JP7257916B2 - Substrate transfer mechanism for vapor deposition equipment - Google Patents

Description

The present invention relates to a substrate transfer mechanism for a vapor phase growth apparatus, and more particularly to a substrate transfer mechanism for automatically setting a substrate on a susceptor in a vapor phase growth apparatus.

In a vapor phase growth apparatus that manufactures semiconductors by the vapor phase growth method, a substrate made of a wafer of silicon, sapphire, or the like is placed on a susceptor, heated to a high temperature in a chamber, and an organic metal, which is a raw material for semiconductors, is deposited on the surface of the substrate. The contained material and carrier gas are flowed to decompose and chemically react, and a thin film of semiconductor crystal is epitaxially grown on the substrate surface.

In a conventional vapor phase growth apparatus, the substrate is placed on and removed from the susceptor manually, and productivity is not high. In addition, manual placement and removal of the substrate may cause tweezers or the like to come into contact with the substrate surface, or particles generated by rubbing the substrate and the susceptor to adhere to the substrate surface. had caused a decline in

Therefore, a vapor phase growth apparatus having a substrate setting mechanism for automatically setting a substrate on a susceptor has been proposed (see Patent Documents 1 to 3, for example). In the vapor deposition apparatuses described in Patent Documents 1 and 2, a plurality of pins for supporting the substrate are provided on the bottom surface of the susceptor so as to be able to move up and down. , and an arm that carries the substrate on which it is placed.

JP-A-2-112255 JP-A-2000-208419 JP 2003-017544 A

However, in such a configuration, it is necessary to provide a plurality of holes through which the pins are inserted in the bottom surface of the susceptor in order to provide the vertically movable pins on the bottom surface of the susceptor. , resulting in a problem that the uniformity of the film formation of the semiconductor crystal is impaired.

Further, in the vapor phase growth apparatus described in Patent Document 3, a vacuum chuck is provided at the tip of an arm that carries the substrate so that the substrate can be gripped from above. The surface of the filmed semiconductor crystal is easily damaged by contact with the vacuum chuck, impairing the uniform film formation of the semiconductor crystal, which is a factor in lowering the yield of semiconductors.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a substrate transfer mechanism for a vapor phase epitaxy apparatus capable of promoting uniform film formation of semiconductor crystals and achieving a high yield of semiconductors.

To achieve the above object, the present invention provides a substrate transfer mechanism for a vapor phase growth apparatus for setting and removing a substrate from a susceptor at a substrate transfer position, wherein the susceptor has the above-described At a position corresponding to the substrate transfer position, a circular through-hole portion and a disk-shaped substrate mounting table closing the circular hole portion are provided. an upper chuck having a plurality of claws capable of supporting the outer periphery of a substrate transported directly above the substrate transfer position by a transport arm that transports the substrate by reciprocating between the case and the substrate transfer position; and a position above the upper chuck. a cylindrical upper cover having a notch through which the claws of the upper chuck pass and whose inner diameter corresponds to the diameter of the substrate; claw opening/closing means capable of opening and closing the claws of the upper chuck; An upper chuck elevating means capable of elevating the upper chuck and an upper cover elevating means capable of elevating the upper cover are provided. It comprises a lower chuck that grips from below, a lower chuck operating section that operates the lower chuck, and a lower elevating means that can elevate the lower chuck, wherein the substrate mounting table has a larger diameter base than the circular hole. and a columnar base projecting above the base portion and having a diameter corresponding to the substrate, and having a cutting portion obtained by flatly cutting off the side surface of the column at a position corresponding to the claw portion of the upper chuck. and a cylindrical portion projecting downward from the base portion and having an outer diameter smaller than that of the circular hole portion. It is characterized by comprising a plurality of fixtures that can expand and contract to fix the cylindrical portion of the substrate mounting table from the inside.

Further, in the substrate mounting table, the height of the arc formed by the cutting portion with respect to the mounting portion is 0.15% to 1.5% of the diameter of the substrate in plan view. The lower chuck is configured to be rotatable about a vertical axis by the lower chuck operating section, the substrate mounting table includes a phase marker on the cylindrical section, and the lower chuck operating section includes: A phase detection sensor capable of detecting the angular position of the phase marker with respect to the rotating shaft of the lower chuck is provided, and the phase marker is positioned at a preset angular position according to the detection result of the phase detection sensor. It is also characterized in that the lower chuck is rotated, and that the mounting section is provided with projections at three or more rotationally symmetrical positions on the outer circumference of the upper surface.

According to the substrate transport mechanism of the vapor phase growth apparatus of the present invention, the substrate placed by the lower chuck is pushed up from the susceptor by the lower elevating cylinder, and the substrate is transported above the substrate transfer position by the transport arm. The upper chuck supports the outer circumference of the substrate and lowers it by the upper elevating cylinder. After the substrate released by the upper chuck is received by the raised substrate mounting table, the substrate mounting table is returned to the susceptor. can be transported and placed on the susceptor without contacting the upper surface of the substrate, so that the substrate surface is not damaged and uniform film formation of semiconductor crystals can be promoted.

In addition, the lower chuck operation part moves the substrate mounting table gripped by the lower chuck according to the position of the phase marker on the cylindrical part of the substrate mounting table detected by the phase detection sensor, and the cutting part of the mounting part moves the cutting part of the upper chuck. By rotating it so as to come to the position of the claw portion, the tip of the claw portion of the upper chuck that has entered the lower surface of the outer circumference of the substrate does not come into contact with the substrate mounting table. When the upper chuck places the substrate on the substrate mounting table, the upper cover descends, and the lower end of the upper cover surrounds the outer periphery of the substrate to restrict horizontal movement, so that the upper chuck releases the substrate. In addition, the substrate is not displaced from the substrate mounting table, and when the substrate placed on the susceptor is heated, the substrate is not displaced from the substrate mounting table and the temperature distribution is not biased. It does not impair uniform film formation.

1 is a side view schematically showing one embodiment of a substrate transfer mechanism of a vapor phase growth apparatus according to the present invention; FIG. It is a top view which shows a substrate mounting table. 4 is a side view showing the III-III cross section of the substrate mounting table in FIG. 3; FIG. It is a side view showing the same IV-IV cross section. It is a side view similarly showing a VV cross section.

FIG. 1 shows a substrate transfer mechanism of a vapor phase growth apparatus according to the present invention, and FIGS. 2 to 5 show a substrate mounting table of the substrate transfer mechanism.

As shown in FIG. 1, the substrate transfer mechanism 12 places a substrate 15 on a circular susceptor 14 in a plan view and is attached to a rotary table 13 that rotates about a rotation axis A extending in the vertical direction. It takes out.

A substrate transfer position 16 for transferring the substrate 15 and a transfer central axis C extending in the vertical direction through the substrate transfer position 16 are set at a position separated by a length D from the rotation axis A. The susceptor 14 is provided with a plurality of circular through-holes 14a at rotationally symmetrical positions on a circle having a radius of length D about the rotation axis A. As shown in FIG. Therefore, the susceptor 14 can move each circular hole 14a to a position where the center of the circle passes through the delivery central axis C by rotating the rotary table 13. As shown in FIG.

A disk-shaped substrate mounting table 17 is installed in each of the circular holes 14a so as to cover the circular holes 14a from above. As shown in FIGS. 2 to 5, the substrate mounting table 17 has a base portion 17a having a larger diameter than the circular hole portion 14a, and a base portion 17a projecting above the base portion 17a and having a diameter corresponding to the diameter d of the substrate 15. A mounting portion 17b, which is a columnar base and is provided with cut portions 17d obtained by cutting off flat side surfaces at four locations that are rotationally symmetrical to the column, and a hole portion with a circular outer diameter that protrudes downward from the base portion 17a. and a cylindrical portion 17c which is smaller than 14a and partially provided with a notched phase marker 17e.

The mounting portion 17b has protrusions 17f that are convexly raised at three rotationally symmetrical locations near the outer circumference of the upper surface. is formed to a length of 0.15% to 1.5% of the

Further, as shown in FIG. 1, above the susceptor 14, a transport arm 18 is provided for transporting the substrate 15 by reciprocating between a substrate case (not shown) and a substrate transfer position 16. An upper chuck 19 and an upper cover 20 centered on the transfer center axis C, and an upper elevating cylinder 21 capable of individually elevating the upper chuck 19 and the upper cover 20 are provided above.

The upper chuck 19 has four claw portions 19a having L-shaped barbs at the ends and claws capable of opening and closing each claw portion 19a. The outer periphery of the substrate 15 can be supported by the opening/closing driving portion 19b, and the barb length L of the claw portion 19a is formed shorter than the height h of the arc formed by the cutting portion 17d. The upper cover 20 is a cylindrical member having an inner diameter corresponding to the diameter of the substrate 15. The upper cover 20 is arranged above the claws 19a of the upper chuck 19 with the transfer center axis C as the center. It has a notch portion 20a through which the claw portion 19a of the upper chuck 19 passes so that it does not collide with the claw portion 19a of the upper chuck 19 at the time.

Below the substrate transfer position 16 are a lower chuck 22 rotatable around the transfer center axis C, a lower chuck operating unit 23 for operating the lower chuck 22 , and a lower elevating cylinder 24 capable of elevating the lower chuck 22 . is provided. Further, the lower elevating cylinder 24 is provided with a phase detection sensor 25 capable of detecting the angular position of the phase marker 17e provided on the cylindrical portion 17c of the substrate mounting table 17 with respect to the transfer central axis C. As shown in FIG.

The lower chuck 22 is equipped with fixtures 22a which are synchronously and radially expanded and contracted in the horizontal direction by the lower chuck operating part 23, which are provided at four locations with 90-degree rotational symmetry about the delivery central axis C, and which are arranged to hold the substrate. By fixing the cylindrical portion 17c of the mounting table 17 from the inside, the substrate mounting table 17 positioned directly above can be gripped from below.

In addition, after the substrate mounting table 17 is gripped by the lower chuck 22, the lower chuck operation unit 23 brings the phase marker 17e to a preset angular position according to the detection result of the phase marker 17e by the phase detection sensor 25. The lower chuck 22 can be rotated like this. Here, as shown in FIG. 2, the angular position is such that the phase difference .theta. The values are set to be (n=0, 1, 2, 3).

Further, although not shown, the plate-like tip portion of the transfer arm 18 on which the substrate 15 is placed has a width narrower than the diameter of the substrate 15 and is bifurcated so that even when the substrate 15 is placed thereon, Since the bottom surface near the outer periphery corresponding to the front side, the back side, the right side, and the left side of the substrate 15 is not covered, the claw portions 19a of the upper chuck 19 do not collide with the claw portions 19a when supporting the outer periphery of the substrate 15. There is no

A series of processes for transferring the substrate 15 from the transfer arm 18 to the susceptor 14 by the substrate transfer mechanism 12 of the present invention will be described below.

First, when the lower chuck 22 is lifted by the lower elevating cylinder 24 and the substrate mounting table 17 is pushed up to a predetermined height, the lower chuck 22 extends each fixture 22a by the lower chuck operation part 23 and lifts the cylinder of the substrate mounting table 17. By pressing against the inner wall of the portion 17c, the raised substrate mounting table 17 is gripped and the center of the substrate mounting table 17 is aligned with the center of the lower chuck 22, that is, the delivery central axis C. Furthermore, the lower chuck operating unit 23 rotates the lower chuck 22 according to the angular position of the phase marker 17e detected by the phase detection sensor 25 so that the phase marker 17e comes to a predetermined angular position.

Next, when the transfer arm 18 transfers the substrate 15 from the substrate case (not shown) in which the substrate 15 is stored to directly above the substrate transfer position 16 , the upper chuck 19 and the upper cover 20 are moved by the upper elevating cylinder 21 to lift the substrate. 15, and the lowered upper chuck 19 grips the substrate 15 by closing the claws 19a by the claws opening/closing drive unit 19b and supporting the outer circumference of the substrate 15. , and the transfer arm 18 that has passed the substrate 15 retreats from directly above the substrate transfer position 16 .

Further, when the upper chuck 19 holding the substrate 15 is lowered together with the upper cover 20 to the height of the substrate mounting table 17 pushed up by the upper elevating cylinder 21, the upper cover 20 is lowered by the upper elevating cylinder 21, and the upper cover 20 is lifted. The lower end of the substrate descends to the base portion 17a of the substrate mounting table 17, covering the outer periphery of the substrate 15 and restricting its movement in the horizontal direction. The substrate 15 is mounted on the substrate mounting table 17 .

Thereafter, when the upper lift cylinder 21 lifts the upper cover 20 above the claws 19a of the upper chuck 19, the upper lift cylinder 21 lifts the upper chuck 19 and the upper cover 20 to their original heights.

Then, when the lower chuck 22 contracts the elongated fixtures 22a by the lower chuck operation part 23 and releases the state of gripping the substrate mounting table 17, the lower chuck 22 is lowered by the lower elevating cylinder 24 to lift the substrate. The substrate mounting table 17 with the substrate 15 mounted thereon is returned to the susceptor 14 .

As described above, according to the substrate transport mechanism 12 of the vapor phase growth apparatus according to the present invention, the substrate is moved by the transport arm 18 while the substrate mounting table 17 gripped by the lower chuck 22 is pushed up from the susceptor 14 by the lower elevating cylinder 24 . The upper chuck 19 supports the outer periphery of the substrate 15 and lowers the substrate 15 by the upper elevating cylinder 21. The substrate 15 released by the upper chuck 19 is pushed up and received by the substrate mounting table 17. After that, by returning the substrate mounting table 17 to the susceptor 14 , the substrate 15 sent from the transfer arm 18 can be transferred and placed on the susceptor 14 without contacting the upper surface of the substrate 15 . A uniform film formation of the semiconductor crystal can be promoted without damaging the surface.

Further, since the substrate 15 is placed on the substrate placing table 17 from directly above when the substrate 15 is transferred, the bottom surface of the substrate 15 is not rubbed, and the generation of particles is suppressed. It can encourage the membrane more.

Furthermore, since the lower chuck 22 is provided with a plurality of fixtures 22a that synchronously expand and contract radially in the horizontal direction, when the lower chuck 22 grips the substrate mounting table 17, the central axis of the fixtures 22a, that is, Since the transfer central axis C coincides with the central axis of the cylindrical portion 17c of the substrate mounting table 17 gripped by the fixture 22a, the substrate 15 is reliably mounted at the center of the substrate mounting table 17. FIG.

Moreover, the lower chuck operation unit 23 moves the substrate mounting table 17 gripped by the lower chuck 22 according to the position of the phase marker 17e on the cylindrical portion 17c of the substrate mounting table 17 detected by the phase detection sensor 25 to the mounting unit. By rotating the cutting portion 17d of 17b so as to come to the position of the claw portion 19a of the upper chuck 19, the tip of the claw portion 19a of the upper chuck 19 can enter the lower surface of the outer periphery of the substrate 15, and the claw portion 19a. does not come into contact with the substrate mounting table 17, the mounting position of the substrate 15 does not shift.

Further, when the upper chuck 19 places the substrate 15 on the substrate placing table 17, the upper cover 20 descends, and the lower end of the upper cover 20 surrounds the outer periphery of the substrate 15 to restrict the movement in the horizontal direction. , when the upper chuck 19 releases the substrate 15 , the substrate 15 is not displaced from the substrate mounting table 17 .

Therefore, when the substrate 15 placed on the susceptor 14 is heated, the substrate 15 is not displaced from the substrate mounting table 17 and the temperature distribution is not biased, so that the uniform film formation of the semiconductor crystal is not impaired.

Further, since the substrate mounting table 17 has no pin holes and the diameter of the mounting portion 17b corresponds to the diameter d of the substrate 15, the temperature distribution when heating the substrate 15 is less likely to be locally biased. A slight gap is formed between the substrate 15 placed on the substrate placing table 17 and the placing portion 17b by providing the protruding portion 17f near the outer circumference of the upper surface of the placing portion 17b. The difference in temperature between a portion inside the cutting portion 17d whose bottom surface is covered with the mounting portion 17b and a portion outside the cutting portion 17d not covered with the mounting portion 17b is reduced to suppress uneven temperature distribution. It is possible to improve the uniformity of the film formation of the semiconductor crystal.

Moreover, since both the cutting portion 17d and the protruding portion 17f are provided in the vicinity of the outer circumference of the mounting portion 17b, a region having an extremely uniform temperature distribution can be widened from the center of the mounting portion 17b. good yield.

It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible within the scope of the invention. For example, in this embodiment, the claw portions of the upper chuck and the cutting portions of the substrate mounting table are provided at four locations. There may be 3 or 5 or more.

DESCRIPTION OF SYMBOLS 12... Substrate transfer mechanism 13... Rotary table 14... Susceptor 14a... Circular hole 15... Substrate 16... Substrate transfer position 17... Substrate mounting table 17a... Base part 17b... Mounting part 17c... Cylindrical portion 17d Cutting portion 17e Phase marker 17f Protrusion 18 Conveying arm 19 Upper chuck 19a Claw portion 19b Claw opening/closing driving portion 20 Upper cover 20a Notch Parts 21... Upper lifting cylinder 22... Lower chuck 22a... Fixing tool 23... Lower chuck operating part 24... Lower lifting cylinder 25... Phase detection sensor

Claims (4)

A substrate transfer mechanism of a vapor phase growth apparatus for setting and removing a substrate at a substrate transfer position on a susceptor,
At a position corresponding to the substrate transfer position of the susceptor, a circular hole portion which is a circular through hole and a disk-shaped substrate mounting table closing the circular hole portion are provided,
Above the substrate transfer position, an upper portion having a plurality of claws capable of supporting the outer circumference of the substrate carried just above the substrate transfer position by a transfer arm that transfers the substrate by reciprocating between the substrate case and the substrate transfer position. a chuck, a cylindrical upper cover positioned above the upper chuck and having a notch portion through which the claw portion of the upper chuck passes, the inner diameter of which corresponds to the diameter of the substrate; and the claw portion of the upper chuck. an upper chuck elevating means capable of elevating the upper chuck; and an upper cover elevating means capable of elevating the upper cover,
Below the substrate transfer position, there is provided a lower chuck positioned below the susceptor to grip the substrate mounting table from below, a lower chuck operating section for operating the lower chuck, and a lower section capable of raising and lowering the lower chuck. and a lifting means,
The substrate mounting table includes a base portion having a diameter larger than that of the circular hole portion, and a cylindrical base projecting above the base portion and having a diameter corresponding to the substrate, and corresponding to the claw portion of the upper chuck. and a cylindrical portion projecting downward from the base portion and having an outer diameter smaller than that of the circular hole,
The lower chuck is characterized by comprising a plurality of fixtures which are operated by the lower chuck operating section and which can extend and contract radially in a horizontal direction to fix the cylindrical section of the substrate mounting table from the inside. A substrate transfer mechanism for a vapor phase growth apparatus. 2. The substrate mounting table is characterized in that, in plan view, the height of the arc formed by the cutting portion is 0.15% to 1.5% of the diameter of the substrate. A substrate transport mechanism of the described vapor phase growth apparatus. The lower chuck is configured to be rotatable about a vertical axis by the lower chuck operating section, the substrate mounting table includes a phase marker on the cylindrical section, and the lower chuck operating section includes the phase marker. a phase detection sensor capable of detecting the angular position of the lower chuck with respect to the rotation axis, and the phase marker is positioned at a preset angular position according to the detection result of the phase detection sensor. 3. The substrate transfer mechanism of a vapor phase growth apparatus according to claim 1, wherein the substrate is rotated. 4. The substrate transfer mechanism for a vapor phase growth apparatus according to claim 1, wherein the mounting portion has projections at three or more rotationally symmetrical positions on the outer circumference of the upper surface.

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