JPH0541349A - Charged particle beam aligner and its adjusting method - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a charged particle exposure apparatus that forms a fine pattern by an electron beam, an ion beam, or the like, and does not need to move the stage when setting exposure conditions, and to provide an adjustment method thereof. To aim. An exposure apparatus in which the current value of the charged particle beam to be irradiated is detected by a Faraday cup 93 provided on the stage 8 and the position where the charged particle beam converges is detected by a mark pattern 91 provided on the stage 8. The mark pattern 91 and the Faraday cup 93 are provided on the stage 8 in the area where the deflection electrode 65 can deflect the charged particle beam.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged particle exposure apparatus for forming a fine pattern by an electron beam, an ion beam or the like, and more particularly to a charged particle exposure apparatus capable of shortening the time of adjustment work performed prior to exposure. Regarding adjustment method.

Photolithography has been used for many years as a method for forming a fine pattern of a semiconductor integrated circuit element, and as a method for forming a fine pattern as the degree of integration of a semiconductor integrated circuit element progresses, a photolithography method is used. Instead, a new exposure method using a charged particle beam such as an electron beam or an ion beam has been highlighted.

However, the mainstream of the electron beam exposure apparatus which has been put into practical use at present is a method of connecting rectangular patterns to form a fine pattern. For example, a basic rectangular pattern is made small in order to narrow the line width of a pattern to be drawn. Then, the number of exposure shots per unit area increases and the throughput, that is, the processing capacity of the exposure apparatus decreases.

Therefore, by providing a block mask having a plurality of basic patterns repeatedly used in the passage region of the electron beam, and selecting and connecting arbitrary basic patterns from the plurality of basic patterns of the block mask, Practical application of a method called a block exposure method capable of forming a desired fine pattern in a short time is under study.

[0005]

2. Description of the Related Art FIG. 2 is a schematic view showing a structure of an electron beam exposure apparatus, FIG. 3 is a view showing an example of a block mask, and FIG. 4 is a schematic view showing a main part of a conventional electron beam exposure apparatus.

As shown in FIG. 2, an electron beam exposure apparatus for forming a desired fine pattern by a block exposure method is an electron gun 2 for emitting an electron beam 1, an electron beam shaping section 3 for shaping a cross section of the electron beam 1, and a basic structure. It is composed of a basic pattern selection unit 4 for selecting a pattern and a beam irradiation unit 6 for drawing a fine pattern on the surface of the sample 5.

The electron beam shaping unit 3 collimates the electron beam 1 emitted from the electron gun 2 and spreads it, and an electron lens 31.
A rectangular aperture plate 32 that shapes the cross section of the electron beam 1 parallelized by the electron lens 31 into a rectangle, and an electron lens that refocuses the electron beam 1 shaped by the rectangular aperture plate 32.
It is composed of 33 and.

The basic pattern selection section 4 has a block mask 41 in which a plurality of basic patterns are formed in advance, a first block deflection electrode 42 and a second block deflection electrode 43 for selecting an arbitrary pattern from the basic patterns. The second block deflection electrode 43 is composed of deflection electrodes 43a, 43b, 43c and 43d arranged before and after the block mask 41.

The block mask 41 has a plurality of basic patterns 47a, 47b, 47c, 47d having different shapes as shown in FIG. 3 (a).
As shown in FIG. 3 (b), the basic pattern has a plurality of various shapes on the substrate 46 made of a semiconductor such as Si or a metal having an extremely thin region in the center and a metal by using etching technology or the like. Is formed by providing a through hole.

The basic pattern selection section 4 has an electron lens 44 in front of the block mask 41 in addition to the first block deflection electrode 42 and the second block deflection electrode 43, and the electron beam made parallel by the action of the electron lens 44. The sectional shape of 1 is shaped according to the basic pattern, and is further returned to the original beam axis by the action of the electron lens 45 provided after the block mask 41.

In the figure, the second block deflection electrode 43c
Unlike the first block deflecting electrode 42 and the second block deflecting electrode 43, the blanking electrode 48 provided between the first and second block deflection electrodes 43 and 43d is an optical camera that passes or blocks the electron beam 1 during exposure regardless of the selection of the basic pattern. Is an electrode corresponding to the shutter in.

Further, the beam irradiating unit 6 reduces the selected basic pattern to an electron lens 61, a circular aperture plate 62 and an electron lens 63, and the electron beam 1 whose cross section is shaped by the basic pattern onto the surface of the sample 5. An electron lens 64 for converging,
It is composed of an exposure deflection electrode 65 for deflecting the converged electron beam 1 into a predetermined area on the surface of the sample 5.

The control device 7 for controlling the electron beam exposure apparatus has an exposure control section 72 connected to a CPU or the like via a signal bus 71, a DA converter 73 and an amplifier 74 for driving the first block deflection electrode 42, Second block deflection electrode 43
And a DA converter 75 and an amplifier 76 for driving the blanking electrode 48, a DA converter 78 and an amplifier 79 for driving the exposure deflection electrode 65, respectively.

The feature of the block exposure system cannot be exhibited when forming a fine pattern having a small number of basic patterns that are repeatedly used, but for example, a DRAM (dynamic random acc)
In essmemory) and the like, most of the exposure area is a repetition of the basic pattern, and the number of exposure shots per unit area is reduced, so that the throughput can be significantly increased.

The beam irradiation unit 6 in the conventional electron beam exposure apparatus will be described in more detail below with reference to FIG. Sample 5
Is mounted on a stage 8 movable in the XY directions, and a mark pattern 81 is engraved on the stage 8. Electronic lens 64
A backscattered electron detector 82 composed of, for example, a photodiode is provided underneath, and the position where the electron beam 1 converges can be detected by detecting a change in the backscattered electron due to the mark pattern 81.

A Faraday cup 83 is provided at a position apart from the mark pattern 81 on the stage 8. The Faraday cup 83 has a cylindrical conductor 85 which is insulated from the stage 8 by an insulator 84 and has an open top.
The current value of the incident electron beam 1 can be detected by detecting the current flowing from the ground side to the ammeter 86.

In the electron beam exposure apparatus for forming a fine pattern by the block exposure method described above, the electron beam is largely deflected from the original beam axis, the basic pattern is selected, and then returned to the original beam axis again to be exposed. In addition, there is a problem that the position shift of the basic pattern and the electron beam are likely to be shaded. Therefore, prior to the exposure, by repeatedly detecting the positional deviation of the basic pattern by the mark pattern 81 and the current value detection of the electron beam 1 by the Faraday cup 83, it is possible to optimize the positional deviation of the basic pattern and the shadow of the electron beam. Exposure conditions must be set.

[0018]

However, in the conventional electron beam exposure apparatus, the mark pattern and the Faraday cup are provided at positions distant from each other on the stage, and the positional deviation of the basic pattern and the shadow of the electron beam are repeatedly detected. It is necessary to move the stage each time. It usually takes about 100 ms to move and settle the stage, depending on the moving distance, and a lot of time is wasted by repeatedly moving and settling the stage each time each basic pattern is exposed. To be done. As a result, there is a problem that the throughput does not increase even if the number of exposure shots per unit area is reduced.

An object of the present invention is to provide a charged particle exposure apparatus that does not require the stage to be moved when setting the exposure conditions and a method for adjusting the same.

[0020]

FIG. 1 is a schematic diagram showing a main part of a charged particle exposure apparatus according to the present invention. Note that the same object is denoted by the same symbol throughout the drawings.

The above-mentioned problems are at least the electron lens 64 for converging the charged particle beam on the surface of the sample 5 placed on the stage 8 and the deflection for deflecting the converged charged particle beam within a predetermined area of the surface of the sample 5. Has an electrode 65, and
An exposure apparatus that detects a current value of a charged particle beam to be irradiated by a Faraday cup 93 provided on the stage 8 and detects a position where the charged particle beam converges by a mark pattern 91 provided on the stage 8. This is achieved by the charged particle exposure apparatus of the present invention in which the mark pattern 91 and the Faraday cup 93 are provided on the stage 8 in the area where the deflection electrode 65 can deflect the charged particle beam.

[0022]

In the charged particle exposure of the present invention, a Faraday cup for current detection and a mark pattern for position detection are provided on a stage in a region where a deflection electrode can deflect a charged particle beam in FIG. The device can alternately detect the current value and the position by deflecting the charged particle beam.

That is, it is possible to realize a charged particle exposure apparatus and its adjusting method that do not require the stage to be moved when setting the exposure conditions. As a result, the stage does not move during the adjustment, and the throughput can be significantly increased.

[0024]

Embodiments of the present invention will be described in detail below with reference to FIG. The mark pattern 91 has a width of several μm or less, and the Faraday cup 93 has an inner diameter of about 2 mm. However, in order to detect the position and the current value without moving the stage, the deflection electrode 65 uses the mark pattern 91 and the Faraday cup 93 as the electron beam. It is necessary to install it in the area for deflecting (± 1 to 2 mm).

In the figure, the Faraday cup 93 implanted in the stage 8 is composed of a cylindrical conductor 95 and an insulator 94. The cylindrical conductor 95 having an opening at the top and a depth larger than the inner diameter has a current of about several microamperes. Is grounded via an ammeter 96 capable of detecting
The surroundings are insulated from the stage 8 by.

An electron reflection element 97 having a mark pattern 91 is attached to the upper edge of the cylindrical conductor 95 so that current can flow therethrough. The electron reflection element 97 needs to be extremely small in order to be mounted on the cylindrical conductor 95 having an inner diameter of about 2 mm. For example, the mark pattern 91 is formed on the substrate 98 made of silicon or the like, and the metal film 99 is formed by vapor deposition or the like. ..

For example, when the electron beam 1 which is not deflected by the deflecting electrode 65 is made incident on the electron reflecting element 97, the electrons reflected by the electron reflecting element 97 are reflected by the backscattered electron detector 82 provided under the electron lens 64. The position where the electron beam 1 converges can be detected by detecting the change in the reflected electrons due to the mark pattern 91.

The electron reflecting element 97 is mounted on the upper edge of the cylindrical conductor 95 forming the Faraday cup 93, and the mark pattern 91 on the electron reflecting element 97 and the Faraday cup 93 cause the deflection electrode 65 to deflect the electron beam. It is in the area. Therefore, the current value of the electron beam 1 can be detected by deflecting the electron beam 1 using the deflection electrode 65.

When detecting the position where the electron beam 1 converges, instead of the electron beam 1 which is not deflected,
The electron beam 1 deflected in a predetermined direction by the deflecting electrode 65 is made incident on the electron reflecting element 97, and the electron beam 1 deflected to the opposite side by the deflecting electrode 65 when the current value is detected.
May be incident on the cylindrical conductor 95.

As described above, the charged particle exposure of the present invention is such that the Faraday cup for current detection and the mark pattern for position detection are provided on the stage in the area where the deflection electrode can deflect the charged particle beam. The device can alternately detect the current value and the position by deflecting the charged particle beam.

That is, it is possible to realize a charged particle exposure apparatus and its adjusting method that do not require the stage to be moved when setting the exposure conditions. As a result, the stage does not move during the adjustment, and the throughput can be significantly increased.

[0032]

As described above, according to the present invention, it is possible to provide a charged particle exposure apparatus which does not require the stage to be moved when setting the exposure conditions and a method for adjusting the same.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a main part of a charged particle exposure apparatus according to the present invention.

FIG. 2 is a schematic diagram showing a configuration of an electron beam exposure apparatus.

FIG. 3 is a diagram showing an example of a block mask.

FIG. 4 is a schematic view showing a main part of a conventional electron beam exposure apparatus.

[Explanation of symbols]

 1 electron beam 5 sample 8 stage 64 electron lens 65 deflection electrode 82 backscattered electron detector 91 mark pattern 93 Faraday cup 94 insulator 95 cylindrical conductor 96 ammeter 97 electron reflective element 98 substrate 99 metal film

Claims (3)

[Claims] 1. An electron lens (64) for converging a charged particle beam on at least a surface of a sample (5) mounted on a stage (8), and the converging charged particle beam for the sample (5).
Having a deflection electrode (65) for deflecting in a predetermined area of the surface, and detecting the current value of the irradiated charged particle beam by a Faraday cup (93) provided on the stage (8),
An exposure device for detecting a position where the charged particle beam converges by a mark pattern (91) provided on the stage (8), wherein the deflection electrode (65) can deflect the charged particle beam. The mark pattern on the stage (8) in a different area.
A charged particle exposure apparatus comprising: (91) and the Faraday cup (93). 2. In the charged particle exposure apparatus according to claim 1, in detecting the converged position of the charged particle beam, the charged particle beam not deflected by the deflection electrode (65) is made incident on the mark pattern (91), and , The charged particle beam deflected by the deflection electrode (65) is moved to the Faraday cup (9) without moving the stage (8) in detecting the current value of the charged particle beam.
Adjustment method characterized in that the light is incident on 3). 3. In the charged particle exposure apparatus according to claim 1, in detecting the convergent position of the charged particle beam, the charged particle beam deflected by the deflection electrode (65) is made incident on the mark pattern (91), and In detecting the current value of the charged particle beam, the charged particle beam deflected by the deflection electrode (65) is moved by the Faraday cup (9) without moving the stage (8).
Adjustment method characterized in that the light is incident on 3).