JPH05267269A - Method and apparatus for vacuum drying - Google Patents

Abstract

PURPOSE:To dry a semiconductor wafer with high cleanliness, to eliminate that a foreign body adheres in a drying operation as a problem in conventional cases and to enhance the safety of the drying operation in a vacuum drying apparatus. CONSTITUTION:A vacuum drying apparatus has the following structure: in a state that a semiconductor wafer 11 is kept clean by a cleaning operation, waterdrops 13 which have adhered to the semiconductor wafer 11 are cooled rapidly and iced; the atmosphere of the semiconductor wafer 11 which has been iced is set to a vacuum state; ice 14 which has been iced is sublimated; and the semiconductor wafer 11 is dried.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drying technique, and more particularly to a technique effectively applied to a wafer drying technique used in a manufacturing process of a semiconductor integrated circuit device, for example.

[0002]

2. Description of the Related Art For example, spin dryers and vapor dryers are used as conventional dryers.

The spin dryer has a structure in which a semiconductor wafer is rotated at a high speed and water droplets attached to the semiconductor wafer are removed by centrifugal force.

Further, the vapor drying device has a structure in which water droplets attached to a semiconductor wafer are replaced with vapor of isopropyl alcohol and dried.

[0005]

However, in the structure of the conventional spin drying apparatus described above, since the semiconductor wafer is rotated at a high speed, foreign matter adheres to the semiconductor wafer due to deterioration of the seal of the rotating mechanism and generation of static electricity. There was a problem that it was easy.

Further, the structure of the conventional vapor dryer described above is excellent in that the semiconductor wafer can be highly cleaned, but since it uses the vapor of combustible isopropyl alcohol, it easily causes a fire and is dangerous. There was a problem of being expensive.

An object of the present invention is to provide a drying technique capable of drying a work with high cleanliness.

Another object of the present invention is to provide a drying technique capable of eliminating the adhesion of foreign matter during drying, which has been a problem in the past, and improving safety.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0010]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

The vacuum drying apparatus according to the present invention has a structure including cooling means for rapidly cooling water droplets or water adhering to a work to be frozen, and vacuum means for bringing the atmosphere of the frozen work into a vacuum state. It was done.

[0012]

[Function] When the washed work is dried, first, the water droplets or water attached to the work is rapidly cooled to be iced while the work is kept clean by washing, and then the work atmosphere is vacuumed. Sublimate the frozen ice and dry the work.

As described above, the water droplets attached to the work by the washing are rapidly cooled to be iced, and the iced ice is sublimated to leave the work without leaving a stain called a watermark on the surface of the work. Highly clean and dry.

Therefore, it is possible to improve the safety by eliminating the adhesion of foreign matter during drying, which has been a problem in the past, and by eliminating the use of flammable isopropyl alcohol.

[0015]

FIG. 1 is a sectional view showing a cleaning / drying system equipped with a vacuum dryer according to an embodiment of the present invention.

The cleaning / drying system for cleaning / drying a semiconductor wafer is composed of a loader section 1, a cleaning section 2, a drying section 3 and an unloader section 4 which are sequentially arranged inside the casing C so as to be adjacent to each other. There is.

The loader unit 1 has a structure in which a storage jig 10a for storing one or more semiconductor wafers 11 transferred by a transfer mechanism or an operator is set on the upper floor 16.

In the cleaning unit 2, a cleaning tank 6 for overflowing the ultrapure water 5 is arranged on the lower floor 17, and the semiconductor wafer 1 is transferred to the ultrapure water 5 in the cleaning tank 6 by a transfer mechanism.
1 has been soaked for cleaning.

In the unloader section 4, a highly clean wafer storage jig 10b transported by a transport mechanism or an operator is set on the upper floor 16, and a highly clean semiconductor wafer 11 which has been dried is transported by the transport mechanism. The structure is such that the wafer is stored in a highly clean wafer storage jig 10b.

The vacuum drying apparatus in this embodiment is applied to the drying section 3 provided adjacent to the cleaning section 2.

That is, the drying section 3 is the lower floor 1
7 is provided with a drying chamber 3a, the open end of the drying chamber 3a is covered with a lid, and the drying chamber 3a is sealed during drying.

Further, a liquefied inert gas supply unit 7 for supplying an inert gas 12 such as liquefied N ₂ or liquefied He and a vacuum pump 8 are connected to the drying chamber 3a through a pipe 15, and the semiconductor wafer is cleaned by cleaning. While keeping 11 clean, the water droplets 13 attached to the semiconductor wafer 11 are rapidly cooled to be iced, and the atmosphere of the semiconductor wafer 11 is brought to a vacuum state to sublimate the iced ice 14 to dry the semiconductor wafer 11. It has a structure.

Next, the operation of this embodiment will be described.

When the semiconductor wafer 11 is washed and dried, when the wafer storage jig 10a containing one or more semiconductor wafers 11 is set in the loader section 1 by the transfer mechanism, the semiconductor wafer 11 is removed from the wafer storage jig 10a. Only the carrier is taken out by the transfer mechanism and transferred to the cleaning unit 2.

In the cleaning unit 2, the semiconductor wafer 11 is cleaned in the cleaning tank 6 in which the ultrapure water 5 has overflowed to clean the surface. The cleaned semiconductor wafer 11 is transferred to the drying unit 3 by the transfer mechanism.

In the drying section 3, the cleaned semiconductor wafer 11 is housed in the drying chamber 3a and sealed with the lid 9. The water droplets 13 attached to the semiconductor wafer 11 are rapidly cooled by the inert gas 12 supplied from the liquefied inert gas supply unit 7 to become ice 14.

After that, the atmosphere of the semiconductor wafer 11 is evacuated by the vacuum pump 8, the ice 14 adhering to the semiconductor wafer 11 is sublimated, the semiconductor wafer 1 is dried, and the semiconductor wafer 1 is transferred to the unloader section 4 by the transfer mechanism.

In the unloader section 4, the highly clean semiconductor wafer 11 that has been dried is stored in the highly clean wafer storage jig 10b by the transfer mechanism, and the cleaning / drying process is completed.

As described above, while the semiconductor wafer 11 is kept clean, the water droplets 13 attached to the semiconductor wafer 11 are rapidly cooled to form ice 14, and the atmosphere of the semiconductor wafer 11 is vacuumed to be attached to the semiconductor wafer 11. By sublimating the ice 14, the semiconductor wafer 11 can be highly cleanly dried without leaving a stain called a watermark on the surface of the semiconductor wafer 11.

Therefore, it is possible to improve the safety by eliminating the adhesion of foreign matter during the drying, which has been a problem in the past, and by eliminating the use of flammable isopropyl alcohol.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, in the above-described embodiment, the case where the cleaning section is provided with a cleaning tank for overflowing ultrapure water has been described, but the invention is not limited to this, and steam cleaning in which pure water is vaporized and semiconductor wafers are vapor-cleaned Units can also be provided.

Further, as the vacuum pump, a combination of a roughing pump and a dry pump such as a turbo molecular pump can be used to prevent mixing of oil mist.

The semiconductor wafer and the wafer storage jig may be washed and dried together.

Further, a chemical cleaning section using an inorganic chemical or an organic solvent may be provided between the loader section and the cleaning section so that cleaning and drying of the semiconductor wafer can be carried out consistently.

In the above description, the invention made by the present inventor was mainly described in the background of the field of application, which is the method and apparatus for vacuum drying semiconductor wafers. However, the method and apparatus for vacuum drying other electronic components are described. Can also be applied to.

[0037]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

(1). A vacuum drying method and apparatus for rapidly cooling water droplets or water adhering to a work to be iced, bringing the atmosphere of the work into a vacuum state and sublimating the iced ice to dry the work. Therefore, the work can be highly cleanly dried without leaving a stain called a watermark on the surface of the work.

(2) Due to the effect of the above (1), it is possible to eliminate the adhesion of foreign matter during drying, which has been a problem in the past, and to eliminate the use of flammable isopropyl alcohol, thereby improving safety. it can.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a cleaning / drying system including a drying device according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 loader section 2 cleaning section 3 drying section 3a drying chamber 4 unloader section 5 ultrapure water 6 cleaning tank 7 liquefied inert gas supply section 8 vacuum pump 9 lid 10a wafer storage jig 10b wafer storage jig 11 semiconductor wafer 12 inert Gas 13 Water drops 14 Ice 15 Piping 16 Upper floor 17 Lower floor C Casing

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Noguchi 5-20-1 Kamimizuhonmachi, Kodaira-shi, Tokyo Hitachi, Ltd. Musashi Factory

Claims (3)

[Claims] 1. A vacuum drying method, characterized in that water droplets or water attached to a work is rapidly cooled to be iced, the atmosphere of the work is brought to a vacuum state to sublimate the iced ice, and the work is dried. 2. A vacuum drying apparatus comprising: a cooling means for rapidly cooling water droplets or water attached to a work to be frozen, and a vacuum means for bringing an atmosphere of the frozen work into a vacuum state. .. 3. The vacuum drying apparatus according to claim 2, wherein a liquefied inert gas is used for the cooling means.