JP2870505B2 - Electron beam exposure equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam exposure apparatus used for manufacturing an integrated circuit of a semiconductor device and a mask for forming the integrated circuit. The present invention relates to a controllable electron beam exposure apparatus.

[0002]

2. Description of the Related Art In recent years, efforts have been made to miniaturize the dimensions of each element of a semiconductor integrated circuit in order to improve the density and speed of the semiconductor integrated circuit. In order to reduce the element size, an optical exposure apparatus using ultraviolet light requires a shorter wavelength of light, a higher NA (numerical aperture), an optical improvement of the exposure apparatus such as a deformed light source, and a phase shift. A new type of exposure method such as a mask was used. In parallel with this, development of a new exposure method such as electron beam or X-ray exposure has been advanced. In particular, various attempts using electron beam exposure have been proposed for forming an integrated circuit having a fine pattern such as a 256 megabit DRAM.

In an electron beam exposure apparatus, not only the accuracy of the shape and dimensions of an exposure pattern but also the accuracy of the exposure position of the pattern are important. For example, "Electron Beam Exposure Apparatus: Practical Electronic Drawing Apparatus" by Heriot et al., IEEE Processing of Electronic Devices, Vol.ED-22, NO. 7, July 1975, 385
Page to 392 (DRHerriott etc.:"EBES:A PracticalE
lectron Lithographic System ", IEEE Transactions on
Electron Devices, Vol.ED-22, NO.7, pp.385-392, July l9
75) discloses an electron beam exposure apparatus as shown in FIG. 6 for improving the accuracy of the exposure position.

The conventional electron beam exposure apparatus shown in FIG.
Based on the beam blanking signal 61 output from the computer 67, the electronic beer is irradiated from the drawing apparatus 60 toward a sample such as a substrate placed on the sample table 63. The sample is fixedly mounted on a sample table 63 which is moved on the XY plane by a servo motor 64. The laser length meter 66 is provided with a mirror 65 attached to the sample stage 63.
The position of the sample table 63 is measured from the position.

Next, the sample stage position data 68 measured by the laser length measuring device 66 and the drawing position data 70 of the pattern information input to the computer 67 are compared. Position error data 6
9, an electron beam deflection signal 62 is applied to the drawing device 60. Further, the signal of the position error data 69 is also applied to the servomotor 64 in order to accurately accelerate the movement of the sample stage 63.

If there is an excessive error, the blanking of the electron beam is stopped, and the drawing is stopped until the position of the sample stage 63 is corrected by the servomotor 64.

[0007]

In the conventional electron beam exposure apparatus, the stability of the deflection position of the electron beam is inferior to that of the laser length meter in the position measurement of the sample stage which is in a stable state for a long time. Therefore, there is a problem that the mutual positional relationship between the two needs to be frequently measured and confirmed. The reason is that the residual gas in the vacuum device provided with the deflection electrode for deflecting the electron beam adheres to the deflection electrode and changes the effective potential of the deflection electrode. As a result, when a large number of fine patterns are exposed, there is a problem in that the time required for exposure over the entire surface of the sample is lengthened, and the accuracy of the electron beam exposure position during that time is deteriorated.

The present invention has been made in view of the above problems, and has as its object to provide an electron beam exposure apparatus capable of controlling an electron beam exposure position with high accuracy and stably for a long time.

[0009]

According to the present invention, there is provided an electron beam exposure apparatus comprising: a base having an electron emission portion for emitting an electron beam to a sample on a sample stage; and an electron emission control for controlling the electron emission of the electron emission portion. Means, a sample stage moving means for moving the sample stage, and a laser length measuring device for measuring the position of the sample stage,
An electron beam exposure apparatus having no mechanism for deflecting an electron beam, wherein a reflection mirror for a laser length measuring instrument is provided on a side surface of the base, and the position variation of the base is controlled by the reflecting mirror and the laser length measuring instrument. Is measured, and the sample stage moving means is controlled based on the amount of substrate position fluctuation.

According to another aspect of the present invention, there is provided an electron beam exposure apparatus comprising: a base provided with an electron emitting portion for emitting an electron beam to a sample on a sample stage; a base moving means for moving the base; An electron beam having electron emission control means for controlling electron emission, sample stage moving means for moving the sample stage, and a laser length gauge for measuring the position of the sample stage, and having no mechanism for deflecting the electron beam An exposure apparatus,
A reflection mirror for a laser length measuring device is provided on a side surface of the base, and the amount of positional change of the base is measured by the reflecting mirror and the laser length measuring device, and the base moving means is controlled based on the amount of positional change of the base. It is characterized by the following.

The base is, for example, a glass substrate.

The electron emission section has a plurality of electron emission elements, and the electron emission control means applies a voltage to a desired electron emission element and controls the electron emission elements to emit electrons independently from each other. Is preferred.

[0013]

Next, the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an electron beam exposure apparatus according to a first embodiment of the present invention.

As shown in FIG. 1, the electron beam exposure apparatus of the first embodiment has an X-axis electron emission source mirror 8 and a Y-axis electron emission mirror 7 on the side and an electron emission section 2 on the main surface. A glass substrate 1, electron emission control means 5 for controlling electron emission of the electron emission section 2, and a sample wafer 3 are mounted, and an X-axis sample stage mirror 10 and a Y-axis sample stage mirror 9 are provided on side surfaces. It has a sample stage 4, a sample stage moving means 12 such as a servomotor for moving the sample stage 4, and a laser length gauge 6 for measuring the position of the sample stage 4 and the position of the glass substrate 1.

Since the electron emission portion 2 on the main surface of the glass substrate 1 and the X-axis electron emission source mirror 8 and the Y-axis electron emission mirror 7 on the side surface of the glass substrate 1 are integrated, the electron emission portion The position of the electron-emitting device that emits the electron beam in the computer 2 is determined from the glass substrate position data and the sample stage position data measured by the laser length meter 6.
3 allows immediate and accurate calculations.

Therefore, if the electron-emitting device and the sample 3 are in a positional relationship to emit electrons and irradiate a small area on the sample with electrons, the electron-emission control means 5 selectively controls only a predetermined electron-emitting device. A predetermined voltage is applied to the device to emit electrons. Thereafter, the sample position is moved by a predetermined moving amount via the sample stage moving means 12 according to a signal from the computer 13. By repeating this, it is possible to expose the required sample surface without remaining. At this time, the electron emission unit 2
Is constantly monitored and measured by the electron emission source mirrors 7 and 8 and the laser length meter 6, so that the computer 13 moves the sample position by a predetermined moving amount via the sample stage moving means 12. And the electron emission unit 2
When the movement is performed in consideration of the position fluctuation amount, the exposure on the sample 3 is accurately performed at a predetermined position.

FIG. 3 is a block diagram showing an electron beam exposure apparatus according to a second embodiment of the present invention. As shown in FIG.
The electron beam exposure apparatus of the second embodiment is basically the same as the first electron beam exposure apparatus, except that an electron emission source moving means 11 is provided. Then, the electron emission unit 2
The position fluctuation amount is feedback-controlled by the computer 13 via the electron-emitting-source moving means 11 so that the position of the electron-emitting portion 2 does not fluctuate. Therefore, according to the electron beam exposure apparatus, when the computer 13 moves the sample stage 4 via the sample stage moving means 12, the stage movement path does not become complicated in consideration of the position fluctuation of the electron emission unit 2. There are advantages.

FIG. 2 is a partially cutaway perspective view showing the electron emission section 2. As shown in FIG. 2, the electron-emitting portion 2 has a plurality of openings 20 formed by arranging vertically and horizontally on the surface of the extraction electrode 22 having a flat plate shape. An element 21 is provided. In order to apply an electric field between the electron-emitting device 21 and the extraction electrode 22, the electron-emitting device 21 includes a contact 23 and wirings 24a and 24a.
b, pad 2 exposed on the side via 24c, 24d
These pads 25a, 25b, 25c, 25d are connected to the electron emission control means 5 of FIG. 1 by electric wires (not shown) or the like.

Then, a voltage is applied to each electron-emitting device 21 according to the position coordinate information to which a voltage is to be applied to the electron-emitting device 21. As a result, the applied electron-emitting device 2
1 emits electrons by an electric field. Electrons from the electron-emitting devices 21 reach the sample through the accelerating electrode plate 29 and the focusing electrode plate 30 having openings corresponding to the positions of the electron-emitting devices 21.

In this embodiment, the apertures 20 of the electron-emitting devices 21 have a diameter of 0.5 μm and are arranged vertically and horizontally at a pitch of 1.0 μm in order to obtain a higher resolution. Then, the voltages of the accelerating electrode and the focusing electrode are adjusted so that the projected image of one electron-emitting device 21 has a diameter of 0.0
It can be transferred as a 5 μm spot image.

Further, the arrangement of the electron-emitting devices 21 is
Arranged in a 0 × 100 lattice, and 10 μm × 1 on the sample wafer 3 irrespective of the pattern shape or arrangement.
A region having a size of 00 μm can be processed by 20 × 20, that is, 400 electron emission irradiations. In an attempt, the voltage applied to the extraction electrode 22 for the electron-emitting device 21 was set to 10.6 V, the acceleration voltage applied to the acceleration electrode plate 29 for the electron-emitting device 1 was 1 KV, and the convergent voltage applied to the converging electrode plate 30 was Is set to −100 V, the resist applied to the sample wafer 3 and having a sensitivity of 10 μC / cm ² is irradiated with the electrons emitted from the electron-emitting device 21. The pattern could be transferred.

The electron emission control means 5 is preferably provided with the same number of power supply circuits as the electron emission elements 21 so that the plurality of electron emission elements 21 can be controlled at appropriate timing. The applied voltage of each power supply is adjusted in units of 0.001 V in order to eliminate the delay due to the wiring length and switching and the variation in the amount of emitted electrons due to the characteristic variation of the electron-emitting device 21. As a result, the variation in the amount of emitted electrons of each electron-emitting device 21 is reduced to 1% or less, and pattern transfer unevenness is eliminated.

Here, as described above, the electron emitting portion 2 emitted electrons at an applied voltage of 10.6 V, and was further accelerated by an acceleration voltage of 1 KV to make the resist on the sample sensitive. Further, it can be used at various application voltages and acceleration voltages, and can make a resist having various photosensitive characteristics sensitive. In the present embodiment, the applied voltage to the electron-emitting device can be set up to several tens of volts,
The voltage applied to the accelerating electrode can be varied from 500 V to 2 KV.

As shown in FIG. 2, a glass substrate 1 having side surfaces serving as reflection mirrors 7 and 8 for a laser length meter and having an electron emission portion 2 on a main surface thereof is manufactured by using a normal semiconductor circuit manufacturing process. Can be manufactured. Hereinafter, the manufacturing process of the glass substrate 1 will be described with reference to the process charts showing the main points of the manufacturing process of FIGS.

As shown in FIG. 4A, first, the side surface of the glass substrate 41 is pre-polished.

Next, as shown in FIG. 4B, a polysilicon film 42 having a thickness of 0.7 μm is formed on the entire surface by a CVD method.

Next, as shown in FIG. 4C, a silicon oxide film 43 having a thickness of 1.0 μm is formed only on the main surface by a CVD method or a thermal oxidation method. However, when formed by the thermal oxidation method, since they are always monitored and measured by the electron emission source mirrors 7 and 8 and the laser length meter 6 in advance,
A silicon nitride film is formed on the outer surface by a CVD method so that a thermal oxide film is not formed except on the main surface.

Next, as shown in FIG. 4D, after forming the electron emitting portion 44, a part of the electron emitting portion 44 is removed using a focused ion beam so as to expose the side surface connection pad portion. . The formation of the electronic device unit 44 at this time is performed in the following order.

After a molybdenum film having a thickness of 0.3 μm is formed on the silicon oxide film by sputtering, unnecessary portions of the molybdenum film are removed by photolithography and dry etching to form wiring. Thereafter, a silicon oxide film having a thickness of 1.0 μm is formed by a CVD method so as to cover the wiring, and an opening is formed by photolithography and dry etching in accordance with the position of the end of the wiring 24d. After a molybdenum film having a thickness of 0.5 μm is formed by sputtering, unnecessary portions of the molybdenum film are removed by photolithography and dry etching to form pads 25d.

Next, a silicon oxide film having a thickness of 1.0 μm is formed by a CVD method so as to cover the wiring 24d and the pad 25d, and the wiring 24 corresponding to the position of the electron-emitting device is formed.
An opening is formed at position d by photolithography and dry etching techniques, a 0.3-μm-thick molybdenum film is formed on the entire surface by sputtering, and the surface is flattened by chemical polishing to leave only the opening. Contact 23
To form

Next, a molybdenum film having a thickness of 0.3 μm is formed by a sputtering method in the same manner as in the case of forming the wiring 24d, and the molybdenum film in an unnecessary region is removed by photolithography and dry etching. The wiring 24c is formed. Thereafter, a silicon oxide film having a thickness of 1.0 μm is formed by a CVD method so as to cover the wiring 24c, and an opening is formed by photolithography and dry etching in accordance with the position of the end of the wiring 24c. After a molybdenum film having a thickness of 0.5 μm is formed by sputtering, the molybdenum film in an invariable region is removed by photolithography and dry etching to form a pad 25c. At this time, the position of the pad 25c formed at the end of the wiring 24c is shifted from the position of the pad 25d formed at the end of the wiring 24d. The thickness is set to 80 μm.

Thereafter, the formation of the insulating layer, the formation of the contact, the formation of the wiring and the pad are repeated to form the required number of layers of the laminated structure. In FIG. 2, the number of layers is set to four for simplification of description, but in the actual embodiment, the number of layers is ten. When forming the wiring 24a of the last layer, the electron emitting element lower pads 30a are formed at the positions of the respective electron emitting elements. The cycle of the pad 30 is set to 1.0 μm. Further, a silicon oxide film having a thickness of 0.5 μm is formed on the entire surface.

Next, a 0.35 μm-thick tungsten film corresponding to the extraction electrode 22 is formed over the entire surface of the silicon oxide film, and the tungsten film and the silicon oxide film are selectively etched and removed by a lithography technique. An opening having a diameter of 0.5 μm is formed in a region corresponding to the position, so that the lower pad 30a of the electron-emitting device is exposed. Then, an aluminum film having a thickness of 0.15 μm is further formed on this opening and the entire surrounding area by 0.1 μm.
An 8 μm thick molybdenum film is formed by a metal deposition method. As the deposition progresses, the opening area of the opening gradually decreases as the deposition progresses, and the tip formed by deposition becomes a cone, and the tip with the optimal shape as a cathode has a sharp electron emission. An element 21 is obtained.

Next, when the aluminum film is removed by wet etching, all of the molybdenum film deposited other than the electron-emitting device 21 is removed by lift-off.

The electron emission portions 2 are formed in the above order.

Next, as shown in FIG. 4E, an organic cover film 45 which is easily dissolved by an organic solvent is formed on the upper surface.
The organic cover film 45 functions to protect the electron-emitting portion 2 from being damaged when the side surface is polished in the next step.

Next, as shown in FIG. 4 (f), the side surface is polished, and a mirror surface material such as aluminum is used so that the side surface of the glass substrate can efficiently reflect laser light as a reflecting mirror for a laser length measuring device. The family is formed by a sputtering method.

Next, as shown in FIG. 4G, the top cover film is removed with an organic solvent.

Thereafter, wiring is connected to the side surface connection pads 25a, 25b, 25c, 25d exposed on the side surface using gold wires or the like, and the wiring is drawn out as a connection cable. Connect to 5. Also,
It is arranged so as to face the sample stage 4 in parallel using a supporting groove 28 provided in the glass substrate 1 in advance. The acceleration electrode plate 29 and the focusing electrode plate 30
Are made of a stainless steel plate having a thickness of 0.2 mm, and are disposed at positions of 3 mm and 5 mm on the upper surface of the electron emission section 2.

The accelerating electrode plate 29 and the focusing electrode plate 30 are provided with openings corresponding to the positions of the respective electron-emitting devices 21 of the electron-emitting section 2, and accelerate the electron beams emitted from the respective electron-emitting devices. And can further converge.

FIG. 5 is a diagram showing the positional relationship between the arrangement of the electron-emitting devices of the electron-emitting section 2 and the drawing pattern. The solid line indicates the pattern area 51 to be exposed. The circle indicates an exposure region 52 for one electron beam from the electron-emitting device, that is, a circular region having a diameter of 0.05 μm. In FIG. 5, as an example, all the circular regions are shown only for the upper two columns and the left two columns. As described above, the period of the electron-emitting device is 1.0 μm, and the position 53 of the electron-emitting device at a certain moment corresponds to all positions blacked out.

Whether or not exposure is actually performed at each of these positions can be controlled by the electron emission control means 5. Controlling and exposing only the electron-emitting devices at the positions included in the drawing pattern to be exposed, and then moving 0.05 μm to control only the electron-emitting devices at the positions included in the drawing pattern to be similarly exposed And expose. This is 20 × 2
If 0 = 400 repetitions, 10 μm × 100 μm irrespective of the type and periodicity of the pattern by the electron emission unit 2 having 10 × 100 = 1000 electron emission elements
Exposure can be performed without any remaining area.

Next, the sample stage 4 is moved to a position of 10 μm next to the 10 μm × 100 μm area where the exposure is completed.
By exposing an area of × 100 μm, an area to be exposed on the sample wafer 3 can be sequentially exposed without any residue.

The order of exposure is not limited to this order, but may be other methods. For example, 10 ×
It means that 20 times, ie, 0.05 μm × 20 = 1 μm, are continuously exposed in the X-axis direction in which 10 out of 100 electron-emitting devices are arranged, and 10 elements, that is, a length of 10 μm is exposed. Then, the same movement was repeated by 0.05 μm in the Y-axis direction, and the same operation was repeated, so that a strip-shaped area extending in the X-axis direction with a width of 100 μm in the Y-axis direction was completely exposed. Later, Y
A method in which the belt-like region is similarly exposed while moving in the axial direction by 100 μm may be used.

In any case, the program for the coordinate values of the electron-emitting devices created according to the individual patterns is called, and the position data of the electron-emitting source by the laser length meter 6 and the preset individual electron-emitting devices are used. The exposure area is irradiated with an electron beam in consideration of the correction of the element.

Thus, 10 × 100, that is, 1000
A power source to be applied to the electron-emitting devices 21 is provided, and the pattern data is programmed on the sample wafer by using a program of the coordinate values of the electron-emitting devices in accordance with the exposure order, regardless of the type of pattern and the presence or absence of a repetitive pattern. A certain area could be exposed with the same exposure time.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the technical matters described in the claims.

[0048]

According to the present invention, a reflection mirror for a laser length measuring device is provided on the side surface of a substrate, and the position mirror of the substrate is measured by the reflecting mirror and the laser length measuring device. Since the sample stage moving means or the substrate moving means is controlled based on the above, the position of the substrate provided with the electron emitting portion can be directly controlled with high precision, and the exposure pattern position can be stably controlled for a long time.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating an electron beam exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view of an electron emitting portion and a glass substrate.

FIG. 3 is a configuration diagram showing an electron beam exposure apparatus according to a second embodiment of the present invention.

FIG. 4 is a process chart showing a manufacturing process of the electron-emitting portion.

FIG. 5 is an explanatory diagram showing a positional relationship between an array of electron-emitting devices of an electron-emitting section and a drawing pattern.

FIG. 6 is a configuration diagram showing a conventional electron beam exposure apparatus.

[Explanation of symbols]

 1: Glass substrate 2: Electron emission part 3: Sample wafer 4: Sample stage 5: Electron emission control means 6: Laser length meter 7: Y-axis electron emission source mirror 8: X-axis electron emission source mirror 9: Y-axis sample stage Mirror 10: X-axis sample stage mirror 11: Electron emission source moving means 12: Sample stage moving means 13: Computer 21: Electron emitting element 22: Extraction electrode 29: Acceleration electrode plate 30: Focusing electrode plate

Claims (4)

(57) [Claims] 1. A base provided with an electron emitting portion for emitting an electron beam to a sample on a sample stage, electron emission control means for controlling electron emission of the electron emitting portion, and a sample stage moving for moving the sample stage. Means, and a laser length measuring device for measuring the position of the sample stage, the electron beam exposure apparatus does not have a mechanism for deflecting the electron beam, the side of the substrate, for the laser length measuring device An electron beam exposure apparatus, wherein a reflection mirror is provided, a position variation of a substrate is measured by the reflection mirror and a laser length meter, and the sample stage moving means is controlled based on the position variation of the substrate. . 2. A base provided with an electron emitting portion for emitting an electron beam to a sample on a sample stage, a substrate moving means for moving the base, and an electron emission controlling means for controlling electron emission of the electron emitting portion. An electron beam exposure apparatus comprising: a sample stage moving unit configured to move the sample stage; and a laser length measuring device that measures a position of the sample stage, and not including a mechanism for deflecting an electron beam. A reflection mirror for the laser length measuring device is provided on a side surface of the device, and a position variation of the substrate is measured by the reflection mirror and the laser length measuring device, and the substrate moving means is controlled based on the substrate position variation. An electron beam exposure apparatus, comprising: 3. An electron beam exposure apparatus according to claim 1, wherein said substrate is a glass substrate. 4. The electron emission section has a plurality of electron emission elements, and the electron emission control means applies a voltage to desired electron emission elements and causes each of the electron emission elements to independently emit electrons. 4. The control according to claim 1, wherein
An electron beam exposure apparatus according to any one of the above items.