JPH11168046A - Charge beam exposure method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the charging of a resist, without increasing a process, for eliminating beam dislocation and to improve exposure precision. SOLUTION: In an electron beam exposure method for forming a desired pattern for a resist, chemically amplified-type resist 23 generating acid by the subjecting electron beam formed on a Si oxide film 22 on a Si substrate 21, the entire surface of the resist 23 is irradiated with an electron beam 24 of low accelerating voltage, and a conduction layer 25 is formed on the surface of the resist. Then, a desired pattern is exposed on the resist 23 through having the electron beam of high accelerating voltage irradiated in a state where the conduction layer 25 on the surface of resist is grounded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged beam exposure method, and more particularly, to a charged beam exposure method for forming a conductive layer on a resist surface to prevent a beam position shift due to charging of the resist.

[0002]

2. Description of the Related Art Conventionally, an electron beam exposure method has been used to form a fine pattern on a semiconductor wafer. However, in the case of electron beam exposure, a pattern displacement due to charge-up of a resist as a photosensitive agent. Is a problem. An organic polymer constituting a resist used for electron beam exposure generally has high insulating properties. Further, in electron beam exposure in a semiconductor manufacturing process, there are many opportunities for exposure on an Si oxide film used as an insulating film between wirings.
When exposure is performed on these insulators, charge-up of the insulator becomes a problem.

[0003] As shown in FIG. 8A, a sample in which an insulating film 82 is formed on a substrate 81 and a resist 83 is coated thereon is considered. The electron beam 84 irradiating the resist 83 reaches the substrate 81, and some of the electron beam 84 incident on the substrate 81 is captured in the insulating film 82 or in the resist 83. The electric charges 85 accumulated in these insulators form an electric field on the substrate surface.
As shown in (b), the activation of the incident electron beam 84 is bent.

In recent years, in order to solve this problem, FIG.
As shown in (a), a conductive film 86 is formed on the resist 83 as an upper layer.
9B, or a method of forming and forming a conductive film 86 under the resist 83 as shown in FIG. 9B. However, these methods have a problem in that productivity is reduced because the number of film forming steps is increased.

In the case of performing exposure with an electron beam having a low acceleration voltage, there are the following problems. For example, when a conductive film is formed on the resist, as shown in FIG. 10A, the incident electron beam 84 is scattered by the conductive film 86, and as a result, the resolution of the pattern is deteriorated. Also,
When a conductive film is formed under the resist, FIG.
As shown in (b), most of the electron beam 84 is captured in the resist 83 because the range of electrons is small. As a result, charge-up easily occurs, and the activation of the electron beam 84 is easily bent because the energy of the electron beam is originally low.

Further, as shown in FIG. 11A, when an attempt is made to form a resist pattern on the same resist 83 by using an excimer laser beam 87 and an electron beam 84, a conductive film 86 is formed on the upper layer of the resist. When formed, the absorption of the excimer laser beam 87 by the conductive film 86 is large. For this reason, as shown in FIG. 11B, there is a problem that it is difficult to form a pattern using the excimer laser beam 87.

[0007]

As described above, in the conventional method of forming a conductive film to prevent charge-up,
There was a problem that productivity dropped. Also, in electron beam exposure using a low-acceleration electron beam, when a conductive film is used as the upper layer of the resist, the resolution deteriorates due to electron scattering, and the conductive film is formed as the lower layer of the resist. Has a problem that the effect of preventing charge-up is hardly obtained. Further, when a conductive film is formed on the resist upper layer, there is a problem that when the same resist is exposed using an excimer laser and an electron beam, the pattern shape by the excimer laser is deteriorated.

The present invention has been made in consideration of the above circumstances, and has as its object to prevent the resist from being charged without increasing the number of processes and to eliminate the beam position shift. An object of the present invention is to provide a charged beam exposure method that can contribute to improvement of exposure accuracy.

[0009]

(Structure) In order to solve the above-mentioned problem, the present invention employs the following structure.
That is, the present invention provides, in a charged beam exposure method for forming a desired pattern on a resist, a step of forming a resist that is made conductive by irradiation of an energy beam on a substrate; Irradiating an energy beam to form a conductive layer on the resist surface; and exposing a desired pattern to the resist by irradiating a charged beam with the conductive layer on the resist surface grounded or connected to a predetermined power supply. And a step of performing

The present invention also provides a charged beam exposure method for forming a desired pattern on a resist, the method comprising: forming a resist that is made conductive by irradiation of an energy beam on a substrate having at least a conductive surface; Irradiating an energy beam on at least the entire surface of the resist to be patterned to form a first conductive layer on the resist surface; and charging the substrate with the surface of the substrate grounded or connected to a predetermined power source. A desired pattern is exposed on the resist by beam irradiation, and a second conductive layer penetrating the resist is formed at the time of the exposure, and a first conductive layer on the resist surface is formed on the surface of the substrate. Electrically connecting).

Here, preferred embodiments of the present invention include the following. (1) Use an electron beam as a charged beam for pattern exposure. (2) The resist must be a chemically amplified resist.

(3) Ultraviolet light, electron beam, ion beam, or X-ray is used as an energy beam for forming the conductive layer. (4) The resist should contain a conductive polymer.

(5) The resist contains a compound that generates an acid upon irradiation with an energy beam. (6) The resist should contain an onium salt as an acid generator.

(7) The penetration depth of the energy beam into the resist is made smaller than the resist film thickness. (8) When the same electron beam exposure apparatus is used for the irradiation of the energy beam for forming the conductive layer on the resist surface and the irradiation of the charged beam for the pattern exposure, and the conductive layer is formed, the first substrate is formed on the substrate side. When applying a bias voltage to reduce the acceleration voltage of the electron beam and exposing the pattern, the substrate side is grounded or a second bias voltage having an absolute value smaller than the first bias voltage is applied to the electron beam. To increase the acceleration voltage.

(9) A conductive substance is brought into contact with the resist surface in order to ground the conductive layer on the resist surface. (10) In order to ground the conductive layer on the resist surface, a conductive layer penetrating the resist by an energy beam having a penetration depth larger than the resist film thickness is formed.

(Operation) According to the present invention, since the conductive layer is formed on the resist surface by the irradiation of the energy beam, the charge accumulated in the resist can be released by grounding the resist surface. For this reason, it is possible to prevent the position of the beam from shifting during the irradiation of the charged beam during the pattern exposure, and to improve the pattern exposure accuracy. In this case, it is only necessary to irradiate the resist surface with an energy beam, and there is no need to apply and form a conductive film on the resist.

Further, by making the penetration depth of the energy beam into the resist smaller than the resist film thickness, the formation of a desired pattern is not affected. Further, by adding a compound that generates an acid by irradiation of an energy beam to the resist, for example, an onium salt, an ionic substance is generated on the resist surface, and as a result, the conductivity of the resist can be improved.

When ultraviolet light is used as the energy beam, a conductive layer thinner than the resist film thickness can be easily formed by adding a substance absorbing ultraviolet light to the resist. Further, when an electron beam is used as the energy beam, the penetration depth into the resist can be easily changed by controlling the acceleration voltage.

In the case where the resist base is a grounded substrate, a conductive layer penetrating the resist is formed by an energy beam having a resist penetration depth larger than the resist film thickness, so that the resist surface is grounded. It is possible to do. By performing the step of exposing a desired pattern at the same time as forming the conductive layer penetrating the resist, it is possible to eliminate waste of drawing time.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an electron beam exposure apparatus used in an embodiment of the present invention will be described. FIG. 1 shows an example of this type of electron beam exposure apparatus. 1 in the figure
Denotes a sample chamber, in which a wafer (sample) is provided.
A sample table 3 on which the sample 2 is placed is accommodated. Reference numeral 10 denotes an electron optical column, and the electron optical column 10 includes an electron gun 1
1, various lens systems 12a to 12e, various deflection systems 13 to 1
6, an aperture mask 17 for blanking, and first and second aperture masks 18 and 19 for beam shaping.

The electron beam emitted from the electron gun 11 is
The beam is irradiated onto the first beam shaping aperture mask 18 by the lenses 12a and 12b and shaped into a rectangular beam, and the formed aperture image (first aperture image) is projected by the projection lenses 12c and 12d to form the second beam. An image is irradiated onto the aperture mask 19 for molding. Here, by adjusting the degree of overlap between the first aperture image and the opening (second aperture) of the second aperture mask 19 by the shaping deflector 14, a beam having an arbitrary dimension can be obtained.
Then, the light is reduced and irradiated onto the wafer 2 by the reduction lens 12e and the objective lens 12f. At this time, a desired position on the wafer 2 is irradiated by the objective deflectors 15 and 16.

In order not to irradiate the wafer 2 with the electron beam, the beam is deflected by the blanking deflection system 13 and blocked by the blanking aperture mask 17 so that the beam is blanked. It has become. Further, in the above apparatus, the acceleration voltage of the beam can be varied.

The present invention relates to an exposure method, and an exposure apparatus used in the following exposure method is not limited to FIG. Next, the resist used in the embodiment of the present invention will be described.

The resist used in the present embodiment has a compound that generates an acid when irradiated with an energy beam. Compounds that generate an acid include sulfonyl,
Onium salts such as iodonium and sulfonyl esters are used. These acid generators need to be in the range of 0.1 to 30 parts by weight of the polymer composition, and preferably 0.3 to 15 parts by weight. If the amount is less than 0.3 part by weight, it is difficult to obtain a sufficient sensitivity, and if the amount is more than 15 parts by weight, the light transmittance of the photosensitive composition at the exposure wavelength may be impaired depending on the type of the acid generator. is there.

Here, triphenylsulfonium triflate, a kind of onium salt, was used as the acid generator. FIG. 7 shows a change in surface resistance due to electron beam exposure when the acid generator is added to a base resin composed of polyhydroxystyrene in an amount of 5% by weight. With an exposure amount of 20 μC / cm ² or more by electron beam exposure, the surface resistance of this resist resin decreases to about 10 ⁸ Ω. Here, an electron beam is used as an energy beam, but a decrease in surface resistance can be similarly observed by using an excimer laser, an X-ray, or an ion beam.

The resist used in the present invention may contain a compound capable of generating an acid upon irradiation with an energy beam. The generated acid does not necessarily need to be involved in the photosensitive mechanism. For example, the same effect can be obtained by adding another acid generator to a main chain-cutting resist such as PMMA.

A small amount of a conductive polymer may be added in addition to the compound that generates an acid. In general, when a large amount of a conductive substance is added, the original patterning characteristics of the resist are impaired. However, when the amount is small, the acid generated by the energy beam irradiation can further reduce the resist surface resistance by the effect of the conductive polymer. .

Hereinafter, embodiments of the present invention will be described. (First Embodiment) FIG. 2 is a process sectional view for explaining an electron beam exposure method according to a first embodiment of the present invention.

First, as shown in FIG. 2A, a resist 23 having a thickness of 0.5 μm was applied to a 2 μm thick Si oxide film 22 formed on a Si substrate 21. The resist 23 is a chemically amplified positive resist using polyhydroxystyrene as a base resin, triphenylsulfonium triflate as an acid generator, and tert-butoxycarbomethyl group as a dissolution inhibiting group. The sensitivity of the resist 23 is 10 μC / cm ² for an electron beam having an acceleration voltage of 50 keV.

The range of electrons in the Si substrate at an acceleration voltage of 50 keV is about 10 μm. However, when the thickness of the Si oxide film 22 is about 2 μm, the silicon oxide film 22 is charged even at an acceleration voltage of 50 keV, resulting in pattern displacement. That has been confirmed.

Next, as shown in FIG. 2B, an electron beam 24 having an acceleration voltage of 1 keV is
Irradiated at μC / cm ² . The range of the electron beam having an acceleration voltage of 1 keV in the resist is 50 nm. Since the exposure here is the entire surface exposure, high-precision beam adjustment is not performed. By performing exposure at a low acceleration of 1 keV,
A large amount of acid can be generated on the surface of the resist 23 at 50 nm. Thereby, the conductive layer 25 was formed on the resist surface, and the conductivity of the resist surface was significantly improved.

Next, as shown in FIG. 2C, the conductive layer 25 on the resist surface is grounded, and the electron beam 26 is applied using a variable-shaped electron beam exposure apparatus with an acceleration voltage of 50 keV.
Exposure of the desired pattern was performed. At the time of exposure, the sample is stored in a cassette dedicated to an exposure apparatus having a grounding needle. The conductive layer 25 on the resist surface is grounded through this grounding needle. For this reason, even if charges accumulate inside the resist and in the Si oxide film, these charges are electrostatically shielded.

Therefore, the position of the incident beam is
And the shift due to the charging of the Si oxide film 22 is eliminated. Actually, as a result of performing such exposure and performing post-exposure baking and development, as shown in FIG. 2D, no pattern displacement or shape deterioration was observed at all. Also, since the resist film thickness that disappears by development is about 50 nm, there is no problem in pattern formation.

As described above, according to the present embodiment, the conductive layer 25 is formed on the resist surface by the irradiation of the low-acceleration electron beam 24, and the conductive layer 25 is grounded to release the electric charge accumulated in the resist 23. In addition, it is possible to prevent the position of the electron beam 26 from being shifted at the time of irradiation with the electron beam 26 during the pattern exposure, and to improve the pattern exposure accuracy. In this case, it is only necessary to irradiate the resist surface with the low-acceleration electron beam 24, and there is no need to apply and form a conductive film on the resist. Further, by making the penetration depth of the electron beam 24 for forming the conductive layer smaller than the resist film thickness, the formation of the desired pattern is not affected.

(Second Embodiment) FIG. 3 shows a second embodiment of the present invention.
FIG. 9 is a process cross-sectional view for describing the electron beam exposure method according to the embodiment. Incidentally, 31 to 36 in FIG.
It corresponds to 21 to 26 in FIG.

In this embodiment, a chemically amplified negative resist is used. 1% of carbon fine particles having a diameter of several nm were added to this resist. The sensitivity to an electron beam having an acceleration voltage of 50 keV is 10 μC / cm ² .

First, as shown in FIG. 3A, a 0.5 μm thick negative resist 33 was applied to a 2 μm thick Si oxide film 32 formed on a Si substrate 31. Next, as shown in FIG. 3B, the entire surface of the resist was irradiated with an electron beam 34 at an acceleration voltage of 1 keV at an exposure amount of 1 μC / cm ² . The range of the electron beam having an acceleration voltage of 1 keV in the resist is 50 nm. Since the exposure here is the entire surface exposure, high-precision beam adjustment is not performed.

Next, as shown in FIG. 3 (c), the conductive layer 35 on the resist surface is grounded, and the electron beam 36 is applied using a variable-shaped electron beam exposure apparatus with an acceleration voltage of 50 keV.
Exposure of the desired pattern was performed. At the time of exposure, the sample was set in a wafer cassette dedicated to an exposure apparatus having a structure in which the resist surface was grounded, and normal exposure was performed.

The exposed sample was developed with a 0.1N aqueous alkaline solution for 30 seconds before baking after exposure,
Rinsing with pure water was performed. After that, when normal post-exposure baking and development were performed, as shown in FIG.
No pattern displacement or shape deterioration was observed at all.

In this embodiment, similarly to the first embodiment, by performing exposure at a low acceleration of 1 keV, a large amount of acid can be generated on the resist surface of 50 nm, and the conductivity of the resist surface is significantly reduced. Improved. further,
Further, since the resist surface is grounded by the grounding needle, even if electric charges accumulate inside the resist and in the Si oxide film, the electric charges are in a form of being electrostatically shielded. Therefore, the position of the incident beam does not shift due to the charging of the resist and the Si oxide film.

In the case of a negative resist, when exposed to a low-acceleration electron beam, a thin skin remains on the resist surface, but this can be removed with a 0.1N aqueous alkaline solution which has been used after the exposure and before the baking.

As described above, according to this embodiment, even if the negative resist 33 is used, the conductive layer 35 can be formed on the surface of the resist by irradiation with the low-acceleration electron beam 34, and the conductive layer 35 can be grounded by grounding. Thus, the charges accumulated in the resist 33 can be released. Therefore, effects similar to those of the first embodiment can be obtained. Further, in the case of a negative resist, a thin skin residue of the resist caused by exposure with a low-acceleration electron beam could be removed.

(Third Embodiment) FIG. 4 shows a third embodiment of the present invention.
FIG. 9 is a process cross-sectional view for describing the electron beam exposure method according to the embodiment. In addition, 41 to 46 in FIG.
It corresponds to 21 to 26 in FIG.

As shown in FIG. 4A, a substrate in which a 2 μm thick Si oxide film 42 was formed on a Si substrate 41 was used. A conductive film 47 was applied on the substrate, and a resist 43 same as that used in the first embodiment was applied thereon to a thickness of 0.15 μm. Exposure was performed as follows.

First, as shown in FIG. 4B, in order to form a first conductive layer 45 on the surface of the resist 43, an electron beam 44 of an acceleration voltage of 1 keV is applied to the entire surface of the resist at an exposure amount of 1 μC / cm ² . Irradiated. Next, as shown in FIG. 4C, the conductive film 47 under the resist is grounded, and a desired pattern 49 is formed using an electron beam 46 having an acceleration voltage of 5 keV.
Was exposed.

At the time of pattern exposure, a second conductive layer 48 is formed along the resist depth direction. Therefore, the conductive layer 45 on the resist surface is electrically connected to the conductive film 47 under the resist through the conductive layer 48. Since the conductive film 47 is grounded, the resist surface is grounded during pattern exposure, and charge-up can be prevented.

In the above embodiment, the conductive layer 48 is formed at the same time as the pattern exposure. However, prior to the pattern exposure, a region other than the element region may be selectively irradiated with an electron beam to form the conductive layer 48. . In this case, the conductive layer 48
Since the electron beam acceleration voltage and the exposure amount can be set independently of the pattern exposure for the formation, the conduction for connection between the conductive layer 45 above the resist and the conductive film 47 below the resist is more reliably performed. be able to.

(Fourth Embodiment) This embodiment is an example in which beam irradiation for forming a conductive layer on the resist surface is performed not partially but partially. The above-mentioned charge-up poses a problem in the pattern exposure region. Therefore, the beam irradiation for forming the conductive layer may be any region that includes the pattern exposure region and can be grounded.

For example, as shown in FIG. 5, when the pattern exposure area on the wafer 51 is 52 and the wafer end 54 is grounded, the beam irradiation for forming the conductive layer includes the pattern exposure area 52, And grounded wafer end 5
Only the region 53 in the figure connected to 4 may be used.

Even in such a method, since the pattern exposure region 52 and its periphery are grounded, there is no influence of charge-up during pattern exposure. Therefore, effects similar to those of the first embodiment can be obtained.

(Fifth Embodiment) FIG. 6 shows a fifth embodiment of the present invention.
FIG. 9 is a process cross-sectional view for describing the electron beam exposure method according to the embodiment. Incidentally, 61 to 66 in FIG.
It corresponds to 21 to 26 in FIG.

This embodiment is an example in which the voltage is applied to the substrate to control the acceleration voltage of the electrons entering the resist. Here, the thickness of the resist 63 is set to 0.15.
μm. The resist composition is a chemically amplified positive resist similar to the resist used in the first embodiment. The acceleration voltage of the electron gun is 10 kV.

First, as shown in FIG. 6A, a potential of 9.5 kV is applied to a Si substrate 61 by a DC power supply 71.
Electron beam irradiation for forming the conductive layer 65 was performed. As a result, the acceleration voltage of the electron beam 64 penetrating into the resist 63 became 500 eV. When the entire surface is exposed in this state, the conductive layer 6 is formed at a depth of 10 nm from the resist surface.
5 was formed, and the surface resistance of the resist was reduced to about 10 ⁸ Ω.

Next, as shown in FIG. 6B, in the exposure for pattern formation, the conductive layer 6 on the resist surface is exposed.
A DC power supply 72 applied a bias voltage of −5 kV to the substrate 5 and the substrate 61, and pattern exposure was performed by the electron beam 66. At this time, the conditions of the exposure apparatus are the same as those in FIG. 6A, but the acceleration voltage of the electron beam 66 is as high as 5 keV because the substrate bias voltage is different.
As a result, a pattern could be formed with high accuracy.

The method of applying the substrate bias is extremely effective for preventing the blur of the electron beam. In addition to controlling the depth of penetration of electrons into the resist so that only the vicinity of the resist surface can be easily exposed, if the electron beam exposure is performed at a low acceleration voltage of 1 to 5 keV, the proximity effect which is a problem in the electron beam exposure can be obtained. And the effect of improving the resist sensitivity.

However, if a substrate bias is applied in the conventional method when, for example, a conductive base pattern is present, the potential distribution on the resist surface reflects the distribution of the base pattern, and the exposure accuracy may be degraded. is there.

On the other hand, in this embodiment, first, the conductive layer 65 is formed on the resist surface by irradiating the entire beam first. When the substrate potential is applied at the time of pattern exposure, the conductive layer 65 on the resist surface and the substrate 61 have the same potential, so that no discharge occurs between the resist surface and the substrate. Also, by applying the substrate potential,
The accelerating voltage of the electron beam incident on the resist surface can be substantially 5 keV, and high-precision patterning can be performed without being affected by the underlying pattern during exposure.

(Sixth Embodiment) This embodiment is an example in which an excimer laser beam is used instead of an electron beam as an energy beam for forming a conductive layer on a resist surface.

The composition of the resist used in this embodiment is the same as that used in the first embodiment, except that the amount of the acid generator is 2% by weight based on the base resin. As in the first embodiment, after forming a resist on the Si oxide film on the Si substrate, the entire surface of the resist was irradiated with KrF excimer laser light having a wavelength of 248 nm. At this time, the beam irradiation amount was 10 mJ. Due to the overall irradiation of the excimer laser light, the ultraviolet light is largely absorbed by the resist surface to generate an acid. In this case, acid is generated strictly not only on the resist surface but also inside the resist, but not so much as to affect patterning.

Next, with the resist surface grounded,
Exposure of a desired pattern was performed using an electron beam having an acceleration voltage of 50 keV. Also in this case, by grounding the conductive layer formed on the resist surface, charges accumulated in the resist can be released, and the same effect as in the first embodiment can be obtained.

Here, an excimer laser beam may be used together with the electron beam at the time of pattern exposure. That is, a repetitive pattern or a pattern that does not require high dimensional accuracy is exposed with an excimer laser beam, and other fine patterns are exposed with an electron beam. At this time, since the conductive layer formed on the resist surface absorbs less excimer laser light than the conductive film formed by the conventional coating film formation, the pattern can be sufficiently formed by excimer laser light even with the conductive layer. It is.

That is, if the resist surface itself is a conductive layer that has been altered by beam irradiation as in the present embodiment, the absorption of excimer laser light in this conductive layer is smaller than that of an existing conductive film. There is no pattern deterioration due to the formation on the surface.

The present invention is not limited to the above embodiments. The energy beam for forming the conductive layer on the resist surface is not limited to an electron beam or ultraviolet light, but may be an ion beam or X-ray. Further, instead of an electron beam for pattern exposure, an ion beam can be used. The resist preferably contains an onium salt as an acid generator, and is generally of the chemically amplified type, but is not necessarily limited to the chemically amplified type. An onium salt may be mixed into a normal resist to form a conductive layer by beam irradiation. In addition, various modifications can be made without departing from the scope of the present invention.

[0064]

As described above in detail, according to the present invention, a resist layer formed on a substrate is irradiated with an energy beam to form a conductive layer on the resist surface. By exposing a desired pattern by irradiating a charged beam while connected to a power supply, it is possible to prevent the resist from being charged without increasing the number of processes, thereby eliminating beam misalignment and contributing to improvement in exposure accuracy. It becomes possible.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an example of an electron beam exposure apparatus used in an embodiment of the present invention.

FIG. 2 is a process sectional view for describing the electron beam exposure method according to the first embodiment.

FIG. 3 is a process sectional view for explaining an electron beam exposure method according to a second embodiment.

FIG. 4 is a process cross-sectional view for explaining an electron beam exposure method according to a third embodiment.

FIG. 5 is a plan view for explaining an electron beam exposure method according to a fourth embodiment.

FIG. 6 is a process cross-sectional view for explaining an electron beam exposure method according to a fifth embodiment.

FIG. 7 is a characteristic diagram for explaining the principle of the present invention and showing a relationship between an exposure amount and a surface resistance.

FIG. 8 is a diagram for explaining a problem caused by charge-up of a resist.

FIG. 9 is a diagram showing an example in which a conductive film is formed to prevent charge-up.

FIG. 10 is a diagram illustrating a problem of an exposure method using a low-acceleration electron beam.

FIG. 11 is a diagram for explaining a problem when a resist pattern is formed using an excimer laser beam and an electron beam.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sample chamber 2 ... Wafer (sample) 3 ... Sample stand 10 ... Electron optical column 11 ... Electron gun 12a-12e ... Various lens systems 13-16 ... Various deflection systems 17 ... Blanking aperture mask 18, 19 ... 1st and 2nd beam forming aperture masks 21, 31, 41, 61 ... Si substrate 22, 42, 42, 62 ... Si oxide film 23,33,43,63 ... Resist 24,34,44,64 ... Conductivity Electron beam for layer formation 25, 35, 45, 65: conductive layer 26, 36, 46, 66: electron beam for pattern exposure 47: conductive film 48, 68: conductive layer 71, 72: DC power supply

Claims (7)

[Claims] 1. A step of forming a resist which is made conductive by irradiation of an energy beam on a substrate, and irradiating an energy beam on at least the entire surface of the resist to be patterned to form a conductive layer on the surface of the resist. And a step of exposing the resist to a desired pattern by irradiating a charged beam while the conductive layer on the resist surface is grounded or connected to a predetermined power supply. 2. A step of forming a resist which is made conductive by irradiation of an energy beam on a substrate having at least a conductive surface, and irradiating the entire surface of at least a region of the resist to be patterned with an energy beam. Forming a first conductive layer on the resist surface, exposing a desired pattern to the resist by irradiating a charged beam with the surface of the substrate being grounded or connected to a predetermined power source; Forming a second conductive layer that penetrates the resist, and electrically connecting the first conductive layer on the resist surface to the surface of the substrate. 3. The charged beam exposure method according to claim 1, wherein the resist contains a compound that generates an acid upon irradiation with an energy beam. 4. An ultraviolet beam, an electron beam, an ion beam or X-rays as an energy beam for forming a conductive layer on the resist surface.
Or the charged beam exposure method according to 2. 5. The charged beam exposure method according to claim 1, wherein the penetration depth of the energy beam into the resist is smaller than the resist film thickness. 6. The method according to claim 1, wherein the same electron beam exposure apparatus is used for irradiating an energy beam for forming a conductive layer on the resist surface and for irradiating a charged beam for pattern exposure. When the first bias voltage is applied to reduce the acceleration voltage of the electron beam and the pattern is exposed, the substrate side is grounded or a second bias voltage having an absolute value smaller than the first bias voltage is applied. The charged beam exposure method according to claim 1 or 2, wherein the acceleration voltage of the electron beam is increased by using the method. 7. A step of forming a resist which is made conductive by irradiation of an energy beam on a substrate having at least a conductive surface, and irradiating the entire surface of at least a region of the resist to be patterned with an energy beam. Forming a first conductive layer on the resist surface, irradiating a part of the resist with an energy beam having a penetration depth larger than the resist film thickness, and penetrating the resist to form a first conductive layer;
Forming a second conductive layer that electrically connects the conductive layer to the substrate surface, and irradiating a charged beam with a desired pattern on the resist while the substrate surface is grounded or connected to a predetermined power supply. And a step of exposing the charged beam.