JPH0574921A - Case - Google Patents

Abstract

PURPOSE:To prevent an aluminum alloy film on the surface of a wafer from being eroded by moisture in the atmosphere within a case after dry etching. CONSTITUTION:A case 1 is composed of a case body 2 and a cover 3, and houses a cassette 7 in which a wafer 6 is stored. This case is a structure of a hermetically sealed container. An airtight state maintaining coupler 10 is connected to the main body of the case. The coupler is connectable to a gas condition setting apparatus 25, and enables the pressure within the case to be applied or reduced, and permits the case to be charged with purified dry air, nitrogen gas, inert gas, or the like. After the plasma etching, when the cassette storing the wafer is housed in the case, an aluminum alloy film on the surface of the wafer is prevented from being eroded by eliminating moisture from the housing space 5 inside the case utilizing the airtight state maintaining coupler, and by charging the case with a positively pressurized inert gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique effectively applied to prevent film corrosion on a wafer surface in a pre-process of a semiconductor device manufacturing process, for example, a case for accommodating a wafer after a plasma etching process.

[0002]

2. Description of the Related Art In the process of manufacturing a semiconductor device, there is a process step of selectively etching a film provided on the surface of a semiconductor substrate called a wafer. Wet etching methods and dry etching methods are known as etching techniques. There is a plasma etching method as one of the dry etching methods. Plasma etching is performed by a plasma etching apparatus, and as a method of transferring wafers at this time, a so-called cassette-type that automatically removes a wafer from the cassette, performs plasma etching in the processing chamber, and then automatically stores the wafer in the cassette again. A load lock system using a toe cassette is known. In the cassette-to-cassette load lock system, the wafer is transferred from the cassette in the load chamber into the vacuum chamber and enters the processing chamber. After the processing, the wafer is transported again in the vacuum chamber and enters the unload chamber. The wafer is purged in the unload chamber and taken out to the atmosphere side after processing. For the cassette-to-cassette type dry etching apparatus, for example, “Monthly Semiconductor Wo published by Press Journal Co., Ltd.
rld (Semiconductor World) ”June 1982
Monthly issue, published on May 15, 1982, P87-P92.

The above-mentioned document describes the following regarding after-corrosion of aluminum.
"It is known as after-corrosion that the Al film is corroded if it is left in the air as it is after being etched. When Cu enters Al, the after-corrosion becomes more severe. It is considered that John is mainly caused by HCl formed by the reaction of Cl remaining on the wafer surface with moisture in the atmosphere.As a method of preventing after-corrosion, cleaning with deionized water immediately after etching, etching After that, post-etching is performed with Freon gas. After etching, the resist is continuously removed. After etching, discharge is performed in NH ₃ to neutralize, and then washed with water. After etching, heat treatment is performed in a vacuum without being exposed to the atmosphere. Is effective in suppressing after-corrosion.In any case, if the Al alloy (especially 2 to 4% Cu) is used, Tsu quenching process can not be said yet well established. The residue is required continuous etch process development problem solving in terms of after-roller John.

On the other hand, "Electronic Materials" 198 published by the Industrial Research Society
March 4 issue, issued March 1, 1984, P63-P65
In order to prevent after-corrosion of aluminum, after etching, the wafer is placed in a third chamber provided in advance, and a corrosion prevention treatment is performed in this chamber by plasma of CF ₄ and O _2. Is disclosed.

On the other hand, the wafer is generally handled by being accommodated in an accommodation jig called a wafer carrier or a wafer cassette. Further, the wafer cassette is accommodated and handled in a case called a cassette case, a wafer carrier box or the like. The wafer carrier is described, for example, in “Electronic Materials”, August 1988 issue, published by Industrial Research Society, August 90, 1988, P90. Regarding the wafer carrier box, "Electronic Materials" published by the Industrial Research Group, November 1988 issue, Showa 63
Issued November 1, 2012, see page 181.

[0006]

After the plasma etching process, when the wafer is exposed to the atmosphere, moisture in the atmosphere adheres to the surface of the wafer and reacts with the film on the surface of the wafer to cause aftercorrosion depending on the processing conditions. It becomes a cause of failure. In particular, when a corrosive gas is used in the etching process, and when a corrosive substance remains on the surface of the wafer after the process, the adhesion of moisture in the atmosphere surely causes the wafer to be defective. In addition, even in a wafer before processing, the attachment of water in the atmosphere leads to contamination of the processing chamber, which causes deterioration of process performance. In a conventional case such as a wafer carrier box for accommodating a wafer cassette, a mechanism for preventing moisture in the atmosphere from adhering to the wafer is not provided.

It is an object of the present invention to provide a case capable of preventing moisture in the atmosphere from adhering to the wafer contained in the case and removing the moisture adhering to the wafer.

Another object of the present invention is to provide a case in which after-corrosion of a wafer after etching processing can be suppressed. The above and other objects and novel features of the present invention will be apparent from the description of the present specification and the accompanying drawings.

[0009]

The outline of a typical one of the inventions disclosed in the present application will be briefly described as follows. The case (cassette case) for accommodating the wafer of the present invention has a closed container structure using a seal in order to protect the wafer from moisture in the atmosphere, and removes moisture in the atmosphere contained in the case. Therefore, an airtightness maintaining coupler connected to the exhaust system (gas condition setting device) is provided. The case is pressurized or depressurized by the gas condition setting device, or is filled with an inert gas or the like.

In another embodiment, as in the case of the previous embodiment, the case has a closed container structure, and a heater is provided in the case so that the inside of the case can be heated at any time by turning on the power source. Moisture in the mixed air can be discharged to the outside of the case by opening the case lid slightly.

In another embodiment, the case has a hermetically sealed container structure as in the case of the previous embodiment and has a hermetically-sealing type coupler. In addition to this, the case itself directly accommodates the wafer. The wafer cassette structure is capable of

[0012]

In the case of the present invention having the closed container structure and the airtightness maintaining type coupler, the airtightness maintaining type coupler is connected to the gas condition setting device at least at the time when the wafer cassette is accommodated, and the inside of the case is added. -By depressurizing, moisture in the atmosphere can be exhausted, or moisture in the atmosphere can be discharged out of the case by filling with an inert gas or the like. As a result, moisture in the atmosphere does not adhere and remain on the surface of the wafer, and damage to the wafer due to moisture can be suppressed. In particular, it is effective in preventing after-corrosion of an aluminum film or the like provided on the wafer surface after plasma etching.

Even in the case of a case having a closed container structure and a built-in heater, the inside of the case can be warmed by the heater. Therefore, after the cassette containing the wafer is housed in the case, the wafer is heated for about several minutes. As a result, water in the atmosphere adhering to the wafer can be discharged to the outside of the case, so that damage to the wafer due to water can be prevented as in the above-described embodiment.

In the case of a case having a hermetically-sealing type coupler and having a hermetically sealed container structure and a wafer cassette structure itself, this case is directly mounted on a loading table or an unloading table of various processing apparatuses such as a plasma etching apparatus. Since the wafer can be placed, the wafer can be housed in the case without being exposed to the atmosphere, and the wafer can be prevented from being damaged by moisture in the atmosphere.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a main part of a case accommodating a wafer cassette according to an embodiment of the present invention, and FIG. 2 is a schematic view showing a state in which an airtightness maintaining type coupler also attached to the case is connected to a gas condition setting device. FIG. 3 is a schematic view showing another example of piping of the gas condition setting device.

The case 1 of this embodiment includes a case body 2 having an upper opening and a lid 3 for closing the upper surface of the case body 2.
It has a rectangular parallelepiped structure. A seal (O-ring) 4 for maintaining airtightness is provided on the mating surface between the case body 2 and the lid 3. This seal 4
Is fitted in a groove provided on the mating surface of the case body 2, and the mating surface of the lid 3 crushes the seal 4 to maintain the airtightness of the accommodation space 5 in the case 1. It is like this. The lid body 3 may have a structure in which it is simply stacked on the case body 2, or may have a structure with a lock mechanism. The case structure is not particularly limited. The case 1 may be made of plastic, but metal or ceramic is preferable in consideration of pressure resistance and heat resistance.

A cassette 7 containing a wafer 6 is housed in the case 1. This cassette 7 is generally 25
A plurality of wafers 6 are set up in parallel and accommodated. Further, this is one of the features of the present invention, and an airtightness maintaining type coupler (so-called one-touch coupler) 10 is attached to the lower part of one side of the case body 2. To be precise, the male type (airtightness maintaining type male type) 11 of the airtightness maintaining type coupler 10 is attached to the outer wall of the case body 2. This airtightness maintaining type male coupler 11 has a male fitting 12 and a valve 1.
Have three. A diamond-shaped top 14 is provided at the tip of the fitting male die portion 12 to automatically close the male hermetically sealed coupler die 11 regardless of whether the valve 13 is opened or closed.
This top 14 is retracted when the fitting female mold portion 17 of the female mold (airtight maintenance coupler female mold) 16 of the airtightness maintaining coupler 10 is fitted into the fitting male mold part 12 and is kept in the airtightness maintaining coupler female. The tube 18 connected to the mold 16 and the tube 19 of the hermetically sealed coupler male mold 11 are communicated with each other.

Since the case 1 is fitted with the airtightness maintaining type coupler male mold 11 as described above, as shown in FIG. 2, the airtightness maintaining type coupler female mold connected to the gas condition setting device 20. 16 to the airtightness maintaining type male coupler 1
When 1 is connected, gas conditions of the accommodation space 5 of the case 1,
That is, the pressure and gas type can be set. The gas condition setting device 25 includes an exhaust pump 26 connected to the pipe 18.
And a valve 28 connected to a branch pipe 27 branched from the pipe 18, and a purge gas cylinder 29 connected to the valve 28 and filled with purge gas.
Therefore, after the airtightness maintaining coupler male mold 11 and the airtightness maintaining coupler female mold 16 are connected, the valve 13 is opened and the exhaust pump 26 is driven to bring the housing space 5 of the case 1 into a decompressed state. be able to. As a result, moisture in the atmosphere mixed in the accommodation space 5 is discharged to the outside of the case 1. Therefore, the inside of the accommodation space 5 is free of water, and the corrosion of the film on the surface of the wafer 6 due to the water can be prevented. Further, when the inside of the accommodation space 5 is pressurized, the valve 28 is opened and the purge gas in the purge gas cylinder 29 is accommodated in the accommodation space 5.
Pump it in. If clean air is used as the purge gas, the storage space 5 is filled with air without moisture, and corrosion due to moisture in the film on the surface of the wafer 6 can be prevented.

On the other hand, FIG. 3 shows an example in which the gas condition setting device 25 is provided with more gas supply systems. That is,
A branch pipe 32 is connected to the pipe 18. The branch pipe 32 branches into a first branch pipe 33 and a second branch pipe 34. The first branch pipe 33 is connected to a valve 35, and a first gas cylinder 36 is connected to the valve 35. The second branch pipe 34 is connected to a valve 37, and the valve 37 is connected to a second gas cylinder 38. The first gas cylinder 36 is filled with, for example, nitrogen gas, and the second gas cylinder 38 is filled with an inert gas. Therefore, after connecting the airtightness maintaining coupler 10 of the case 1, that is, the airtightness maintaining male coupler 11 to the airtightness maintaining coupler female mold 16, the valve 13 is opened and the valve 28 is opened to dry and clean air of the case 1. The nitrogen gas can be fed into the accommodation space 5, or the valve 35 can be opened to feed the nitrogen gas into the accommodation space 5, and the valve 37 can be opened to feed the inert gas into the accommodation space 5. In this case, before the desired gas is sent into the accommodation space 5, the exhaust pump 26 is driven to exhaust the moisture in the atmosphere in the accommodation space 5, so that the moisture remains in the accommodation space 5. It is desirable in that it is not allowed.

[0020]

(1) The case of the present invention uses the airtightness maintaining type coupler connected to the case before or after accommodating the cassette accommodating the wafer in the case, and Since the water content can be removed, it is possible to prevent the occurrence of defects due to the water content of the wafer.

(2) In the case of the present invention, before or after accommodating the cassette accommodating the wafer in the case, the moisture in the accommodating space in the case is removed by using the airtightness maintaining type coupler connected to the case. In addition to being removed, it is possible to positively prevent the occurrence of wafer corrosion by filling dry and clean air, nitrogen gas or an inert gas.

(3) According to the above (2), the case of the present invention can remove water in the housing space and then depressurize or pressurize the housing space, so that the wafer is corroded by the water. Can be prevented. In particular, when the accommodation space is pressurized (positive pressure), the outside air is prevented from entering the case, which is suitable for long-term wafer storage.

(4) Due to the above (1) and (2), the case of the present invention is particularly suitable for accommodating a wafer processed by using a corrosive gas or a corrosive chemical. That is, when moisture in the atmosphere is mixed into the accommodation space of the case, the moisture adheres to the surface of the wafer and causes a chemical reaction with a corrosive residual substance, which corrodes the coating film provided on the wafer surface. However, by removing water from the housing space in the case and further filling the housing space with nitrogen gas or an inert gas, the effect of positively preventing the corrosion of the coating film can be obtained.

(5) According to the above (1) to (4), by using the case of the present invention, it is suitable for storing the wafer after plasma etching and for suppressing the after-corrosion of the coating film such as aluminum. A synergistic effect is obtained.

Although the invention made by the present inventor has been specifically described based on the embodiments, the invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say, for example,
FIG. 4 is a sectional view showing a main part of a case according to another embodiment of the present invention. In this embodiment, the case 1 has a hermetically sealed container structure having a seal 4 on the mating surface of the case body 2 and the accommodation space 5 as in the case of the above embodiment. Further, the case 1 has a cartridge heater 40 built therein. For example, the cartridge heater 40 is arranged on both inner wall surfaces of the case body 2. This cartridge heater 4
An outlet 41 electrically connected to 0 is provided on one outer surface side of the case body 2. Therefore, if an electric plug is connected to the outlet 41, the cartridge heater 40 heats up and heats the accommodation space 5 of the case 1. Therefore, the wafer 6 is mounted on the case 1.
When the cassette 7 containing therein is put into the cartridge heater 40, and then the power is applied to the cartridge heater 40, the temperature in the housing space 5 rises, and the moisture in the atmosphere that has entered the housing space 5 is heated to form steam. 1 is discharged. Therefore, after a certain time, the lid 3 is closed and the cartridge heater 4 is
Turn off 0. If the inside of the accommodation space 5 of the case 1 is preheated before the cassette 7 is accommodated in the case 1, the working time is shortened and the moisture in the atmosphere is more effectively exhausted. Further, if the airtightness maintaining type coupler is provided also in this embodiment, it is natural that the moisture is forcibly exhausted and the desired gas is supplied into the accommodation space.
It is also possible to pressurize and depressurize the accommodation space.

FIG. 5 is a perspective view showing a main part of a case according to another embodiment of the present invention. In this embodiment, the cassette 7 is integrally formed in the case 1. Therefore, the case 1 can be directly attached to a loading / unloading table (table 45) of a processing apparatus such as a plasma etching apparatus, and the wafer 6 is unloaded from the inside of the case 1 by a transfer mechanism (not shown). It can be carried into the case 1. The lid 3 can be opened and closed by a hinge (not shown), and a seal (O-ring) 4 is provided on its mating surface, that is, on the case body 2 side. Although not shown, the case body 2 and the lid 3 are provided with a lock mechanism so that they can be easily locked and unlocked by an external operation. It is desirable that the lock mechanism has a commonly used one-touch structure, that is, a simple structure. The case 1 of this embodiment is placed directly on the table 45 of the processing apparatus, and the lid 3 can be opened / closed on the table 45. Therefore, in the processing apparatus, the moisture in the atmosphere does not come into contact with the wafer 6 and the processing is performed. It is possible to prevent the after-corrosion of the coating film of the wafer 6 later. In addition, the cassette 7 is placed in case 1 before processing.
If the airtightness-maintaining coupler 10 is used to remove the water in the accommodation space 5 when the above is accommodated, the processing efficiency can be further enhanced. In this embodiment, if the case itself can also be used as a load lock chamber, the wafer can be more completely protected from moisture in the atmosphere.

In the above description, the case where the invention made by the present inventor is mainly applied to the technique of a case (cassette case) for accommodating a wafer cassette, which is the field of application of the background, has been described, but the invention is not limited thereto. Not a thing. The present invention can be similarly applied to at least cases for products and parts that do not like atmospheric moisture.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a case accommodating a wafer cassette according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a gas condition setting device for a housing space in the case of the present invention.

FIG. 3 is a schematic view showing another example of piping of the gas condition setting device.

FIG. 4 is a sectional view showing a main part of a case according to another embodiment of the present invention.

FIG. 5 is a perspective view showing a main part of a case according to another embodiment of the present invention.

[Explanation of symbols]

1 ... Case, 2 ... Case body, 3 ... Lid, 4 ... Seal,
5 ... Accommodation space, 6 ... Wafer, 7 ... Cassette, 10 ... Airtight maintenance type coupler, 11 ... Airtight maintenance type coupler male, 12 ... Fitting male mold part, 13 ... Valve, 14 ... Coma, 16 ... Airtight maintenance type coupler Female mold, 17 ... Fitting female mold part, 18 ... Pipe, 19 ... Pipe,
25 ... Gas condition setting device, 26 ... Exhaust pump, 27 ... Branch pipe, 28 ... Valve, 29 ... Purge gas cylinder, 32 ... Branch pipe, 33 ... First branch pipe, 34 ... Second branch pipe, 35 ... Valve, 36 … First gas cylinder, 37… Valve, 38… Second
Gas cylinder, 40 ... Cartridge heater, 41 ... Outlet, 45 ... Table.

Claims (6)

[Claims] 1. A case for accommodating an object to be housed, comprising a case body and a lid, wherein a seal for maintaining airtightness is provided on a mating surface between the case body and the lid, and the case is provided. An airtightness-maintaining coupler communicating with the housing space is attached to at least one outer wall of the main body or the lid. 2. The gas condition setting device, which is temporarily connected to the case via the airtightness-maintaining coupler, sets the kind and pressure of the gas filling the storage space. The case described in item 1. 3. The case according to claim 1, wherein the housing space is set in a pressurized or depressurized state for use. 4. The storage space according to claim 1, wherein the storage space is set in an inert gas atmosphere for use.
Case described in section. 5. A case for accommodating an object to be housed, which comprises a case body and a lid body, wherein a mating surface between the case body and the lid body is provided with a seal for maintaining airtightness, and A case characterized by being provided with a heating device. 6. The case according to claim 1, wherein the case has a cassette structure in which a plurality of wafer accommodating grooves are provided so as to face the inner walls of both side walls of the case.
The case described in any of the items.