JPH0394445A - Semiconductor wafer transfer system - Google Patents

Abstract

PURPOSE:To reduce foreign bodies adhering to the surface of a semiconductor wafer by installing a transfer device which transports the semiconductor wafer while a temperature of the wafer is being kept at a high temperature; and a wafer stocker which holds the semiconductor wafer while the temperature of the wafer is being kept at the high temperature. CONSTITUTION:In a transfer device 3 which transfers a wafer 2 to individual treatment devices 1, one route of the transfer device is formed as a module; a transfer operation between modules is executed by using another intermodule transfer device 4. A wafer stocker 5 which temporarily keeps the wafer is provided at an entrance of the module to execute the transfer operation smoothly; a clean bench 6 is provided at the upper part of the wafer stocker 5. That is to say, the following are provided: the transfer device 3 which keeps a temperature of the semiconductor wafer 2 at a temperature higher than an ambient temperature and which transports the wafer 2; and the wafer stocker 5 which keeps the temperature of the semiconductor wafer 2 at the temperature higher than the ambient temperature and which keeps the wafer 2. Thereby, it is possible to prevent a foreign body from adhering as far as possible in a wafer transfer system and to enhance yield during manufacturing operation of the wafer at a low cost and surely.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention... This invention relates to a conveying V-stem that is used in semiconductor wafer manufacturing.

[Conventional technology]

In semiconductor wafer manufacturing, the transport of wafers between devices has changed from the traditional manual transport to automatic transport using robots and transport vehicles. This is done by eliminating human labor. Reduced foreign matter adhering to wafers (humans are the largest source of foreign matter). The aim is to handle complex process transportation.

Traditionally, containers containing multiple wafers (wafer cassettes) were often transported between devices using robots or transport vehicles, but in recent years, wafers have become larger in diameter. To support high-mix, low-volume production. It has become necessary to transport wafers one by one.

FIG. 9 shows an example of a conventional single wafer transfer system.

In the figure, (1) is a wafer processing device, and wafers (2) pass through these devices in a predetermined order and are processed. A pattern is formed on the wafer (2). The device is completed. (3) is each processing unit It (
1) is a transfer device that transfers a wafer (2) to a wafer (2).
r1JJ transport is performed by another inter-module transport device @(4). A wafer stocker (5) is installed at the entrance of the module to temporarily store wafers (2), with the aim of making transportation smoother. Transfer device (3) and wafer stocker
A clean bench (6) is provided above (5) to prevent foreign matter from adhering to the surface of the wafer (2).

[Problems that the invention helps solve]

However, the above is a problem. In the conventional single wafer transfer system. There were more problems than mentioned below.

(i) A case in which wafers were transported one by one in a bare state. Compared to the conventional method of transporting 25 sheets in a container for storage. Foreign matter easily adheres to the wafer surface.

(it) To transport wafers one by one. @Even if the speed of the transport system is improved, the number of transport lines will inevitably increase. The cost of a clean bench to be provided above the transport system increases. If we try to compensate for the tendency for foreign matter to adhere as mentioned in section (i) by improving the cleanliness of the clean bench,
Clean benches require increasingly expensive cabinets, increasing costs.

(i'li) Also, even if a clean bench is installed. Human intervention is inevitable in the top pulls of equipment and transport systems, and foreign matter adheres to the wafers during this time.

For the reasons stated above, in single wafer transfer systems. There is a problem in that foreign matter tends to adhere to the wafer surface, resulting in a decrease in yield in wafer manufacturing.

This invention was made in view of the above circumstances. This provides a low cost single wafer transfer system with less foreign matter adhering to the wafer surface.

[Means to solve the problem]

The single wafer transfer system according to this invention is. It has a transport device that transports the semiconductor wafer while keeping the temperature of the semiconductor wafer slightly higher than the ambient temperature, and a wafer storage device that stores the wafer while keeping the temperature of the semiconductor wafer higher than the ambient temperature.

[Effect]

In this invention, the transfer device or wafer holding force applied to the transfer system is equipped with a function to maintain the wafer temperature during transfer or storage at a higher temperature than the surrounding temperature. This prevents foreign matter from adhering.

According to an experiment by a certain person, when the wafer temperature is heated to 4o○℃, the temperature decreases by about 175~
It has been demonstrated that foreign matter adhesion can be reduced by 1/10. By incorporating this into the conveyance system, it is possible to prevent foreign matter from adhering.

By heating the wafer to a higher temperature than its surroundings, foreign matter can be prevented from adhering to the wafer.

Reason. This is thought to be due to thermophoretic phenomena. However, no clear theory has been established.

What is thermophoresis? Aeroso IV (gas containing microparticles)
When a temperature gradient exists at
This is a phenomenon in which aerosol moves from a high-temperature side to a low-temperature side under the influence of force.

This phenomenon creates a space that does not contain aerosol particles in the close vicinity of the surface of a high-temperature object. Aerosol particles (foreign matter) do not adhere to the surface of a high-temperature object. This situation is shown in FIG.

〔Example〕

below. An embodiment of this Yumei will be explained with reference to the drawings.

FIG. 1 shows a perspective view of an embodiment of a semiconductor wafer transport system according to the present invention. FIG. 2 is a perspective view of the transfer device constituting this system, and FIG. 3 is a perspective view of the wafer holding force.

As shown in Figure 1. (3) The wafer (
2) A conveying device that conveys the. In this example. One path of the transport device is a module μ, and transport between modules is performed by another inter-module transport device (4).

A wafer storage device (5) for temporarily storing wafers is provided at the entrance of the module. We are trying to make transportation easier.

Above the wafer stocker (5) is a clean bench (6).
).

Figure 2 is. Conveyance device (which constitutes the above-mentioned conveyance system)
This is an example of 3). Wafer (2) is heater (7)
placed on a heating stage with a built-in It is transported heated to around 400 degrees Celsius. (8) is the transport rail μ.
It is moved between processing devices at high speed by obtaining υ driving force from a linear motor (not shown) or the like.

Figure @3 is an example of a wafer stocker (5) that also monitors the transfer system. The wafer (2) is placed on a heating shelf (9) containing a heater (7) and stored in a heated state of about 400°C. A separate transfer device (not shown) takes wafers into and out of the heating shelf (9).

In addition. In this embodiment, the conveyance device is a stage type on a rail μ, but the present invention is not limited to this. @4 A transfer robot type as shown in Figure 4 may also be used.

In that case, a heater (7) will be provided in the grip as shown in the figure. 1. It may also be a transport vehicle type as shown in Figure 5. in this case. As shown in the figure, a heater (7) may be provided on the transport vehicle to maintain the wafer temperature at a higher temperature than the surrounding temperature.

Also, regarding this example. The heating source for the wafer was a heater and a stage. It is not limited to that. As shown in Fig. 6, radiant heating by lamp αG or heating by microwave (not shown) fk may be used. In any case, all you have to do is keep the wafer temperature higher than the surrounding temperature.

1, book'4i! As for the example. By heating the wafer to 400°C, the wafer temperature was maintained at a higher temperature than the surrounding temperature. However, if heating the wafer is inconvenient, the air outside the wafer is cooled as shown in Figure 7, and the heat is kept between the wafer and the surrounding temperature. A gradient may also be provided. If the wafer heating and outside air cooling in this example are used together. It is possible to create a large temperature gradient without raising the wafer temperature too much, making it more effective in preventing foreign matter from adhering.

It was a cabinet. In the wooden example, the wafer is transported with the surface facing upward. I indicated that I would keep it. Not only that, but as shown in Figure @H, if the wafer surface is facing downward, it is very effective in preventing the adhesion of large falling foreign particles that cannot be prevented by thermophoresis due to the temperature gradient. In combination with the present invention, attachment of foreign matter can be almost completely eliminated.

〔Effect of the invention〕

Based on the above, the present invention provides a transfer device for transporting a semiconductor wafer to a temperature between the ambient temperature and F)K, a wafer stocker for keeping the temperature of the semiconductor wafer at a higher temperature than the ambient temperature, and storing the wafer. This wafer transport system has the advantage of being able to prevent foreign matter from adhering to the wafer transport system and reliably improve yields in wafer manufacturing at a low cost.

[Brief explanation of drawings]

Figures 1 to 3 show an embodiment of the present invention, and Figure 1 is a perspective view of an embodiment of a semiconductor wafer transfer system. FIG. 2 is a perspective view showing a transfer device that makes up a semiconductor wafer transfer system, FIG. 3 is a perspective view showing a wafer transport device that makes up a semiconductor wafer transfer system, FIGS. 4, 5, and 6. ．． Figures 7 and 8 are schematic diagrams showing other embodiments of the conveying device according to the present invention. Figure 9 is a perspective view showing a conventional semiconductor wafer transport system. @Figure 10 is a schematic diagram showing the principle of the present invention. In the figure. (l> is the processing device, (2) is the wafer. (3) is the wafer transfer device. (4) is the module μ transfer device, (5)
(6) is clean pliers. (7)
is the heater (8), and (9) is the heating shelf. αO is a lamp. inside. The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] A semiconductor wafer transport system includes a transport device that transports a semiconductor wafer while keeping the temperature of the semiconductor wafer higher than the surrounding temperature, and a wafer stocker that stores the semiconductor wafer while keeping the temperature of the semiconductor wafer higher than the surrounding temperature.