JP2014138163A - Electronic exposure apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic exposure apparatus which allows for drastic reduction in the time required for stage movement or stage establishment, while enhancing the throughput drastically.SOLUTION: An electronic exposure apparatus 1 includes: a surface pattern electron generation unit 2 for generating electrons in planar pattern; a surface pattern control unit 3 for controlling the pattern of electrons generated from the surface pattern electron generation unit 2; and a mapping projection unit 9 for projection mapping the electrons generated from the surface pattern electron generation unit 2 to an imaging position on the exposed surface of an exposed member S. The mapping projection unit 9 is arranged in the vicinity of the surface pattern electron generation unit 2, and includes an electromagnetic lens 14 for generating magnetic field lines penetrating the surface pattern electron generation unit 2, and a magnetic field control unit 15 for making the electrons generated from the surface pattern electron generation unit 2 form an image a plurality of times by the magnetic field of the electromagnetic lens 14 alone, by controlling the strength of a magnetic field generated from the electromagnetic lens 14.

Description

  The present invention relates to an electronic exposure apparatus that performs exposure by projecting electrons onto a surface to be exposed.

  2. Description of the Related Art Conventionally, an electronic exposure apparatus that performs exposure by projecting electrons onto an exposed member such as a semiconductor wafer has been used in a semiconductor device manufacturing process. In a conventional electronic exposure apparatus, for example, electrons are generated in a planar pattern (two-dimensional pattern) from a photocathode, and exposure is performed by projecting the electrons onto an exposed surface (for example, patents). Reference 1 and Patent Document 2).

  In general, when performing exposure using such a conventional electronic exposure apparatus, a step & repeat method has been adopted. For example, when electrons generated from a rectangular photocathode (rectangular pattern electrons) are projected onto a surface to be exposed, the exposed area becomes a rectangular area. In the step-and-repeat method, one rectangular area is first exposed, and when the exposure is completed, the stage is moved and the adjacent rectangular area is exposed. Thereafter, this process is repeated.

Japanese Patent Publication No. 7-44144 Japanese Patent No. 3340468

  In a conventional electronic exposure apparatus, exposure is performed by batch exposure (without changing imaging conditions). However, when exposure is performed with collective exposure (one imaging condition), image blur due to off-axis aberration occurs when the exposure area is increased. Therefore, there is a problem that there is a limit to the size of the exposure area that can be exposed by batch exposure.

  For example, when the focus (dz) of the electromagnetic lens used for mapping projection is 0.3 μm, the beam spread is 6 nm at the center of the optical axis (the distance from the optical axis is 0 μm), and the distance from the optical axis is At 50 μm and 100 μm, the beam spread is less than 6 nm, when the separation distance from the optical axis is 150 μm, the beam spread is 9 nm, and when the separation distance from the optical axis is 200 μm, the beam spread is 18 nm (see FIG. 6). ). Assuming that the image blur (expansion of beam) on the surface to be exposed can be tolerated up to 7.5 nm, when the focus (dz) is 0.3 μm, the distance from the optical axis is 0 μm to 100 μm. Only exposure (batch exposure) can be performed.

  The present invention has been made in view of the above problems, and it is possible to increase the exposure area as compared with the prior art. As a result, the time required for stage movement and stage establishment can be greatly reduced, and the throughput can be greatly increased. It is an object of the present invention to provide an electronic exposure apparatus that can be improved.

  The electron exposure apparatus of the present invention includes a surface pattern electron generator that generates electrons in a planar pattern, a surface pattern controller that controls the pattern of electrons generated from the surface pattern electron generator, and the surface pattern electrons. A mapping projection unit that maps and projects electrons generated from the generation unit to an imaging position on an exposed surface of a member to be exposed, and the mapping projection unit is disposed in the vicinity of the surface pattern electron generation unit, An electromagnetic lens that generates a magnetic force line penetrating the surface pattern electron generator, and a strength of a magnetic field generated by the electromagnetic lens is controlled, so that electrons generated from the surface pattern electron generator are generated by a magnetic field of the previous electromagnetic lens alone. And a magnetic field control unit that causes image formation at least twice.

  In this way, the electrons generated from the surface pattern electron generator can form an image at least twice with a single lens, thereby making it possible to perform batch exposure as compared with the conventional one-time image formation. The exposure area can be increased. Therefore, the number of stage movements and stage establishments can be reduced as compared with the case where stage movements and stage establishments are performed many times in a small exposure area as in the prior art. Therefore, the time required for stage movement and stage establishment can be greatly reduced, and the throughput can be greatly improved.

  In the electronic exposure apparatus of the present invention, the surface pattern electron generation unit includes a surface pattern light generation unit that generates light in a planar pattern, a transparent base material that transmits the light, and the transparent base material. The surface pattern control unit may control the pattern of the light generated from the surface pattern light generation unit.

  Thus, by configuring the surface pattern electron generator with the surface pattern light generator, the transparent substrate, and the photoelectric conversion member, the surface pattern electrons are controlled by controlling the pattern of light generated from the surface pattern light generator. The pattern (planar pattern) of electrons generated from the generation unit can be controlled.

  In the electron exposure apparatus of the present invention, the surface pattern electron generation unit is configured by an array of a plurality of electron sources arranged in a plane, and the surface pattern control unit is configured to transmit electrons from the plurality of electron sources. The generation may be controlled to generate electrons in a planar pattern.

  In this way, by configuring the surface pattern electron generator with an array of a plurality of electron sources, the generation of electrons from the surface pattern electron generator (by controlling the generation of electrons from the plurality of electron sources ( The planar pattern) can be controlled.

  According to the present invention, it is possible to enlarge the exposure area as compared with the prior art, and as a result, the time required for stage movement and stage establishment can be greatly reduced, and the throughput can be greatly improved.

It is explanatory drawing of the electronic exposure apparatus in the 1st Embodiment of this invention. It is a graph which shows the relationship between the focus and image blurring (beam spread) in the electronic exposure apparatus (when forming an image once with one lens) of the first embodiment of the present invention. It is a graph which shows the relationship between the focus and image blurring (beam spread) in the electronic exposure apparatus of the first embodiment of the present invention (when imaging is performed twice with one lens). It is a graph which shows the relationship between the focus and image blurring (beam spread) in the electronic exposure apparatus (when forming an image three times with one lens) of the first embodiment of the present invention. It is explanatory drawing of the electronic exposure apparatus in the 2nd Embodiment of this invention. It is a graph which shows the relationship between the focus and image blurring (beam spread) in the conventional electronic exposure apparatus.

  Hereinafter, an electronic exposure apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, an example of an electronic exposure apparatus used in a semiconductor process or the like is illustrated.

(First embodiment)
The configuration of the electronic exposure apparatus according to the first embodiment of the present invention will be described with reference to the drawings. 1 and 2 are explanatory views showing the configuration of the electronic exposure apparatus of the present embodiment. As shown in FIGS. 1 and 2, the electron exposure apparatus 1 includes a surface pattern electron generator 2 that generates electrons in a planar (two-dimensional) pattern and electrons generated from the surface pattern electron generator 2. A surface pattern control unit 3 for controlling the pattern is provided.

  In the present embodiment, the surface pattern electron generator 2 includes a surface pattern light generator 4 that generates light in a planar (two-dimensional) pattern, a transparent substrate 5 that transmits light, and a transparent substrate. And a photoelectric conversion member 6 that emits electrons upon receiving the light transmitted through 5. The surface pattern control unit 3 controls the pattern of light generated from the surface pattern light generation unit 4. The surface pattern light generating unit 4 irradiates surface pattern light having two-dimensionally selective brightness. The photoelectric conversion member 6 is, for example, a thin film (photoelectric conversion film) that receives light and emits electrons by a photoelectric effect. When the surface pattern light generator 4 and the photoelectric conversion member 6 are separated from each other, an optical system for projecting the pattern light generated from the surface pattern light generator 4 onto the photoelectric conversion member 6 is provided. In addition, when the surface pattern light generation unit 4 and the photoelectric conversion member 6 are in close contact with each other, or when light having good straightness (laser light or the like) is used, an optical system is unnecessary.

  The electronic exposure apparatus 1 also includes a stage 7 on which the exposed member S is placed, a stage movement control unit 8 that controls the movement of the stage 7, and electrons generated from the surface pattern electron generating unit 2. A mapping projection unit 9 that performs projection projection onto an imaging position on the surface to be exposed S and an imaging condition control unit 10 that controls the imaging conditions of the mapping projection unit 9 are provided. The exposed member S is a substrate to be exposed such as a semiconductor wafer. The stage 7 can also be called a substrate stage.

  The projection unit 9 is a cylindrical equipotential tube 11 to which a potential can be applied, an electromagnetic lens 12 formed coaxially with the equipotential tube 11 outside the equipotential tube 11, and an opening angle of the imaging electron optical system. An aperture stop 13 is provided. The equipotential tube 11 is arranged away from the surface pattern electron generator 2. The equipotential tube 11, the surface pattern electron generator 2 and the DC power supply are connected, and the voltage Vacc is applied so that the equipotential tube 11 has a positive potential with respect to the surface pattern electron generator 2. In addition, the equipotential tube 11 is arranged away from the substrate S to be exposed. The equipotential tube 11 and the substrate S to be exposed are connected to a DC power source, and a voltage Vrtd is applied so that the equipotential tube 11 has a positive potential with respect to the substrate S to be exposed. The electromagnetic lens 12 applies a current to the coil so that the electrons emitted from the surface pattern electron generator 2 are imaged on the exposed surface of the substrate S to be exposed. The imaging condition control unit 10 controls the current applied to the coil of the electromagnetic lens 12, thereby controlling the imaging condition (focus) of the electromagnetic lens 12. In order to change the imaging conditions more quickly, a mini lens (not shown) is provided on the inner periphery of the electromagnetic lens 12, and the imaging condition control unit 10 controls the current applied to the coil of the mini lens. Also good.

  Furthermore, the electron exposure apparatus 1 is disposed in the vicinity of the surface pattern electron generator 2, and generates an electromagnetic lens 14 that generates a magnetic force line penetrating through the surface pattern electron generator 2, and the strength of the magnetic field generated by the electromagnetic lens 14. Is provided with a magnetic field control unit 15 for controlling. Then, the magnetic field control unit 15 controls the strength of the magnetic field generated by the electromagnetic lens 14 and causes the electrons generated from the surface pattern electron generating unit 2 to form an image at least twice by the magnetic field of the electromagnetic lens 14 alone. Let The electromagnetic lens 14 may be constituted by an in-lens or a semi-in lens. The electromagnetic lens 14 may be composed of a plurality of electromagnetic lenses. For example, it may be configured by two electromagnetic lenses (two electromagnetic lenses having the same magnetic field direction) sandwiching the electron generation position of the surface pattern electron generation unit 2.

  For example, in the example of FIG. 1, the electrons generated from the surface pattern electron generator 2 are imaged three times by the magnetic field of the electromagnetic lens 14 alone. By changing the strength of the magnetic field generated by the electromagnetic lens 14, it is possible to control the number of times the electrons generated from the surface pattern electron generator 2 are imaged by the magnetic field of the electromagnetic lens 14 alone.

  FIG. 2 is a graph showing the relationship between focus and image blur (beam spread) when electrons generated from the surface pattern electron generator 2 are imaged once by the magnetic field of the electromagnetic lens 14 alone. As shown in FIG. 2, in this case, an effective illumination field of 600 μmΦ is obtained.

  FIG. 3 is a graph showing the relationship between focus and image blur (beam spread) when electrons generated from the surface pattern electron generator 2 are imaged twice by the magnetic field of the electromagnetic lens 14 alone. As shown in FIG. 3, in this case, an effective illumination field of 800 μmΦ is obtained.

  FIG. 4 is a graph showing the relationship between focus and image blur (beam spread) when electrons generated from the surface pattern electron generator 2 are imaged three times by the magnetic field of the electromagnetic lens 14 alone. As shown in FIG. 4, in this case, an effective illumination field of 1000 μmΦ is obtained.

  As seen in FIGS. 2 to 4, when the electrons generated from the surface pattern electron generator 2 are imaged a plurality of times by the magnetic field of the electromagnetic lens 14 alone, the change in the beam spread on the exposed surface due to the focus change becomes slow. In addition, it can be seen that the effective illumination field is expanded by two effects that the minimum value of the spread of the beam on the surface to be exposed at the position where the object height is large is lowered.

  As described above, according to the electronic exposure apparatus 1 of the first embodiment of the present invention, the exposure area can be increased as compared with the conventional case, and as a result, the time required for stage movement and stage establishment is greatly increased. The throughput can be greatly improved.

  That is, in the present embodiment, the electrons generated from the surface pattern electron generator 2 are imaged at least twice or more by the magnetic field of the electromagnetic lens 14 alone. Thereby, the exposure area which can be exposed collectively can be enlarged compared with the case of the conventional image formation of 1 time (refer FIGS. 2-4). Therefore, the number of stage movements and stage establishments can be reduced as compared with the case where stage movements and stage establishments are performed many times in a small exposure area as in the prior art. Therefore, the time required for stage movement and stage establishment can be greatly reduced, and the throughput can be greatly improved.

  Further, since the exposure area that can be collectively exposed increases, the maximum generated current that allows image blur (image blur due to space charge effect) also increases. That is, image blur (image blur due to space charge effect) at the same generated current can be reduced.

  Moreover, in this Embodiment, the surface pattern electron generation part 2 is comprised with the surface pattern light generation part 4, the transparent base material 5, and the photoelectric conversion member 6. FIG. Therefore, by controlling the pattern of light generated from the surface pattern light generator 4, the electron pattern (planar pattern) generated from the surface pattern electron generator 2 can be controlled.

(Second Embodiment)
Next, an electronic exposure apparatus 1 according to the second embodiment of the present invention will be described. Here, the electronic exposure apparatus 1 according to the second embodiment will be described focusing on differences from the first embodiment. Unless otherwise specified, the configuration and operation of the present embodiment are the same as those of the first embodiment.

  FIG. 5 is an explanatory diagram showing the configuration of the electronic exposure apparatus 1 of the present embodiment. As shown in FIG. 5, in the present embodiment, the surface pattern electron generator 2 is constituted by an array 20 of a plurality of electron sources arranged in a plane. Then, the surface pattern control unit 3 controls the generation of electrons from a plurality of electron sources to generate electrons in a planar pattern. That is, the surface pattern electron generator 2 is an electron source array 20 that is two-dimensionally arranged and can selectively emit / non-emit electrons individually. Then, the surface pattern control unit 3 controls the emission / non-emission of each electron source of the electron source array 20.

  Such an electronic exposure apparatus 1 according to the second embodiment of the present invention also provides the same operational effects as the first embodiment.

  In the present embodiment, the surface pattern electron generator 2 is constituted by an array 20 of a plurality of electron sources. Therefore, by controlling the generation of electrons from a plurality of electron sources, the pattern of electrons (planar pattern) generated from the surface pattern electron generator 2 can be controlled.

  The embodiments of the present invention have been described above by way of example, but the scope of the present invention is not limited to these embodiments, and can be changed or modified according to the purpose within the scope of the claims. is there.

  As described above, the electronic exposure apparatus according to the present invention has the effect that the time required for stage movement and stage establishment can be greatly reduced, and the throughput can be greatly improved. Used and useful.

DESCRIPTION OF SYMBOLS 1 Electronic exposure apparatus 2 Surface pattern electron generation part 3 Surface pattern control part 4 Surface pattern light generation part 5 Transparent base material 6 Photoelectric conversion member 7 Stage 8 Stage movement control part 9 Mapping projection part 10 Imaging condition control part 11 Equipotential tube 12 Electromagnetic lens 13 Aperture stop 14 Electromagnetic lens 15 Magnetic field control unit 20 Array S Exposed member

Claims (3)

A surface pattern electron generator that generates electrons in a planar pattern;
A surface pattern control unit that controls a pattern of the electrons generated from the surface pattern electron generation unit;
A mapping projection unit that maps and projects electrons generated from the surface pattern electron generation unit to an imaging position on an exposed surface of an exposed member;
With
The map projection unit
An electromagnetic lens that is disposed in the vicinity of the surface pattern electron generation unit and generates lines of magnetic force penetrating the surface pattern electron generation unit;
A magnetic field control unit that controls the intensity of the magnetic field generated by the electromagnetic lens, and causes the electrons generated from the surface pattern electron generation unit to form an image at least twice by the magnetic field of the previous electromagnetic lens alone;
An electronic exposure apparatus comprising: The surface pattern electron generator includes a surface pattern light generator that generates light in a planar pattern, a transparent substrate that transmits the light, and a photoelectric that emits electrons by receiving light transmitted through the transparent substrate. It consists of a conversion member,
The electronic exposure apparatus according to claim 1, wherein the surface pattern control unit controls a pattern of the light generated from the surface pattern light generation unit. The surface pattern electron generator is composed of an array of a plurality of electron sources arranged in a plane,
The electron exposure apparatus according to claim 1, wherein the surface pattern control unit controls generation of electrons from the plurality of electron sources to generate electrons in a planar pattern.

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