JPH06196395A - Electron-beam aligner - Google Patents

Abstract

PURPOSE:To provide an electron-beam aligner wherein it eliminates the dislocation between a laser length-measuring axis and an electron-beam axis and it can perform an accurate drawing operation. CONSTITUTION:Slit plates 23x, 23y in which slits 22x, 22y partly transmitting laser beams 21x, 21y from laser length-measuring instruments 8x, 8y have been opened are arranged in positions which are separated from the mounting position of an object 7, to be worked, on a stage, and photodetectors 24x, 24y which detect the quantity of light of the laser beams 21x, 21y transmitted the respective slits 22x, 22y are arranged at their back parts. An electron-beam alignment mark 25 which is crossed on extensions of the slits 22x, 22y is formed at the back part of the photodetectors 24x, 24y. After a working chamber has been evacuated, the position of the stage is set in such a way that outputs from the photodetectors 24x, 24y become maximum, and an electron-beam irradiation system is adjusted in this state in such a way that the center of the alignment mark 25 coincides with the center of the electron beams.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron beam exposure apparatus for improving drawing accuracy.

[0002]

2. Description of the Related Art Conventionally, in an electron beam exposure apparatus, alignment of a laser measuring system is performed in a state where a processing chamber is in the atmosphere.
The position of the laser length measurement axis is confirmed by means such as blocking the laser optical path. Regarding the electron beam, before installing the objective lens in the processing chamber, assume that the position directly below the center of the objective lens is the workpiece installation position, check the alignment between the laser measurement axis and the electron beam axis, and then attach the objective lens. It was done to evacuate the processing chamber.

[0003]

In such a conventional electron beam exposure apparatus, the laser measuring axis and the electron beam axis are misaligned due to an error in the mounting of the objective lens, a misalignment of the machining chamber during vacuum exhaustion, and the like. Occurs. This positional deviation causes a point to be positioned according to the Abbe's principle, that is, an error in measuring the position of the exposure apparatus, thus making precise electron beam drawing difficult.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an electron beam exposure apparatus capable of performing precision drawing by eliminating a deviation between a laser length measuring axis and an electron beam axis. To do.

[0005]

The present invention is provided with an electron beam irradiation system for irradiating an electron beam and a laser length measuring device capable of placing and moving a work piece in a working chamber for measuring the position of the work piece. In an electron beam exposure apparatus having a stage, adjusting means is provided for aligning the laser measurement axis and the electron beam axis at a position apart from the workpiece mounting position on the stage, and the adjusting means is provided. A slit plate provided on the stage for transmitting a part of the laser light beam of the laser length measuring device, and a photodetector provided on the stage for detecting the light amount of the laser light beam transmitted through the slit plate. An electron beam alignment mark arranged at the slit position of the slit plate behind the photodetector on the stage, and a secondary electron when the mark is irradiated with an electron beam. Or it is characterized by having an electron signal detector for detecting at least one of the backscattered electron signal.

[0006]

According to the present invention, the electron beam irradiation system is assembled, the machining chamber is evacuated, and the electron beam is emitted by the adjusting means provided at a position apart from the workpiece mounting position. The electron beam axis and the laser measuring axis can be aligned. Therefore, the mounting error of the objective lens, the positional deviation between the electron beam axis and the laser length measuring axis due to the vacuum evacuation, and the like are corrected, and highly accurate electron beam drawing can be performed.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic configuration of an electron beam exposure apparatus according to an embodiment of the present invention. The electron beam irradiation system includes an electron gun 1, electron lenses 2 and 3, a deflection coil 4 and the like. Below the electron irradiation system is a processing chamber 5. In the processing chamber 5, a stage 6 which is movable in the X and Y biaxial directions is provided, on which a workpiece 7 is placed. A stage driving device 10 and a laser length measuring device 8 are provided outside the processing chamber 5. A laser mirror 9 that reflects the laser light beam from the laser length measuring device 8 is arranged on the stage 6. An electronic signal detector 12 for detecting a secondary electron or a reflected electron signal from the stage 6 is provided above the processing chamber 5. The control circuit 11 controls the entire system.

FIGS. 2 and 3 show the relationship between the part on the stage of the adjusting means for aligning the electron beam axis and the laser length measuring axis, and the workpiece 7 and the laser length measuring device 8. There is. Here, the relationship between FIG. 2 and FIG. 3 is that FIG. 2 is a state in which alignment adjustment of the electron beam axis and laser length measuring axis is performed, and FIG. 3 is a state in which laser length measuring device alignment and electron beam drawing are performed. The state can be switched by moving the stage. That is, FIG. 3 shows a state in which the stage is moved diagonally downward left from the state of FIG. The laser length measuring device 8 includes an X-axis laser length measuring device 8x for emitting a laser light beam 21x in the X-axis direction and a Y-axis laser length measuring device 8y for emitting a laser light beam 21y in the Y-axis direction as shown in the figure. is there. Laser mirror 9
Are arranged near the position where the workpiece 7 is placed so as to have two surfaces orthogonal to these two laser light beams 21x and 21y.

Two laser length-measuring devices 8x and 8y are provided at a position separated from the mounting position of the workpiece 7 on the stage by a predetermined distance.
The slit plates 23x and 23y are provided with slits 22x and 22y, respectively, so as to transmit a part of the laser light beams 21x and 21y. Behind these slit plates 23x and 23y, photodetectors 24x and 24y for detecting the light amounts of the laser light beams transmitted through the slits 22x and 22y, respectively, are arranged. The outputs of these photodetectors 24x and 24y can be monitored by an output monitor 28 provided outside the processing chamber.

Behind the photodetectors 24x and 24y, electron beam alignment marks 25 are formed which cross the extension of the slits 22x and 22y. In FIG. 2, the deflection region 26 of the electron beam and the electron beam center 27 which strike near the alignment mark 25 are shown.

The adjusting operation of the apparatus of this embodiment will be described in detail below. First, after the electron beam irradiation system is assembled, the two laser length measuring devices 8x and 8y are aligned before the processing chamber 5 is evacuated. At this time, the state is as shown in FIG. 3, and since the laser light beams 21x and 21y from the laser length measuring devices 8x and 8y are totally reflected by the laser mirror 9, the laser length measurement is performed by observing the reflected laser light beam. Alignment of vessels 8x and 8y is possible. Then, the processing chamber 5 is evacuated to generate an electron beam from the electron gun, and the output of the electron signal detector is monitored by observing the scanning image, so that the beam center portion having the maximum brightness of the electron beam is the lens system light. To irradiate the workpiece or electron beam alignment mark through the center of the axis,
Align the electron beam.

After that, the stage 6 is moved to the state shown in FIG. 2, and the photodetector 2 is passed through the slit plates 23x and 23y.
The position of the stage 6 is finely adjusted so that the outputs detected at 4x and 24y are maximized. The relationship between the diameter a of the laser light beam and the width b of the slits 22x and 22y is shown in FIG.
It is in the state shown in. For example, if a is about 6 mm and b is about 1 mm, a part of the laser light beam 21 can be taken out by the slit 22, and a photodetector can be used when the position of the slit 22 becomes the center position of the laser light beam 21. The maximum output is obtained at 24. Therefore, by adjusting the stage position so as to maximize the light detection output while monitoring with the output monitor 28, the laser measurement axes in the X and Y directions can be aligned with the slits 22x and 22y, respectively.

At this time, the region of the alignment mark 25 is scanned with an electron beam, and the SEM image obtained by processing the signal obtained by the detector 12 is observed, whereby the electron beam axis and the laser measuring axis are measured. You can know the deviation of.
Therefore, the electron beam irradiation system is adjusted so that this deviation is eliminated, that is, the center of the alignment mark 25 is the center of the SEM image. Thereby, the electron beam axis and the laser length measuring axis can be aligned.

[0014]

As described above, according to the present invention, the electron beam irradiation system is assembled and the electron beam axis is aligned with the laser measuring axis while the electron beam is emitted while the processing chamber is evacuated. It is possible to provide an electron beam exposure apparatus that can perform electron beam exposure with high accuracy.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of an electron beam exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a method of aligning an electron beam axis and a laser light beam axis in the same example.

FIG. 3 is a diagram for explaining an alignment and an electron beam drawing method of the laser length measuring device of the embodiment.

FIG. 4 is a diagram showing a relationship between a laser light beam and a slit in the example.

[Explanation of symbols]

1 ... Electron gun, 2, 3 ... Electron lens, 4 ... Deflection coil, 5
... Processing room, 6 ... Stage, 7 ... Workpiece, 8 (8x, 8
y) ... laser length measuring device, 9 ... laser mirror, 10 ... stage driving device, 11 ... control circuit, 12 ... electronic signal detector,
21 (21x, 21y) ... laser light beam, 22 (22
x, 22y) ... slit, 23 (23x, 23y) ... slit plate, 24 (24x, 24y) ... photodetector, 25 ...
Alignment mark, 26 ... Electron beam deflection area, 27
... electron beam center, 28 ... output monitor.

Claims (1)

[Claims] 1. An electron beam irradiation system for irradiating an electron beam,
In an electron beam exposure apparatus having a stage with a laser length measuring device for measuring the position of a work piece, which is capable of placing and moving the work piece in a processing chamber, Adjustment means is provided for aligning the laser length measurement axis and the electron beam axis at a position, and the adjustment means is provided on the stage and is a slit plate for transmitting a part of the laser light beam of the laser length measurement device. A photodetector provided on the stage for detecting the light amount of the laser light beam transmitted through the slit plate; and a photodetector arranged on the stage in the rear of the photodetector in accordance with the slit position of the slit plate. And an electron signal detector for detecting at least one of secondary electron and reflected electron signals when the mark is irradiated with an electron beam. Electron beam exposure apparatus characterized by.