JPS635514A - Beam annealing device - Google Patents

Abstract

PURPOSE:To anneal a plurality of samples continuously by a method wherein a plurality of wafers are concentrically placed on a sample placing table, and energy ray beam is made to irradiate scanningly while the beam scanning regulator, provided opposing to the sample placing table, is being rotated. CONSTITUTION:The title beam annealing device is equipped with the sample placing table 7 whereon a plurality of sample placing stands are concentrically arranged, the rotating table 8 arranged opposing to the sample stands on the sample table, a beam output device, the beam scanning regulator, arranged on the surface opposing to the sample stand of the rotating table, with which an energy ray beam 2 is scanningly projected on the surface of the sample by shifting the scanning line of the energy ray beam 2 in axial direction when the rotating table 8 is rotated, and the beam scanning controller with which the direction of projection of the energy ray beam to the sample is controlled. As a result, a uniform annealing can be performed for the sample heving a large area, a plurality of wafers 6 can be annealed continuously, and the productivity of the title beam annealing device can be improved.

Description

[Detailed Description of the Invention] [Purpose of the Invention (Industrial Field of Application) The present invention is directed to heating (annealing) a non-single-crystal semiconductor layer such as a wafer by irradiating and heating the non-single-crystal semiconductor layer with an energy beam. The present invention relates to a beam annealing device that can achieve single crystallization, thermal diffusion of introduced impurities, and activation.

(Technical background) In recent years, as interest in three-dimensional circuit elements has increased, silicon single crystals are further formed on the insulating film formed on the surface of the substrate, and elements are formed on this silicon single crystal. , (Silicon On In5ulat
or) technology is attracting attention.

In this SOI technology, beam annealing technology is expected to be an important technology as one of the methods for forming a single crystal on an insulating film.

This beam annealing technique is a chemical vapor deposition method (CVD:C
chemical vapor deposition
) is a technique in which a non-single-crystal silicon layer formed on an insulating film is annealed by irradiating an energy beam such as a laser beam, thereby converting the non-single-crystal silicon layer into a single crystal.

As a beam annealing device used in this beam annealing technique, one is known that uses an XY table with a sample placed on the sample table and scans the sample with this XY table. There was a problem in that there was a limit to mechanical accuracy and uneven beam irradiation occurred.

There are also devices that use a fixed sample table to scan and irradiate the irradiation beam onto the wafer, but these devices use a rotating reflector or the like to adjust the irradiation angle of the beam onto the sample. The beam irradiation power density is not constant due to differences in the incident angle of the beam between the periphery and the center of the sample surface, the deviation between the beam focal point and the sample surface, etc. It was difficult to perform proper annealing.

Therefore, in order to solve this problem, we used a beam irradiation system in which the focal point of the incident beam coincides with the sample surface or its extension, so that the beam irradiation power density is constant at any location on the sample surface. A technology has been developed (see JP-A-60-176221@publication).

(Problems to be Solved by the Invention) However, the conventional techniques described above have a problem in that productivity cannot be improved because a plurality of samples cannot be continuously annealed.

The purpose of the present invention is to eliminate such drawbacks, and in particular to provide a beam annealing device that can uniformly anneal the surface of a sample even if the sample area is large, and that can anneal multiple samples continuously. shall be.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a sample table in which a plurality of sample stands on which samples are placed are arranged concentrically, and a sample table on the sample table. A rotary table placed opposite to the table, a beam output device for irradiating the sample with an energy beam beam, and a beam output device for irradiating the sample with an energy beam beam arranged on the surface facing the sample table. A beam scanning adjustment device moves the scanning line of the beam to scan and irradiate the sample surface with the energy ray beam, and the irradiation direction of the energy ray beam onto the sample is adjusted so that the scanning line of the energy ray beam becomes a straight line on the sample surface. A beam annealing apparatus is used, which is characterized by having a beam scanning control device for controlling the beam.

(Function) In the present invention, a plurality of wafers are placed concentrically on a sample table, and an energy beam is scanned and irradiated while rotating a beam scanning adjustment device provided opposite to the sample table. Multiple wafers can be annealed sequentially.

Uniform annealing of the sample surface can be achieved by controlling the direction of irradiation of the energy beam onto the wafer so that the locus of the beam spot on the wafer is formed roughly in a straight line.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

The drive system of the rotary table 220 in which the beam scanning section 110 that adjusts the beam from the beam output section 100 that outputs an energy beam, for example, a CW-Ar gas laser beam, is arranged includes a rotary table drive section 210, and this rotary table drive section, for example. Rotary table control unit 2 that controls the motor
00. The rotational speed detection section 230 detects the rotational speed of the rotary table 220. Information from rotational speed detection section 230 is input to rotary table control section 200.

A part of the information output from the rotary table control section 200 is input to the beam scanning control section 300, and the scanning speed is controlled to equalize the scanning speed or the amount of irradiation beam depending on the location.

- The power steering system includes a beam output unit 100 that outputs an energy beam beam, such as a CW-Ar gas laser beam, and a rotation unit that adjusts the irradiation angle of the beam with respect to the wafer 130 and the amount of movement of the rotary table in the radial direction. A beam scanning unit 110 fixed to the table, a beam spot forming unit 1201 which is also fixed to the rotary table and converts the beam spot shape into an arbitrary shape such as linear or bimodal shape, detects the position of the wafer on the sample table. Wafer position detection section 140
It is composed of.

Information from the wafer position detection section 140 is input to the beam scanning control section 300.

As described above, the beam scanning control section 300 receives information from the wafer position detection section 140 and the rotational speed detection section 230, and controls the beam scanning section 110 based on this information.

The operation of the beam annealing apparatus having the above configuration will be explained.

In the embodiment, a CW-Ar laser is used as the irradiation beam, but an energy beam such as an electron beam can also be used.

In FIG. 2, reference numeral 1 indicates a CW-Ar laser output device, and a laser beam 2 output from this CW-Ar laser output device 1 is sent to a beam scanning section consisting of an X-axis mirror 3 and a Y-axis mirror 4. After being reflected, the light passes through the condenser lens 5 and is guided onto the wafer 6 . The optical system of these X-axis mirror 3 and Y-axis mirror 4 is suspended from a rotary table 9.
It rotates together with the rotary table 9.

As shown in FIG. 3, a plurality of wafers 6 are placed on a sample table 7 in a concentric row. Of course, double rows may be provided.

The X-axis mirror 3 can be rotated in the direction of arrow A, and the Y-axis mirror 4 can be rotated in the direction of arrow B. Roughly speaking, the Y-axis mirror 4 can be rotated in the direction of arrow Y.
It is possible to move in the direction, that is, in the radial direction of the rotary table. These two mirrors adjust the irradiation position of the laser beam 2.

In the present invention, beam irradiation is performed while rotating the rotary table, so it is sufficient that the beam spot 8 of the laser beam can be moved only in the Y-axis direction, as shown in FIG. 6a shows the annealed portion of the wafer surface.

Now, when the annealing for one row of beam spots on one wafer is completed, the work moves on to the next wafer, and in this way, when the rotary table 9 has made one revolution, the position of the beam spot 8 is determined. Shift it in the Y-axis direction and move on to the annealing process for the next row. As is clear from the above operations, all the wafers on the rotary table 9 will have been annealed when all the work is completed. Note that the laser output device has layering that stops irradiation of the laser beam between the wafers.

However, in the above-described method, since the beam spot 8 moves along the concentric circles of the sample table 7, the locus of the beam spot 8 on the wafer 6, that is, the scanning line, is shaped like an arc as shown in FIG. 5(a). turn into. For this reason, a gap is created between the scanning lines on the wafer where the beam is not irradiated, and uneven irradiation of the laser beam is likely to occur.

In this embodiment, a beam scanning controller is provided to control the amount of movement of the beam spot 8 in the Y-axis direction based on the rotational speed of the rotary table 9, the size of the wafer, etc., so that the beam spot can be adjusted as shown in FIG. 5(b). The above problem is solved by making the trajectory linear.

In this embodiment, the rotation speed detection section detects the rotation speed of the rotary table 9, and the wafer position detection section detects the position of the wafer on the sample table 7, and both of these pieces of information are input to the beam scanning control section. The amount of movement of the beam spot 8 in the Y-axis direction is controlled.

By the way, in this embodiment, the amount of movement of the beam spot in the Y-axis direction is determined by the following equation if defined as shown in FIG. 6, for example.

Y=R (1-cosθo/CO3θ) where R is Ro-r≦R≦Ro+r In the above formula, r is the radius of the wafer, R is the beam scanning radius, Ro is the pitch radius at the wafer center, θ is the rotation angle, θ0
indicate the angular range of Y-axis control.

Note that the linear velocity of the rotary table is 250 mm/sec to 500 mm/sec, depending on the irradiation power density of the laser beam.
About sec is preferable.

The beam spot shape of the laser beam is shown in Figure 7 (a
A bimodal shape as shown in ) or a linear shape as shown in FIG. 7(b) is convenient for uniform annealing. It is desirable that the scanning lines of the beam be scanned so that adjacent scanning lines partially overlap.

Further, in the embodiment, a CW-Ar laser was used as the energy beam, but it is a matter of course that the present invention is applicable even when a pulse excavation laser such as a Q-switched YAG laser or an electron beam is used.

By using the beam annealing apparatus configured as described above, approximately 10 wafers can be annealed in 30 minutes, and even wafers with a wide area can be uniformly annealed.

[Effects of the Invention] As explained above, by using the beam annealing apparatus of the present invention, it is possible to uniformly anneal even a wide sample area, and furthermore, it is possible to anneal multiple wafers continuously. It also has the effect of improving productivity.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a beam annealing apparatus according to the present invention, FIG. 2 is a diagram showing the configuration of a laser annealing apparatus according to an embodiment, and FIG. 3 is a diagram showing a wafer placed on a sample table. , Fig. 4 shows the scanning state of the beam spot on the wafer, Fig. 5 shows the trajectory of the beam spot, Fig. 6 shows the positional relationship of the wafer on the sample table, and Fig. 7 shows the beam spot scanning state. It is a figure showing the shape of a spot. 1...CW-Ar laser output device, 3...
...X-axis mirror, 4...Y-axis mirror, 6...
...Wafer, 7...Sample table, 8...
...beam spot, rotary table, 110...
...beam scanning unit, 140...wafer position detection unit, 200...rotary table control unit, 220...
... Rotating table, 230 ... Rotation speed detection section, 300 ... Beam scanning control section. Figure 2. Figure 3 Figure 4 Figure 5

Claims (3)

[Claims] (1) A sample table on which a plurality of sample stands on which samples are placed are arranged concentrically, a rotary table placed opposite to the sample stand of the sample table, and a rotary table for irradiating the sample with an energy beam. a beam output device; and a beam disposed on a surface of the rotary table facing the sample stage, which moves a scanning line of the energy beam in a radial direction when the rotary table rotates, and scans and irradiates the sample surface with the energy beam. Beam annealing comprising: a scanning adjustment device; and a beam scanning control device that controls the direction of irradiation of the energy ray beam onto the sample so that the scanning line of the energy ray beam is linear on the surface of the sample. Device. (2) The beam annealing apparatus according to claim 1, wherein the energy beam is a continuous wave laser or a pulsed laser. (3) The beam annealing apparatus according to claim 1, wherein the beam output device has a mechanism for stopping emission of the energy ray beam between the sample stands.