JPS5922369B2 - Electron beam lithography equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electron beam lithography apparatus, and more particularly to an electron beam lithography apparatus suitable for blanking an electron beam at high speed.

Conventionally, in order to blank the electron beam on the sample surface in accordance with the drawing signal of the electron beam drawing device, a constant voltage is applied to a pair of electrostatic electrodes provided in the electron beam path. The electron beam being irradiated and drawn was deflected out of the aperture hole placed in the electron beam path.

In such cases, the area of the blanking plates and the spacing between them cannot be reduced below a certain limit due to physical configuration constraints of the device, and therefore, in order to obtain complete blanking on the sample surface, It was necessary to apply a large deflection voltage to the blanking plate.

As a result, time was wasted in switching the electron beam on and off and replanking, which resulted in the drawback that the writing speed could not be increased. In addition, in order to shorten the on/off switching time of the electron beam, if the blanking deflection voltage is reduced, the scattered electrons from the electron beam that is deflected outside the aperture hole and irradiated onto the aperture during blanking will be reflected onto the aperture hole. Since the amount of deflection was small, the irradiation leaked through the aperture hole onto the sample, making it impossible to blank for a long time.

An object of the present invention is to provide an electron beam lithography apparatus that can perform high-speed blanking by applying a relatively large voltage and a relatively small voltage to the blanking deflection voltage and selecting the voltage appropriately. It's about doing.

The present invention allows different voltages to be applied to the blanking deflection means, and when high-speed blanking during writing is required, a low voltage is applied as the blanking deflection voltage, thereby deflecting the electron beam at a relatively small angle. On the other hand, when complete blanking for a long period of time is required, a high voltage is applied as the blanking deflection voltage to deflect the electron beam by a relatively large angle.

FIG. 1 is an optical diagram of an electron beam lithography system showing an embodiment of the present invention.
The electron beam 2 emitted from the electron beam 2 is narrowly converged by a converging lens 3, and the spot is focused on the sample 8 by a projection lens 4.
This is scanned and blanked by the deflection means 5, the blanking plate 6, and the blanking aperture T, and a desired figure is drawn on the sample 8.

FIG. 2 shows a block diagram of one embodiment of the blanking deflection means of the present invention.

An on/off signal for the electron beam 2 during drawing, that is, a blanking signal, is supplied to inverters 9 and 11. As shown in Table 1, during the short-time blanking state, the output of the inverter 9 becomes high level, and the switching element 10
becomes non-conductive. On the other hand, the output of the inverter 11 becomes low level, the switching element 12 becomes conductive, a voltage a (+15V in this example) is applied to the blacking plate 6, and the electron beam becomes relatively low as shown by the solid line 2a in FIG. Deflected at a small angle. In the unblanking state, the output of the inverter 9 is at a low level and the switching element 10 is conductive, while the output of the inverter 11 is at a low level and the switching element 12 is conductive. Therefore, a deflection voltage of 0 V is applied to the blanking plate 6, and the electron beam 2c passes through the blanking aperture 7 without being blanked. During a long blanking state, the outputs of inverters 9 and 11 are both at a high level, so switching elements 10 and 12
Both become non-conductive.

Therefore, Va-(-Vb)=V on the blacking plate 6.
A voltage of a+b is applied. In this example, Vb is 5
If 0V is used, a deflection voltage of (Va + Vb) = 65V is given, so the electron beam will move along the dotted line 2b in Figure 2.
is deflected at a relatively large angle. In this embodiment, during short-time blanking such as during drawing, the deflection voltage applied to the blanking plate 6 is set to a low value (15 in this embodiment) to control on/off of blanking. This allows for high-speed blanking, or high-speed drawing.

In addition, when long blanking is required, such as when replacing a sample, the blanking deflection voltage is set to a high value, so there is no leakage of electrons from the blanking aperture 7, and complete blanking is performed on the sample. You can do rankings. It goes without saying that the deflection voltage in FIG. 2 can be applied arbitrarily, and electromagnetic deflection can also be used as the blanking deflection means.

It goes without saying that an analog switch may be used as the switching element for switching the electron beam on and off, and that the deflection voltage may be switched using a circuit configuration other than that shown.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an electron beam lithography apparatus showing an embodiment of the present invention, and FIG. 2 is a circuit diagram of an embodiment of blanking deflection means of the present invention. DESCRIPTION OF SYMBOLS 1... Electron gun, 2... Electron beam, 3... Converging lens, 4... Projection lens, 5... Deflection lens, 6...
Blanking plate, 7... Blanking aperture, 8...
sample.

Claims (1)

[Claims] 1 means for generating an electron beam, means for converging the electron beam, means for scanning and drawing a sample with the focused electron beam, and means for deflecting and blanking the electron beam scanning the sample. In the electron beam lithography apparatus, the blanking means is configured to deflect the electron beam scanning the sample by a larger angle during long-time blanking than during short-time blanking. An electron beam lithography device characterized by: