JPH0442916A - Electron beam aligner - Google Patents

Abstract

PURPOSE:To remarkably shorten a time required for regulating the angles of shaping apertures and improve an operation rate by automatically pivoting the shaping apertures so that the current density distribution of an electron beam may be uniform. CONSTITUTION:An electron gun 1, an irradiation lens 2, a first shaping aperture 3, a shaping deflector 4, a shaping lens 5, a second shaping aperture 6, a reduction lens 7, a projection lens 8, and a positioning deflector 9 are arranged in that order from the incidence side and a beam shape inspector 10 and a mask dry plate 11 are arranged thereunder. An electron beam 12 passed through the optical system forms an image on the mask dry plate 11. The shaping aperture 3 and motors 13 are used for pivoting with a neutral value, which is determined when designed, used as a central value. A motor controlling circuit 14 compares current densities 16 and 17 at 0.1 mum inner from the outer beam diameter 15 with each other and pivots the motors 13 so as to minimize the difference. The angles of the shaping apertures are thus regulated and mask pattern is drawn on the mask dry plate and observed for final regulation of the angles.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a variable shaped beam electron beam exposure apparatus used for manufacturing photomasks for semiconductor integrated circuits.

BACKGROUND OF THE INVENTION In recent years, electron beam enrichment devices have come to be widely used in the production of photomasks.

Electron beam exposure equipment has a spot beam type in which the electron beam emitted from an electron gun is focused by a lens and irradiated onto a mask dry plate, and a type in which the electron beam is focused by a lens and passed through a slit called a shaping aperture. There is a variable shaping beam shape that can shape an electron beam into a rectangular shape of a desired size. As mask patterns become finer, it is expected that a variable shaped beam type electron beam exposure apparatus that can be easily adjusted will become advantageous.

FIG. 4 shows the configuration of the electron optical system of this variable shaping type electron beam exposure apparatus. As shown in FIG. 4, the electron gun 1. Irradiation lens 2. First shaping aperture 3. Shaping deflector 4. Orthopedic lenses5. A second shaping aperture 6, a reduction lens 7, a projection lens 8, and a positioning deflector 9 are arranged in this order, and a beam shape measuring device 10. Mask dry plate] 1
or placed. The electron beam 12 passes through the optical system and forms an image on the mask dry plate 1. An electron beam emitted from an electron gun is focused by an irradiation lens 2 and irradiated onto a first shaping aperture 3. Here, a rectangular electron beam is formed, which is transmitted to a second shaping aperture 6 by a shaping deflector 4 and a shaping lens 5.
Focus the image on any position above. By changing this imaging position, a rectangular beam of arbitrary thickness can be obtained. After that, the mask dry plate 1 is
The image is formed on 1. Further, the electron beam 12 is imaged on a beam shape measuring device by the positioning deflector 9, and the shape of the beam can be measured.

Problems to be Solved by the Invention Generally, in the case of a variable shaped beam type electron beam exposure apparatus, each side of the rectangular beam needs to be parallel to the coordinate axes set when drawing a mask pattern on a mask dry plate. Typically, the shaping aperture is rotated manually or by a motor so that each side of the rectangular electron beam is parallel to the coordinate axes.

In conventional electron beam exposure equipment, this adjustment of the shaping aperture angle involves drawing a mask pattern on a mask dry plate,
I did it after observing it.

In this method, in order to adjust the angle of the shaping aperture, it is necessary to draw a test pattern, develop it, and observe it under a microscope, which is a process that is repeated many times, which is time consuming and slows down the electron beam exposure equipment. There was a problem that the operating rate decreased.

The present invention is intended to solve these problems, and aims to provide an electron beam exposure apparatus that reduces the time required to adjust the angle of a shaping aperture and has a high operating rate.

Means for Solving the Problems In order to achieve this object, the electron beam exposure apparatus of the present invention has the following features:
The shaping aperture is automatically rotated by a motor activated by the output signal of the beam shape measuring device, and the shape of the electron beam can be adjusted in a short time, thereby increasing the operating rate of the device.

Effect: With this configuration, the angle of the shaping aperture can be automatically adjusted, the time required for the angle adjustment can be significantly shortened, and the operating rate of the electron beam exposure apparatus can be improved.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of an electron optical system of an electron beam exposure apparatus according to an embodiment of the present invention. As shown in FIG. 2, the electron gun 1. Irradiation lens 2. First shaping aperture 3. Shaping deflector 4. A shaping lens 5, a second shaping aperture 6, a reduction lens 7, a projection lens 81 and a positioning deflector 9 are arranged in this order, and a beam shape measuring device 10. A mask dry plate 11 is arranged. The electron beam 12 passes through the optical system and forms an image on the mask drying plate 11. These configurations are the same as those of the conventional electron beam exposure apparatus, but a shaping aperture rotation motor 13 and a motor control circuit section 14 are added. The operation of the electron beam exposure apparatus configured as described above will be described below.

FIG. 2 shows the current density distribution waveform of the electron beam measured by the beam shape measuring device 10. For this measurement, the Knifezi method, which is commonly used in electron beam exposure equipment, was used. FIG. 2(A) shows a case where the angle of the shaping aperture is adjusted correctly, and FIG. 2(B) shows a case where it is not adjusted correctly. If the angle of the shaping aperture is insufficiently adjusted, the current density distribution will be measured as if it were non-uniform, as shown in FIG. 2(B). By shaping aperture 3 and motor 13, the angle of 8° is centered around its designed neutral value.
It is now possible to rotate only. The motor control circuit section 14 compares the current densities 16 and 17 at a portion inside the beam by 0.1 μm from the beam diameter 15, and rotates the motor 13 so that the difference is minimized. After adjusting the angle of the shaping aperture in this way, the final adjustment of the angle is performed by drawing a mask pattern on a mask dry plate and observing it. Figure 3 is a diagram showing the time required from setting the shaping aperture in the electron beam exposure apparatus to completing the angle adjustment. In this case, FIG. 3 CB) is the case of an electron beam exposure apparatus according to an embodiment of the present invention. As is clear from FIG. 3, the electron beam exposure apparatus according to the present invention takes approximately no.
It is possible to shorten it to 2.

Effects of the Invention According to the present invention, by automatically rotating the shaping aperture so that the current density distribution of the electron beam becomes most uniform, the time required for adjusting the angle of the shaping aperture can be significantly reduced. , it is possible to realize an electron beam exposure apparatus with high availability.

[Brief explanation of the drawing]

Figure 2 is a configuration diagram of an electron optical system of an electron beam chromatography device according to an embodiment of the present invention, and Figure 2 (A) shows that the angle of the shaping aperture measured by a beam shape measuring device is adjusted correctly. Figure 2 (B) is a graph showing the current density distribution of the electron beam when the angle of the shaping aperture is not adjusted correctly. Figure 3 (A) is the graph showing the current density distribution of the electron beam when the angle of the shaping aperture is not adjusted correctly. FIG. 3(B) is a graph showing the time distribution required for adjusting the angle of the adjusting aperture according to an embodiment of the present invention, and FIG. 1 is a configuration diagram of an electron beam exposure apparatus of FIG. 3... First shaping aperture, 4... Shaping deflector, 5... Shaping 1 nons, 6...
・Second shaping aperture, JO...beam shape measuring device, ], 2...electron beam, ko3...
・Motor for rotating the shaping aperture, ]-4... Morph control circuit section, 15... Electron beam diameter, 16
．． 18...Current density 0, l 7Jm inside the electron beam diameter. Name of agent: Patent attorney Shigetaka Awano

Claims (1)

[Claims] It is equipped with a shaping aperture, a shaping deflector, a shaping lens, a shaping aperture rotation motor, and a beam shape measuring device, and the shaping aperture rotation motor is operated by the output signal of the beam shape measuring device to rotate the shaping aperture. Electron beam exposure equipment.