JPH0551180B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is used in a device, such as an ion implantation device, that irradiates a substrate on a holder with an ion beam, and detects the presence or absence of a substrate on the holder. The present invention relates to a substrate detection device for detecting a substrate.

[Background technology]

FIG. 3 is a plan view partially showing an example of the holder and surroundings of the ion implantation device, and FIG. 4 is a schematic sectional view taken along the line - in FIG. 3. For example, a holder (also called a platen in this case) 6 attached to a rotating shaft 4 is provided in a vacuum container (not shown) provided in an end station of an ion implanter. By such rotation, the holder 6 is rotated, for example, to a substrate loading/unloading position (for example, a horizontal position) as shown by the solid line in FIG. It will be done. Further, on the upper surface of the holder 6, there is provided a holding plate (also called a clamper) 8 which has an opening 8a of a size approximately corresponding to the substrate (for example, a wafer) 2 to be held and is movable up and down. Therefore, the substrate 2 is pressed and held on the holder 6. 10 is a conveyor belt for attachment and detachment to the substrate 2.

Then, the substrate 2 is attached to and removed from the holder 6 at the substrate attachment/detachment position, for example, the substrate 2 is carried in and out as shown by arrow B in FIG. 3, and the ion beam 12 is irradiated onto the substrate 2 on the holder 6 at the substrate processing position. Then, ion implantation is performed.

In that case, when performing the above-mentioned control etc., it is preferable to detect the presence or absence of the substrate 2 on the holder 6, and a substrate detection device as shown in the figure may be used for this purpose. That is, in this device, a through hole 16 is formed perpendicularly to the surface of the holder 6, and an optical sensor 18, such as a light emitter 18a, is placed below the through hole 16, and a light receiver 18b, for example, is placed above the through hole so as to face each other. Yes, opaque substrate 2 is placed on holder 6
When the substrate 2 is carried in, the substrate 2 blocks the light 20 from the light emitter 18a from entering the light receiver 18b, thereby detecting the presence or absence of the substrate 2.

[Problems with background technology]

However, in the substrate detection device as described above, since it detects the interruption of the light 20 due to the substrate 2, it is not possible to detect the presence or absence of a transparent substrate 2 such as quartz glass. In addition, since the through hole 16 is perpendicular to the holder 6, the substrate 2 may for some reason be moved against the holder 6 at the substrate processing position.
If the ion beam 12 is irradiated without the ion beam 12, the ion beam 12 will pass through the through hole 16 to the back side of the holder 6, which will have an adverse effect on other equipment (the ion beam 12 shown in FIG. 'reference).

SUMMARY OF THE INVENTION Therefore, the main object of the present invention is to provide an improved substrate detection device that is capable of detecting a transparent substrate and prevents an ion beam from accidentally passing through to the back side of a holder.

[Means to achieve the purpose]

The substrate detection device of the present invention has two inclined holes provided in a holder so as to pass through the holder, which are inclined in an inverted V shape so that the ion beam does not pass through the inclined holes to the back side of the holder. and an optical sensor consisting of a combination of a light emitting device and a light receiving device provided on or near the back of the holder, and the light from the light emitting device passes through one inclined hole to the substrate on the holder. and reflected light from the substrate enters the light receiver through the other inclined hole.

[Effect]

When the substrate is loaded onto the holder, light from the light emitter is reflected by the surface of the substrate and enters the light receiver. This reflected light can be obtained regardless of whether the substrate is transparent or opaque. Therefore, the substrate can be detected in either case. Further, since the holder is provided with an inclined hole, the ion beam is blocked by the inner wall of the inclined hole and is prevented from passing to the back side of the holder.

〔Example〕

FIG. 1 is a schematic cross-sectional view showing a substrate detection device according to an embodiment of the present invention. This figure corresponds to what is seen in the direction of the line in FIG. 3, where the holder 6 is, for example, in the board attachment/detachment position, and the holding plate 8 is not shown (the same applies to FIG. 2). Further, the same or equivalent parts as in FIGS. 3 and 4 are given the same reference numerals, and the explanation thereof will be omitted.

The substrate detection device of this embodiment includes two inclined holes 22a and 22b provided in the holder 6 at an angle so as to penetrate the holder 6, as described above;
Each inclined hole 22a, 22 on the back side of the holder 6
a light sensor 18 consisting of a combination of a light emitter 18a and a light receiver 18b respectively embedded in the rear of the light emitter 18a, and light 20 from the light emitter 18a enters the substrate 2 on the holder 6 through an inclined hole 22a;
The structure is such that reflected light 20' from the substrate 2 enters the light receiver 18b through the inclined hole 22b.
Both inclined holes 22a and 22b are provided to be inclined in an inverted V shape so that the ion beam 12, which will be described later, does not pass through the inclined holes 22a and 22b to the back side of the holder 6.

When the substrate 2 is loaded onto the holder 6, light 20 from the light emitter 18a is reflected by the surface of the substrate 2 and enters the light receiver 18b as reflected light 20'. This reflected light 20' is obtained regardless of whether the substrate 2 is transparent or opaque, and since the reflected light 20' is received by the light receiver 18b located near the substrate 2, the light receiver 18b receives the reflected light 20'.
The reflected light 20' can be sufficiently detected at 8b. The light receiver 18b is, for example,
When the reflected light 20' is present, a signal indicating that the substrate is present is output, and when the reflected light 20' is absent, a signal indicating that the substrate is not present is output.

In this way, in this substrate detection device, the light 20 from the light emitter 18a is reflected diagonally from the back surface of the substrate 2, and the reflected light 20' is received by the light receiver 18b located near the substrate 2. , not only opaque substrates but also transparent or highly transmittance substrates 2, the reflected light 20'
can be sufficiently detected by the light receiver 18b to detect the presence or absence of the substrate 2.

Moreover, the light from the light emitter of an optical sensor generally has a certain divergence angle, and the light receiver has a certain viewing angle. Although there is a high possibility of false detection due to reflected light from nearby structures, in this board detection device, the two inclined holes 22a, 2
2b acts like a collimator, condensing the light from the emitter 18a and making it incident on the substrate 2, and also narrowing the field of view of the photodetector 18b to the reflective area of the substrate 2, thereby preventing false detection. The probability is lower, thus increasing the reliability of substrate detection. especially,
This effect is significant when the substrate 2 is transparent or has high transmittance and the reflected light 20' is weak.

On the other hand, when the holder 6 is in the substrate processing position,
The ion beam 12 is connected as shown by the broken line in the figure.
will be irradiated (this relationship will become clearer with reference to FIGS. 3 and 4). In that case, even if the ion beam 12 is irradiated without the substrate 2 for some reason, the holder 6 has inclined holes 22a, 22 which are inclined in an inverted V shape, unlike the conventional case.
b is provided to direct the ion beam 12 through the inclined holes 22a, 2.
Since the ion beam 12 is blocked by the inner wall of the holder 6, the ion beam 12 does not pass to the back side of the holder 6. Therefore, it is possible to prevent other devices from being adversely affected. In addition, considering the above case, the light emitter 18a and the light receiver 18b are
It is preferable to retreat to a position where the ion beam 12 will not be accidentally irradiated, as shown in the illustrated example.

FIG. 2 is a schematic cross-sectional view showing a substrate detection device according to another embodiment of the invention. Mainly, the difference from the embodiment shown in FIG. 1 will be explained. In this embodiment, a light emitter 18a and a light receiver 18b of the optical sensor 18 are provided near the back surface of the holder 6. The inclined holes 22a and 22b are substantially the same as those shown in FIG. 1, except that they extend straight through to the back side of the holder 6. In this embodiment, there is no possibility that the ion beam 12 will accidentally irradiate the light emitter 18a or the light receiver 18b. Other effects are almost the same as in the case of FIG.

[Effects of the Invention] As described above, according to the present invention, the light from the light emitter is reflected diagonally on the back surface of the substrate, and the reflected light is received by the light receiver near the substrate, so that it is not opaque. Not only a transparent substrate but also a substrate with high transmittance, the reflected light from the substrate can be sufficiently detected by the light receiver to detect the presence or absence of the substrate.

Moreover, the light from the light emitter of an optical sensor generally has a certain divergence angle, and the light receiver has a certain viewing angle. There is a high possibility of false detection due to reflected light from nearby structures, but in this board detection device, each of the two slanted holes acts like a collimator and narrows down the light from the light emitter. Since the light can be incident on the substrate and the field of view of the photoreceiver can be focused on the reflective area of the substrate, the possibility of false detection is low, and therefore the reliability of substrate detection is improved. This effect is particularly significant when the substrate is transparent or has high transmittance and the reflected light is weak.

Also, even if the ion beam is irradiated without the substrate for some reason, the ion beam will be blocked by the inner wall of the inclined hole and will not pass through to the back side of the holder.
It is possible to prevent adverse effects on other devices.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing a substrate detection device according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing a substrate detection device according to another embodiment of the invention. FIG. 3 is a plan view partially showing an example of the holder and surroundings of the ion implantation device. FIG. 4 is a schematic sectional view taken along the line - in FIG. 3. 2... Substrate, 6... Holder, 12... Ion beam, 18... Optical sensor, 18a... Light emitter, 1
8b... Light receiver, 20... Light, 20'... Reflected light,
22a, 22b...slanted holes.

Claims (1)

[Claims] 1. In a substrate detection device used in a device that irradiates an ion beam onto a substrate held on the front side of a holder, two inclined holes are provided in the holder so as to pass through the holder, and the ion beam is It is provided with an inverted V-shaped incline so as not to pass through the hole to the back side of the holder, and a light sensor consisting of a combination of a light emitter and a light receiver provided on or near the back side of the holder. ,
A substrate detection device characterized in that light from a light emitter is incident on a substrate on a holder through one inclined hole, and reflected light from the substrate is incident on a light receiver through another inclined hole.