JPS62206828A - Charged-particle beam lithography device - Google Patents

Abstract

PURPOSE:To control a charged particle beam and simplify adjustment by subse quent lens and deflection system by selecting a unit pattern and conforming the charged particle beam again onto the central axis once. CONSTITUTION:Holes molding electron beams to various unit pattern shapes are bored to a pattern plate 9 at intervals, and electron beams 1 formed to a quadrilateral cross section by an aperture plate 5 collide onto the pattern plate 9 as a quadrangle having size coating one unit pattern in said various unit patterns. A deflecting plate 7 deflects electron beams 1, and introduces electron beams 1 onto the unit pattern required. Electron beams 1 molded to the shape of the unit pattern selected are returned in the direction on the extension of the central axis of an electron gun by the focussing action of the latter half section of a second condenser lens 8, and proper deflecting voltage previously set at every unit pattern selected is applied to a deflecting plate 10 for preliminary correction and a deflecting plate 11 for main correction and electron beams 1 are made to proceed along the central axis. A reduced image is formed onto a wafer 15 by first and second reducing glasses 12, 13, and a deflecting coil 14 controls the position of irradiation of electron beams 1.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to charged particle beam lithography, which forms patterns such as circuits on workpieces such as semiconductor wafers for integrated circuit manufacturing using charged particle beams such as electron beams and iono beams. Regarding equipment.

[Conventional technology]

Recently, to form patterns such as circuits on semiconductor wafers (workpieces) in the integrated circuit manufacturing process, electron beams and charged ion beams, which have advantages such as high resolution, have been used over conventional devices that use sources. Particle beam lithography equipment is attracting attention.

Etch, Sea, 7 Eyes, IEEE Transaction/Nzuo/Electron Deviceme. 1
979, pp. 663-674 (H, C, Pf-eiffe
r, IEEE Transactions on
El-ectron Devices, Vol, ED-
26, No. 4゜April 1979. PP663
The electron beam lithography apparatus as shown in FIG. 2, described in JP-674), can project a unit pattern onto a wafer at a time, and therefore can perform lithography at a relatively high speed. In this figure, electron beam 1
is generated at the cathode 2, controlled and accelerated by the grid 3 and anode 4, and the cross section of the electron beam 1 is shaped into a square shape by the aperture plate 5 having a square hole. In this figure, for convenience, only the portions of the trajectory of the electron NM 1 before and after the pattern plate 9 and the first reduction lens 12 are shown. The electron beam 1 shaped by the aperture plate 5 is projected onto the pattern plate 9 by the first condenser lens 6 and the first half of the second condenser lens 8.

The pattern plate 9 has holes of a plurality of types of unit patterns (for example, letter-shaped patterns), and the selection deflection plate determines which of the unit patterns 7 on which the electron beam will be projected is formed. The electron beam 1 is deflected by the second selection deflector 7 and the second selection deflection plate 8, passes through the selected 0 pattern 7 plate 9, and is shaped into the shape of the selected unit pattern. 8 (the part after the pattern plate) is bent toward the central axis by the focusing action, and reaches the space between the magnets 1 of the first reduced/zi 12. Hereinafter, a unit pattern is selected by the first reduction lens 12, the second reduction lens 13, and the projection lens (3317) each focusing magnetic field and the deflection electromagnetic field by the electrostatic correction deflection plate 31 and the main deflection yaw 732. An electron beam l having a cross-sectional shape similar to is projected onto a predetermined position on the wafer 15.

Next, the same or different unit patterns on the pattern plate 9 are selected and projected onto a desired location on the wafer 15. By repeating the same operation for a long time, circuits and other patterns are synthesized and drawn on the wafer 15.

[Problems to be Solved by the Invention] The conventional -s and fM shown in FIG. 2 have the following first-order problems. First, after the electron beam 1 (charged particle beam) passes through the pattern plate 9 and before entering the region of the first reduction lens 12, the electron beam 1 (charged particle beam)
Since the electron beam 1 is not made to travel along the central axis in line with the path of the electron beam 1 in the case where the electron beam 1 is not fully biased by the first and second selection deflection plates 7 and 8, the first reduction lens 12゜Second reduction lens 13. The electromagnetic fields of the projection lens 33, the electrostatic correction deflection plate 31, and the main deflection yoke 32 each cause the electron beam 1
This is a factor that changes the projection position 1 onto the wafer 15. Therefore, it is necessary to take these comprehensive effects into consideration and to generate and correct an appropriate deflection electric field using the electrostatic correction deflection plate 31, which poses the problem of complicated adjustment and poor position reproducibility. Also, the electrons IIi! pass through the first reduction lens 12 and the second reduction lens 13! 1 does not pass through the central axis (it deviates from the center line of rotational symmetry of these lenses or crosses obliquely), so deviation from the condition of a paraxial electron beam with small aberrations tends to become large. Therefore, the first and second selection deflecting plates 7 and 8 are used to prevent the electron beam 1 from being deflected too much, and the first reduction lens 12-? It is necessary to suppress the occurrence of lens aberration in the second reduction lens 13, and there is also the problem that the number of unit patterns provided on the pattern plate 9 has to be limited to a relatively small number of types.

An object of the present invention is to provide a charged particle beam lithography apparatus that allows easy control and adjustment of the trajectory of a charged particle beam, has good projection position reproducibility, and can use a relatively large variety of unit patterns.

[Means to solve all problems]

According to the present invention, there is provided a pattern plate in which a plurality of types of unit patterns are drilled at intervals, a means for directing a charged particle beam to a selected unit pattern on the pattern plate, and a pattern having a cross section formed in the shape of the unit pattern. A charger equipped with a focusing side system that allows the charged particle beam passing through the plate to follow a fixed trajectory, and a mechanism that synthesizes the charged particle beam projection trace on the workpiece in a predetermined pattern using unit patterns selected one after another. 'ix particle beam drawing device is obtained.

〔Example〕

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

FIG. 1al is a cross-sectional perspective view showing essential parts of an embodiment of the present invention, and in this figure, an electron beam 1, a cathode 2, a grid 3, an anode 4. Aperture plate 5J selection electrostatic polarizing plate 7, pattern plate 9, preliminary correction side same plate 10. Main correction polarizing plate 11, wafer 15, blanking deflecting plate 16. The blanking aperture plate 17 occupies a highly vacuum space. Cathode 2% grid 3, anode 4
A triode electron gun generates an electron beam 1, which passes through an aperture plate 5 having a rectangular hole and is projected onto a pattern plate 9 by a first condenser lens 6 and a front half of a second condenser lens 8. be done.

The pattern plate 9 has holes for forming electron beams into various unit pattern shapes at intervals, and the electron beam 1, which has a rectangular cross section on the aperture plate 5, is formed in one of the unit pattern parts 7. It forms a rectangle with a size of about 100 mm and hits the pattern board 9. The selection electrostatic plate 7 deflects the electron beam 1 and guides it onto the desired unit Batano. The NFC electron beam 1 formed into the shape of the selected unit butter 7 is returned to the direction on the extension line of the central axis of the electron gun by the final action of the wheat half part of the second condenser lens 8, and is passed through the deflection plate 10 for preliminary correction and the main axis. An appropriate bias voltage preset for each selected unit butter 7 for the correction l#4 same plate? t:I], the electronic element 1 is made to advance along the above-mentioned central axis. The second half of the second condenser lens 8 performs a lens action to form an enlarged (imaginary) image of the electron beam 1 in the unit pattern shape, but the first reduction lens 12 and the second reduction lens 1 continue to do so.
3, place a reduced image of M on Que.15. “The positioning eccentric coil 14 controls the irradiation position of the electron beam 1 on the wafer 15.
5. irradiate or block (blanking).

FIG. 1 (bl and IcI indicate the electron-optical imaging relationship in the apparatus shown in FIG. On the other hand, the electron beam 1 is narrowed down by a crossover 22 near the electron gun, but the first condenser lens 6 focuses the image near the electrostatic polarizing plate 7 for selection. Then, the second condenser lens 8 re-images near the main correction deflection plate 11, and the first reduction lens 12 and second reduction lens 13 align the image formation position with the entire positioning deflection coil 14. The electron beam 1 in each deflection plate or deflection coil is made as thin as possible to reduce the occurrence of distortion due to deflection.The first condenser lens 6 and the front half of the second condenser lens 8 make the aperture plate 5 as narrow as possible. Aperture (square) image pattern plate 9
formed on top.

Of course, as a measure against aberrations, coils for dynamic focus, (dynamic) stigmator, etc. may be additionally provided as appropriate. Furthermore, in this embodiment, the electron beam 1 is formed into a rectangular shape in advance by the aperture plate 5;
Other shapes may be used instead of rectangular, and the entire shape may be circular. Alternatively, the aperture plate 5 may not be provided here, but may be provided at an appropriate location between the butter 7 plate 9 and the wafer 15. In addition, various modifications can be made without changing the basic configuration of the present invention.

In addition, for the 7 parts of butter that cannot be drawn with only the unit pattern (combination of groups), a unit pattern consisting only of circular or square apertures is also provided on the pattern board, and the charged particle beam that passes through it is used to The butter 7 in that part may be formed by the drawing method shown in the formula.

An example of pattern formation using this device is as follows.

Possible methods include exposure of photoresist using an electron beam or ion beam, and ion implantation and etching directly into the wafer (without a resist mask) using an ion beam. Furthermore, since the patterns to be formed in semiconductor integrated circuit memories and gate arrays in the wafer process are relatively simple, there is no need to prepare so many types of unit patterns, making them suitable for application to the present invention. .

〔Effect of the invention〕

In the present invention, after the unit butter 7 is selected, the charged particle beam is once re-aligned on the central axis.

This has the effect of simplifying the subsequent control and adjustment of the charged particle beam using lenses and deflection systems.

In addition, the edges of the charged particles pass through the central axis of these lenses, causing less lens aberration, and the reproducibility of the projection position is the same as above, so a variety of unit patterns can be handled and the range of applications is widened. .

[Brief explanation of drawings]

FIG. 1 (at is a cross-sectional perspective view of the main part of an embodiment of the present invention,
Figure 1 121, (cl is 'd of the apparatus in Figure 1 (al)
FIG. 2 is a relational diagram of a molecular a-image, FIG. 1...electron beam, 2...cando, 5.
...Aperture plate, 6...First condenser lens, 7...Static 11L41M same plate for selection,
8...Second condenser lens. 9...Pattern plate, 10...Example plate for preliminary correction, 11...Deflection plate for main correction, 12...
...First reduction lens, 13...Second reduction lens, 14...Mark/positioning deflection coil, 15...
...Wafer, 21...Intermediate imaging position, 22.
...Crossover. Tsuf5fTji"Jtanosuji 2 figure

Claims (1)

[Claims] A pattern board in which multiple types of unit patterns are punched out, a means for directing a charged particle beam to a selected unit pattern on the pattern board, and shaped charged particles whose cross section is formed in the shape of the unit pattern and pass through the pattern board. A charged particle beam characterized by being equipped with a focusing/deflecting system that causes the line to follow a constant trajectory, and a mechanism that synthesizes a charged particle beam incident trace on a workpiece in a predetermined pattern using unit patterns selected one after another. drawing device.