JPH10102249A - Substrate holder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the cracking and chipping of a substrate by adopting the constitution to house balls movable on the substrate side surface of a clamper in such a manner that these balls project from the clamper surface. SOLUTION: The plural points on the substrate 2 side surface of the clamper 6 are provided with recessed parts 16 and the balls 18 are rollably housed respectively in these recessed parts 16 in such a manner that the top parts of the balls 18 project outside from the clamper surface 6a. The substrate 2 is retained toward a base 4 by the balls 18. When there is a heat input to the substrate 2 by irradiation with ion beams, etc., and thermal expansion arises in an arrow B direction, the balls 18 roll in the thermal expansion direction as shown by an arrow C in the recessed part 16 and, therefore, the balls 18 do not restrain the thermal expansion of the substrate 2 even if the substrate 2 is held by the balls 18. The clamper 6 does not come into contact with the substrate 2 and, therefore, the thermal expansion of the substrate 2 is not restrained. Then, the successful escape of the thermal expansion of the substrate 2 is made possible and the generation of thermal stresses in the substrate 2 is averted. Consequently, the occurrence of the trouble, such as cracking and chipping, of the substrate 2 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an ion implantation apparatus, an ion doping apparatus (non-mass separation type ion implantation apparatus), an ion beam etching apparatus, etc.
The present invention relates to a substrate holding device used when particles having energy such as an ion beam and plasma are incident on a substrate in a vacuum or an atmosphere close thereto, and more particularly to a means for preventing cracks or chipping of the substrate during thermal expansion.

[0002]

2. Description of the Related Art FIGS. 5 and 6 show a conventional example of this type of substrate holding apparatus.

This substrate holding device comprises a base 4 for supporting a substrate (eg, a glass substrate or a semiconductor substrate) 2 and a substrate 2
And a frame-shaped (in other words, annular) clamper 6 that presses the peripheral portion of the substrate 2 toward the base 4, and holds the substrate 2 between the base 4 and the clamper 6. I have. The base 4 and the clamper 6 are usually made of a metal such as aluminum or stainless steel. The base 4 may be accompanied by movements such as rotation and inclination during the substrate processing.
Is relatively strongly held by the above structure.

A plurality of clamper shafts 8 penetrate the base 4 so as to be vertically movable, a clamper 6 is attached to an upper end thereof, and a connecting plate 12 is attached to a lower end thereof. Around each clamper shaft 8, a spring (for example, a compression coil spring) 10 that elastically pushes down each clamper shaft 8 and the clamper 6 toward the base 4 is provided. A spring 10 is used to press the clamper 6.
Other means, such as an actuator, may be used.

The substrate 2 held as described above can be subjected to a process such as ion implantation by irradiating the substrate 2 with, for example, an ion beam 14 through the opening of the clamper 6.

At the time of processing, the substrate 2 receives a heat input due to incidence of the ion beam 14 or the like. Most of the heat is transferred from the substrate 2 to the base 4 and further discharged to the outside by a refrigerant (not shown) normally flowing in the base 4.
Thus, the cooling of the substrate 2 is performed.

[0007]

When the substrate 2 is processed, the substrate 2 is cooled to some extent by the above-mentioned means, but it cannot be completely cooled, and the temperature of the substrate 2 inevitably increases. I do. For example, the temperature of the substrate 2 is 3
It may rise to about 00 ° C.

In this case, in the conventional substrate holding apparatus, the peripheral portion of the substrate 2 is strongly restrained by the clamper 6 by directly abutting the clamper 6 on the peripheral portion of the substrate 2. Even if thermal expansion due to the rise (thermal expansion in the direction along the plate surface of the substrate 2; the same applies hereinafter), the thermal expansion cannot be released, and a large thermal stress is generated in the substrate 2 and 2 had a problem that defects such as cracks and chips occurred. Particularly, the glass substrate has a large thermal expansion coefficient and is easily broken.

SUMMARY OF THE INVENTION Therefore, the present invention mainly provides a substrate holding device capable of preventing a problem such as cracking or chipping from occurring in a substrate by properly releasing the thermal expansion even if the substrate is thermally expanded. Aim.

[0010]

According to the present invention, there is provided a substrate holding apparatus in which a rollable ball is housed at a plurality of positions on a substrate side of the clamper such that a tip portion thereof protrudes from the clamper surface. Is held down by the ball.

According to the above arrangement, when thermal expansion occurs due to heat input to the substrate, the sphere in the clamper rolls in the direction of the thermal expansion, so that the clamper and the sphere do not restrict the thermal expansion of the substrate. Therefore, the thermal expansion of the substrate can be well escaped. As a result, it is possible to prevent a problem such as cracking or chipping from occurring on the substrate.

[0012]

FIG. 1 is a sectional view showing an example of a substrate holding device according to the present invention. FIG. 2 is a plan view of the substrate holding device of FIG. FIG. 3 is an enlarged sectional view of a portion A in FIG. 5 and 6 are denoted by the same reference numerals, and differences from the conventional example will be mainly described below.

In this embodiment, recesses 16 are provided at a plurality of positions on the surface of the clamper 6 on the substrate 2 side, and a ball 18 is rolled in each of the recesses 16 so that the ball 18 can be rolled in the recess 16. The tip of the ball 18 is the clamper surface 6a
(See Fig. 3)
The substrate 2 is configured to be pressed toward the base 4 by the balls 18. Therefore, the upper surface of the substrate 2 is the sphere 1
8 only.

In this embodiment, as shown in FIG. 3, a ball holder 20 is provided in each of the recesses 16, and the ball 18 is held by the ball holder 20 so as to be able to roll (roll). I have. This structure is similar to a ball bearing.

The spheres 18 are preferably arranged substantially uniformly around the periphery of the substrate 2. In the example of FIG. 1 and FIG.
Has a square shape, and accordingly, the clamper 6 also has a square shape. Each of the four sides of the clamper 6 has a sphere 1
8 are arranged two by two. However, one ball 18 may be arranged on each side, or three or more balls 18 may be arranged. In any case, it is preferable to arrange the balls 18 around the substrate 2 as evenly as possible from the viewpoint of holding the substrate 2 as evenly as possible.

When the substrate 2 has a circular shape as in the example shown in FIG. 4 and the clamper 6 has a corresponding circular shape, a plurality of, preferably four, Preferably, one, six, eight or more spheres 18 are arranged as evenly as possible (ie at equal intervals).

Since the temperature of the substrate 2 becomes high during processing, for example, about 300 ° C. as described above, it is preferable to use a material having high heat resistance, such as ceramics or metal, for the sphere 18.

The substrate 2 is irradiated with an ion beam 14 or the like.
When there is a heat input to the substrate 2 and thermal expansion occurs on the substrate 2 as shown by an arrow B in FIG. 3, for example, the sphere 18 moves in the concave portion 16 of the clamper 6 as shown by an arrow C in FIG. Since the ball 2 rolls in the direction of thermal expansion, the ball 18 does not restrict the thermal expansion of the substrate 2 even if the ball 2 is pressed against the substrate 2. Of course, since the clamper 6 is not in contact with the substrate 2, it does not restrict the thermal expansion of the substrate 2. Therefore, the thermal expansion of the substrate 2 can be successfully released, and no thermal stress is generated on the substrate 2. As a result, it is possible to prevent a problem such as cracking or chipping from occurring in the substrate 2.

It is to be noted that a roller may be used as a rolling element instead of the ball 18. In this case, since the rolling direction of the rollers is determined, the rollers must be arranged so as to be orthogonal to the direction of thermal expansion of the substrate 2. However, the direction of thermal expansion of the substrate 2 is not uniform. And substrate 2
Is not always fixed due to uneven cooling performance of Therefore, it is difficult for the rollers to escape the thermal expansion of the substrate 2 properly. On the other hand, if the ball 18
Since it can roll in any direction 360 degrees, the substrate 2
Whatever the direction of thermal expansion of the material, the thermal expansion can be successfully released.

From the viewpoint of releasing the thermal expansion of the substrate 2, the sphere 18 may be provided only on one of the opposing sides of the rectangular clamper 6 (for example, on the upper side and the right side in FIG. 2). By doing so, even if the substrate 2 is strongly restrained by the clamper 6 on the opposite side, the substrate 2 can freely thermally expand in the direction of the side where the ball 18 is provided. 2 can escape the thermal expansion well. The same applies to the case where the clamper 6 is circular. In the case described above, for example, the clamper 6
By slightly increasing the side on which the ball 18 is not provided, the clamper 6 can be made parallel to the substrate 2.

[0021]

As described above, according to the present invention, since the clamper and the sphere provided thereon do not restrain the thermal expansion of the substrate, the thermal expansion of the substrate can be satisfactorily released. It is possible to prevent a problem from occurring.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a substrate holding device according to the present invention.

FIG. 2 is a plan view of the substrate holding device of FIG.

FIG. 3 is an enlarged sectional view of a portion A in FIG. 1;

FIG. 4 is a plan view showing another example of the substrate holding device according to the present invention.

FIG. 5 is a sectional view showing an example of a conventional substrate holding device.

FIG. 6 is a plan view of the substrate holding device of FIG. 5;

[Explanation of symbols]

 2 substrate 4 base 6 clamper 16 recess 18 ball

Claims (1)

[Claims] 1. A substrate holding apparatus comprising: a base for supporting a substrate; and a frame-shaped clamper for pressing a peripheral portion of the substrate toward the base, wherein the clamper can be rolled at a plurality of positions on a substrate-side surface of the clamper. A substrate holding device, wherein a base ball is housed so that a tip portion thereof protrudes from a clamper surface, and the substrate is pressed by the ball.