JP2000150336A - Charged particle beam aligner and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charged particle beam aligner and a method capable of forming a highly accurate pattern, by compensating deformation of a pattern form even when the extension of charged particle beam is caused by the amount of coulomb. SOLUTION: A charged particle beam aligner has an aperture mask with a formation opening part for forming a cross sectional form of charged particle beams and used for exposing a pattern, according to the form of formation opening, onto an exposing object. In this case, a field with given intensity and a given distribution in potential is formed in formation opening parts 6a, 10a, 10b of the aperture masks 6 and 10 to change the cross section of charged perticle beams (EB), which pass the formation opening parts 6a, 10a, and 10b, into desired form with desired dimensions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a charged particle beam exposure apparatus for forming a pattern by a charged particle beam and a method thereof.

[0002]

2. Description of the Related Art With the increase in the density of integrated circuits, an exposure technique using a charged particle beam such as an electron beam has attracted attention instead of the photolithography technique which has been the mainstream of fine pattern formation techniques. In charged particle beam exposure technology, high throughput is required to form large-scale integrated circuit patterns, so instead of the point beam method that forms patterns by one stroke of electron beam,
While changing the cross-sectional shape and area of the charged particle beam, each pattern is divided into rectangles and trapezoids with different dimensions and drawn, so-called variable shaping exposure method, or multiple repeated patterns of large-scale integrated circuits are cut out and stenciled in advance. A so-called partial batch exposure method has been proposed in which a unit cell group is formed on a mask called a mask, and a desired unit cell is selected with a charged particle beam and irradiated and exposed.

[0003]

In the above-mentioned charged particle beam exposure apparatus of the variable shaping exposure system or the partial batch exposure system,
In the peripheral region of the forming opening of the aperture mask for shaping the shape and size of the cross section of the charged particle beam, it passed through the forming opening of the aperture mask due to the superposition of Coulomb forces interacting with the charged particles passing through the peripheral region. The charged particles spread (deflect) outside the forming aperture. In addition, the superposition of Coulomb forces acting on charged particles passing through the peripheral region differs depending on the shape of the formed opening of the aperture mask. For example, when the opening is rectangular, sides and corners in the peripheral region of the opening are different. As compared with the above, the superposition of the Coulomb forces acting on the charged particles passing through the sides is larger than the superposition of the Coulomb forces acting on the charged particles passing through the corners. For this reason, the cross-sectional shape of the charged particle beam that has passed through the shaping opening of the aperture mask is deformed from the shape of the shaping opening of the aperture mask, and the finer the charged particle beam, the greater the effect of the above deformation. When the cross-sectional shape of the charged particle beam that has passed through the forming aperture of the aperture mask is deformed, it appears as, for example, a pattern shape deformation on a sample surface such as a wafer.

The present invention has been made in view of the above-described problem, and can correct a deformation of a pattern shape due to a spread of a charged particle beam caused by a Coulomb force acting between charged particles of the charged particle beam. It is an object of the present invention to provide a charged particle beam exposure apparatus capable of forming a highly accurate pattern.

[0005]

A charged particle beam exposure apparatus according to the present invention has an aperture mask formed with a forming opening for forming a cross-sectional shape of a charged particle beam. A charged particle beam exposure apparatus that exposes a pattern corresponding to the shape of an opening, forming an electric field having a strength specified by a potential distribution specified in a forming opening of the aperture mask, and forming the forming opening. An electric field forming means for deforming the cross section of the passing charged particle beam into a desired shape and size is provided.

[0006] The electric field forming means keeps the potential of the peripheral portion of the shaping opening constant and forms an electric field having a potential distribution according to the shape of the shaping opening.

[0007] The shape of the forming opening is a combination of a corner-shaped portion and a straight-shaped portion.

[0008] The aperture mask is formed of a conductive member, and the electric field forming means has voltage applying means for applying a voltage for setting the potential of the aperture mask to a designated potential.

The electric field forming means includes an electric field forming electrode formed continuously along a periphery of a forming opening of the aperture mask, and a voltage applying means for applying a specified voltage to the electric field forming electrode. Having.

The electric field forming means includes a plurality of electric field forming electrodes provided around a forming opening of the aperture mask, and a voltage applying means for independently applying a specified voltage to the plurality of electric field forming electrodes. And

The first and second aperture masks are separated from each other, and the charged particle beam is provided between the first and second aperture masks and deflects the charged particle beam passing through the shaping opening of the first aperture mask. Deflecting means for entering the shaping opening of the second aperture mask, and the electric field forming means is provided in each of the first and second aperture masks.

According to the present invention, a cross section of a charged particle beam formed by the aperture mask is formed in a desired shape and size in order to form an electric field having a specified strength in a specified potential distribution in a forming opening of the aperture mask. Can be transformed into Therefore, by forming an electric field in the forming opening in accordance with the spread of the charged particle beam due to the Coulomb force interacting between the charged particles, it is possible to correct the deformation of the pattern exposed on the object to be exposed.

Further, in the present invention, the electric field forming means forms an electric field having a potential distribution corresponding to the shape of the shaping opening, whereby the spread of the charged particle beam due to the Coulomb force according to the shape of the shaping opening is self-contained. Corrected consistently.

According to the present invention, there is provided an aperture mask having a shaping opening for shaping a cross-sectional shape of a charged particle beam, and an object to be exposed is exposed to a pattern corresponding to the shape of the shaping opening. A charged particle beam exposure method, wherein an electric field of a specified intensity is specified by a specified potential distribution in a shaping opening of the aperture mask, and a cross section of the charged particle beam passing through the shaping opening is desired. And a pattern deformed into a desired shape is exposed on an object to be exposed.

The electric field is formed by applying a charge to the aperture mask.

The charge density at the periphery of the forming opening is made constant.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of a charged particle beam exposure apparatus according to one embodiment of the present invention. In FIG. 1, a charged particle beam exposure apparatus 1 includes a charged particle beam source 2, a blanker 4, a first aperture mask 6, a shaping deflector 8, and a second aperture mask 10.
, A sub-deflector 12, a focus correction lens 14, a main deflector 16, an irradiation lens 18, a molded lens 20, a reduction lens 22, an objective lens 24, and a voltage application unit 31.

The charged particle beam source 2 has, for example, a cathode electrode, a grid electrode and an anode electrode, and emits a charged particle beam EB. The blanker 4 has a function of blocking and passing the charged particle beam EB emitted from the charged particle beam source 2 according to the input blanking signal.

The first aperture mask 6 is made of, for example, a conductive material such as a semiconductor or a metal material, has a rectangular shaped opening 6a, and has a charged particle beam EB.
Is formed by the forming opening 6a. The shaping deflector 8 deflects the charged particle beam EB shaped by the first aperture mask 6 and causes the charged particle beam EB to enter a selected position on the second aperture mask 10. The irradiation lens 18 shapes the charged particle beam EB so that the charged particle beam EB emitted from the charged particle beam source 2 is irradiated so as to cover the forming opening 6 a of the first aperture mask 6. The shaping lens 20 reduces the charged particle beam EB that has passed through the first aperture mask 6 so that the focal point of the charged particle beam EB is present in the shaping deflector 8.

The second aperture mask 10 is, for example,
It is made of a conductive material such as a semiconductor or a metal material.
The second aperture mask 10 has, for example, a rectangular variable shaping opening 10 a for shaping the charged particle beam EB having an arbitrary shape and dimension in cooperation with the shaping opening 6 a of the first aperture mask 6. Are formed.
The second aperture mask 10 receives the charged particle beam EB having passed through the first aperture mask 6 and forms a plurality of collective figure forming openings of various shapes for shaping the cross section of the charged particle beam EB into a predetermined shape. 10b are formed. The selection of the variable forming opening 10a and the collective figure forming opening 10b is performed by the forming deflector 8 described above.

The sub deflector 12 deflects the charged particle beam EB deflected by the shaping deflector 8 so as to return to the center axis direction. The reduction lens 22 reduces the shaped charged particle beam EB that has passed through the second aperture mask 10 to form a focus in the focus correction lens 14. The focus correction lens 14 is formed by the reduction lens 22 and corrects a focus position. The main deflector 16 deflects, for example, the charged particle beam EB to a position to be exposed on the wafer W on which a resist as an object to be exposed is formed. Objective lens 2
Reference numeral 4 focuses the charged particle beam EB such that a focal point is formed on the resist of the wafer W.

The voltage application unit 31 applies a voltage specified independently to the first aperture mask 6 and the second aperture mask 10. When a voltage is applied to the first aperture mask 6 and the second aperture mask 10, the first aperture mask 6
Electric charges corresponding to the magnitudes of the applied voltages are applied to the aperture mask 6 and the second aperture mask 10, respectively, and the shaping opening 6a of the first aperture mask 6, the variable shaping opening 10a of the second aperture mask 10, and An electric field is formed in the collective figure forming opening 10b.

In the charged particle beam exposure apparatus 1 having the above-described structure, the charged particle beam EB output from the charged particle beam source 2 is shaped into a circle having a predetermined cross section and covers the entire forming opening 6a. The light enters the first aperture mask 6. The charged particle beam EB shaped by the first aperture mask 6 is deflected by the shaping deflector 8 and formed in the variable aperture 10 a formed in the second aperture mask 10.
Alternatively, the charged particle beam EB which is incident on one of the collective figure forming openings 10 b and whose cross section is formed into a predetermined shape by the second aperture mask 10 passes through the sub deflector 12, the focus correction lens 14, and the main deflector 16 Exposure is performed at a specified position on W.

FIG. 2A is a view showing an example of the shape of the shaping opening 6a of the first aperture mask 6 and the shape of the variable shaping opening 10a of the second aperture mask 10. As shown in FIG.
FIG. 3B is a view showing an example of the shape of the collective figure forming opening 10 b of the second aperture mask 10. As shown in FIG. 2, the shapes of the forming opening 6a and the variable forming opening 10a are rectangular, and the shape of the collective figure forming opening 10b is L-shaped. Charged particle beam EB passing through each opening
As described above, the Coulomb force acts on the charged particles of each other, and the charged particles passing through the side (straight line portion) Rh of each opening have more openings than the charged particles passing through the corner Rc. The force spreading outward acts strongly. For this reason, as shown by the dotted line K in FIG. 2, the charged particle beam EB is unlikely to spread outward near the corner Rc, is deflected toward the side Rh and spreads outward, and the cross section of the charged particle beam EB has an opening Will be out of shape.

On the other hand, for example, the first aperture mask 6
When a positive voltage is applied to the second aperture mask 10 by the voltage application unit 31 to apply a positive charge, an electric field is formed in each opening. Since the first aperture mask 6 and the second aperture mask 10 are formed of a conductive member, the density of positive charges at the periphery of each opening becomes uniform.

FIG. 3 shows an electric field B formed at a corner Rc of each opening and an equipotential line E of the electric field B.
As shown in FIG. 3, when an electric field B is formed with a uniform charge density on the periphery of the opening, near the corner Rc,
Electric fields B orthogonal to each other are superimposed to form a corner portion R
The potential increases as approaching c, and decreases as approaching the side Rh.

Therefore, a positive charge is applied to the first aperture mask 6 and the second aperture mask 10,
In a state where the charged particles of the charged particle beam EB have a negative charge, the charged particle beam EB is deflected so that the region closer to the corner portion Rc spreads outside the opening. Therefore,
By adjusting the applied voltage of the voltage applying unit 31, the amount of deflection of the charged particle beam EB by the electric field formed in the opening is adjusted, and the amount of deflection and the opening of the charged particle beam EB itself due to the Coulomb force are adjusted. It is possible to make the total amount of the outwardly extending portion and the opening amount uniform at each position of the opening. That is, in the present embodiment, the spread of the charged particle beam EB due to the Coulomb force of the charged particle beam EB itself, and the charged particle beam EB due to the application of charges to the first aperture mask 6 and the second aperture mask 10 are described.
The deflection of the charged particle beam EB can be corrected in a self-aligned manner by adjusting the applied voltage of the voltage applying unit 31.

As described above, according to the present embodiment, the first
The aperture mask 6 and the second aperture mask 10 are formed of a conductive positive material, and the deformation of the pattern due to the spread of the charged particle beam EB due to the Coulomb force of the charged particle beam EB itself is corrected only by adjusting the voltage applied thereto. Can be.

Second Embodiment FIG. 4 is a view for explaining a configuration of a charged particle beam exposure apparatus according to a second embodiment of the present invention. In the above-described first embodiment, the second aperture mask 10 is formed of a conductive member, and a predetermined voltage is applied to the second aperture mask 10 so that the collective figure opening 10b of the second aperture mask 10 is formed.
, An electric field having a uniform charge density was formed. In the present embodiment, as shown in FIG. 4, the electric field forming electrode 32 is continuously provided around the collective figure opening 10b of the second aperture mask 10. Also, the second aperture mask 10
Is made of a non-conductive material. With the above configuration, the second
An electric field having a uniform charge density is formed around the collective figure opening 10b of the aperture mask 10, and the same effect as that of the first embodiment can be obtained.

In the present embodiment, only the collective figure opening 10b of the second aperture mask 10 has been described.
The above-mentioned electric field forming electrode 32 can be applied to the variable shaping opening 10a of the aperture mask.

Third Embodiment FIG. 5 is a view for explaining a configuration of a charged particle beam exposure apparatus according to a second embodiment of the present invention. In the first and second embodiments described above, the first and second
A configuration for forming an electric field having a uniform charge density around each opening of the aperture masks 6 and 10 has been disclosed. In the present embodiment, as shown in FIG. 5, for example, a plurality of electrodes 33 are arranged around the collective figure forming opening 10b of the second aperture mask 10. Further, a voltage of a designated potential can be independently applied to each electrode 33.

According to the above configuration, for example, each electrode 33
When a voltage equal to is applied, the deformation of the pattern due to the spread of the charged particle beam EB due to the Coulomb force of the charged particle beam EB itself can be corrected in substantially the same manner as in the first and second embodiments.

Further, by applying a voltage to some of the electrodes 33 to form an electric field in a part of the collective figure forming opening 10b of the second aperture mask 10, a charged particle beam is formed. Only a part of the EB can be deflected. Therefore, the cross-sectional shape and cross-sectional size of the charged particle beam EB can be arbitrarily controlled by independently designating the potential of each electrode 33 and forming an electric field having an arbitrary potential distribution and intensity in the collective figure forming opening 10b. And a more accurate pattern can be drawn. Also,
Since only a part of the charged particle beam EB can be deformed (deflected), the connection margin can be improved by deflecting the charged particle beam at the pattern connection portion in the direction of the pattern to be connected.

In the present embodiment, only the collective figure opening 10b of the second aperture mask 10 has been described.
The above-mentioned electric field forming electrode 32 can be applied to the variable shaping opening 10a of the aperture mask.

[0035]

According to the present invention, the deformation of the beam cross-sectional shape due to the spread of the charged particle beam can be corrected, and a highly accurate pattern can be formed. Further, an electric field of an arbitrary strength can be formed in the forming opening, and similar figure patterns having different dimensions can be formed using one forming opening. Furthermore, by deflecting a part of the charged particle beam, it is possible to improve the connection accuracy between the patterns transferred on the object to be exposed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a charged particle beam exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of a shape of an opening of a first and a second aperture mask.

FIG. 3 is a diagram showing an electric field distribution in orthogonal conductive members.

FIG. 4 is a diagram for explaining a configuration of a charged particle beam exposure apparatus according to a second embodiment of the present invention.

FIG. 5 is a diagram for explaining a configuration of a charged particle beam exposure apparatus according to a third embodiment of the present invention.

[Explanation of symbols]

1 ... charged particle beam exposure apparatus, 2 ... charged particle beam source,
4 blanker, 6 first aperture mask, 6a forming opening, 8 forming deflector, 10 second aperture mask, 10a variable forming opening, 10b collective figure forming opening, 12 sub-deflector , 14 ... Focus correction lens, 16 ...
Main deflector, 18 irradiation lens, 20 molded lens, 22
... Reduction lens, 24. Objective lens, 31. Voltage application unit.

Claims (10)

[Claims] A charged particle beam having an aperture mask formed with a shaping opening for shaping a cross-sectional shape of a charged particle beam, and exposing an object to be exposed to a pattern corresponding to the shape of the shaping opening. An exposure apparatus, wherein an electric field of a specified intensity is formed by a specified potential distribution in a shaping opening of the aperture mask, and a cross section of the charged particle beam passing through the shaping opening has a desired shape and size. A charged particle beam exposure apparatus having an electric field forming means for deforming a charged particle beam. 2. The charged particle beam exposure according to claim 1, wherein said electric field forming means keeps the potential of the peripheral portion of said shaping opening constant and forms an electric field having a potential distribution according to the shape of said shaping opening. apparatus. 3. The charged particle beam exposure apparatus according to claim 2, wherein the shape of the forming opening comprises a combination of a corner portion and a linear portion. 4. The charging device according to claim 1, wherein said aperture mask is formed of a conductive member, and said electric field forming means has a voltage applying means for applying a voltage for setting a potential of said aperture mask to a designated potential. Particle beam exposure equipment. 5. An electric field forming means, comprising: an electric field forming electrode formed continuously along a periphery of a forming opening of the aperture mask; and a voltage applying means for applying a specified voltage to the electric field forming electrode. 3. A charged particle beam exposure apparatus according to claim 2, further comprising: 6. An electric field forming means, comprising: a plurality of electric field forming electrodes provided around a forming opening of the aperture mask; and a voltage for independently applying a specified voltage to the plurality of electric field forming electrodes. The charged particle beam exposure apparatus according to claim 1, further comprising an application unit. 7. A charged particle beam provided between a first aperture mask and a second aperture mask separated from each other, and passing through a shaping opening of the first aperture mask. 2. A charging device according to claim 1, further comprising: a deflecting unit for causing the light to enter a shaping opening of the second aperture mask, wherein the electric field forming unit is provided in each of the first and second aperture masks. Particle beam exposure equipment. 8. A charged particle beam having an aperture mask formed with a shaping opening for shaping the cross-sectional shape of the charged particle beam, and exposing an object to be exposed to a pattern corresponding to the shape of the shaping opening. An exposure method, wherein an electric field of a specified strength is formed by a specified potential distribution in a shaping opening of the aperture mask, and a cross section of the charged particle beam passing through the shaping opening has a desired shape and size. A charged particle beam exposure method comprising exposing a pattern deformed to a desired shape on an object to be exposed. 9. The charged particle beam exposure method according to claim 8, wherein the electric field is formed by applying a charge to the aperture mask. 10. The charged particle beam exposure method according to claim 9, wherein a charge density at a peripheral portion of said forming opening is made constant.