JPH0222811A - Electronic beam heating apparatus - Google Patents

Abstract

PURPOSE:To heat a predetermined region to be heated correctly and uniformly by providing a beam intercepting mask having an aperture for allowing only a part of electronic beams to reach the surface of a wafer and preheating the region of the wafer around the aperture before heating the wafer with the electronic beams. CONSTITUTION:Linear electronic beams 10 emitted from a cathode 2 of an electronic gun 1 are accelerated by an accelerating electrode 4 and focused by a lens coil 5 such that a linear image of the cathode 2 is formed on a wafer 8. The electronic beams 10 are then deflected by a deflecting coil 6 and reach a beam intercepting mask 7. A signal is applied to the deflecting coil so that the linear electronic beams 10 scan uniformly over the beam intercepting mask 7 without passing through the aperture of the mask 7. The beam intercepting mask 7 is heated to about 1000 deg.C, whereby the wafer 8 is preheated by radiant heat from the beam intercepting mask 7 particularly in the region around the aperture of the mask. Then, the linear electronic beams 10 are made to scan so as to pass through the aperture of the mask 7, whereby the whole region to be heated is heated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electron beam heating device, and particularly to an 80I (Si)
The present invention relates to an electron beam heating apparatus used for annealing semiconductor films such as silicon on indulator films, or for welding and processing mechanical parts.

(Prior Art) When an electron beam heating device is used to anneal a semiconductor film or to weld or process mechanical parts, it is desirable that the region of the sample to be heated can be heated as uniformly as possible by the electron beam. However, when a wide area is generally treated, the temperature at the edges of the treated area becomes lower because more heat flows out to the surrounding area than at the center. For example, when heating a sample with a linear electron beam, the temperature distribution within the heating area 13 on the sample surface of the sample to be processed as shown in FIG. This creates a region 15 with a low temperature.

Therefore, in order to avoid this problem of uneven temperature distribution, for example, Hamasaki et al.
Physics (J, Appl, Phys, )59
As described in Vol. (1986), p. 2971, an electron beam heating device that performs processing using an electron beam with a bimodal intensity distribution having a beam intensity peak at the edge of the region of the sample to be processed has conventionally been used. Often used.

(Problems to be Solved by the Invention) According to the above-described conventional electron beam heating apparatus that uses a beam with a bimodal intensity distribution, it is possible to uniformly heat a certain region of a sample to be processed.

However, it is difficult to obtain a bimodal intensity distribution of the electron beam over a relatively long region. For example, it is relatively easy to obtain a bimodal intensity distribution using the quasi-linear beam method, which scans a point beam at high speed in one direction to obtain a linear heating area. It is not suitable for area processing, and when processing a large area, the processing time becomes long.

On the other hand, with the method of obtaining a linear electron beam using a linear cathode, a large current can be easily obtained and large area processing is possible, but it is difficult to extract a bimodal linear beam stably with good reproducibility. is difficult due to problems such as thermal deformation of the cathode filament.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electron beam heating device that solves these conventional problems and can accurately and reproducibly obtain a uniform heating area.

(Means for Solving the Problems) The present invention provides an electron beam heating device that heats a sample with an electron beam, and includes a beam shielding mask having an aperture that allows only a portion of the electron beam to reach the sample surface. The method is characterized in that it has means for heating the periphery of the opening before heating the sample with the electron beam.

(Function) When heating the surface of a sample using a conventional heating method, for example, using a linear beam with a uniform intensity distribution over the entire length, the edges of the heating area are less likely to lose heat to the surroundings than the center. It gets louder and gets colder. To avoid this, first preheat only the area around the heating area of the sample to be processed, and then heat the entire heating area of the sample. In order to process such samples,
The electron beam heating device of the present invention has means for heating the periphery of the aperture that allows only a portion of the electron beam to reach the sample surface. That is, since the area around the opening of the beam shielding mask is heated to a high temperature, the area around the heated area is preheated by thermal radiation. Thereafter, by irradiating an electron beam with a uniform intensity distribution so as to pass through the aperture of the beam shielding mask, it is possible to obtain a uniform temperature distribution over the entire heating region.

(Example) Next, an example of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of the present invention. This electron beam heating device includes an electron gun 1 consisting of a cathode 2 and a Wehnelt 3, an accelerating electrode 4, a lens coil 5,
a deflection coil 6, a beam shielding mask 7 made of metal,
It consists of a sample stage 9.

The electron gun 1 generates and emits a linear electron beam 10 using a cathode 2 and a Wehnelt 3. Electron gun 1 cathode 2
has a linear shape.

The accelerating electrode 4 supports a linear electron beam 10 emitted by the electron gun 1.
is accelerated toward the sample stage 9.

The lens coil 5 focuses the linear electron beam 10 accelerated by the accelerating electrode 4 onto the sample 8 on the sample stage 9 .

In order to scan the processing surface of the sample 8 with the linear electron beam 10, the deflection coil 6 deflects the linear electron beam 1 incident onto the processing surface.
Deflect 0.

The beam shielding mask 7 shields a part of the linear electron beam 10 from reaching the sample surface, and has a rectangular opening through which the electron beam passes.
The material and structure are such that there is no problem even when heated to temperatures as high as 00°C. In this example, tungsten was used as the material. Further, as shown in FIG. 2, the shape was such that the opening was closest to the sample.

In such an electron beam heating device, a linear electron beam 10 emitted from a cathode 2 of an electron gun 1 is accelerated by an accelerating electrode 4, and is passed through a lens coil 5 so as to focus an image of the linear cathode 2 on a sample 8. The beam is focused by the beam, is deflected by the deflection coil 6, and reaches the beam shielding mask 7. First, the linear electron beam 10 is prevented from passing through the aperture of the beam shielding mask 7, and a signal is applied to the deflection coil so that the linear electron beam 10 uniformly scans the beam shielding mask 7. , the beam shielding mask 7 is heated to about 1000°C.
Heat to.

By heating the beam shielding mask 7, the sample 8 is preheated by thermal radiation from the beam shielding mask 7, particularly in the vicinity of the mask opening.

As described above, by heating the beam shielding mask 7, the sample 8
After preheating the area around the heating area, the linear electron beam 10 is passed through the opening of the beam shielding mask 7.
The entire heating area is heated by scanning.

In this way, it becomes possible to uniformly heat the entire sample surface heating area of the sample 8. According to the apparatus of this example, a wide uniform heating area of 2 mm x 8 mm could be stably obtained.

In this embodiment, the beam shielding mask has a shape that is closest to the sample at the opening, but it may also have a shape that brings the entire mask closer to the sample as shown in FIG.

Further, the beam shielding mask may be heated by other means, such as by incorporating a heater 12 into the beam shielding mask and passing a current through it, as shown in FIG. However, in this case, the path of the electron beam is disturbed by the magnetic field generated by the current, so the heater needs to be non-inductively wound. Furthermore, the sample may be directly preheated by a heater as shown in FIG. 5 without preheating the sample by thermal radiation from the beam shielding mask.

(Effects of the Invention) As explained above, the present invention includes a beam shielding mask having an aperture that allows only a part of the electron beam to reach the sample surface, and an aperture that is opened before heating the sample with the electron beam. By having means for heating the area around the hole, a defined area can be heated accurately, uniformly, and with good reproducibility.

This has the effect that a semiconductor film having uniform film quality can be obtained, and that mechanical parts can be accurately welded and processed.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of an embodiment of the present invention, Fig. 2 is an enlarged view of a beam shielding mask used in the embodiment of Fig. 1, Fig. 3 is a block diagram of another embodiment, and Fig. 4 is a further diagram of another embodiment. A configuration diagram of an example of
FIG. 5 is a block diagram of still another embodiment, and FIG. 6 is a diagram showing the temperature distribution within the heating region obtained by the conventional heating device. 1... Electron gun 9... Sample stage 2...
・Cathode 10... Linear electron beam 3...
... Wehnelt 11 ... Opening part 4 ...
Accelerating electrode 12... Heater 5... Lens coil 13... Heating area 6... Deflection coil 14... Direction of heat flow 7... Beam shielding mask 15...・・Low temperature region 8・・・Sample Patent Kozo Iizuka, Director of Institute of Industrial Science and Technology Figure 1 Figure 10 Linear electron beam Figure Cathode Figure Figure

Claims (1)

[Claims] An electron beam heating device that heats a sample with an electron beam is equipped with a beam shielding mask having an aperture that allows only a portion of the electron beam to reach the sample surface, and the aperture is removed before heating the sample with the electron beam. An electron beam heating device characterized by having means for heating the periphery of the hole.