JPS6174325A - Linear energy beam irradiating device - Google Patents

Abstract

PURPOSE:To perform a uniform preheating as well as to unify the condition of process of recrystallization by a method wherein the material to be processed is preheated through the aperture provided on a rotary stand corresponding to the range of movement of the material to to processed in the radial direction of the rotary stand. CONSTITUTION:Retaining stands 41 and 42 are driven by a motor 51, to be used for shifting of wafers, in such a manner that the center of wafers 11 and 12 is positioned directly below the two windows 22 of a beam mask 21. The mask 21 is fixed to retaining stands 41 and 42 by a mask raising and lowering device 23. After the wafer 1 is preheated by an infrared ray lamp 12 through the oblong aperture 2l of the turn table 2, the turn table 2 is rotated. The radiation rays 5d, 5e and 5f of the linear electron beam 5 emitted momentarily from the electron beam source 6 (6a-6c), which rotates in synchronization with the turn table 2, are brought in parallel with the radius of the turn table 2 which passes the center of the wafer 1, and the density of radiation rays on the wafer 1 is made uniform.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention is directed to a wire-line system suitable for application to, for example, an apparatus for recrystallizing a polycrystalline silicon film on an insulating substrate to form a single-crystal silicon film. The present invention relates to an apparatus for irradiating an object to be processed with a beam of energy.

[Conventional technology]

In response to the demand for higher density and higher performance for silicon semiconductor devices such as LSI, so-called 5ol (Silicon
On In5ulator) technology has been developed.

This is a quartz substrate or silicon crystal substrate (wafer)
A polycrystalline silicon film is deposited on top of which an oxide film is formed as an insulating layer, and this polycrystalline silicon film is locally melted for a short time by, for example, irradiation with a linear electron beam.
By cooling it, it is recrystallized to form a silicon single crystal film.

First, with reference to FIGS. 6 to 8, an example of the configuration of a conventional linear energy beam irradiation device for recrystallizing a polycrystalline silicon film on an insulating substrate to form a single crystal silicon film. I will explain about it. In FIGS. 6 and 7, (2) is a turntable, and a plurality of wafers (1) coated with a polycrystalline silicon film are placed on the turntable (2), and Opening (2a)
It is placed so as to cover the The turntable (2) is rotated by a motor (4) via a rotating shaft (3). (6) is an electron beam source that generates a linear electron beam (5), which is arranged so as to face each wafer (1) sequentially, and a control power source (7) that controls the beam source (6). A rotational position information signal is supplied from an encoder (8) directly connected to the motor (4). A known rotation control circuit (9) is connected between the encoder (8) and the motor (4).

Wafer (1), turntable (2) and beam source (
6) is housed in the vacuum container Ql as a whole, and the vacuum container Q
1 is provided with an appropriate number of quartz glass windows (11) facing each opening (2a) of the turntable (2),
An infrared lamp (12) for preheating the wafer (1) is arranged outside the window (11). The exhaust pipe (13) of the vacuum container QOI is connected to a vacuum pump (not shown). Note that the infrared lamp (12) is arranged so as not to face the electron beam source (6).

The operation of a conventional linear beam irradiation device is as follows.

The wafer (1) is placed on the opening (2a) of the turntable (2).
) is preheated by an infrared lamp (12) through a window (11). When the wafer (13) reaches a predetermined temperature, the infrared lamp (12) is deactivated and the turntable (2) is driven by the motor (4), e.g.
Rotates at about rp. When the turntable (2) reaches a predetermined speed, the control power source (7) is timed and controlled by the rotational position information signal supplied from the encoder (8).
As shown in FIG. 8, an electron beam (5) is emitted from a linear electron beam source (6) while the turntable (2) rotates by an angle of 2θ. (Then, as shown in FIG. 8, (lp) + (lq), (
The SOI pattern represented by lr) is (5a),
(5b).

The polycrystalline silicon film is melted by being scanned by the irradiation rays of the electron beam (5) represented by (5c).
Recrystallization is performed by subsequent cooling, and a single crystal silicon film is formed.

[Problem that the invention seeks to solve]

However, with such conventional linear beam irradiation equipment, the size of the wafer 1' that can be processed is limited by the length of the beam (5), and it is not possible to process large diameter wafers. There were drawbacks.

In order to eliminate this drawback, it is possible to move the wafer, but if you try to simply move the wafer, the relative position with the opening (2a) of the turntable (2) will shift, causing the wafer (1) to move. Since the wafer (1) cannot be preheated uniformly and the preheating temperature of the wafer (1) varies depending on the location, there is a drawback that the processing conditions for recrystallization are not constant.

[Means for solving problems]

The present invention includes a turntable (2) on which an object to be processed (1) is placed, a linear energy beam source (6) arranged in the radial direction of the turntable (2), and a turntable value). The heating hand Vjt (
12), which irradiates the object (1) with a linear energy beam from the linear energy beam source (6).
moving means (41) for moving in the radial direction of the rotary table (2);
).

(42) and the object to be processed (1) on the rotary table (2).
The object to be processed (1) is heated by a heating means (12) through the opening (21).

[Operation] According to the present invention, the object to be processed (1) is moved by the moving means (4).
1) and (42) in the radial direction of the rotary table (2), and the heating means (12) passes through the opening (21) arranged in the rotary table (2) corresponding to this movement range. The body (1) is preheated. Thereafter, the object to be processed ω is irradiated with a linear energy beam from a linear energy beam source (6).

C Embodiment] Hereinafter, an embodiment of the linear energy and one beam irradiation device according to the present invention will be described with reference to FIGS. 1 to 4. In FIGS. 1 and 2, parts corresponding to those in FIGS. 6 and 7 are designated by the same reference numerals, and redundant explanation will be omitted.

In FIGS. 1 and 2, (21) is a beam mask made of a high-melting point metal such as molybdenum, and is disposed above and coaxially with the turntable (2). A carbon sheet or the like is adhered to the side surface. A pair of windows (22) in the shape of a plurality of continuous rectangles are arranged in the beam mask (21) at an angular interval of 180°, and the linear electron beam (5) passing through the windows (22) causes Two wafers (11 ((lx).

(12) A predetermined area of ) is irradiated. The window (22) will be explained in detail later.

(23) is an elevating mechanism for elevating the mask (21), which is integrally attached to the lower end of the rotating shaft (3) of the turntable (2), and is connected to a connection disposed within the rotating shaft (3). The beam mask (21) is raised and lowered via the culm (24). A gear (31) is attached to the lower part of the rotating shaft (3),
A gear (32) meshing with this is attached to the motor (4). The turntable (2) and the mask (21) are driven by the motor (4) via both gears (31) and (32) to rotate together.

(41) and (42) are wafer holding stands, (43) is a guide rod, (44) is a screw for movement, and both holding stands (4
1) and (42), one end (41a) and (42)
a) respectively engage the guide rod (43), and the other end (41b) and (42b'') engage the moving screw (4
4) into the left-hand threaded portion (441) and right-hand threaded portion (44r), respectively. Guide rod (43) and moving screw (44)
Both ends and the center of the turntable (2) are respectively supported by bearings B1 to B6 appropriately arranged on the turntable (2).

Both wafer holding tables (41) and (42) are disposed symmetrically on the turntable (2) with respect to the rotation axis (3), and are configured to move symmetrically with respect to the rotation axis (3). Regardless, the dynamic balance of the turntable (2) is maintained. Furthermore, in order to make the rotation of the turntable (2) even smoother, a pair of balancers (2b) are arranged on the turntable (2) symmetrically about the rotation axis (3).

(51) is a motor for moving both wafer holding tables (41) and (42), and is a drive shaft (52) of the motor (51).
) is slidably supported on the airtight bearing (15) of the vacuum container (14), and the four ends (53) of the drive shaft (52) are supported by the moving screw (
Latch CL that can be engaged with and separated from the tip (45) of 44)
Configure. The movement motor (
The driving force of (51) is transmitted to both holding tables (41) and (
42) is movable symmetrically about the rotation center of the turntable (2) by a distance approximately equal to the diameter of the wafer +11. A pair of oval preheating openings (21) are provided in the turntable (2) facing the movable ranges of both the holding stands (41) and (42).

In addition, a position detector (not shown) common to both wafer holding stands (41) and (42) is appropriately provided on the same side of the turntable (2) as the electron beam source (6), and A position detection light source (not shown) common to (41) and (42) is connected to one wafer holding table, for example (4).
2), for example (42a); in this case, the beam mask (21) only needs to be able to shield the vicinity of the window (22) through which the electron beam passes.

(71) is a motor that drives the electron beam source (6), and its drive shaft (72) passes through the vacuum vessel (also) and is coupled to the electron beam source (6). An encoder (73) is directly connected to the motor (71). (74) is a comparison circuit to which the reference rotational position information signal of the turntable (2) is supplied from the encoder (8), and the rotational position information signal of the electron beam source (6) is supplied from the encoder (73). be done. The output of the comparator circuit (74) is connected to the drive amplifier (7
5) to the motor (71).

The operation of this embodiment is as follows.

First, the electron beam hits two wafers (b).

A moving motor (51) is coupled to a moving screw (44) via a clutch CL so as to irradiate the same position, for example, the center of each of the two wafers (11), (12).
Holding base (41) such that each center of each of
, (42). In this case, before moving both wafer holding tables (41) and (42), the mask lifting mechanism (23) is operated to raise the mask (21) to the position indicated by the broken line (21u) in FIG. Then, the mask (21) is kept out of contact with the wafers (11), (12) and the holding tables (41), (42). Then, both wafer holding stands (41), (4
After the movement of step 2), the mask (21) is lowered by the mask lifting mechanism (23) and returned to the position shown in FIG.
2) evenly press each holding table (41),
(42), and the mask (2I) is clamped with the wafers (11) and (12) securely held on the holding tables (/11) and (42).

Disconnect the clutch CL, and as before, turn on the infrared light (12) through the oval opening (21) of the turntable (2).
After the wafer (1) is preheated, the turntable (2) is rotated. When the rotation control circuit (9) controls the °ζ turntable (2) to reach a constant speed rotation state and the electron beam source (6) starts emitting the linear electron beam (5), the first The wafer (11) is in the position indicated by the circle (1a) in FIG. At this time, the longitudinal direction (83a) of the linear electron beam source (6) is parallel to the straight line (82a) connecting the center (81a) of the wafer (la) and the center (2c) of the turntable (2). .

During the emission period of the linear electron beam, the turntable (2) rotates counterclockwise by an angle of 2θ, so that the wafer (1) passes through the position indicated by the circle (1b) and then moves to the position indicated by the circle (1c).
) to the position shown. During this period, the motor (
71), the electron beam source (6) rotates counterclockwise around its rotation center CG at the same speed as the turntable (2), and in FIG.
Move from the position shown in b) to the position shown in area (6c) via ζ. Longitudinal direction (83c) of area (6c)
) is parallel to a straight line (82c) connecting the center (81c) of the wafer (lc) and the center (2C) of the turntable (2).

As mentioned above, the irradiation rays (5d
).

As shown in Figure 4, (5e) and (5f) are parallel to the radius of the turntable (2) passing through the center of the wafer (1), so the irradiation density on the wafer (1) is becomes uniform.

By the way, if there is no beam mask (21), the irradiation area of the electron beam is a collection of the irradiation rays (5d) to (5f) at each moment, and has a wide arc shape as shown in FIG. Both the edge (84) and the lower edge (85) have a radius of curvature equal to the distance 1i1iR between the center (2c) of the turntable (2) and the rotation center CG of the electron beam source (6).

However, the above-mentioned irradiation area regulated by the beam mask (21) is equal to the '#gt shadow (22P) of the window (22) of the mask (21) on the wafer (1). As shown in FIG. 4, the projection (22P), that is, the window (22) has a plurality of rectangles (2
2a).

(22b) and (22c) have a shape in which their long sides are parallel to each other and are connected at their short sides (length W). Also, the squares at both ends (22a)
, the outer vertex (22e) of (22c),
(22f) and the inner vertex (22i), (
22j) are the lower edges (84) and (85) of the irradiation area.
, the irradiation lines (5d) to (5r) touch the arcs (84e) and (85e) that have entered inside by the length of the uneven intensity portion at the edge, and the arcs (84e) and (85e) (22a), (22b) so that the long sides of the central square (22b) do not intersect.
, (22c) is set. In this way, the window (22) removes the uneven intensity at both ends of the linear beam (5) in the longitudinal direction, and the irradiation energy density within the irradiation regulation area becomes uniform.

Even after the irradiation of the center of the first wafer (11) is completed,
The turntable (2) continues to rotate at a constant speed, and the second wafer (12) is placed in the window (22) of the beam mask (21).
) and approaches below the electron beam source (6). At this time, the electron beam source (6) is in the area (6a) in FIG.
) must have returned to the position indicated. That is,
The electron beam source (6) is also the same as the turntable (2) <1
It must be rotated 80 degrees.

Since the linear beam has no directivity in its longitudinal direction, in this embodiment, the electron beam source (6) can be continuously rotated, and its rotation control becomes extremely simple. In this case, the electron beam source (6) is supplied with power via a slip ring.

Note that a microcomputer can also be used to control the rotation of the motors (71) and (4).

First time (7)i for both wafers (11) and (12)
When the f beam beam irradiation is finished, the rotation of the turntable (2) is stopped and the mask (
22), engage the clutch CL, and move both holding stands (41) and (42) in the radial direction of the turntable (2) symmetrically with respect to the rotation axis (3) of the turntable (2). do. In order to make the second beam irradiation regulation area (the area outlined by the chain line (22S) in Fig. 4) adjacent to the first beam, the moving distance is set equal to the width W of the window (22) of the beam mask (21). be done. Below, the clutch CL is separated, the mask (2 parts) is lowered, the turntable (
By repeating the wafer movement through the cycle of rotation, electron beam irradiation, and stop of the turntable in step 2), the entire surface of the wafer can be uniformly processed.

Incidentally, the radius of curvature of the upper and lower edges of the wide arc-shaped irradiation area on the wafer to be processed is equal to the distance R between the respective rotation centers of the turntable and the electron beam source, as described above. When the rotation angle 2θ of the turntable and beam plate during one beam irradiation period is constant, the length of the arc of the irradiation area increases as the distance R between the rotation centers increases, and the irradiation area becomes thicker. Therefore, the number of irradiations per wafer can be reduced.

This situation is shown in FIG. In FIG. 5, C6° is the center of rotation of the electron beam source (6). Since the other parts correspond to those in FIG. 3, they are given the same reference numerals and redundant explanation will be omitted.

As shown in Figure 5, the electron beam source (6t ((6a)
- (6c)), for example, move the motor (71) in Fig. 2 in the radial direction of the turntable (2), and fix the center of the arm member to its rotation axis (72). A pair of linear electron beam sources may be attached to both ends of the arm member so that the longitudinal directions of the beams are on the same straight line, and the arm member may be continuously rotated in synchronization with the turntable (2).

Alternatively, the electron beam source (6) is attached to only one end of the arm member, an appropriate balancer is attached to the other end, and a drive motor (71) with excellent start-up characteristics, such as a step motor, is used. Electron beam #(6) may be rotated clockwise during the electron beam pause period.

In order to perform the required constant speed rotation even in such reciprocating rotation, it is preferable to provide a rising period and a falling period before and after the required constant speed period.

Note that as the distance between the rotation centers of the turntable and electron beam source increases, the shape of the irradiation area on the wafer becomes smaller.
The beam mask becomes close to a rectangular shape, and the portion shielded by the beam mask can be reduced.

Although the present invention has been described above in the case where it is applied to silicon wafer processing using an electron beam, the present invention is not limited to the above embodiments, and linear beams such as laser light, X-rays, heat rays, ion beams, etc., and the object to be processed can be applied to not only semiconductors but also insulators and metals.

〔Effect of the invention〕

As described in detail above, according to the present invention, the object to be processed is preheated through the opening provided in the rotating table corresponding to the movement range of the object to be processed in the radial direction of the rotating table. Uniform preheating is possible regardless of the movement of the body, and the recrystallization processing conditions are constant.

[Brief explanation of drawings]

1 and 2 are a plan view and a block diagram showing one embodiment of a linear energy beam irradiation device according to the present invention, and FIG.
5 to 5 are route maps for explaining the present invention, FIGS. 6 and 7 are plan views and block diagrams showing an example of a conventional linear energy beam irradiation device, and FIG. 8 is an explanation of the conventional device. This is a route map provided for. (2) is a turntable, (6) is a linear energy beam source, (12) is an infrared lamp, (21) is a beam mask,
(23) is the mask lifting mechanism, (41), (42)
is a wafer holding table, (51) is a moving motor, (71)
is the motor for rotating the beam plow. Figure 1 Figure 2 Figure 4 Figure 8

Claims (1)

[Claims] A rotating table on which an object to be processed is placed, a linear energy beam source arranged in a radial direction of the rotating table, and a heating means arranged on the opposite side of the linear energy beam source with respect to the rotating table. A linear energy beam irradiation device that irradiates the object to be processed with a linear energy beam from the linear energy beam source, further comprising a moving means for moving the object to be processed in a radial direction of the rotary table. and a linear energy beam irradiation device, characterized in that the rotary table is provided with an opening corresponding to a movement range of the object to be processed, and the object to be processed is heated by the heating means through the opening. .