JP2009123860A - Wafer automatic transfer apparatus, and wafer transfer method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic wafer transfer apparatus enhancing the productivity of an epitaxial wafer, and to provide a wafer transfer method using the same. <P>SOLUTION: The automatic wafer transfer apparatus is of an automatic wafer transfer apparatus for loading or unloading a wafer onto a susceptor of an epitaxial growth reactor and is characterized by having a movable arm, a wafer holding hand attached to the movable arm, a position sensor fixed to the wafer holding hand and monitoring a relative position between the wafer holding hand and the susceptor, and a distance sensor fixed to the wafer holding hand and measuring the distance between the wafer holding hand and the susceptor. This wafer transfer method is of a wafer transfer method using this wafer transfer apparatus. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an automatic wafer transfer apparatus and a wafer transfer method using the same, and more particularly to an automatic wafer transfer apparatus for loading or unloading a wafer on a susceptor of an epitaxial growth apparatus.

  In manufacturing processes of various semiconductor devices such as bipolar, CMOS, and discrete, an epitaxial growth apparatus for growing a single crystal semiconductor film on a semiconductor wafer (hereinafter also simply referred to as “wafer”) has been used.

  Examples of the epitaxial growth apparatus that performs epitaxial growth include a vertical epitaxial growth apparatus (or pancake type apparatus, for example, Patent Document 1, hereinafter also simply referred to as “vertical apparatus”), a barrel type epitaxial growth apparatus (or cylinder apparatus, for example, Patent Document 2). Hereinafter, also simply referred to as “barrel type device”), a single wafer device, and the like. Among them, the vertical type apparatus and the barrel type apparatus are widely used for manufacturing epitaxial wafers because they can process a large number of wafers at a time and are excellent in mass productivity.

  In such an epitaxial growth apparatus, the semiconductor single crystal film is epitaxially grown by placing the wafer on a circular concave counterbore (or counterbore) provided on the susceptor. Conventionally, loading and unloading of a wafer to a susceptor has been performed manually. This is because, when an automatic transfer device is used when placing a wafer on the susceptor, the wafer or the wafer holding hand of the automatic transfer device collides with the susceptor surface or the edge of the counterbore, thereby causing a chipping or dusting of the wafer. This is because it is difficult to avoid contamination. Even if chipping or dust generation of the wafer can be suppressed to some extent, the positional accuracy of the wafer with respect to the susceptor is poor, and the wafer may be displaced from the center of the counterbore. It depends on what was connected to.

Thus, manual loading and unloading of wafers has been an impediment to improving the productivity of epitaxial wafers. In addition, variations in product characteristics due to differences in the skill levels of workers have also been a problem.
JP-A-8-250429 JP-A-10-87394

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an automatic wafer transfer apparatus and a wafer transfer method using the same, which improve the productivity of epitaxial wafers. is there.

  An automatic wafer transfer apparatus according to an aspect of the present invention is an automatic wafer transfer apparatus for loading or unloading a wafer on a susceptor of an epitaxial growth apparatus, a movable arm, a wafer holding hand attached to the movable arm, A position sensor fixed to the wafer holding hand and monitoring a relative position between the wafer holding hand and the susceptor; and a distance sensor fixed to the wafer holding hand and measuring a distance between the wafer holding hand and the susceptor. It is characterized by having.

  Here, it is preferable that the epitaxial growth apparatus is a barrel type epitaxial growth apparatus, and the wafer holding hand is provided with a pair of wafer guides having a tapered shape at a portion in contact with the wafer.

  Here, it is preferable that a portion of the wafer guide that contacts the wafer is polyimide.

  A wafer transfer method according to an aspect of the present invention is a wafer transfer method using the above-described wafer automatic transfer apparatus according to an aspect of the present invention, the step of gripping the wafer by the wafer holding hand, Using a position sensor and a pattern on the susceptor to move the wafer holding hand to a desired position relative to the susceptor; and using the distance sensor to determine a distance between the wafer holding hand and the susceptor. While measuring, the method has a step of bringing the wafer holding hand closer to the susceptor and a step of placing the wafer on a spot facing provided on the susceptor.

  A wafer transfer method according to an aspect of the present invention is a wafer transfer method using the wafer automatic transfer apparatus according to an aspect of the present invention provided in the above-described wafer guide, and holds the wafer on the wafer holding hand. Moving the wafer holding hand to a desired position with respect to the susceptor using the position sensor and a pattern on the susceptor; and using the distance sensor, the wafer holding hand and the susceptor. Measuring the distance between the wafer holding hand and the susceptor, and placing the wafer on a counterbore provided on the susceptor by sliding on the wafer guide. It is characterized by.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the wafer transfer method and wafer transfer method using the same which improve the productivity of an epitaxial wafer.

  Embodiments of an automatic wafer transfer apparatus and a wafer transfer method using the same according to the present invention will be described below with reference to the accompanying drawings.

(First embodiment)
The wafer automatic transfer apparatus according to the first embodiment of the present invention is an automatic wafer transfer apparatus for loading or unloading a wafer on a susceptor of an epitaxial growth apparatus. A movable arm, a wafer holding hand attached to the movable arm, a position sensor fixed to the wafer holding hand and monitoring a relative position between the wafer holding hand and the susceptor, and a wafer holding hand fixed to the wafer holding hand. It has a distance sensor that measures the distance between the hand and the susceptor.

  In the present embodiment, a case where the epitaxial growth apparatus is a vertical apparatus will be described as an example.

  FIG. 2 is a sectional view of the vertical apparatus used in the first embodiment. As shown in FIG. 2, the vertical apparatus 60 includes a rotating disk-shaped susceptor 64 in a hemispherical quartz bell jar 62 having a large volume serving as a reaction furnace. A plurality of wafers 66 are horizontally arranged on the susceptor 64. The reaction gas is ejected radially from the gas ejection hole 70 of the gas supply pipe 68 provided at the center of the susceptor 64 along the upper surface of the susceptor 64. Then, the reaction gas and the reaction product gas generated by the reaction are discharged out of the quartz bell jar 62 from, for example, two exhaust holes 2 provided below the quartz bell jar 62 on the outer periphery of the susceptor 64. Further, the wafer 66 is heated by high-frequency induction heating by a coil 64 provided inside the quartz bell jar 62. Then, the disk-shaped susceptor 64 rotates to uniformize the heating of the wafer 66 and the supply of the reaction gas to the wafer 66.

  FIG. 3 is an explanatory diagram of the wafer automatic transfer apparatus according to the present embodiment for loading or unloading a wafer on the susceptor of the vertical apparatus as shown in FIG. In the wafer automatic transfer apparatus 10 of the present embodiment, a movable arm 14 is provided on a gantry 12. A wafer holding hand 16 capable of holding the wafer 66 is attached to the tip of the movable arm 14.

  The automatic wafer transfer device 10 loads or unloads a wafer 66 between a wafer transfer unit 40 and a plurality of circular concave counterbore 68 provided on a susceptor 64 of a vertical device 60. Here, a wafer cassette 42 is placed on the wafer delivery unit 40, and the wafer 66 can be moved between the wafer delivery unit 44.

  FIG. 1 is an explanatory diagram of a wafer holding hand according to the present embodiment. FIG. 1A is a side view, and FIG. 1B is a front view.

  The wafer holding hand 16 is provided with three claws 18 for holding the wafer 66. The claws 18 are movably provided to hold the wafer 66. The portion of the claw 18 in contact with the wafer 66 is made of a material having higher elasticity than ceramics or metal, for example, a resin such as polyimide, so that the wafer 66 is not damaged during the operation of holding the wafer 66. It is desirable.

  Here, the claw 18 is used as the mechanism for holding the wafer. However, for example, a mechanism for holding the wafer surface by suction may be applied.

  The wafer holding hand 16 is provided with a position sensor 20 that is fixed to the wafer holding hand 16 and monitors the relative position between the wafer holding hand 16 and the susceptor. The position sensor 20 is an imaging device that optically recognizes the susceptor surface. For example, a TV camera, a CCD, a CMOS sensor, or the like can be applied.

  The wafer holding hand 16 is provided with a distance sensor 22 that is fixed to the wafer holding hand 16 and measures the distance between the wafer holding hand 16 and the susceptor. As this distance sensor, for example, a laser interferometer or the like is applicable.

  Next, a wafer transfer method using the wafer automatic transfer apparatus of the present embodiment will be described with reference to FIGS.

  The wafer transfer method of the present embodiment includes a step of holding the wafer in the wafer holding hand, a step of moving the wafer holding hand to a desired position with respect to the susceptor using a position sensor and a pattern on the susceptor, And measuring the distance between the wafer holding hand and the susceptor using a distance sensor, and bringing the wafer holding hand closer to the susceptor and placing the wafer on a spot facing provided on the susceptor. To do.

  First, a case where the wafer 66 is loaded on the vertical apparatus 60 will be described. The wafer 66 is introduced into the wafer cassette 42 of the wafer delivery unit 40 shown in FIG. Then, the wafer 66 is moved to the wafer transfer unit 44 by the transfer arm of the wafer transfer unit 40.

  Thereafter, the movable arm 14 of the automatic wafer transfer device 10 is moved, and the wafer holding hand 16 is moved so as to be directly above the wafer delivery unit 44. Thereafter, with the claw 18 (FIG. 1) opened outward, the wafer holding hand 16 is lowered to the wafer 66 and the claw 18 is closed to hold the wafer 66 horizontally.

  Thereafter, by moving the movable arm 14, the wafer holding hand 16 holding the wafer 66 is moved up and horizontally moved to a position directly above the predetermined counterbore 68 on the surface of the susceptor 64 of the vertical apparatus 60. At this time, the position sensor 20 (FIG. 1) is used to ensure that the wafer 66 is placed on the center of a predetermined spot facing 68.

  For example, the position sensor 20, which is a CCD, recognizes a pattern on the susceptor 64, for example, a reference mark provided exclusively for alignment, adjusts the position of the wafer holding hand 16, and only relies on, for example, machine accuracy. Align with higher accuracy.

  The wafer holding hand 16 is lowered to the surface of the susceptor 64 by moving the movable arm 14 after moving it to a position just above the predetermined counterbore 68. At this time, for example, the distance sensor 22 (FIG. 1), which is a laser interferometer, adjusts the vertical position of the wafer holding hand 16 by monitoring the distance, and the wafer holding hand 16 and the wafer 66 held by the wafer holding hand 16 are moved to the susceptor. 64 Control is performed so as not to collide with the surface or the counterbore 68.

  Then, the claw 18 of the wafer holding hand 16 is opened outward, the wafer 66 is detached, and soft landing is performed on a predetermined spot facing 68.

  The unloading of the wafer 66 from the susceptor 64 is performed in the reverse procedure of the above-described loading.

  The loading and unloading of the wafer is controlled by a computer (not shown) connected to the automatic wafer transfer apparatus 10.

  According to the wafer automatic transfer apparatus and the wafer transfer method using the same according to the present embodiment, the position sensor fixed to the wafer holding hand and monitoring the relative position between the wafer holding hand and the susceptor, and the wafer holding hand It is possible to monitor and control the horizontal and vertical positions of the wafer holding hand with respect to the susceptor with extremely high accuracy by the distance sensor fixed to the wafer and measuring the distance between the wafer holding hand and the susceptor. Therefore, it is possible to avoid contamination due to chipping or dust generation caused by the wafer or the wafer holding hand of the automatic wafer transfer apparatus colliding with the susceptor surface or the counterbore edge. It is also possible to avoid wafer defects caused by the wafer being displaced from the center of the spot facing.

(Second Embodiment)
The automatic wafer transfer apparatus according to the second embodiment of the present invention is used in a barrel type apparatus, and the wafer holding hand is provided with a pair of wafer guides having a tapered shape at a portion in contact with the wafer. Is the same as in the first embodiment.

  FIG. 4 is a cross-sectional view of a barrel type apparatus used in the second embodiment.

  For example, in a cylindrical container 72 made of transparent quartz, a susceptor 74 provided with a plurality of circular concave counterbore 78 is mounted, on which a wafer (not shown) is placed in a substantially upright state. Has been lowered.

  Here, the susceptor 74 has a polygonal frustum shape, here a hexagonal frustum shape, as shown in the perspective view of FIG. 5B, the susceptor 74 includes a plurality of trapezoidal panels 84, here, six trapezoidal panels. The susceptor 74 is made of, for example, carbon (C) whose surface is coated with silicon carbide (SiC).

  As shown in FIG. 4, the cylindrical container 72 covers the susceptor 74 coaxially. In the upper part of the cylindrical container 72, a gas introduction port 76 for introducing a reaction gas is provided. In addition, a gas discharge port 80 for discharging unreacted reaction gas or gas generated by the reaction is provided at the lower portion of the cylindrical container 72. The reaction gas introduced from the gas introduction port 76 is introduced between the susceptor 74 and the cylindrical container 72 and flows downward as indicated by a dotted arrow in the figure.

  A heater 22 such as a halogen lamp is provided outside the cylindrical container 72. With this heater 82, the wafer placed on the susceptor 74 can be heated.

  The pyramidal trapezoidal susceptor is rotatable about its own axis. By rotating in this way, the heating of the wafer and the supply of the reaction gas to the wafer are made uniform. In this way, it is possible to form a single crystal epitaxial layer on the wafer placed on the susceptor 74 by supplying the reaction gas while heating the wafer.

  FIG. 5 is an explanatory diagram of the wafer automatic transfer apparatus of the present embodiment for loading or unloading a wafer on the susceptor of the barrel type apparatus as shown in FIG. As in the first embodiment, the automatic wafer transfer apparatus 10 of the present embodiment is provided with a movable arm 14 on a gantry 12. A wafer holding hand 16 capable of holding the wafer 66 is attached to the tip of the movable arm 14.

  This automatic wafer transfer device 10 loads or unloads a wafer 66 between a wafer transfer unit 40 and a plurality of circular concave counterbore 78 (FIG. 5) provided on the susceptor 74 of the barrel type device 70. To do. Here, a wafer cassette 42 is placed on the wafer delivery unit 40, and the wafer 66 can be moved between the wafer delivery unit 44.

  FIG. 7 is an explanatory diagram of the wafer holding hand 16 of the present embodiment. FIG. 7A is a side view and FIG. 7B is a front view.

  The wafer holding hand 16 is provided with three claws 18 for holding the wafer 66. One of the claws 18 is movably provided to hold the wafer 66. The portion of the claw 18 in contact with the wafer 66 is made of a material having higher elasticity than ceramics or metal, for example, a resin such as polyimide, so that the wafer 66 is not damaged during the operation of holding the wafer 66. It is desirable.

  Here, the claw 18 is used as the mechanism for holding the wafer. However, for example, a mechanism for holding the wafer surface by suction may be applied.

  Further, the wafer holding hand 16 is provided with a pair of wafer guides 26 in which a portion in contact with the wafer 66 has a tapered shape. The portion of the wafer guide 26 that contacts the wafer 66 is also made of a material having higher elasticity than ceramics or metal, for example, a resin such as polyimide, so that the wafer 66 is not damaged during the holding operation. It is desirable that

  As in the first embodiment, the wafer holding hand 16 is provided with a position sensor 20 that is fixed to the wafer holding hand 16 and monitors the relative position between the wafer holding hand 16 and the susceptor. The position sensor 20 is an imaging device that optically recognizes the susceptor surface. For example, a TV camera, a CCD, a CMOS sensor, or the like can be applied.

  The wafer holding hand 16 is provided with a distance sensor 22 that is fixed to the wafer holding hand 16 and measures the distance between the wafer holding hand 16 and the susceptor. As this distance sensor, for example, a laser interferometer or the like is applicable.

  Next, a wafer transfer method using the wafer automatic transfer apparatus of the present embodiment will be described with reference to FIGS.

  The wafer transfer method of the present embodiment includes a step of holding the wafer in the wafer holding hand, a step of moving the wafer holding hand to a desired position with respect to the susceptor using a position sensor and a pattern on the susceptor, While measuring the distance between the wafer holding hand and the susceptor using a distance sensor, the wafer holding hand is moved closer to the susceptor, and the wafer is slid on the wafer guide in a spot facing provided on the susceptor. And a step of mounting.

  First, a case where the wafer 66 is loaded on the vertical apparatus 70 will be described. The wafer 66 is introduced into the wafer cassette 42 of the wafer delivery unit 40 shown in FIG. Then, the wafer 66 is moved to the wafer transfer unit 44 by the transfer arm of the wafer transfer unit 40.

  Thereafter, the movable arm 14 of the automatic wafer transfer device 10 is moved, and the wafer holding hand 16 is moved so as to be directly above the wafer delivery unit 44. Thereafter, with the movable claw 18 (FIG. 7) opened, the wafer holding hand 16 is lowered to the wafer 66 and the claw 18 is closed to hold the wafer 66.

  Thereafter, by moving the movable arm 14, the wafer holding hand 16 holding the wafer 66 is raised and horizontally moved, and a predetermined counterbore 78 (FIG. 5) on the surface of the susceptor 74 of the vertical device 70 which is substantially vertical. Move to the front. At this time, the position sensor 20 (FIG. 7) is used to ensure that the wafer 66 is placed on the center of a predetermined spot facing 78.

  For example, the position sensor 20, which is a CCD, recognizes a pattern on the susceptor 74, for example, a reference mark provided exclusively for alignment, and adjusts the position of the wafer holding hand 16. Align with higher accuracy.

  Then, after moving to a predetermined counterbore 78 front, the movable arm 14 is operated to bring the wafer holding hand 16 closer to the susceptor 74 surface. At this time, for example, the horizontal position of the wafer holding hand 16 is adjusted by monitoring the distance by the distance sensor 22 (FIG. 7) which is a laser interferometer, and the wafer holding hand 16 and the wafer 66 held by the wafer holding hand 16 are moved to the susceptor. 74 Control is performed so as not to collide with the surface or the spot facing 78.

  Then, the movable claw 18 of the wafer holding hand 16 is opened downward, the wafer 66 is detached, and the predetermined spot facing 78 is soft-landed using the wafer guide 26.

  FIG. 8 illustrates the operation of the wafer guide. As shown in FIG. 8A, the wafer 66 held by the wafer holding hand is moved to the counterbore 78 using the movable arm. Thereafter, the movable claw 18 (FIG. 7) of the wafer holding hand 16 is moved downward to move the wafer 66 downward as indicated by an arrow.

  As a result, the wafer 66 is placed on the wafer guide 26 as shown in FIG.

  Thereafter, as shown in FIG. 8C, the wafer guide 26 is pulled out by moving the movable arm in the direction of the arrow. At this time, the wafer 66 slides on the wafer guide 26 and is placed on the spot facing 78.

  Conventionally, it has been difficult to transfer a wafer using an automatic wafer transfer device, particularly in a barrel type device having a susceptor surface that is nearly vertical. This is because when the wafer is detached from the nail holding the wafer, the wafer falls downward and contacts the lower side surface of the counterbore at one lower portion of the wafer, so that the impact on the wafer is large and the wafer is easily damaged. Because.

  According to the wafer automatic transfer apparatus of the present embodiment, the impact when the wafer falls downward is mitigated. This is because, since the wafer is first dropped onto the wafer guide 26 that is already close to the wafer holding state, the impact is reduced as compared with the case of dropping onto the lower side surface of the spot facing. For this reason, wafer damage is unlikely to occur. Then, by sliding the taper-shaped surface and finally placing the wafer on the lower side surface of the counterbore in the state where the lower side surface of the counterbore and the lower end of the wafer are close to each other, soft landing is performed because the fall distance is reduced. Is possible.

  Further, unlike the spot facing portion, the wafer guide portion is not exposed to high temperatures. For this reason, as described above, it is possible to apply a resin such as polyimide, which is more thermally unstable than ceramics or metal but has high elasticity. Therefore, it is possible to further absorb the impact of dropping the wafer.

  The unloading of the wafer 66 from the susceptor 74 is performed in the reverse procedure of the above-described loading.

  The wafer loading and unloading described above is the same as in the first embodiment in that it is controlled by a computer (not shown) connected to the automatic wafer transfer apparatus 10.

  And according to the wafer automatic transfer apparatus and the wafer transfer method using the same according to the present embodiment, the position sensor fixed to the wafer holding hand and monitoring the relative position between the wafer holding hand and the susceptor, and the wafer The distance sensor fixed to the holding hand and measuring the distance between the wafer holding hand and the susceptor makes it possible to monitor and control the horizontal and vertical positions of the wafer holding hand with respect to the susceptor with extremely high accuracy. Therefore, it is possible to avoid contamination due to chipping or dust generation due to the wafer or the wafer holding hand of the automatic transfer device colliding with the susceptor surface or the counterbore edge. Further, it is also the same as in the first embodiment in that it is possible to avoid a wafer defect due to the wafer being displaced from the counterbore center.

  The embodiments of the present invention have been described above with reference to specific examples. In the description of the embodiment, the description of the parts that are not directly required for the description of the present invention is omitted in the automatic wafer transfer device and the wafer transfer method using the same, but the required automatic wafer transfer Elements related to the transfer apparatus and the wafer transfer method using the transfer apparatus can be appropriately selected and used.

  In addition, all wafer automatic transfer apparatuses that include elements of the present invention and whose design can be changed as appropriate by those skilled in the art and wafer transfer methods using the same are included in the scope of the present invention.

Explanatory drawing of the wafer holding hand of 1st Embodiment. Sectional drawing of the vertical apparatus used in 1st Embodiment. Explanatory drawing of the wafer automatic transfer apparatus of 1st Embodiment. Sectional drawing of the barrel type apparatus used in 2nd Embodiment. The perspective view which shows the susceptor of the barrel type apparatus used in 2nd Embodiment. Explanatory drawing of the wafer automatic transfer apparatus of 2nd Embodiment. Explanatory drawing of the wafer holding hand of 2nd Embodiment. The figure explaining the effect | action of the wafer guide of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wafer automatic transfer apparatus 14 Movable arm 16 Wafer holding hand 20 Position sensor 22 Distance sensor 26 Wafer guide 64, 74 Susceptor 66 Wafer

Claims (5)

An automatic wafer transfer device for loading or unloading a wafer on a susceptor of an epitaxial growth apparatus,
A movable arm, a wafer holding hand attached to the movable arm,
A position sensor fixed to the wafer holding hand and monitoring a relative position between the wafer holding hand and the susceptor;
An automatic wafer transfer apparatus comprising a distance sensor fixed to the wafer holding hand and measuring a distance between the wafer holding hand and the susceptor.   2. The wafer automatic transfer apparatus according to claim 1, wherein the epitaxial growth apparatus is a barrel type epitaxial growth apparatus, and the wafer holding hand is provided with a pair of wafer guides having a tapered shape at a portion in contact with the wafer. .   3. The wafer automatic transfer device according to claim 2, wherein a portion of the wafer guide that contacts the wafer is polyimide. A wafer transfer method using the wafer automatic transfer device according to claim 1,
Holding the wafer in the wafer holding hand;
Using the position sensor and a pattern on the susceptor to move the wafer holding hand to a desired position relative to the susceptor;
Using the distance sensor to measure the distance between the wafer holding hand and the susceptor while bringing the wafer holding hand closer to the susceptor;
A wafer transfer method comprising a step of placing the wafer on a spot facing provided on the susceptor. A wafer transfer method using the wafer automatic transfer device according to claim 2,
Holding the wafer in the wafer holding hand;
Using the position sensor and a pattern on the susceptor to move the wafer holding hand to a desired position relative to the susceptor;
Using the distance sensor to measure the distance between the wafer holding hand and the susceptor while bringing the wafer holding hand closer to the susceptor;
A wafer transfer method comprising the step of: sliding the wafer on a wafer guide on a spot facing provided on the susceptor.

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