JP2001308170A - Material cassette - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of distortion of a charge-up preventing cover due to thermal expansion. SOLUTION: A mask substrate 2 is fixed to a cassette body 1 by top limiting plates 3 at three points of the cassette body 1. Charge-up preventing covers 7A', 7B' and 7C' for relieving electric charge on the mask substrate 2 which are in contact with the periphery of the mask substrate 2 between the limiting plates are mounted on the cassette body 1. Each of the covers is divided between its screws and the cross sections of the joining parts of the divided covers are L-shaped and shaped like an inverted letter L in such a way that the joining parts are fitted when they are joined. When the divided covers are joined in reality, there is no space in the vertical direction perpendicular to the mask substrate and spaces Sa and Sb are formed in the direction perpendicular to the Z direction in consideration of the amount of thermal expansion of the divided covers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a material cassette for a charged particle beam writing apparatus.

[0002]

2. Description of the Related Art An electron beam drawing apparatus is an apparatus for drawing a pattern by irradiating a predetermined position on a material to be drawn such as a mask substrate or a wafer coated with a resist with an electron beam.

[0003] Such an electron beam writing apparatus is capable of writing an extremely high-density pattern as compared with other writing apparatuses (for example, an writing apparatus by irradiating a light beam). It is attracting attention as a leader in production.

In such an electron beam writing apparatus, a material to be drawn is set in a cassette outside the writing chamber, and the cassette is placed on a stage in the writing chamber by an arm of a cassette transport mechanism (not shown). Thereafter, a pattern is drawn on the material to be drawn by an electron beam.

FIG. 1 schematically shows a cassette on which a mask substrate is set, and FIG. 2 is a sectional view taken along line AA of FIG.

In FIG. 1, reference numeral 1 denotes a cassette main body made of a conductive material, and three places of the cassette main body are provided with an upper surface regulating plate 3 made of a conductive material for restricting an upper surface position of a mask substrate 2 set in the cassette. Is attached. A spring 4 having a protruding portion T at its tip is disposed with the mask substrate 2 interposed therebetween corresponding to the position of the upper surface regulating plate. The spring is attached to the tip of the screw 5 and is housed together with the screw 5 in a hole 6 formed in the cassette body 1. 7A, 7B and 7C are charge-up prevention covers attached to the cassette body 1 so as to surround the upper surface regulating plate 3 from both sides. The cover is made of a conductive material. Are located in the same height direction as the mask substrate facing surface, so that when the mask substrate 2 is set, the substrate facing surface at the inner end portion of each cover comes into contact with the surface of the mask substrate. .
Since the charge-up preventing cover is in contact with the substantially peripheral surface of the mask substrate 2 as described above, even if the charges accumulate anywhere on the surface of the mask substrate, the charges are not covered by the cover 7.
And, it is possible to flow to the ground through the cassette body 1.

When the mask substrate 2 is set in the cassette, the mask substrate 2 is inserted into the space between each upper surface regulating plate and the projection T of the spring 4 with the screw 5 loosened. Is performed by pressing the mask substrate 2 against the upper surface regulating plate 3 with the spring 4. Reference numeral 8 denotes a pin for regulating the position of the mask substrate in the X and Y directions. Reference numeral 9 denotes a screw for attaching each charge-up preventing cover to the cassette body 1.

[0008] Such a cassette is set on a stage in a drawing chamber of an electron beam drawing apparatus, and a pattern is drawn on a mask substrate by an electron beam. At this time, the surface of the mask substrate may be charged by electron beam irradiation. However, since the electric charge flows to the ground through the charge-up preventing covers 7A, 7B, 7C, the cassette body 1, and the stage at the ground potential, the electric charge does not accumulate on the mask substrate surface.

[0009]

Now, as described above,
The mask substrate 2 is set in a cassette outside the drawing chamber, and the cassette is set on the stage in the drawing chamber. Then, a pattern is drawn on the mask substrate by an electron beam. As a result, the charge-up prevention cover 7 is distorted. That is, since the temperature in the writing chamber is usually higher than that in the writing chamber, when the cassette in which the mask substrate 2 is set is set on the stage in the writing chamber,
The temperature difference causes thermal expansion of the cassette body 1.
At this time, charge-up prevention covers 7A, 7B, 7C
Expands in the X and Y directions on a plane (horizontal plane) parallel to the mask substrate 2. At this time, in each cover, as shown by the arrow in FIG. 1, the expansions in the longitudinal direction while being screwed interfere with each other, and the cover itself is distorted.

The present invention solves such a problem.
A new material cassette is provided.

[0011]

A material cassette according to the present invention has a cassette body to which a material to be drawn is fixed, contacts at least a part of the periphery of the material to be drawn, and transfers a charge on the material to be drawn. In a material cassette in which a cover for escape is attached to the cassette main body, the cover is divided between the attachment portions, and a gap is provided between the divided covers. The material cassette of the present invention has a cassette body to which a material to be drawn is fixed, and a regulating plate for fixing the material to be drawn to the cassette body at a plurality of positions of the cassette body is attached to the cassette body,
In a material cassette in which a cover for contacting at least a part of the periphery of the material to be drawn between the respective regulating plates and releasing a charge on the material to be drawn is attached to the cassette main body, the cover is provided between the attaching portions. It is divided, and a gap is provided between each divided cover.

[0012]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 3 shows an example of a material cassette according to the present invention. In the drawing, components denoted by the same symbols as those in FIGS. 1 and 2 indicate the same components.

The difference between the material cassette shown in FIG. 3 and the material cassette shown in FIG.
, 7B ', and 7C' are divided between the screws in each cover, and as shown in FIG. 4, each divided cover (for example, 7A'1, 7A'2 )
Are formed such that their cross sections are L-shaped and inverted L-shaped, respectively, so as to fit each other when they are joined. Then, when actually joining the divided covers, as shown in FIG. 4, the gaps Sa and Sb in the Z direction (up and down directions perpendicular to the mask substrate) in consideration of the thermal expansion amounts of the divided covers. In the direction perpendicular to the Z direction.

After setting the mask substrate 2 in a cassette outside the drawing chamber and setting the cassette on a stage in the drawing chamber, a pattern is drawn on the mask substrate by an electron beam. At this time, thermal expansion occurs in the cassette body 1 due to a temperature difference between the outside of the drawing chamber and the drawing chamber. At this time, the charge-up preventing covers 7A ', 7B', and 7C 'tend to expand in the X and Y directions on a plane (horizontal plane) parallel to the mask substrate 2. However, in actuality, FIG. As shown by an arrow, expansion in the longitudinal direction occurs while being screwed. However, since each screw stop is divided and joined so that gaps Sa and Sb are formed, the gaps are reduced or eliminated only by the expansion. Therefore, the expansion in the longitudinal direction during the screwing does not interfere with each other, so that the cover itself is not distorted.

In the above example, a cassette for setting a mask substrate has been described. However, the present invention is also applicable to a cassette for setting a semiconductor material such as a wafer.

In the above example, the cover is divided so that the cross section of each divided portion of the divided cover is L-shaped and inverted L-shaped, respectively. However, the present invention is not limited to such division.
For example, the cover may be simply divided in the optical axis direction, and a gap corresponding to the thermal expansion amount of the cover may be provided between the divided covers.

In the above-described embodiment, the material cassette having the upper surface regulating plate has been described. However, the present invention can be applied to a material cassette in which the charge-up preventing cover also functions as the upper surface regulating plate.

In the above embodiment, the material cassette used in the electron beam drawing apparatus has been described. However, the present invention can be applied to a material cassette used in the ion beam drawing apparatus.

[Brief description of the drawings]

FIG. 1 shows an example of a conventional material cassette.

FIG. 2 shows an AA cross section of FIG.

FIG. 3 shows an example of a material cassette of the present invention.

FIG. 4 shows details of some components in FIG. 3;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cassette main body 2 ... Mask board 3 ... Upper surface regulating plate 4 ... Spring 5 ... Screw 6 ... Hole 7A, 7B, 7C, 7A ', 7B', 7C '... Charge-up prevention cover 8 ... Pin 9 ... Screw

Claims (5)

[Claims] 1. A cassette body to which a material to be drawn is fixed, and a cover for contacting at least a part of the periphery of the material to be drawn and releasing a charge on the material to be drawn is attached to the cassette body. In the material cassette, the cover is divided between the mounting portions, and a gap is provided between the divided covers. 2. A cassette body to which a material to be drawn is fixed, and a regulating plate for fixing the material to be drawn to the cassette body at a plurality of positions of the cassette body is attached to the cassette body.
In a material cassette in which a cover for contacting at least a part of the periphery of the material to be drawn between the respective regulating plates and releasing a charge on the material to be drawn is attached to the cassette main body, the cover is provided between the attaching portions. A material cassette which is divided and a gap is provided between each divided cover. 3. The material cassette according to claim 1, wherein the gap provided between the divided covers corresponds to at least a thermal expansion amount of the divided covers. 4. The material cassette according to claim 1, wherein three regulating plates are used. 5. The divided portion of each of the divided covers has an L-shaped cross section and an inverted L-shaped cross section, respectively.
Or the material cassette according to 2.