is hardly absorbed. That is, most of the electron beam was transmitted by thinning the membrane. Since this transmitted electron beam is scattered by the membrane, a desired circuit pattern could be exposed by removing the scattered electron beam with an electron beam imager.

On the other hand, when the membrane is made thin, there is a problem that the strength of the membrane itself becomes small. Therefore, in a conventional electron beam exposure apparatus, as shown in FIG. 5, the pattern portion is divided into a plurality of portions so that the membrane is not bent, and the holding member 22 holds the membrane. As described above, the mask is composed of the pattern portion 23 where the pattern is formed and the non-pattern portion 24 where the pattern is not formed. And the pattern part was substantially comprised by the membrane, and the non-pattern part was comprised substantially by the holding member.

When an electron beam exposure apparatus is configured using such a mask, a part of the electron beam may be irradiated to a non-pattern portion. At this time, since the electron beam incident on the holding member is absorbed by the holding member, heat is generated and the holding member thermally expands. As a result, there is a problem that the mask is distorted. The present invention has been made in view of such a problem, and an object of the present invention is to provide an electron beam exposure apparatus having less mask distortion.

[0010]

Therefore, the present invention firstly provides a mask having at least a plurality of pattern portions on which circuit patterns are formed and a non-pattern portion other than the pattern portion, and irradiating the mask with an electron beam. Irradiating apparatus, and an electron beam exposure apparatus having an electron beam imaging apparatus that projects an electron beam transmitted through the mask onto a substrate, wherein at least a part of the electron beam is interposed between the irradiation apparatus and the mask. An electron beam exposure apparatus, wherein a shielding member for shielding is arranged (claim 1).

Further, the present invention secondly provides "an electron beam exposure apparatus according to claim 1, wherein the shielding member is arranged so as to shield the electron beam irradiating the non-pattern portion. Claim 2) "is provided. In the third aspect of the present invention, "the shielding member is formed of a plate-shaped member, and the plate-shaped member is provided with a plurality of through holes corresponding to the pattern portions. 3. The electron beam exposure apparatus according to any one of claims 1 to 2.
(Claim 3) "is provided.

[0012] Further, according to the present invention, fourthly, "the shielding member is arranged near the mask.
4. The electron beam exposure apparatus according to any one of items 1 to 3. (Claim 4) "is provided. Fifth, the present invention provides "an electron beam exposure apparatus according to any one of claims 1 to 4, wherein the shielding member is made of a material having conductivity.

A sixth aspect of the present invention provides “an electron beam exposure apparatus according to any one of claims 1 to 5, wherein a scanning mechanism is provided on the shielding member.

[0014]

FIG. 1 is a diagram showing a schematic configuration of an electron beam exposure apparatus according to this embodiment. This exposure apparatus mainly includes an electron beam irradiation device 1, a mask 2, an electron beam imaging device 3, and a shielding member 5. On the mask 2, an enlarged pattern having a size four times as large as the pattern to be drawn is formed. Further, the pattern portion of the mask has holes in the silicon membrane in a pattern. The electron beam irradiator 1 includes an electron gun and an electron lens (illumination optical system), and irradiates an electron beam 11 to a partial area of the mask 2.

The electron beam 12 that has passed through the mask 2 passes through the electron beam imaging device 3 and irradiates the substrate 4. At this time, a quarter reduced image of the circuit pattern of the mask 2 is formed on the substrate 4. A resist is applied on the surface of the substrate 4, and the resist is exposed by an electron beam, so that a resist pattern can be obtained. At the time of exposure, the electron beams 11, 1
By scanning (deflecting) 2 and 13 and scanning the mask 2 and the substrate 4 synchronously, a desired region can be exposed.

A shielding member 5 is provided between the electron beam irradiation device 1 and the mask 2. An enlarged view (part) of the mask 2 and the shielding member 5 is shown in FIG. The mask includes a membrane 21 and a holding member 22. The size of the pattern portion 23 is 4 mm square, and a plurality of pattern portions are arranged at a pitch of 5 mm. The non-pattern portion 24 has a lattice shape with a pitch of 5 mm and a width of 1 mm.

The shielding member 5 provided between the electron beam irradiation device 1 and the mask 2 was formed of a stainless steel plate having a thickness of 1 mm.
Since the shielding member 5 is irradiated with an electron beam, it is preferable that electrons incident on the shielding member 5 do not cause charging. For this purpose, the shielding member 5 is preferably made of a conductive material, and the conductive material is preferably a metal such as Fe, Cr, or Al. It is preferable to use a material having sufficient rigidity because it is easy to reduce the thickness. The board was provided with a plurality of 4 mm square through holes. The through hole is 5m
They were arranged at m pitch.

The shielding member 5 was fixed to the scanning mechanism of the mask, and at the time of fixing, the position was adjusted so that the electron beam did not irradiate the non-pattern portion of the mask. As described above, the scanning mechanism of the shielding member 5 may be shared with the scanning mechanism of the mask, but the scanning mechanism 6 may be provided on the shielding member 5 as shown in FIG. The shielding member 5 includes a non-pattern portion 24 of the mask 2.
It is advisable to scan so as not to irradiate the electron beam. For example,
It is preferable to move the shielding member 5 in the same direction and at the same speed as the mask 2. The shielding member 5 can irradiate a desired region on the mask with an electron beam incident on the mask 2. At this time, it is preferable to arrange the shielding member 5 so that the mask 2 is not easily heated by the electron beam, that is, the non-pattern portion 24 is not irradiated with the electron beam. Therefore,
It is preferable to determine the form and arrangement of the shielding member 5 so that the shielding member 5 shields the electron beam directed to the non-pattern portion 24. Since the non-pattern portion 24 is provided with the holding member 21, the mask 2 is less likely to be heated unless an electron beam is applied thereto. The shielding member 5 may be any member as long as it shields the electron beam, but is preferably formed of a plate-like member. With the plate shape, the space required for disposing the shielding member is reduced, and the electron beam exposure apparatus can be made compact. Further, the shielding member 5
Is preferably located near the mask because, similarly, the electron beam exposure apparatus can be made compact. Further, a water cooling mechanism (not shown) is provided around the shielding member 5 to suppress a temperature rise. In addition, a ground (not shown) was attached so that the shielding member 5 was not charged.

It is necessary to position the shielding member 5 with the mask 2. For example, the positioning may be performed by providing a positioning mark on the shielding member 5. In the above-described embodiment, the shape and the like of the shielding member 5 are determined so that the non-pattern portion is not irradiated with the electron beam. However, in order to perform alignment and the like, it is necessary to irradiate the mask 2 with the electron beam. In such a case, a through hole is also formed in that region.

When exposure is performed by the electron beam exposure apparatus of this embodiment, the electron beam incident on the through hole 51 is blocked by the shielding member 5.
And is incident on the mask 2. On the other hand, the electron beam incident on a portion other than the through hole 51 is absorbed by the shielding member 5, so that the electron beam cannot pass through the shielding member 5 and does not reach the mask 2.
A resist pattern with almost no pattern distortion was obtained. As a result, it was possible to manufacture a semiconductor pattern with a high yield. Even if the exposure was continued for a long time, almost no change was observed in the yield. still,
It is preferable that unnecessary electron beams are completely absorbed in the shielding portion 5, but not all of them need to be attenuated as necessary.

On the other hand, in the case of the conventional electron beam exposure apparatus, many large pattern distortions occurred in the resist pattern. As a result, the yield of semiconductor pattern manufacturing was low, and the yield was further lowered, especially as the exposure time increased.

[0022]

As described above, the use of the electron beam exposure apparatus according to the present invention can suppress a rise in the temperature of the mask. Therefore, a resist pattern with less positional distortion can be obtained. As a result, semiconductor circuit patterns can be manufactured with high yield.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an electron beam exposure apparatus (one example) according to the present invention.

FIG. 2 is an enlarged view of a mask and a shielding member of the electron beam exposure apparatus (one example) according to the present invention.

FIG. 3 is a schematic configuration diagram of an electron beam exposure apparatus (one example) according to the present invention.

FIG. 4 is a schematic configuration diagram of a conventional electron beam exposure apparatus (one example).

FIG. 5 is an enlarged view of a mask of a conventional electron beam exposure apparatus (one example).

FIG. 6 is an enlarged sectional view of a pattern portion of a mask of a conventional electron beam exposure apparatus (one example).

[Explanation of symbols]

 1. . . 1. Electron beam irradiation device . . Mask 3. . . 3. Electron beam imaging device . . Substrate 5. . . Shielding member 6. . . Scanning stage 11-16. . . Electron beam or electron beam bundle 21. . . Membrane 22. . . Holding member 23. . . Pattern part of mask 24. . . Non-pattern part of mask 51. . . Through hole

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/30 541S

Claims (6)

[Claims] 1. A mask having at least a plurality of pattern portions on which a circuit pattern is formed and a non-pattern portion other than the pattern portion, an irradiation device for irradiating the mask with an electron beam, and an electron beam transmitted through the mask. An electron beam exposure apparatus having an electron beam imager for projecting onto a substrate, wherein a shielding member for shielding a part of the electron beam is arranged between at least the irradiation apparatus and the mask. Line exposure equipment. 2. An electron beam exposure apparatus according to claim 1, wherein said shielding member is arranged to shield an electron beam irradiating said non-pattern portion. 3. The device according to claim 1, wherein the shielding member is formed of a plate-shaped member, and the plate-shaped member is provided with a plurality of through holes corresponding to the pattern portions. Electron beam exposure equipment. 4. An electron beam exposure apparatus according to claim 1, wherein said shielding member is arranged near said mask. 5. An electron beam exposure apparatus according to claim 1, wherein said shielding member is made of a conductive material. 6. An electron beam exposure apparatus according to claim 1, wherein a scanning mechanism is provided on said shielding member.