JP2674147B2 - Charged beam exposure equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] A charged-beam exposure apparatus using a transmission mask, which aims to improve the throughput of the charged-beam exposure apparatus by shortening the time required for the exposure, has a circuit pattern of an integrated circuit. In a charged beam exposure apparatus having a shaping transmission mask in which a plurality of small sections including through-holes corresponding to the constituent elements are formed, all the small sections on the transmission mask are grouped into a plurality of collective sections, The arrangement of the collective compartments and the arrangement of the small compartments within one collective compartment are such that those used in time proximity based on the order of exposing the sample to be exposed are closely located in space,
Further, the transmission mask is provided with small sections necessary for pattern exposure of the same integrated circuit, and the pattern exposure required for manufacturing the integrated circuit is performed without replacing the transmission mask.

[Industrial applications]

The present invention relates to a charged beam exposure apparatus, and more particularly, to a charged beam exposure apparatus in which the time required for exposure is shortened and throughput is improved by improving a transmission mask.

[Conventional technology]

In a conventional charged beam exposure apparatus, a rectangular beam having a required shape is formed using a transmission mask having a rectangular through hole, and a rectangular pattern exposed by the rectangular beam is combined to form a circuit pattern such as an IC on an exposed sample. Although it was exposed above, the number of combinations of the rectangular beams increased depending on the shape of the circuit pattern, and therefore the number of times of exposure increased and it took a long time to perform the exposure. Therefore, paying attention to the fact that a unit pattern of the same shape often appears repeatedly in a circuit pattern such as an IC, together with a variable rectangular pattern on a transmission mask, the unit pattern that is exposed and used repeatedly at once, that is, A method has been proposed in which an assembly of small sections including through holes corresponding to the constituent elements of a circuit pattern is formed, and necessary small sections are selected from the group and exposed. Such a method is disclosed in, for example, JP-A-62-260322, and the number of times of exposure can be saved and the throughput of the charged beam exposure apparatus can be improved.

[Problems to be solved by the invention]

In order to effectively reduce the number of exposures by the method as described above, the area of the small section which is the repeating unit is made as large as possible, and as many through holes as possible are accommodated therein, and the exposure is performed once. It is necessary to be able to form as many patterns as possible. However, if the area of the small section is increased and the charged beam is expanded accordingly, the charge density of the charged beam decreases, so that the exposure time for one exposure must be lengthened. Therefore, there is a certain limit in improving the throughput by the above exposure method. Therefore, a method has been considered in which a large number of small sections having a small area are formed on a transmission mask, and one of the small sections is selected and exposed as necessary, but when the number of the small sections increases. The area of the transmission mask itself becomes large, the necessary ones are searched for each time, and the mechanical movement of the mask and deflection of the charged beam are repeated, so there is a lot of dead time and there is still a problem in improving throughput. Remain.

Therefore, the present invention provides a charged particle beam exposure apparatus capable of shortening the time required to select a necessary small section from a transmission mask on which many small sections are formed, as compared with the conventional method, and thus the throughput is improved. The purpose is to improve.

[Means for solving the problem]

FIG. 1 (A) is a principle view of the charged beam exposure means for explaining the charged beam exposure apparatus according to the present invention. In the figure, the charged beam 9 emitted from the charged beam generating means 1 is deflected by the deflecting means 2 and projected onto the transmission mask 3, shaped into a predetermined shape, and then reduced exposure means 6 is formed.
And is projected onto the exposed sample 7. The transparent mask 3
Can be moved by the transmission mask moving means 8a, 8b,
By using the deflection means 2 and the transmission mask moving means 8a and 8b together, the charged beam 9 can be projected on the transmission mask 3 at an arbitrary position. FIG. 1 (B) is a conceptual diagram of the arrangement of the small sections formed on the transparent mask 3,
It shows a state in which the small sections 4 including through holes corresponding to the constituent elements of the circuit pattern such as are arranged in groups into a plurality of collective sections 5.

In order to understand the present invention more specifically, FIG. 1 (C) shows a specific example of the subdivisions 4 arranged in one collective division 5.
4a, 4b and 4c are shown. For example, 4a is a small section including through holes corresponding to the components of the IC memory pattern, 4b is a small section including through holes corresponding to a single pattern for variable shaping, and 4c.
Is a small section including a through hole corresponding to the alignment pattern, and each of the small sections has an area of a range exposed at one time. Further, the size of one collective section 5 is set such that any small section 4 in the collective section can be selected only by the deflection means of the charged beam without mechanically moving the transmission mask 3. Can be decided

Therefore, all the small sections on the transmission mask are grouped into a plurality of collective sections, and the arrangement of the collective sections and the arrangement of the small sections within one collective section are set in the order of exposing the sample to be exposed. On the basis of the above, it is determined that the ones to be used in time proximity are close to each other in location, and the transmission mask is provided with small sections necessary for pattern exposure of the same integrated circuit, and the integration is performed without exchanging the transmission mask. The problem can be solved by the charged particle beam exposure apparatus characterized by performing the pattern exposure required for manufacturing a circuit.

(Operation)

According to the present invention, the small sections on the transmission mask are arranged based on the temporal order of exposure within one collective section, and similarly, the collective sections are also arranged based on the temporal order of exposure. . Therefore, the time required for mechanical movement of the mask and the time required for deflecting the charged beam in order to search for and expose the necessary small section depends on the size of the transmission mask.
It can be minimized without depending on the number of subsections. Therefore, the time required to expose all the necessary patterns on the sample to be exposed can be greatly saved as compared with the conventional case.

〔Example〕

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

FIG. 2 is a schematic configuration diagram of the electron beam exposure apparatus according to the embodiment of the present invention.

The electron beam emitted from the electron gun 10 is focused by the first transmission mask plate 11, focused by the condenser lens 12, enters the deflector 13 and electrostatically deflected, and passes through the projection lens 14 to pass through the transmission mask. 3 is projected on. It is possible to project the electron beam at an arbitrary position on the transmission mask 3 by mechanically moving the transmission mask 3 by the mask moving means 8a and 8b. Here, the electron beam shaped into a predetermined shape is projected onto the wafer 19 through the reduction lens 16 and the objective lens 17. At this time, the position of the shaped electron beam on the wafer 19 is determined by the electrostatic deflector 15 and the electromagnetic deflector.
Determined by 18.

A method of forming a pattern on an IC memory chip using the apparatus having the above configuration will be described below.

FIG. 3A is composed of a memory cell section and a peripheral circuit section.
1 schematically shows an IC memory chip. The pattern of an IC memory or the like is usually formed by stacking patterns of several to ten or more layers. From all of these layer patterns, a small section containing the pattern that is a component of the layer pattern is extracted and exposed. These subsections are formed on the transmission mask based on the temporal order. In FIG. 3 (B), a to i show small sections extracted from the patterns of the memory cell section and its peripheral circuit section in the wiring layer pattern among the layer patterns constituting the IC memory. . These sub-sections are arranged in one collective section 5 on the transmission mask in the order as shown in FIG. 3 (C), and the exposure is performed by, for example, i. Rojo ...
D) Perform the following steps in the order of: Here, () is
Indicates that it can be used repeatedly as necessary. The size of the collective section 5 is determined to a size such that any small section in the collective section 5 can be selected only by the deflection means of the charged beam without mechanically moving the transmission mask 3. If the number of extracted small sections is large and cannot be accommodated in one collective section, they are formed in the next adjacent collective section. Further, in order to reduce the number of mechanical movements of the transmission mask, it is possible to arrange small sections including the same pattern in different collective sections, if necessary.

After mounting the transmission mask formed as described above on the electron beam exposure apparatus having the configuration shown in FIG. 2, the small sections are sequentially selected by the transmission mask moving means, the deflector, etc. and exposed. As a result, the wiring layer pattern as shown in FIG.

For layer patterns other than the wiring layer, small sections are extracted by the same method as above, and these are arranged on the transmission mask in the same manner as described above, so that all the pattern exposures necessary for manufacturing the IC memory are made uniform. This can be done with a single transparent mask.

Further, a variable rectangular pattern can be obtained at the same time by forming a small section including a non-repeating pattern on the transmission mask together with the small section and using it in combination with the rectangular pattern on the first transmission mask. .

〔The invention's effect〕

As described above, according to the present invention, the movement distance of the transmission mask, the number of movements, and the deflection distance of the charged beam can be suppressed to the necessary minimum, so that the time required for exposure can be saved as compared with the conventional case. It has a great effect on improving the throughput of the charged beam exposure apparatus.

[Brief description of the drawings]

1 (A) to (C) are explanatory views of the principle of the present invention, FIG. 2 is a schematic configuration diagram of an electron beam exposure apparatus according to an embodiment of the present invention, and FIGS. 3 (A) to (C) are main drawings. It is a figure for demonstrating the Example of invention. In the figure, 1 is a charged beam generating means, 2 is a deflecting means, 3 is a transmission mask, 4 is a small section, 4a, 4b and 4c are specific examples of small sections, 5 is a collective section, 6 is a reduction exposure section, and 7 is Sample to be exposed, 8a and 8b are transmission mask moving means, 9 is a charged beam, 10 is an electron gun, 11 is a first transmission mask, 12 is a condenser lens, 13 is a deflector, 14 is a projection lens, and 15 is a deflector. , 16 is a reduction lens, 17 is an objective lens, 18 is an electromagnetic deflector, 19 is a wafer, and is a small section extracted from the IC memory pattern.

Claims (2)

(57) [Claims] 1. A charged particle beam exposure apparatus having a shaping transmissive mask in which a plurality of small sections including through holes corresponding to components of a circuit pattern of an integrated circuit are formed. The groups are grouped into a plurality of collective sections, and the arrangement of the collective sections and the arrangement of the small sections in one collective section are spatially close to each other based on the order of exposing the sample to be exposed. The charged particle beam exposure apparatus is characterized in that it is determined so as to be close to. 2. The transmission mask according to claim 1 is provided with a small section necessary for pattern exposure of the same integrated circuit, and the pattern exposure required for manufacturing the integrated circuit can be provided without replacing the transmission mask. A charged beam exposure apparatus characterized by being performed.