JPH0542099B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a linear electron beam device.

(Prior art) Conventionally, one method of heat treating semiconductor substrates, etc. has been to irradiate and scan a fixed substrate with a linear electron beam whose cross section is approximately rectangular (linear). . (“Energy Beam Processing” Edited by Energy Beam Analysis Society, Japan Society of Precision Machinery Engineers, Realize Inc.,
1985, 268 pages. "Proceedings of the 5th New Functional Device Technology Symposium" New Functional Device Development Association, 1986, 145
p.-152). In a conventional electron beam device, as shown in the schematic diagram of FIG. 5, a linear electron beam is focused on a sample 9 and the electron beam is deflected by a deflector 6 to scan over a wide range of the sample. ,
Sample 9 has been heat treated.

(Problem to be Solved by the Invention) However, the convergence state of the linear electron beam 4 is determined by the electron gun of the linear cathode 1, the Wehnelt electrode 2, and the anode 3, and the electron optical system of the lens 5 and the deflector 6. However, because the linear electron beam is non-axisymmetric and the deflection width is large, it is difficult to control the linear electron beam to obtain a linear electron beam with good beam current density over a wide range. It was difficult. For this reason, for example, when electron beam annealing is used in SOI (Silicon-On-Insulator) formation technology, it is difficult to anneal a wide area uniformly over the entire surface of a 2-inch or 4-inch wafer, which is a major obstacle to practical application. I was getting used to it.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a linear electron beam device that can evenly and uniformly heat-treat a large area by electron beam irradiation.

(Means for Solving the Problem) The linear electron beam device of the present invention is disposed in close proximity to the linear electron beam irradiation surface of a sample, has a substantially drum-shaped opening, and only allows the electron beam to pass through the opening. The structure is characterized in that a mask is provided as a means for blocking the electron beam except for the opening.

(Function) According to the electron beam device of the present invention, the aperture width of the mask is set to be equal to or less than the maximum deflection width that can obtain a stable beam with extremely few aberrations, and the sample is aligned with the irradiation position of the electron beam that has passed through the mask aperture. After that, by scanning a linear electron beam wider than the aperture width of the mask, the heat-treated area by electron beam irradiation is irradiated with the electron beam that has passed through the mask aperture, which is in a good condition with very little electron beam aberration. It can be limited to an area. The electron beam heats the sample using the kinetic energy of the polar electrons irradiated onto the sample, and when the temperature rises above the melting point, the sample melts, but the heat escapes to the lower sample temperature. Considering this heat escape, if the mask opening 21 of the mask 20 is rectangular as shown in FIG.
Where the sample is irradiated with the electron beam and annealing begins and ends, more heat escapes 22 from both ends (section A in FIG. 4) where the linear electron beam is irradiated than from the center (section C in FIG. 4). Therefore, melting starts from the center and the annealed shape becomes convex at the front and rear ends in the scanning direction, and since the heat escape is considered to be constant on both sides in the scanning direction (section B in Figure 4), the overall annealed shape is similar to the electron beam irradiation area. Although 20 is rectangular, it is considered that the sample melting region 21 becomes as shown. Therefore, as shown in FIG.
6, the two sides crossed by the linear electron beam during scanning are made concave inside the opening, and the sample is irradiated with the electron beam from both ends in the longitudinal direction of the line first, resulting in an annealed shape as shown in the sample melting region 17 in Fig. 2. You can arrange it into a rectangle like this. Since this effect is the same whether or not the long side of the linear electron beam is cut by the mask, the length of the electron beam may be adjusted by cutting both ends of the long side of the linear electron beam using the mask.

(Embodiment) FIG. 1 shows a main configuration diagram of an embodiment of the present invention.

A linear electron beam 4 emitted from an electron gun consisting of a linear cathode 1, a Wehnelt electrode 2, and an anode 3 in a vacuum vessel 14 is imaged by a lens 5 onto a sample 9 as a linear electron beam. Ru. The focused linear electron beam is directed to the sample 9 by the deflector 6.
However, the linear electron beam is blocked by the mask 8 and passes only through the mask opening 7, and only the sample 9 in the irradiation area of the electron beam that has passed through the mask opening 7 is heat-treated by the electron beam. is done. The sample 9 is set in the sample holder 10 and preheated to, for example, about 600° C. by a sample heater 13 or the like. Furthermore, a mechanism for moving the sample may be provided, for example, the sample holder 10.
is set on the XY table 12, and the sample 9 is moved by the XY table drive system 11 so that the sample area to be heat treated by electron beam irradiation is located within the irradiation area of the electron beam that has passed through the mask opening 7, and the line Heat treatment is performed by irradiating a shaped electron beam. After the heat treatment by electron beam irradiation, the sample is moved so that the area of the sample to be heat treated is within the irradiation area of the electron beam through the mask opening 7, and heat treatment is performed by electron beam irradiation. By repeating this process, a predetermined region of the sample can be evenly and uniformly heat-treated over a wide range with the electron beam.

FIG. 2 shows the mask shown in FIG. 1, electron beam scanning, sample irradiation state, and annealing state.

The linear electron beam 4 is scanned across the concave side of the mask opening 7 provided in the mask 8 . The electron beam scanning range 15 is set larger than the mask aperture width, and the scanned electron beam passes through the mask aperture 7 and forms an electron beam irradiation area 1 on the sample.
The area irradiated as shown in 6 and annealed by heat escape becomes a sample melting area 17. Various mask aperture shapes are possible; for example, as shown in Figure 3, the side that the linear electron beam crosses can be curved as in (a), triangular as in (b), or triangular as in (c). It may also be a polygon. Further, the mask opening recess does not need to be symmetrical, and may be deformed as appropriate depending on the condition of heat escape.

(Effects of the Invention) As described above, according to the present invention, the area to be heat-treated by electron beam irradiation is limited to only the area where the linear electron beam is in a good condition by using a mask, thereby preventing electron beam aberrations and other problems. Stable elements can be reduced. Furthermore, since the annealed shape can be arranged into a rectangular shape, it becomes easy to match the annealed shape to the chip size. Furthermore, if necessary, heat treatment can be performed by uniformly irradiating the sample with an electron beam over a wide range while moving the sample sequentially, for example, in an intermittent manner. These effects can dramatically improve the yield of large-area heat treatment by electron beam irradiation of large-diameter wafers and the like.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic configuration diagram of an embodiment of the apparatus according to the present invention, FIG. 2 is a conceptual diagram of the mask in FIG. 1, electron beam scanning, irradiation state, and annealing state, and FIG. 3 is a mask opening according to the present invention. Figure 4 is a conceptual diagram of the mask, electron beam scanning, irradiation state, and annealing state when the mask opening shape is rectangular, and Figure 5 is a schematic diagram of the overall configuration of the conventional device. This is what is shown. In the figure, 1 is a linear cathode, 2 is a Wehnelt electrode, 3 is an anode, 4 is a linear electron beam, 5 is a lens, 6 is a deflector, 7 is a mask aperture, 8 is a mask, 9 is a sample, 10 11 is a sample holder, 11 is an XY table drive system, 12 is an XY table, 13 is a sample heater, 14 is a vacuum container, 15 is an electron beam scanning range, 16 is an electron beam irradiation area, 17 is a sample melting area, and 18 is a mask , 19 is a mask opening,
Reference numeral 20 indicates an electron beam irradiation region, 21 indicates a sample melting region, and 22 indicates a heat escape region.

Claims (1)

[Claims] 1. In a linear electron beam device, it is placed in close proximity to the linear electron beam irradiation surface of the sample and has an approximately drum-shaped opening, and only this opening allows the electron beam to pass through, while other parts other than the opening do not pass the electron beam. A linear electron beam device characterized by being equipped with a mask as a blocking means.