JPH1140477A - Electron beam projection exposure apparatus and inspection / treatment method for exposure mask - Google Patents

Abstract

[PROBLEMS] To provide an electron beam projection exposure apparatus capable of easily and accurately detecting fine dust or a defect of a mask or the like adhered to an exposure mask or the like and quickly treating the defect. ,
An inspection / treatment method for an exposure mask or the like performed by using the apparatus. An electron beam projection exposure apparatus that performs pattern exposure by irradiating a mask or a reticle 200 with an electron beam and projecting it by a projection electron optical system 212 includes:
A visible light image forming section 220 for receiving and visualizing an enlarged image of the mask or reticle 200 by the projection electron optical system 212.
An electron beam projection exposure apparatus, comprising: a defect treating unit 242 for removing foreign substances adhering to the mask or the reticle 200 and for repairing defects of the mask or the reticle 200.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam projection exposure apparatus and a method for inspecting and treating an exposure mask or reticle (hereinafter, may be abbreviated as a mask or the like) using the apparatus. is there.

[0002]

2. Description of the Related Art In a current semiconductor manufacturing process, when a fine circuit is formed on a silicon wafer, a method in which a pattern formed on a mask or the like is reduced and projected on a resist-coated wafer is exposed. Is common. Since a pattern formed in this process is very fine, if dust (foreign matter) such as fine particles adheres to a mask or the like or a wafer and is contaminated, it is fatally affected.

[0003] In particular, when a mask or the like is contaminated, the cleanliness of the mask or the like is very important because all the patterns projected and transferred from the mask and the like are affected.
At present, the exposure light used for this reduction projection is mainly ultraviolet light, and therefore, a thin film called a pellicle transparent to the exposure light is arranged at a certain distance from both surfaces of the mask, etc. This prevents dust from adhering to the equipment.

[0004] This is because even if dust adheres to the surface of the pellicle, the image is blurred on the image forming surface, so that it does not affect the pattern formation.

[0005]

The size of the processing required in the semiconductor manufacturing process has been miniaturized year by year with the increase in the degree of integration. It is thought that the minimum size that can be processed with the exposure light used for the current projection is limited by the diffraction limit, and the use of X-rays and electron beams for pattern processing of smaller sizes is considered. Have been.

When performing projection exposure using an electron beam,
Since electron beams are strongly scattered and absorbed by all substances, a pellicle cannot be used to protect the surface of a mask or the like from dust. Therefore, when projection exposure is performed using an electron beam, dust may always adhere to the surface of a mask or the like. If dust actually adheres, it is necessary to remove it immediately.

Therefore, it is very important to detect the adhesion of dust to a mask or the like. However, since dust having a diameter of 100 nm or less is targeted, it is not easy to actually detect such fine dust. There was a problem. In addition, even when there is a defect such as distortion or breakage in a mask or the like, it is important to detect the defect because it has a large effect on a pattern to be projected and transferred, but it is important to detect such a defect. There was a problem that it was not easy.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is intended to easily and accurately detect fine dust or a defect of a mask or the like adhering to an exposure mask and quickly and accurately detect the defect. Electron beam projection exposure apparatus that can perform treatment on the surface, and inspection and inspection of exposure masks and the like performed using the apparatus.
It is intended to provide a method of treatment.

[0009]

Therefore, the present invention firstly provides an electron beam projection exposure apparatus for performing pattern exposure by irradiating an electron beam on a mask or a reticle and projecting it by a projection electron optical system. A visible light image forming unit that receives and visualizes an enlarged image of the mask or reticle by the projection electron optical system, and removes foreign substances attached to the mask or reticle, and repairs a defect of the mask or reticle. An electron beam projection exposure apparatus (Claim 1) is provided.

The present invention also provides, in a second aspect, an electron beam projection exposure apparatus that performs pattern exposure by irradiating a mask or a reticle with an electron beam and projecting the pattern with a projection electron optical system. A visible light image forming unit for receiving and visualizing an enlarged image of the mask or reticle, an imaging unit for capturing the visible light image, removing foreign substances attached to the mask or reticle, and repairing defects of the mask or reticle And an electron beam projection exposure apparatus (claim 2), comprising:

The present invention also relates to a third inspection / treatment method which is performed when the pattern exposure is not performed by using the apparatus according to the first aspect of the present invention, wherein the projection electron optical system is used to inspect the mask or reticle. By forming an enlarged image on the visible light image forming unit and forming an enlarged visible light image, by observing or evaluating the enlarged visible light image,
A process for inspecting the mask or reticle, such as distortion or damage, adhesion of foreign matter, or non-uniformity of electron beam scattering, and the defect treatment unit, for removing foreign matter attached to the mask or reticle, A method of inspecting and treating a mask or reticle for electron beam projection exposure, the method comprising: repairing a defect in the mask or reticle.

Also, the present invention is a fourth inspection / treatment method using the apparatus according to claim 2 when the pattern exposure is not performed, wherein the projection electron optical system is used to inspect the mask or reticle. Forming a magnified image on the visible light image forming unit to form an enlarged visible light image; capturing the visible light image by the imaging unit; and displaying the visible light image captured by the imaging unit. By observing or evaluating an image, a process of inspecting the mask or reticle for distortion or breakage, adhesion of a foreign substance, or non-uniformity of electron beam scattering, and the mask or reticle by the defect treatment unit A method of inspecting and treating a mask or reticle for electron beam projection exposure, the method including a step of removing foreign matter adhering to a mask and a step of repairing a defect of the mask or reticle (Claim 4) " To provide.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An electron beam projection exposure apparatus according to the present invention (claims 1 and 2) has a visible light image forming section for receiving an enlarged image of a mask or the like by a projection electron optical system and visualizing the same, and a mask or reticle. Whether there is a defect handling unit that removes foreign matter adhering to the mask or repairs defects on the mask or reticle,
Alternatively, it is provided with the visible light image forming unit, an imaging unit that captures a visible light image, and the defect processing unit.

Therefore, according to the electron beam projection exposure apparatus of the present invention (claims 1 and 2), fine dust adhering to an exposure mask or the like or a defect of the mask or the like can be detected easily and accurately. , It can be treated promptly and accurately. Further, an inspection / treatment method for a mask or reticle for electron beam projection exposure according to the present invention (claims 3 and 4) is performed when pattern exposure is not performed using the apparatus according to claim 1 or 2. This is an inspection and treatment method that can easily and accurately detect fine dust adhering to an exposure mask or the like or a defect of the mask or the like, and can quickly and accurately treat the defect.

According to the method of inspecting a mask or reticle for electron beam projection exposure according to the present invention, a mask or the like is irradiated with an electron beam and an enlarged image is projected by an electron optical system to detect fine dust and defects. Is to make it easier. Here, an example of the inspection method according to the present invention will be described with reference to FIG. A reticle 100 for electron beam projection exposure is arranged on a stage 101, and electrons generated from an electron source 110 are irradiated on the reticle 100 via an illumination optical system 111.

The image of the reticle is projected onto the projection electron optical system 11.
2, the image is enlarged and projected at the image forming position. A fluorescent plate (one example of a visible light image forming unit) 120 is disposed at the image forming position, and an image of the reticle converted into a visible light image by the fluorescent plate 120 is captured by a CCD camera (one example of an image pickup unit) 121. I have. The magnification is about 5 times, for example,
Particles (foreign matter) of about 50 nm are also enlarged to about 250 nm in diameter, so that foreign matter (dust) can be observed or evaluated with visible light.

In addition to the case where foreign matter (dust) adheres to the reticle, the electron scattering becomes uneven due to the adhesion of carbon or the like, and the pattern is distorted due to the generation of heat.
The distortion can be easily detected. After the inspection of a certain portion on the reticle is completed, the reticle is scanned by the stage 101, and the other portions on the reticle are sequentially inspected to inspect the entire reticle.

According to such a reticle inspection method,
Adhesion of fine particles to the reticle surface, destruction / distortion of the pattern, and non-uniformity of electron beam scattering can be detected easily and accurately, and treatment for the defect can be performed quickly and accurately. Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[0019]

Embodiment 1 FIG. 2 shows a schematic configuration of an electron beam projection exposure apparatus according to the present embodiment. The inside of the vacuum vessel 240 is evacuated to a pressure of 10 ⁻⁴ Pa or less by an exhaust device (not shown) so that electrons are not scattered. In the vacuum container 240,
Electron source 210, illumination electron optical system 211, reticle stage 201, projection electron optical system 212, wafer stage 23
The pattern on the reticle 200 is projected and transferred onto the wafer 230 by the electron beam.

When the inspection of the reticle 200 is performed, the wafer 230 is moved out of the projection area of the reticle image by the wafer stage 231, and at the same time, the current of the projection electron optical system 212 is adjusted and the wafer stage 23 is adjusted.
A fluorescent plate (an example of a visible light image forming unit) arranged below 1
At 20, a reticle image enlarged about 4 times is projected and visualized. The wafer stage 231 has a shape that does not block the reticle image.

The magnified image of the reticle visualized by the fluorescent screen 220 is converted into a CCD camera system (an example of an imaging unit) 2
The image data is captured by the camera 21 and becomes image data, which is sent to an evaluation device (not shown). In the evaluation device, the image data of the reticle when no dust is attached is compared with the image data captured by the CCD camera system 221.
The presence / absence of fine particles and the presence / absence of pattern destruction / distortion are evaluated.

The reticle 200 is a reticle stage 20
1 and finally the entire pattern is evaluated. If the reticle 200 is determined to be abnormal by this evaluation, the reticle 200 is transported to the reticle treatment room (an example of a failure treatment section) 242 to remove attached fine particles, remove attached carbon, and repair a broken pattern. Is performed. If it is determined that the reticle cannot be repaired, the reticle is replaced.

As described above, according to the present embodiment, the reticle image is enlarged and projected by the electron beam and further visualized, so that observation or evaluation of fine particles adhering to the reticle and defects of the reticle can be easily and accurately performed. It can be carried out. Further, according to the present embodiment, it is possible to quickly and accurately take a measure for the attached fine particles and defects by easily and accurately observing or evaluating the attached fine particles and defects, thereby improving the yield and throughput in electron beam projection exposure. Can be achieved.

In this embodiment, the fluorescent plate and the imaging unit for the reticle magnified image are arranged below the wafer stage. However, the arrangement of the fluorescent plate and the imaging unit is not limited to this position. It may be arranged upstream of the shaft.
However, in that case, a mechanism for moving the fluorescent plate and the imaging unit out of the optical axis of the electron beam when performing exposure is required.

In this embodiment, observation or evaluation is performed by imaging a visualized enlarged electron beam image with a CCD camera. However, the technique for observing or evaluating an electron beam image is not limited to this. Alternatively, it may be performed using a photosensitive film or a resist. And an imaging unit, a film,
The means for observing or evaluating an electron beam image such as a resist is preferably provided with an openable / closable cover, shutter, lid or the like so that dust or the like does not adhere to the surface when not in use.

In this embodiment, the reticle image is magnified four times by the projection electron optical system. However, the present invention is not limited to this magnification. The magnification may be set so that observation or evaluation can be performed. That is, when observation or evaluation with higher resolution can be performed using an imaging unit, a film, a resist, or the like, a lower magnification may be used. If the resolution cannot be increased, the magnification needs to be increased.

[0027]

Embodiment 2 FIG. 3 shows a schematic configuration of an electron beam projection exposure apparatus according to this embodiment. The apparatus configuration is the same as that of the first embodiment shown in FIG. 2 except that a fluorescent screen 320 and an imaging unit 321 that captures an enlarged electron beam image are incorporated in a wafer stage.
Is the same as By incorporating the fluorescent plate 320 and the imaging unit 321 in the wafer stage, there is no need to have a structure in which an electron beam passes to the back side of the stage, and it is not necessary to move the fluorescent plate or the imaging unit out of the electron beam optical axis during exposure. .

Also in this embodiment, the reticle image is enlarged and projected by an electron beam and further visualized, so that observation or evaluation of fine particles adhering to the reticle and defects of the reticle can be easily and accurately performed. Also in the present embodiment, it is possible to take corrective and prompt measures for the attached fine particles and defects by easily and accurately observing or evaluating the attached fine particles and defects, thereby improving the yield and throughput in electron beam projection exposure. Can be achieved.

[0029]

As described above, according to the present invention,
It is possible to easily and accurately detect fine dust attached to an exposure mask or the like or a defect of the mask or the like, and to take quick and accurate measures. That is, according to the present invention, an image of a mask or the like for electron beam projection exposure is enlarged and projected by an electron beam, and further visualized, thereby observing a fine dust attached to the mask or the like or a defect of the mask or the like. Evaluation can be performed easily and accurately.

According to the present invention, it is possible to quickly and accurately take measures against fine dust and defects by easily and accurately observing or evaluating fine dust and defects, and to improve the yield in electron beam projection exposure. Thus, an improvement in throughput can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic device configuration diagram for explaining an example of an inspection method according to the present invention.

FIG. 2 is a schematic configuration diagram of an electron beam projection exposure apparatus according to the first embodiment.

FIG. 3 is a schematic configuration diagram of an electron beam projection exposure apparatus according to a second embodiment.

[Explanation of symbols]

100, 200, 300 Reticle 101, 201, 301 Reticle stage 110, 210, 310 Electron source 111, 211, 311 Illumination electron optical system 112, 212, 312 Projection electron optical system 120, 220, 320 Fluorescent plate (visible light image forming unit) 121, 221 CCD camera (example of imaging unit) 321 Electron beam image imaging unit 230 wafer 231, 331 wafer stage 240, 340 vacuum container 241, 341 gate valve 242, 342 reticle treatment room (example of defect treatment unit) 243,343 Reticle transfer device

Claims (4)

[Claims] An electron beam projection exposure apparatus for performing pattern exposure by irradiating a mask or a reticle with an electron beam and projecting the pattern by a projection electron optical system, wherein an enlarged image of the mask or reticle by the projection electron optical system is An electron beam projection exposure apparatus, comprising: a visible light image forming unit that receives and visualizes the image; and a failure treatment unit that removes foreign matter attached to the mask or the reticle and repairs a defect of the mask or the reticle. . 2. An electron beam projection exposure apparatus for performing pattern exposure by irradiating an electron beam on a mask or a reticle and projecting the pattern by a projection electron optical system, wherein an enlarged image of the mask or reticle by the projection electron optical system is provided. A visible light image forming unit that receives and visualizes the image, an imaging unit that captures the visible light image, and a failure treatment unit that removes foreign matter attached to the mask or reticle and repairs a defect of the mask or reticle. Electron beam projection exposure apparatus. 3. An inspection / treatment method using the apparatus according to claim 1, wherein the pattern exposure is not performed, and an enlarged image of the mask or reticle is converted into a visible light image by the projection electron optical system. Forming an image on the forming portion, and forming an enlarged visible light image, By observing or evaluating the enlarged visible light image, the mask or reticle, distortion or damage, adhesion of foreign matter, Or a step of inspecting for non-uniformity of electron beam scattering, and a step of removing foreign substances adhering to the mask or the reticle and repairing a defect of the mask or the reticle by the defect treatment unit. Inspection and treatment methods for projection exposure masks or reticles. 4. An inspection / treatment method which is performed when the pattern exposure is not performed using the apparatus according to claim 2, wherein an enlarged image of the mask or the reticle is converted into a visible light image by the projection electron optical system. Forming an enlarged visible light image by forming an image on the forming unit; capturing the visible light image by the imaging unit; and observing or evaluating the visible light image captured by the imaging unit. By the mask or reticle,
Inspection of distortion or breakage, adhesion of foreign matter, or non-uniformity of electron beam scattering, etc., and removal of foreign matter adhering to the mask or reticle, and repair of defects of the mask or reticle by the defect handling unit And a method for inspecting and treating a mask or reticle for electron beam projection exposure, comprising: