JP2000173901A - Electron beam exposing device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the degree of resolution in a critical resolution region by decreasing the proximity effect caused by the forward scattering of an electron beam. SOLUTION: An electron beam exposure device is contracted the electron beam B emitted from a source of electron beams by a first aperture 3a and radiates it into the pattern of a second aperture 3 and the radiated pattern is exposed and transferred to a resist R of a wafer W by the projection optical system 5 in an electron beam path A. In this case, a first incident angle changing deflector 6a and a second incident angle changing deflector 6b, with which an electron beam B can be made incident with a prescribed tilt angle θi on the surface of the resist R, are provided in the electron beam path A in this electron beam exposing device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an electron beam exposure apparatus and method suitable for use in manufacturing, for example, a ULSI semiconductor device.

[0002]

2. Description of the Related Art In recent years, as semiconductor devices such as ICs have become highly integrated, fine processing techniques for semiconductor wafers have been developed. In a manufacturing process of a semiconductor device using such a fine processing technology, an electron beam exposure apparatus that projects and exposes a pattern image by an electron beam onto a photosensitive substrate is used.

Conventionally, this type of electron beam exposure apparatus includes an electron beam source for emitting an electron beam, a first aperture for making the electron beam emitted from the electron beam source a rectangular cross section, and a first aperture. A shaping deflector for changing the diameter of the transmitted electron beam, and a second aperture for shaping the electron beam shaped by the shaping deflector into a shape corresponding to a predetermined pattern,
A projection optical system for exposing and transferring a pattern formed by the second aperture onto a photosensitive substrate is employed.

In the electron beam exposure apparatus configured as described above, the projection of the electron beam on the photosensitive substrate is performed by narrowing the electron beam from the electron beam source with the first aperture, and then reducing the electron beam transmitted through the first aperture. The shaping is performed by shaping with a shaping deflector and a second aperture, and exposing and transferring the light onto a photosensitive substrate by a projection optical system.

In this type of electron beam exposure apparatus, when exposing and transferring an electron beam from an electron beam source onto a photosensitive substrate, the electron beam is incident on the photosensitive substrate by a positioning deflector. In this case, when the electron beam is incident on the photosensitive substrate, the electron beam proceeds so that the scattering diameter gradually increases in the photosensitive substrate due to forward scattering.

[0006]

However, in the conventional electron beam exposure apparatus, since the electron beam is made incident on the photosensitive substrate by a positioning deflector, the angle of incidence of the electron beam on the surface of the photosensitive substrate can be arbitrarily set. Could not be adjusted. As a result, there is a problem that the resolution in the limit resolution region is reduced due to the proximity effect caused by the forward scattering of the electron beam.

Japanese Patent Application Laid-Open No. 9-134866 discloses a prior art as "an electron beam lithography apparatus and a pattern forming method". This means that, for example, the mask thickness is set to a desired size, or a part of the mask is made of gold or the like in accordance with the size of the opening for forming the pattern of the batch transfer mask, the type of the pattern, or the density of the pattern. Of the mask to change the electron transmission inhibiting ability of the mask. Therefore, in such an electron beam lithography apparatus and pattern forming method, the manufacture of the mask is complicated and the cost is increased.

The present invention has been made in view of such circumstances, and an electron beam exposure apparatus capable of reducing a proximity effect caused by forward scattering and thereby improving resolution in a limit resolution region. The purpose is to provide a method.

[0009]

According to a first aspect of the present invention, there is provided an electron beam exposure apparatus, wherein an electron beam from an electron beam source is exposed by a projection optical system in an electron beam path. In an electron beam exposure apparatus for exposing and transferring an image thereon, a deflector for changing an incident angle capable of entering an electron beam at a predetermined inclination angle onto the surface of a photosensitive substrate is arranged in an electron beam path. Therefore, at the time of exposure, the electron beam from the electron beam source changes the inclination angle with respect to the surface of the photosensitive substrate by the deflector for changing the incident angle, and enters into one of the pattern forming region and the pattern non-forming region. .

According to a second aspect of the present invention, in the electron beam exposure apparatus of the first aspect, the tilt angle is set to an angle corresponding to a scattering angle due to forward scattering of the electron beam in the photosensitive substrate. Therefore, the electron beam changes the inclination angle corresponding to the scattering angle due to forward scattering by the deflector for changing the incident angle, and enters the photosensitive substrate in one of the pattern forming region and the pattern non-forming region.

According to a third aspect of the present invention, in the electron beam exposure apparatus according to the second aspect, the inclination angle θi is determined from an arithmetic expression θi = tan−1 (1 / θs), where the scattering angle is θs. There is a configuration. Accordingly, the electron beam changes the tilt angle θi determined from the arithmetic expression θi = tan−1 (1 / θs), where the scattering angle is θs, and one of the pattern forming region and the pattern non-forming region of the photosensitive substrate is changed. Light enters the region.

According to a fourth aspect of the present invention, in the electron beam exposure apparatus of the first, second or third aspect, the deflector comprises two deflectors arranged in parallel in a direction perpendicular to the surface of the photosensitive substrate. . Therefore, the incident position of the electron beam on the photosensitive substrate is positioned directly below the electron beam source.

According to a fifth aspect of the present invention, in the electron beam exposure apparatus according to any one of the first to fourth aspects, the deflector is arranged in the projection optical system. Therefore, at the time of exposure, the electron beam from the electron beam source changes the inclination angle with respect to the surface of the photosensitive substrate by the deflector for changing the incident angle in the projection optical system, and any one of the pattern formation region and the pattern non-formation region is used. Light enters the region.

The invention according to claim 6 (electron beam exposure method)
Discloses an electron beam exposure method for exposing and transferring an electron beam from an electron beam source onto a photosensitive substrate by a projection optical system in an electron beam path, and exposing a boundary portion between a pattern forming region and a pattern non-forming region on the photosensitive substrate. At this time, the electron beam is incident on the surface of the photosensitive substrate at a predetermined inclination angle. Therefore, at the time of exposure, the electron beam from the electron beam source changes the inclination angle with respect to the surface of the photosensitive substrate, and enters one of the pattern formation region and the pattern non-formation region.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 is an optical path diagram schematically showing an electron beam exposure apparatus according to the first embodiment of the present invention. In the figure, an electron beam exposure apparatus indicated by reference numeral 1 is an electron beam source 2
, An aperture 3, a shaping deflector 4, a projection optical system 5 and an incident angle changing deflector 6. Electron beam source 2
Consists of an electron gun that emits an electron beam B to a resist R on a wafer W, and is arranged in an electron beam path A.

The upper and lower apertures 3a and 3b (the upper aperture 3a are firstly arranged in parallel with each other in a direction perpendicular to the resist surface of the wafer W on a wafer stage (not shown) at a predetermined interval). And the lower aperture 3b is referred to as a second aperture 3b), and is disposed below the electron beam source 2.

The first aperture 3a has a flat rectangular opening 3a1. Thus, when the electron beam B from the electron beam source 2 passes through the opening 3a1 of the first aperture 3a, the cross section of the electron beam B becomes rectangular. The second aperture 3b has an opening pattern 3b corresponding to the formation pattern.
One. Thus, when the electron beam B passes through the opening pattern 3b1 of the second aperture 3b, the planar shape of the electron beam B becomes a shape corresponding to the formation pattern.

The shaping deflector 4 comprises a single shaping deflector for changing the diameter of the electron beam B transmitted through the first aperture 3a, and is arranged between the first aperture 3a and the second aperture 3b. . The projection optical system 5 has a reduction lens 5a and an objective lens 5b, and is arranged below the second aperture 3b.

The incident angle changing deflector 6 includes upper and lower two incident angle changing deflectors 6a and 6b (the first incident angle changing deflector 6a is parallel to each other at predetermined intervals in the vertical direction). And a lower incident angle changing deflector 6b is referred to as a second incident angle changing deflector.), And is disposed in the projection optical system 5.

Thus, for example, if the resist R on the wafer W is a negative resist, the electron beam B is incident on the pattern formation region of the resist R. In this case, the incident position of the electron beam B on the resist R on the wafer W is positioned directly below the electron beam source 2. That is, the emission position of the electron beam B from the electron beam source 2 matches the incident position of the electron beam B on the surface of the resist R.

The first incident angle changing deflector 6a is located near the reduction lens 5a and has a predetermined inclination with respect to the surface of the resist R on the wafer W at the time of exposure to the boundary between the pattern forming area and the pattern non-forming area. Angle (180 °-
The electron beam B is deflected by θi). The second incident angle changing deflector 6b is located in the vicinity of the objective lens 5b and has a predetermined inclination angle θi with respect to the surface of the resist R on the wafer W at the time of exposure to the boundary between the pattern forming area and the pattern non-forming area. An electron beam B is incident.

The inclination angle θi of the first incident angle changing deflector 6a and the second incident angle changing deflector 6b is determined by the scattering angle θs due to forward scattering of the electron beam B in the resist R on the wafer W (see FIG. 2). (Shown). The tilt angle θi of the electron beam B is controlled by changing the output of each of the incident angle changing deflectors 6a and 6b. Thus, the electron beam B is exposed when the resist R is exposed to the boundary between the pattern forming region and the pattern non-forming region.
When the electron beam B is deflected at an inclination angle θi corresponding to the scattering angle θs due to the forward scattering of the electron beam B, the electron beam B enters the pattern formation region of the resist (negative resist) R.

In this case, the inclination angle θi is determined by θs = 90 ° −θi, where θs is the scattering angle. here,
The scattering angle θs can be expressed as θs = βf / t, where t and βf are the resist thickness and the forward scattering diameter, respectively.

The irradiation position of the electron beam B with respect to the resist R, the exposure dose and the inclination angle are given according to the pattern data.

An electron beam exposure method using the electron beam exposure apparatus configured as described above will be described with reference to FIGS.
This will be described with reference to FIG. First, the electron beam B from the electron beam source 2 is narrowed down by the opening 3a1 of the first aperture 3a and emitted to the opening pattern 3b1 of the second aperture 3b.

Next, the opening pattern 3b1 is transferred to the resist R on the wafer W by the projection optical system 5 in the electron beam path A.
Exposure transfer. In this case, the pattern formation region R1 and the non-pattern formation region R2 of the resist R on the wafer W
When exposing the boundary part of the first incident angle, the first incident angle changing deflector 6
a and the output of the second incident angle changing deflector 6b are controlled (ON control), and the electron beams B3 and B4 are incident on the surface of the resist R at a predetermined inclination angle θi as shown in FIG.

The resist R has a pattern forming region R1.
When the exposure is performed, the outputs of the first incident angle changing deflector 6a and the second incident angle changing deflector 6b are controlled (OF).
F control), the electron beams B1, B2, B perpendicular to the surface of the resist R (with an inclination angle of 90 °) as shown in FIG.
5, B6 is incident. In this manner, the resist R on the wafer W can be exposed by the electron beam B. Thereafter, as shown in FIG.
Is removed.

Therefore, in the present embodiment, at the time of exposure, the electron beam B from the electron beam source 2 is inclined by the first incident angle changing deflector 6a and the second incident angle changing deflector 6b with respect to the surface of the resist R. Change θi and change resist R
, The proximity effect due to forward scattering by the electron beam B can be reduced.

Further, in this embodiment, since the electron transmission inhibiting ability of the mask is not changed unlike the related art (Japanese Patent Laid-Open No. Hei 9-134866), the mask (aperture) is not used.
Etc. can be easily manufactured, and the cost can be reduced.

In the present embodiment, the case where both the upper and lower deflectors are incident angle changing deflectors has been described, but the present invention is not limited to this, and one of the deflectors is used for positioning. In addition to the deflector, the other deflector may be a deflector for changing the incident angle.

In this embodiment, the case where the two incident angle changing deflectors 6a and 6b are arranged above the objective lens 5b has been described. However, the present invention is not limited to this, and the second embodiment is not limited to this. As shown in FIG. 3A, it may be arranged in the objective lens 5b as shown in FIG. 3A, and as in the third embodiment, it may be arranged below the objective lens 5b as shown in FIG. Has the effect of

In addition, in the present embodiment, an example in which the resist on the wafer is a negative resist has been described. However, the present invention is not limited to this, and the present invention is also applicable to the case where the resist is a positive resist. The same can be applied. In this case, the electron beam B is made to enter the non-pattern forming region in the resist R by the incident angle changing deflector.

[0033]

As described above, according to the present invention, since the deflector for changing the incident angle capable of making the electron beam incident on the surface of the photosensitive substrate at a predetermined inclination angle is disposed in the electron beam path, At the time of exposure, the electron beam from the electron beam source changes the inclination angle with respect to the surface of the photosensitive substrate by a deflector for changing the incident angle,
The light enters one of the pattern forming region and the non-pattern forming region.

Therefore, the proximity effect caused by forward scattering by the electron beam can be reduced, so that the electron beam is not radiated to a portion other than the desired radiated portion unlike the related art, and the critical resolution region is not changed. Resolution can be increased.

[Brief description of the drawings]

FIG. 1 is an optical path diagram schematically showing an electron beam exposure apparatus according to a first embodiment of the present invention.

FIGS. 2A and 2B are cross-sectional views illustrating an electron beam exposure method according to the first embodiment of the present invention.

FIGS. 3A and 3B are optical path diagrams showing a part of an electron beam exposure apparatus according to a second embodiment and a third embodiment of the present invention, respectively.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electron beam exposure apparatus 2 Electron beam source 3 Aperture 3a First aperture 3b Second aperture 4 Shaping deflector 5 Projection optical system 5a Reduction lens 5b Objective lens 6 Incident angle changing deflector 6a First incident angle changing deflector 6b Second incident angle changing deflector A Electron beam path B Electron beam R Resist R1 Pattern forming area R2 Pattern non-forming area W Wafer θi Tilt angle

Claims (6)

[Claims] An electron beam exposure apparatus for exposing and transferring an electron beam from an electron beam source onto a photosensitive substrate by a projection optical system in an electron beam path, wherein the electron beam is incident on the surface of the photosensitive substrate at a predetermined inclination angle. An electron beam exposure apparatus, wherein a deflector for changing a possible incident angle is arranged in the electron beam path. 2. The electron beam exposure apparatus according to claim 1, wherein the inclination angle is set to an angle corresponding to a scattering angle due to forward scattering of the electron beam in the photosensitive substrate. 3. The electron beam exposure apparatus according to claim 2, wherein the inclination angle θi is determined from an arithmetic expression θi = tan−1 (1 / θs), where the scattering angle is θs. 4. The electron beam exposure apparatus according to claim 1, wherein said deflector comprises two deflectors parallel to each other in a direction perpendicular to the surface of said photosensitive substrate. 5. The electron beam exposure apparatus according to claim 1, wherein the deflector is arranged in the projection optical system. 6. An electron beam exposure method for exposing and transferring an electron beam from an electron beam source onto a photosensitive substrate by a projection optical system in an electron beam path, wherein a boundary between a pattern forming region and a pattern non-forming region on the photosensitive substrate. An electron beam exposure method, wherein an electron beam is incident on the surface of the photosensitive substrate at a predetermined inclination angle when exposing the portion.