JPS6146970B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a package for storing and storing semiconductor wafers.

Semiconductor wafers are formed through manufacturing processes such as impurity diffusion, oxidation, photolithography, cleaning, and metallization. Thereafter, semiconductor elements are separated from the wafer through a pelletizing process and assembled into semiconductor devices. It is generally known that the electrical characteristics of semiconductor devices, especially current amplification factor, leakage current, low frequency noise, etc., are controlled and adversely affected by various types of contamination on the surface of semiconductor elements, such as moisture, inorganic contamination, and organic contamination. It is being Therefore, care must be taken to prevent this contamination as much as possible during the entire manufacturing process from semiconductor wafer manufacture to completion of assembly. However, conventionally, for production control reasons, wafers that have completed the metallization process are often stored in the wafer state for a while while being sent to the pelletizing process. For example, if the manufacturing plant for the pelletizing process is far away, or if the wafers are sold and shipped in wafer form, the wafers are stored in an appropriate storage method, packaged, and then transported.
Furthermore, even within the same factory, wafers are stored and stored in the form of wafers for production adjustment. Traditionally, semiconductor wafers have been stored in glassine paper bags coated with polyethylene on the inside, or by placing multiple wafers in a line in a plastic box, stacking the boxes on top of each other, and using tape, etc. A sealing device is used. However, the former has the disadvantage that the wafer surface comes into contact with the inner surface of the bag and becomes dirty, and the latter does not maintain sufficient airtightness, so the wafer surface is exposed to the atmosphere and various types of dirt adhere to the wafer surface. It had the disadvantage of being adsorbed. For this reason, the surfaces of these conventional storage packages become contaminated during storage, which often has a negative effect on quality and reliability after assembly into semiconductor devices, and the longer the storage period is, the more contamination occurs. The impact was significant.

An object of the present invention is to provide a wafer storage package that can accommodate and store wafers while maintaining their cleanliness and is convenient and simple to transport.

In the present invention, a plurality of wafers are first placed with their surfaces facing up on an aluminum foil, and a hard plastic film, such as a vinyl chloride film, having a recess of approximately the same volume is covered from the top of the wafer, and the wafers are placed with their surfaces facing up. The surface of the aluminum foil in the blank space and the flat part of the vinyl chloride film are thermocompressed in an inert gas atmosphere, for example, a nitrogen atmosphere, and are hermetically sealed. At this time, it is important that the sides of the recess in the plastic film are tapered so that the inner wall of the hard plastic film does not come into contact with the wafer surface. In other words, even if the stored wafer is subjected to vibration during transportation or the surface is turned downward during handling, the taper on the side of this recess has the role of fixing the wafer, and the wafer surface is always located in the space. keep.

The cleanliness of the wafers stored in this way remains in good condition, with no change at all compared to before storage, even if the wafers are placed in an envelope-like container and transported to the appropriate location. was confirmed. Furthermore, it has been confirmed that the product can be kept in good condition even if it is stored for a long period of time in a place where cleanliness is not particularly important, such as an office. Furthermore, the state in which the aluminum foil is in contact with the back side of the wafer is ideal for preventing static electricity when storing wafers that are easily charged inside plastic, such as MOS type semiconductor wafers. As described above, in the wafer storage and storage package of the present invention, the wafer surface is located in an airtight space within an inert gas, completely blocking contamination from the outside air, and further reducing the volume of the package for easy handling, transportation, and storage. It has the characteristic of being extremely small.

Next, the present invention will be explained based on preferred embodiments thereof with reference to the drawings. Figure 1 shows a clean wafer 1 after completing all the wafer manufacturing processes such as diffusion and metallization and before entering the pelletizing process.
It is shown that the aluminum foil 2 is placed with its surface facing up on a pre-cleaned aluminum foil 2 with a thickness of approximately 0.1 mm. A polyethylene coating 3 is provided on the surface of the aluminum foil 2 other than where the wafer is to be placed so as to facilitate subsequent thermocompression bonding. Next, a hard vinyl chloride film 4 as shown in FIG. 2 is separately prepared. This vinyl chloride film 4 serves as a cover that is airtightly placed over the wafer 1 in the state shown in Fig. 1.It has a thickness of about 1 mm and comes into contact with the shoulder around the wafer, preventing the wafer from vibrating or The wafer surface is processed into a tapered shape 5 so that the wafer surface does not come into contact with the inner wall of the cover 4 when the surface is turned upside down. Then the first
The wafer in the state shown in the figure is covered with a vinyl chloride film 4 having the shape shown in FIG. The coated aluminum foil is thermocompression bonded. Thus, as shown in FIG. 3, the wafer 1 is hermetically sealed with the aluminum foil 2 and the vinyl chloride film 4. This sealed portion 6 is completely isolated from the atmosphere by thermocompression bonding. Moreover, the surface of wafer 1 has a height of approximately 3 to accommodate the wafer.
The space 7 is kept in a clean state by being constantly exposed to nitrogen gas. Furthermore, the tapered portion 5 of the vinyl chloride film 4 acts as a stopper even if vibrations from the outside occur. Of course, it is possible to store a plurality of wafers in a similar manner at the same time, and it goes without saying that this can be done automatically.

FIG. 4 shows an example in which a plurality of wafers are stored. In this state, it can be transported to another location or stored for a long period of time. For example, if the wafer is left in the general atmosphere for two years, the surface condition of the wafer will be exactly the same as the initial state, and furthermore, the electrical characteristics after being assembled into a semiconductor device will deteriorate due to storage. There wasn't any.

As described above, the wafer storage package of the present invention can be implemented in an extremely simple manner, and the storage case has a very thin shape, making it easy to handle, store, and store.
It is convenient to transport and has the characteristics of not having any negative effect on the quality or reliability of the wafer. Note that the present invention is not limited to the specific materials, shapes, etc. listed in the above embodiments.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a semiconductor wafer placed on an aluminum foil according to the present invention, Fig. 2 is a sectional view of a plastic cover, Fig. 3 is a sectional view of a storage package of the present invention, and Fig. 4 is a sectional view of a plurality of storage packages. FIG. 3 is a sectional view of the package storage package. DESCRIPTION OF SYMBOLS 1... Semiconductor wafer, 2... Aluminum foil, 3... Polyethylene coating, 4... Vinyl chloride film, 5... Tapered part of vinyl chloride film, 6... Sealing part, 7... Inner space for wafer storage. , inert gas filled section.

Claims (1)

[Scope of Claims] 1. A metal film on which a large number of semiconductor wafers are placed, and a hard plastic cover sealed to the metal film, which contacts the shoulders of each semiconductor wafer to fix each semiconductor wafer. a hard plastic cover having a shape that does not contact the surface of each semiconductor wafer, and the space formed by the metal film and the cover is filled with an inert gas to seal each semiconductor wafer. Storage package cage. 2. The metal film is partially coated with a plastic film, and the sealing is achieved by thermocompression bonding between the plastic coating part on the metal film and the flat part of the plastic cover. A semiconductor wafer storage package according to claim 1, characterized in that: