JPH07240356A - Storage of wafer and its transportation - Google Patents

Abstract

PURPOSE:To make the storage or transportation of wafers possible as the cleanness of the wafers is maintained by a method wherein the wafers are cleaned with a cleaning agent, the cleaning agent is cooled as the cleaning agent is adhered on the surfaces of the wafers to freeze the cleaning agent and the surfaces of the wafers are covered with a frozen layer which is the cleaning agent. CONSTITUTION:A plurality of sheets of wafers 22 are pinched by a clamp 21 and are dipped in a frozen tank 24 housing liquid nitrogen 23 or the like. In this state, the wafers 22 are quenched, ultrapure water or the lily, which is adhered on the surfaces of the wafers 22 and is a cleaning agent, is frozen and the surfaces of the wafers 22 are covered with a frozen layer 24. In such a way, the surfaces of the wafers 22 are covered with the layer 24, such as the ultrapure water, whereby the cleanness of the wafers 22 at the time of the final cleaning is kept. Accordingly, the wafers can be stored or transported as the cleanness is maintained.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention enables a wafer to be stored or transported while maintaining its cleanliness after being cleaned with a cleaning agent such as ultrapure water or isopropyl alcohol (hereinafter referred to as IPA). The present invention relates to a storage method and a transportation method for the completed wafer.

[0002]

2. Description of the Related Art Conventionally, in the process of manufacturing a semiconductor integrated circuit, in order to remove undesired deposits on a wafer,
A cleaning process for cleaning the wafer using ultrapure water, isopropyl alcohol, etc. is provided.

In such a wafer cleaning process, the wafer which is finally cleaned with ultrapure water or the like is dried by a dryer such as a rinser dryer and then stored in a storage container. It has been transported to a storage location.

[0004]

As described above, in the conventional semiconductor integrated circuit manufacturing process, after cleaning and drying the wafer, the wafer is housed in the container for transportation and storage.

However, when the wafer is transported and stored in this manner, fine dust or the like may adhere to the wafer surface during transportation and storage. However, as the degree of integration of semiconductor integrated circuits increases more and more, contamination of dust and the like on the surface of a wafer has an extremely great adverse effect on high integration and high yield of semiconductor integrated circuits. It is desired to prevent dust from adhering and maintain cleanliness. Further, vapors of organic solvents and the like in the atmosphere may adhere to the surface of the wafer, which has become a big problem in recent years as the degree of integration of semiconductor integrated circuits increases.

The present invention has been made in consideration of such conventional circumstances, and provides a method of storing and transporting a wafer which can be stored or transported after cleaning the wafer while maintaining the cleanliness. With the goal.

[0007]

According to the method of storing a wafer of the present invention, a wafer is cleaned with a cleaning agent, and the cleaning agent is cooled while the cleaning agent is attached to freeze the cleaning agent. Is covered with a frozen layer of detergent.

In the above wafer storage method, ultrapure water, isopropyl alcohol or a mixture thereof can be used as the cleaning agent.

Further, the wafer transport method of the present invention has a heat insulating property in which a wafer whose surface is covered with a frozen layer of a cleaning agent is provided with a freezing means and the inside is kept at a temperature lower than the freezing point of the frozen layer of the cleaning agent. It is characterized in that it is stored in a storage container and transported.

In the above wafer transportation method, ultrapure water, isopropyl alcohol or a mixture thereof can be used as the cleaning agent.

Further, in the above-mentioned wafer transport method, a cryogen contained in a container can be used as the freezing means.

Further, in the above-described wafer transportation method, a Peltier electric element mounted in a storage container can be used as the freezing means.

[0013]

According to the method of storing a wafer and the method of transporting the same of the present invention, after cleaning the wafer, the cleaning agent on the wafer surface is rapidly cooled and frozen, and the wafer surface is covered with a frozen layer of the cleaning agent. Store and transport wafers.

Thus, the wafer can be stored and transported while maintaining the cleanliness at the time of the final cleaning, and it is possible to prevent the vapor of the organic solvent and the like and the dust from adhering in the atmosphere. Then, when further processing is performed in a subsequent step, the frozen layer of the cleaning agent on the wafer surface is melted with running water such as ultrapure water and removed to immediately perform processing in the subsequent step while maintaining cleanliness. Etc. can be carried out.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows each step in this embodiment.
In the cleaning step shown in the figure, a plurality of wafers are arranged in parallel in a basket or the like, and each basket is sequentially immersed in an ultrapure water cleaning tank or a cleaning solution tank containing a predetermined cleaning solution to perform cleaning. Usually, the final cleaning in this cleaning step is ultrapure water cleaning or IPA cleaning.

When the final cleaning is completed, a wafer cooling process is next performed by the freezing device. In this cooling step, for example, as shown in FIG. 2, one or a plurality of wafers 22 are clamped by a clamp 21, and liquid nitrogen 23 is used.
It is carried out by immersing in a freezing tank 24 in which

That is, while the ultrapure water or the like as the cleaning agent remains attached to the surface of the wafer 22, the wafer surface is rapidly cooled to cover the wafer surface with a frozen layer of the ultrapure water or the like. In this way, the surface of the wafer 22 is covered with the frozen layer of ultrapure water or the like, so that the cleanliness during the final cleaning is maintained.

Then, the wafer 22 is stored and transported with the frozen layer of ultrapure water or the like formed on the surface thereof.

FIG. 3 shows the structure of a storage container for transporting the wafer which has been rapidly cooled as described above.

In the figure, 31 is a wafer having a frozen layer of ultrapure water or the like formed on its surface, 32 is a wafer carrier made of resin or the like for arranging a plurality of cleaned wafers 31 in parallel, and 33 is a wafer carrier. It is a storage container made of a heat insulating material or the like for storing and transporting 32.

Further, in the figure, 34 is a freezing agent such as dry ice which can be kept at a temperature lower than the freezing point of the frozen layer of the cleaning agent as a refrigerating means in order to maintain a low temperature state, and 35 is an upper opening of the storage container. It is a lid made of a heat insulating material or the like for closing the.

A plurality of wafers 31 on which a frozen layer of ultrapure water or the like is formed as described above are stored in a wafer carrier 32. When the wafer carrier 32 is stored for a long period of time, the wafer carrier 32 is stored in a freezer or the like.

When carrying the wafer carrier 32, the wafer carrier 32 is housed in a housing container 33 as shown in FIG. 3 and carried. As a result, the wafer 31
Can be transported to the next step or the like while the frozen layer of ultrapure water or the like is still formed on the surface.

Then, in the next step or the like which is the destination of conveyance,
When the wafer 31 is subjected to a predetermined process, ultrapure water or the like is brought into contact with the wafer 31 to melt the frozen layer of the cleaning agent that covers the surface of the wafer 31.

As a result, the wafer 31 can be stored and transported while maintaining the cleanliness after cleaning, and it is possible to immediately carry out the subsequent processes and the like without performing cleaning again. . Therefore, it is possible to improve the yield and the productivity.

In the cooling step described above, liquid inert gas such as liquid nitrogen and acetone-dry ice can be used. There is also a method in which a liquid inert gas such as liquid nitrogen or a gas cooled with acetone-dry ice is sprayed from a nozzle or the like onto the surface of the wafer to freeze it.

Further, when the wafers 22 are frozen, it is possible to rapidly cool the plurality of wafers in a bundle and freeze these wafers integrally. It is also possible to do so.

[0029]

As described above, according to the wafer storage method and the wafer transportation method of the present invention, after cleaning the wafer, the wafer can be stored or transported while maintaining the cleanliness.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a cooling process according to an embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a wafer transfer device according to an embodiment of the present invention.

Claims (6)

[Claims] 1. A wafer is cleaned with a cleaning agent, and the cleaning agent is cooled while the cleaning agent is adhered to freeze the cleaning agent, thereby covering the surface of the wafer with a frozen layer of the cleaning agent. A method of storing a wafer, which is characterized in that 2. The method for storing a wafer according to claim 1, wherein the cleaning agent is ultrapure water, isopropyl alcohol, or a mixture thereof. 3. A wafer, the surface of which is covered with a frozen layer of a cleaning agent, is transferred by being accommodated in a heat-insulating storage container which is equipped with a freezing means and whose inside is kept at a temperature lower than the freezing point of the frozen layer of the cleaning agent. A method of transporting a wafer, which is characterized in that: 4. The method of transporting a wafer according to claim 3, wherein the cleaning agent is ultrapure water, isopropyl alcohol, or a mixture thereof. 5. The method of transporting wafers according to claim 3, wherein the freezing means is a cryogen stored in a storage container. 6. The method of transporting a wafer according to claim 3, wherein the freezing means is a Peltier electric element mounted in a storage container.