JPH04271112A - Electron beam lithography equipment - Google Patents

Abstract

PURPOSE:To improve the throughput of electron beam lithography by shortening the average travelling distance of a rectangular electron beam. CONSTITUTION:In an electron beam lithography equipment, a rectangular aperture 9 is formed in the vicinity of the center part or the corner part of a submask part 14 in a mask for gang transfer use, and a plurality of aperture groups 10 for gang transfer use are arranged on the peripheral part of the rectangular aperture 9. Said rectangular pattern is irradiated with a rectangular electron beam 8, and a rectangular pattern is formed. Another pattern is formed by selectively irradiating one of the aperture groups 10 for gang transfer use.

Description

[Detailed description of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam lithography system, and more particularly to an electron beam lithography system that improves the throughput of lithography by repeatedly transferring figures all at once in patterns for large-capacity memory ICs and the like.

0001

[Prior Art] Electron beam lithography equipment cannot draw patterns all at once, so its throughput is low and mass-produced LS for memory, etc.
Although it is not suitable for I, it is valued as a lithography apparatus for high-mix, low-volume production because of its good resolution and flexible drawing ability. However, JP-A-59-16
As described in Publication No. 9131, an aperture for batch transfer is formed adjacent to a conventional rectangular aperture for beam forming, and this is selectively exposed by a deflector, thereby repeatedly drawing figures into an electron beam lithography system. A method to add a batch transcription function is being considered.

FIG. 2 is a block diagram of an electron beam lithography apparatus that performs the above-mentioned batch transfer. An electron beam 2 emitted from an electron beam source 1 passes through a rectangular opening of a rectangular mask 3, and is shaped into a rectangular beam by shaping lenses 41 and 42. The first beam deflector 51 deflects the rectangular beam to select a predetermined group of batch transfer apertures in a plurality of sub-masks in the batch transfer mask 6, and directs the electron beam that has passed through the group to the first batch transfer aperture group. 2 deflector 52 is used to deflect and irradiate a predetermined position on the wafer 7.

0003

[Problems to be Solved by the Invention] The above-mentioned conventional technology is effective because it can shorten the drawing time to 1/10 to 1/100 when a single cell is repeatedly drawn, such as in a semiconductor memory. However, when multiple irregularly transferred figures are selected and transferred one after another, the figure selection switching time (response delay of the beam deflector) becomes a problem. - If the moving distance of the beam is long, there is a problem that the beam deflection time becomes long and the beam deflection control becomes complicated. SUMMARY OF THE INVENTION An object of the present invention is to provide an electron beam lithography apparatus that can increase throughput by selecting the plurality of figures transferred at once at high speed.

0004

[Means for Solving the Problems] In order to solve the above problems, a rectangular opening is provided at the center of the sub-mask portion, and further, a rectangular shape for the batch transfer is provided along two adjacent sides of the rectangular opening. Arrange the aperture groups. When transferring a rectangular pattern, adjust the irradiation position of the rectangular electron beam with respect to the rectangular opening to set its size; when transferring other patterns, set the size of the rectangular electron beam. - the beam is irradiated onto the predetermined batch transfer aperture group.

Further, the length of each side of the rectangular electron beam is larger than the length of the two sides, and the length of each side of the group of apertures for batch transfer is larger than the length of each of the two sides of the group of apertures for batch transfer, and The effect of scattering of the electron beam is prevented by making the spacing length between them smaller than the added length. Further, from a practical standpoint, the number of aperture groups for batch transfer in the sub-mask section is set to five. In addition, this book also describes two sub-mask portions as another pattern arrangement within the sub-mask portion according to the invention.
A rectangular opening is provided close to a corner formed by a side, and a group of apertures for batch transfer having a plurality of rectangular outlines are arranged along the other two sides.

[0006]

[Operation] The rectangular electron beam is irradiated to a rectangular opening provided at the center of the sub-mask portion to generate a rectangular pattern, and the rectangular electron beam is used for batch transfer around the rectangular opening. The group of apertures is irradiated to generate other patterns. Furthermore, by making each side length of the rectangular electron beam larger than each two side lengths of the batch transfer aperture group and smaller than the sum of the spacing length, scattering of the electron beam can be prevented. Prevent effects. Furthermore, by setting the number of aperture groups for batch transfer in the sub-mask section to five, the moving distance of the rectangular electron beam can be minimized on average, and the number of masks at the memory cell level can be accommodated in the sub-mask section. do it like this. . Further, by providing the rectangular opening close to the corner formed by the two sides of the sub-mask portion, the rectangular electronic beam
further reduce the average distance traveled by the system.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an example of a pattern arrangement of a mask 6 for batch transfer according to the present invention. The batch transfer mask 6 is provided with a plurality of sub-mask parts 14, and each sub-mask part 14 is provided with a rectangular opening 9 and a batch transfer aperture group 10. The rectangular opening 9 is used, for example, to form IC bonding pads and various other rectangular pattern parts. For example, if the rectangular beam 8 obtained by the rectangular mask 3 is placed at the position shown by the dotted line in FIG. By irradiating the wafer 7 with the beam deflected by the second deflector 52, bonding pads, rectangular patterns, etc. of arbitrary sizes can be formed at predetermined positions on the wafer 7.

Further, the rectangular beam 8 is transferred to the aperture group 1 for batch transfer.
By superimposing the pattern on one of the openings 0, the pattern of the opening group can be selected all at once and similarly transferred onto the wafer 7. The present invention is characterized in that the rectangular opening 9 is arranged at the center of the sub-mask section 14, and the batch transfer opening group 10 is arranged around the rectangular opening 9. In FIG. 1, a rectangular opening 9 is provided at the center of the sub-mask section 14, five batch transfer opening groups are arranged on the upper and right sides of the rectangular opening 9, and no opening is provided on the lower left side. As a result, when a rectangular pattern is generated by the rectangular opening 9, the rectangular beam 8 is connected to the sub-mask portion 1 as shown in the figure.
4, the size of the rectangular pattern can be set toward the lower left side of
This prevents the beam 8 from leaking and being irradiated. In addition, since the rectangular opening 9 arranged at the center of the sub-mask section 14 and the group of batch transfer openings 10 at its periphery are close to each other,
Since the moving distance of the rectangular beam 8 is shortened, its deflection time can be shortened and throughput can be increased.

FIG. 3 is a diagram showing in more detail the positional relationship between the rectangular opening 9 and the batch transfer opening group 10 in FIG. 1. Reference numeral 11 denotes a deflectable area at the beam center of the rectangular beam 8, and the five batch transfer aperture groups 10 are arranged so that their centers do not extend outside the deflectable area 11 as shown in the figure. . Therefore, the array length R of the batch transfer aperture group 10 is shorter than the length of the side of the deflectable region 11. Also,
A space S is provided between the batch transfer aperture groups 10 to prevent beam leakage and scattering. The space S is determined in consideration of the acceleration voltage of the electron beam, the material of the mask, etc.

13 is a rectangular beam when using the rectangular opening 9.
This is the deflection area at the beam center of the beam 8, and an aperture-prohibited area 12 is determined corresponding thereto. That is, the batch transfer aperture group 10 can be arranged only outside the aperture-prohibited area 12. Assuming that the length of one side of the rectangular opening 9 is L1, and the length of one side of the batch transfer aperture group 10 is L2, these dimensions are determined so as to satisfy the relationship of equation (1). L2<L1<L2+S
(1)

In FIGS. 1, 3, etc., the number N of the batch transfer aperture group 10 is five. For example, when considering the case of transferring a memory cell pattern, the number of patterns required to transfer the cell, including reversal and 90° rotation, is often less than five, and rectangular beads Since the deflection control in the vertical and horizontal directions of the beam can be controlled with 2 bits each, it is quite reasonable to set N to 5 as shown in Figures 1 and 3. , it's also practical. On the other hand, if N is increased to 5 or more, it becomes necessary to reduce the size of each batch transfer aperture group 10, and the number of spaces S increases, reducing space utilization efficiency. , N, the number of shots increases in proportion to N, so the throughput decreases.

FIG. 4 is a diagram showing another layout of the sub-mask section 14 according to the present invention. Since the rectangular opening 9 is set at the lower left side of the sub-mask section 14, various rectangular patterns can be generated by placing the rectangular beam 8 at the center of the sub-mask section 14 as shown. Therefore, the distance traveled by the rectangular beam 8 to the batch transfer aperture group 10 is reduced, and throughput can be increased. As shown in FIG. 1, the batch transfer mask 6 includes a plurality of sub-mask portions 1.
4 are arranged in a grid. In order to increase throughput, the patterns in each of these sub-mask parts 14 are normally made to be different from each other, but since frequently used sub-mask parts are easily contaminated, identical sub-mask parts are provided as spare parts. do it like this.

[0013]

Effects of the Invention: Since the distance between the rectangular opening provided at the center of the sub-mask section and the batch transfer opening group at the periphery is short, the moving distance of the rectangular electron beam is shortened on average, and the electron beam Drawing throughput can be improved. Also,
Each side length of the above rectangular electron beam is transferred to each of the aperture groups for batch transfer.
The influence of scattering of electron beams can be prevented by making the length larger than the side length and smaller than the sum of the side length and the spacing length.

Furthermore, by setting the number of aperture groups for batch transfer in the sub-mask section to five, the number of masks at the memory cell level can be accommodated in the sub-mask section, and rectangular electron beams can be simultaneously transferred.
To minimize the moving distance of the system on average and improve throughput. Further, by providing the rectangular opening close to the corner formed by the two sides of the sub-mask section, the average moving distance of the rectangular electron beam can be further shortened, and the throughput can be further improved. .

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of a mask for batch transfer according to the present invention.

FIG. 2 is a configuration diagram of a conventional electron beam lithography apparatus.

FIG. 3 is a plan view illustrating the relationship between the layout of each pattern of the batch transfer mask and the rectangular beam according to the present invention.

FIG. 4 is a plan view of another embodiment of the batch transfer mask according to the present invention.

[Explanation of symbols]

1 Electron source 2　Electron beam 3 Rectangular mask 6 Batch transfer mask 7 Wafer 8 Rectangular beam 9 Rectangular opening 10 Aperture group for batch transfer 11 Deflectable area at the center of the beam 12 Opening prohibited area 14 Submask part 41 Molded lens 51 First deflector 52 Second deflector

Claims (5)

[Claims] Claim 1: Generate a rectangular electron beam, select and irradiate a predetermined batch transfer aperture group in a plurality of sub-mask parts provided in a batch transfer mask, and use the electron beam image that passes through the In an electron beam drawing device that draws on a sample,
An electron beam lithography apparatus characterized in that a rectangular opening is provided in the center of at least one of the plurality of sub-mask parts. 2. The electron beam lithography apparatus according to claim 1, wherein the batch transfer aperture group is arranged along two adjacent sides of the rectangular aperture. 3. In claim 2, each of the plurality of batch transfer aperture groups has a rectangular peripheral shape, and the lengths of two sides of the rectangular electron beam image on the batch transfer mask are each set as above. Greater than the length of two sides of the batch transfer aperture group, and smaller than the sum of the lengths of the two sides of the batch transfer aperture group plus the spacing length between the batch transfer aperture groups. An electron beam lithography device characterized by: 4. The electron beam lithography apparatus according to claim 2, wherein the number of batch transfer aperture groups in the sub-mask portion is five. 5. A rectangular electron beam is generated to select and irradiate a predetermined batch transfer aperture group in a plurality of sub-mask parts provided in a batch transfer mask, and the electron beam image that has passed through the mask is In an electron beam drawing device that draws on a sample,
Each of the plurality of sub-mask parts has a rectangular outline, a rectangular opening is provided in at least one of the plurality of sub-mask parts near a corner formed by two sides thereof, and a plurality of rectangular openings are provided along the other two sides. An electron beam lithography apparatus characterized in that a group of batch transfer apertures having a rectangular outline are arranged.