JPH0661331A - Substrate transfer system - Google Patents

Abstract

PURPOSE:To reduce the dust by forming the molded ceramic surface state on the part in contact with a substrate fork. CONSTITUTION:Since a substrate 30 is molded of a ceramic material e.g. alumina particles filled up in a substrate fork mold for molding the particles by thermal pressurizing at specific pressure and temperature, the surface of the substrate fork 30 is to be composed of smooth and particulate ceramic particles when observed by a micrometer. Accordingly, the substrate 30 will not be damaged at all even if the substrate 30 comes into contact with the surfaces of sintered body particles themselves in high smoothness. On the other hand, since the substrate fork 30 and the substrate itself are supported by multiple projections 41, 43, the contact area and contact friction as well as the lateral slip thereof surrounding the substrate due to the vibration during shifting time can be minimized. Through these procedures, the raising dust caused by the contact between the substrate fork 30 and semiconductor wafers 4 can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate transfer device.

[0002]

2. Description of the Related Art It is known that the largest cause of reducing the yield in the semiconductor manufacturing process is that the dust floating in the atmosphere adheres to a semiconductor wafer to reduce the yield of semiconductor elements. In order to improve the reduction in yield due to the dust floating inside, a means of manufacturing semiconductors in a clean room having an expensive and complicated structure is taken.

However, even in this clean room, it is very difficult to remove the dust caused by the contact between the substrate fork of the semiconductor manufacturing apparatus and the semiconductor wafer, and the semiconductor heat treatment apparatus, for example, the semiconductor wafer is transferred. The substrate fork used in the substrate transfer device to be mounted is made of ceramic material, such as alumina, which is a material that does not contaminate the semiconductor wafer even if it comes into contact with the semiconductor wafer at high temperature. Was used. When the surface of the flattened substrate fork was observed with a microscope, it was confirmed that there were sharp edge-shaped ceramic particles having a diameter of 5 μm as shown in FIG.

[0004]

When a semiconductor wafer is placed and transported on the substrate fork processed as described above, a lateral force is applied to the semiconductor wafer due to the vibration generated during the transportation, for example, plus or minus. The back surface of the semiconductor wafer processed to 10 μm is ground by the sharp-edged ceramic particles confirmed above, and the fine debris carved from this semiconductor wafer becomes dust floating in the atmosphere. There has been an improvement point that it adheres to the wafer surface and reduces the yield of semiconductor elements.

The present invention eliminates sharp edge-shaped ceramic particles on the substrate fork that cause damage to the semiconductor wafer, thereby reducing dust generation due to contact between the substrate fork and the semiconductor wafer. The purpose is to provide.

[0006]

According to the present invention, there is provided a substrate fork for mounting and transporting a thin plate-shaped substrate, and a position for accommodating a convex portion for supporting a flat portion of the substrate and a peripheral portion of the substrate. In a substrate transfer arm integrally provided with a positioning convex portion, at least a portion of the substrate fork that comes into contact with the substrate is a ceramic surface state that has been processed and molded, and is a substrate transfer device.

[0007]

According to the present invention, at least the portion of the substrate fork that comes into contact with the substrate to be transported has a surface state in which powdery ceramics have been pressure-heat-molded, so that the surface of the sintered particles themselves having a high smoothness can be obtained. The substrate will not be damaged even if it comes into contact with the substrate. Further, since the substrate fork and the substrate are supported by the plurality of convex portions, the contact area is reduced and the contact friction is also reduced, and the convex portions provided around the substrate reduce lateral displacement due to vibration during transfer. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a vertical heat treatment apparatus will be specifically described with reference to the drawings.

As shown in FIG. 1, this vertical heat treatment apparatus 1
Is made of a heat-resistant material, for example, quartz glass, and is formed into a cylindrical shape. A reaction tube 2 having an upper end portion closed and a lower end portion opened is provided in the reaction tube 2, and a heat-resistant material, for example, a quartz glass wafer board. An object to be processed, for example, a semiconductor wafer 4, which is stacked and mounted in a vertical direction at a predetermined pitch, is housed in the unit 3.

A heating element, for example, a resistance heating heater 5 is coaxially provided on the outer circumference of the reaction tube 2, and the resistance heating heater 5 is provided on the outer circumference thereof with a heat insulating material 6 for example made of stainless steel. The cylindrical outer shell 7 is provided and constitutes a heating furnace as a whole.

A gas introduction pipe 8 for supplying a processing gas is connected to one end of the reaction tube 2, and an exhaust pipe 9 for discharging a processing gas is connected to the other end of the reaction tube 2. The discharger 9 is connected to an exhaust device (not shown) so that the inside of the reaction tube 2 can be exhausted.

The wafer board 3 is placed on a heat retaining cylinder 10 made of, for example, quartz.
Is placed on a lid body 11 made of, for example, quartz, and the lid body 11 is held by an elevating mechanism, for example, a wafer elevator 20, so that the wafer board 3 can be loaded and unloaded in a soaking region in the reaction tube 2. Is configured.

Below the reaction tube 2, there is provided a mechanism for transferring the semiconductor wafer 4 onto the wafer board 3, for example, a wafer transfer machine 21.

As shown in FIG. 2, this wafer loading machine 21
The five thin plate-shaped substrate forks 30 on which the semiconductor wafers 4 are mounted can be vertically moved by the elevating mechanism 22, horizontally rotated by the rotating mechanism 23, and the horizontal moving mechanism 24.
It is configured so that it can be expanded and contracted in the horizontal direction. In addition, a carrier 3 containing a plurality of semiconductor wafers 4
1 is placed on the carrier loading table 32.

As shown in FIG. 3, the wafer transfer machine 21
Is a predetermined interval by stacking the five substrate forks 30.
For example, the carrier 31 is provided at intervals of 3/16 inch which is a semiconductor wafer storage pitch. Then, the wafer transfer machine 21 is connected to a belt 38 stretched around the shaft of the motor 37, and by the rotation of the motor 37,
The board forks 30 can be moved horizontally in one operation.

As shown in FIG. 4, the substrate fork 30 is provided.
Has a thickness of 1.3 mm, a length of 240 mm, and a width of 40 mm, and has a rectangular shape with corners cut off. When the semiconductor wafer 4 is placed on the surface of the substrate fork 30, the semiconductor A convex portion 40 for supporting the back surface of the wafer 4, a convex portion 41 arranged so as to be fitted to the peripheral edge of the semiconductor wafer 4, a hole portion 42 for mounting a substrate fork, and a peripheral edge portion of the hole portion 42. The convex portion 43 is provided.

The convex portion 4 provided on the substrate fork 30.
The structures of 0, the convex portion 41, the hole portion 42, and the convex portion 43 will be described in more detail.

As shown in FIG. 5, the shape of the convex portion 40 is such that the substrate, for example, the semiconductor wafer 4 to be placed has a smooth shape without scratching edges, for example, a hemispherical upper portion 1 with a radius of 1.5 mm. The trapezoidal shape has a rounded width of 2 mm, and the place where the convex portion 40 is arranged is near the outer periphery of the semiconductor wafer 4 when it is mounted in order to stably support the mounted semiconductor wafer 4. , 3 mm inside from the outer periphery of the semiconductor wafer 4, one place near the tip of the substrate fork 30 and two places on the mounting part of the substrate fork 30, and three places so that the lines connecting these convex portions 40 are triangular. It is provided.

The shape of the convex portion 41 has a side of 5 m.
It has a square shape of m and a height of 2 mm, and surrounds the semiconductor wafer 4 to be mounted, and three corners are provided on the outer peripheral portion of the convex portion 40 so as to be rounded.

Further, holes 42 for assembling and fixing the board fork 30 are provided on the board fork 30 mounting side, for example, at three places. At the upper and lower edges of the hole 42, for example, a convex portion 43 having a height of 2 mm for maintaining a predetermined parallel spacing when a plurality of the substrate forks 30 are stacked.
Are installed around. By machining this convex portion 43, for example, with a milling machine, the relative position to the semiconductor wafer 4 at the time of placement and the respective substrate forks 30 are placed.
It is provided so that the parallel spacing of can be adjusted.

Further, since the substrate fork 30 is filled in a substrate fork mold for molding ceramic raw material, for example, powder of alumina particles, and is heated by pressurizing at a predetermined pressure and temperature, the substrate fork is formed. The surface of 30 is composed of spherical ceramic particles that are smooth even when observed with a microscope.

Then, as shown in FIG. 3, a plurality of substrate forks 30 are laminated, for example, five, and screws 36 are connected to the holes 42 and fixed through a holding member 35. 21 constitutes a mounting portion of the semiconductor wafer.

Next, the operation of the apparatus configured as described above will be described. Substrate fork 3 on wafer transfer machine 21
0 is positioned in front of the carrier 31 by a predetermined movement of the elevating mechanism 22 and the rotating mechanism 23.

Next, the substrate fork 30 is inserted into a predetermined position between the wafers in the carrier 31 by the forward horizontal movement of the wafer transfer device 21, and the substrate fork 30 is raised by about 2 mm by the elevating mechanism 22. The semiconductor wafers 4 are fitted and placed in the three convex portions 41 of the substrate fork 30.

Next, the semiconductor wafer 4 is taken out of the carrier 31 by the backward horizontal movement of the wafer transfer machine 21,
By a predetermined operation of the elevating mechanism 22 and the rotating mechanism 23, it is moved to a desired position in front of the wafer board 3.

Next, the substrate fork 30 is attached to the wafer transfer machine 2
When the semiconductor wafer 4 is moved forward in the direction of the wafer board 3 by the forward horizontal movement of 1, the semiconductor wafer 4 is fitted into a groove portion (not shown) provided in the wafer board 3, and the substrate fork 30 is lowered by 2 mm by the elevating mechanism 22.
Are mounted on the wafer board 3. By repeating the above operation, a desired number of semiconductor wafers 4 are transferred from the carrier 31 to the wafer board 3.

Next, the wafer board 3 accommodating a plurality of semiconductor wafers 4 is moved into the reaction tube 2 of the heat treatment furnace by the raising and lowering mechanism 22.

The reaction tube 2 is preheated to, for example, 1000 ° C. by the resistance heating heater 5, and the gas supply tube 8 is used.
A processing gas such as water vapor is supplied from the above to form an oxide film on the surface of the semiconductor wafer 4, and the high temperature processed gas after processing the semiconductor wafer 4 is exhausted from an exhaust pipe 9 by an exhaust device (not shown).

After the heat treatment is completed, the semiconductor wafer 4 is moved below the heat treatment furnace by descending the elevator 22. After the semiconductor wafer 4 is naturally cooled to a predetermined temperature, for example, 50 ° C., the semiconductor wafer 4 which has been subjected to the heat treatment is transferred from the wafer board 3 to the carrier 31 in the reverse procedure of the transfer of the semiconductor wafer 4, The predetermined heat treatment is completed.

As shown in FIG. 6, since the substrate fork 30 is subjected to pressure molding of alumina, the portion contacting the semiconductor wafer 4 is not machined at all.
The surface maintains a smooth surface state made of sintered particles produced by pressure molding, and a smooth surface is formed. When the semiconductor wafer 4 is placed, a force is applied in the lateral direction. However, since there are no sharp edge-shaped ceramic particles generated during machining as shown in FIG. 7 on the surface of the substrate fork, the semiconductor wafer 4 is not scraped.

In addition, the plurality of convex surfaces 40 provided inside the substrate fork 30 contact the entire rear surface of the semiconductor wafer 4 on the substrate fork 30, as compared with the case where the entire rear surface of the semiconductor wafer 4 is in contact with the substrate fork 30 plate plane. Since the contact is made only by 40, the contact area with the semiconductor wafer 4 is made small and the friction portion due to the contact is made small, and the convex portions 41 provided circumferentially reduce the lateral displacement due to vibration during transfer.

Furthermore, during pressure molding of the substrate fork 30,
In order to make the relative position of the substrate fork 30 correct when the semiconductor wafer 4 is placed, the convex portion 43 that can be machined is provided in the attachment portion of the substrate fork 30, and the substrate fork 3 is provided.
Since the 0 and the convex portion 43 are integrally pressure-molded, the relative position can be easily adjusted by shaving the pressure-molded convex portion 43 with a milling cutter or the like. There is no need for special members.

Since the whole surface of the substrate fork 30 and the shape necessary for placing the wafer, for example, the convex portions 40, 41, 43 and the hole portion 42 are all pressure-molded, the surface of the sintered particles is smooth. It is possible to scratch the sintered particles on the surface of the substrate fork 30 without mechanically processing the other portions by simply machining the convex portion 43 that is formed as described above and serves as a mounting reference surface of the substrate fork 30. Absent.

In addition, the substrate fork 30 and the semiconductor wafer 4
The contact surface with the contact area is reduced by the convex portion 40 provided internally, the circumferential convex portion 41 prevents lateral displacement during mounting, and the convex portion 43 provided at the mounting portion is mounted. The relative position with respect to the semiconductor wafer at the time of placement can be precisely adjusted by machining such as milling.

The present invention is not limited to the above-mentioned embodiment, but may be any device as long as it is a device for carrying a flat object such as a glass substrate which is a liquid crystal substrate, not limited to a semiconductor wafer. Can also be applied.

As described above, according to the present invention,
Even if the substrate and the substrate fork are placed and transported, dust is not generated and the yield of semiconductor elements can be significantly improved.

[0036]

[Brief description of drawings]

FIG. 1 is an overall sectional view of the present invention applied to a vertical heat treatment apparatus.

FIG. 2 is a perspective explanatory view of a semiconductor wafer transfer device section of FIG.

FIG. 3 is an explanatory diagram of a transfer machine unit in FIG.

FIG. 4 is a perspective view of a substrate hawk.

5 is a cross-sectional view of the substrate hawk of FIG. (1) is an enlarged view of the hole. (2) is an enlarged view of a convex portion.

FIG. 6 is a cross-sectional view of alumina particles after pressure molding of a substrate fork.

FIG. 7 is an enlarged cross-sectional view of conventionally processed alumina.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vertical heat treatment apparatus 2 Reaction tube 3 Wafer board 4 Semiconductor wafer 20 Wafer elevator 21 Wafer transfer machine 22 Elevating mechanism 23 Rotating mechanism 24 Horizontal moving mechanism 30 Substrate fork 31 Carrier 32 Carrier loading platform

Claims (1)

[Claims] A substrate transfer arm in which a convex portion for supporting the flat surface portion of the substrate and a positioning convex portion for accommodating the peripheral portion of the substrate are integrally provided on a substrate fork for mounting and transporting a thin substrate. 2. A substrate transfer device according to claim 1, wherein at least a portion of the substrate fork that comes into contact with the substrate has a ceramic surface state that has been processed and molded.