JP2907221B2 - Blanking aperture array and method of manufacturing the same - Google Patents

Description

The present invention relates to an electron beam exposure apparatus used for manufacturing a semiconductor device, and more particularly, to a blanking aperture array of the exposure apparatus and a method for manufacturing the same. The present invention provides a ranking aperture array and a method of manufacturing the same, and aims to enable high-precision beam pattern irradiation. A substrate having a large number of openings at predetermined intervals, and opposing side surfaces of the openings. A pair of opposing electrodes made of conductive polycrystalline silicon, and an insulating film is formed between the electrodes and the side surface of the substrate to form a blanking aperture array of an electron beam exposure apparatus.

[Industrial applications]

The present invention relates to an electron beam exposure apparatus used for manufacturing a semiconductor device, and more particularly, to a blanking aperture array of the exposure apparatus and a method for manufacturing the same.

2. Description of the Related Art In recent years, semiconductor devices such as ICs and LSIs have improved their functions, and have contributed to technological progress in industries such as computers, communication devices, and various machines. A major pillar of semiconductor device manufacturing process technology is to achieve high integration by microfabrication, and photolithography is said to limit the microfabrication to about 0.3 μm. Processing can be performed with a phase matching accuracy of 0.05 μm or less. Therefore, if an electron beam exposure apparatus capable of exposing 1 cm ² in about 1 second is realized, it is more advantageous than other lithography means in terms of fineness, alignment accuracy, quick turnaround, reliability, etc. It contributes to the manufacture of 1 or 4 gigabit memories and 1M gate LSI.

[Conventional technology]

There are several types of electron beam exposure apparatuses. Point beam exposure apparatuses have very low throughput, and are mainly used for research and development. The variable rectangular beam exposure apparatus has a throughput of one to two orders of magnitude higher than that of the point beam method. However, when exposing a pattern in which a fine pattern of about 0.1 μm is densely packed, the throughput is still low. Even so, it is said that the throughput of about 3 digits is low in 1GARAN drawing.

As a method having much higher throughput than these methods and capable of performing electron beam exposure for any pattern, there is a method using a blanking aperture array with a large number of holes proposed by the present applicant (for example, see Japanese Utility Model Publication No. 56-19402). . In this publication, a gate plate having a large number of holes is referred to as a set of a plurality of gate plates.
You can use only one sheet. The blanking aperture array uses a semiconductor crystal such as silicon as a substrate and forms a large number of openings in the two-dimensional arrangement at predetermined intervals in the substrate.
A pair of blanking electrodes are formed on both side surfaces of each opening, and whether or not a voltage is applied between the blanking electrodes is controlled by pattern data. For example, if one electrode at each aperture is grounded and a voltage is applied to the other electrode, the electron beam passing through the aperture is bent, so that after passing through the lens installed at the bottom, a single aperture aperture And the electron beam does not reach the sample surface (the resist layer on the semiconductor substrate). On the other hand, unless a voltage is applied to the other electrode, the electron beam passing therethrough is not bent, so that the electron beam reaches the sample surface without being cut by the aperture after passing through the lens arranged below.

In this way, a set of point-like electron beams that can be turned on and off in a plane is arranged. For example, a beam with a diameter of 0.02 μm
An array of 200 × 200 = 40,000 lines is a collective electron beam of 4 μm × 4 μm that can be formed in any pattern. Normally, the spherical aberration and chromatic aberration of the final lens of the electron beam exposure device can be suppressed only to about 0.02 μm,
The individual beams that have passed through the blanking aperture array are overlapped and illuminated on the sample surface by 0.02μ.
The individual beams of m diameter do not separate.

By the way, the blanking electrode of this blanking aperture array is made of metal.
Digging a pair of grooves in the substrate, forming an insulating film on the surface of the grooves,
A metal (for example, tungsten) is deposited in the groove by an evaporation method, a sputtering method, or the like. Then, the substrate portion between the metal electrodes is removed by etching to form an opening, and the insulating film on the side surface of the opening is removed by etching.

[Problems to be solved by the invention]

In the conventional metal electrode formation, when depositing (filling) metal in the groove, the depth is larger than the opening of the groove, so that the center is slid as shown in FIGS. 3A and 3B. It is difficult to completely fill the cells due to the occurrence of phenomena. Here, for example, a groove is formed in the silicon substrate 1 by selective etching (trench etching), an SiO ₂ insulating film 2 is formed on the entire surface including the groove by thermal oxidation, and tungsten 3 is deposited by sputtering. Since the entire surface is an insulating film, filling in the groove using the selected wavelength cannot be performed, and a cavity 4 occurs as shown in FIG. 3B.

If such a pit is formed on the metal electrode, a part of the metal electrode may be chipped during removal of the side surface insulating film in a later process, and the electrode surface is deformed due to heat during use. For example, the electrode interval fluctuates. Then, appropriate deflection of the electron beam cannot be performed, and the beam pattern is disturbed.

An object of the present invention is to provide a blanking aperture array having blanking electrodes without defects and a method for manufacturing the same, and to enable high-precision beam pattern irradiation.

[Means for solving the problem]

The object described above is a substrate having a large number of openings at a predetermined interval, and has a pair of opposing electrodes made of conductive polycrystalline silicon on opposing side surfaces of each of the openings, and the electrodes and the side surfaces of the substrate. Is achieved by a blanking aperture array of an electron beam exposure apparatus in which an insulating film is formed between the substrates. Further, the following steps (A) to (G): (A) Selectively etching a substrate to form a pair of fine grooves. (A) forming an insulating film on a silicon substrate including the inside of the trench; (c) filling conductive polycrystalline silicon in the trench covered with the insulating film. (D) etching the substrate from the back surface side until the bottom of the groove is exposed to make it thin; (e) selectively etching the substrate portion between the insulating films with a pair of grooves to form an opening Performing the step;
(F) a step of etching away the insulating film on the side surface of the opening; and (g) a step of forming wiring for a filled polycrystalline silicon electrode. This is also achieved by a method of manufacturing an aperture array.

[Action]

In the present invention, by using conductive polycrystalline silicon as the electrode material, the blank can be formed easily and without any problem by filling the groove without generating any pits. This is not derivable from conventional deflectors and their method of formation.

〔Example〕

Hereinafter, the present invention will be described in detail by way of example embodiments of the present invention with reference to the accompanying drawings.

1A to 1E are partial cross-sectional views of a blanking aperture array in steps according to a manufacturing method according to the present invention, and can be manufactured as follows.

As shown in FIG. 1A, a pair of grooves 12 is formed in a single crystal silicon substrate (wafer) 11 by a reactive ion etching (RIE) method. The thickness of the silicon substrate 11 is, for example, about 500 μm, and the opening width of the groove 12 is 1 μm.
m, the depth is 30 μm, and its length is 7 μm.

Next, as shown in FIG. 1B, an SiO ₂ insulating film 13 is formed on the entire surface of the silicon substrate 11 by a thermal oxidation method. Then, according to the present invention, a conductive polycrystalline silicon film 14 is formed by chemical vapor deposition (CVD) so as to completely fill the groove 12.

The polysilicon film 14 is removed by polishing to leave a conductive polysilicon portion 14A only in the groove, as shown in FIG. 1C. This is the blanking electrode.

Next, the silicon substrate 11 in a predetermined area corresponding to a predetermined number of openings is selectively etched from the back side without the polycrystalline silicon electrode 14A, and as shown in FIG. 1D, the silicon substrate thickness is changed to the groove depth (electrode depth). Height). The silicon substrate 11
Has given the mechanical strength to the substrate while maintaining the original thickness. Then, a resist 16 is applied, exposed, and developed to cover an area other than the area corresponding to the opening. Using this resist as a mask, the SiO ₂ on the surface is removed by dry etching such as RIE on the insulating film 13 (FIG. 1D). Subsequently, by changing the etching gas, the silicon substrate portion 11A is removed by etching to form an opening (through hole) 15 as shown in FIG. 1E. After the silicon substrate portion 11A is removed between the pair of electrodes 14A, the insulating film 13 is exposed. Then, etching is performed using an etching gas for SiO ₂ to remove the SiO ₂ insulating film 13 on the side surface of the opening 15 (first E).
Figure). Next, when the resist 16 is removed with a solution or by ashing, a large number (a predetermined number) of openings 15 having a pair of opposed polycrystalline silicon electrodes 14A are arranged at predetermined intervals as shown in the plan view of FIG. 3A. A blanking aperture array is obtained. In FIG. 2A, 4 × 4 = 16
In FIG. 2B, the formed holes 15 are divided into four blocks, and each block 17 corresponds to one irradiation area. This array 18
It is possible to form a predetermined beam pattern using the openings 15 of any of the blocks 17 without moving due to the tendency of the electron beam.

Finally, wiring (not shown) connected to the pair of electrodes 14A of each opening 15 is formed in a conventional manner to complete a blanking aperture array. This wiring forming step may be performed after the polishing step of the polycrystalline silicon film.

〔The invention's effect〕

As described above, according to the present invention, since a conductive polycrystalline silicon electrode which is easy to form and does not cause defects is used in place of a metal electrode which may cause a defect, a blanking aperture with improved reliability is used. An array is obtained. Use of this array further increases the accuracy and reliability of electron beam exposure in a multiple aperture blanking aperture array system.

[Brief description of the drawings]

1A to 1E are partial cross-sectional views of a blanking aperture array in a manufacturing process according to a manufacturing method according to the present invention, and FIGS. 2A and 2B are schematic plan views of the blanking aperture array. 3A and 3B are partial cross-sectional views of a substrate and electrodes showing a state in which a conventional metal electrode is formed in a groove. 11 ... substrate, 12 ... groove, 13 ... insulating film, 14 A ... polycrystalline silicon electrode, 15 ... aperture, 16 ... blanking aperture array.

Continuation of the front page (56) References JP-A-2-54855 (JP, A) JP-A-2-3220 (JP, A) JP-A-1-307222 (JP, A) JP-A-62-118526 (JP) JP-A-60-31226 (JP, A) JP-A-59-189627 (JP, A) Jiko 56-19402 (JP, Y2) (58) Fields investigated (Int. Cl. ⁶ , DB (Name) H01L 21/027

Claims (2)

(57) [Claims] 1. A substrate having a large number of openings at predetermined intervals, comprising a pair of opposing electrodes (14A) made of conductive polycrystalline silicon on opposing side surfaces of each of said openings. A blanking aperture array for an electron beam exposure apparatus, wherein an insulating film (13) is formed between the insulating film (13) and the side surface of (11). 2. The following steps (a) to (g): (a) a step of selectively etching the substrate to form a large number of a pair of fine grooves at predetermined intervals; (a) the substrate including the inside of the grooves. A step of forming an insulating film thereon; (c) a step of filling the trench covered with the insulating film with conductive polycrystalline silicon; and (d) a bottom of the trench is exposed from the back side of the substrate. (E) selectively etching the substrate portion between the insulating films with the pair of grooves to form an opening; and (f) etching the insulating film on the side surface of the opening. A method of manufacturing a blanking aperture array of an electron beam exposure apparatus, comprising: a step of removing; and (g) a step of forming wiring for the filled polycrystalline silicon electrode.