JP2680933B2 - Silicon wafer cleaning method and cleaning apparatus therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning a silicon wafer and a cleaning apparatus therefor.

[0002]

2. Description of the Related Art Conventionally, to clean a silicon wafer,
(1) A method of immersing a silicon wafer in a bath filled with a cleaning solution of hydrofluoric acid, (2) a method of spraying a cleaning solution of hydrofluoric acid using a high-pressure injection device on a silicon wafer are known. There is.

[0003]

However, the cleaning method has the following drawbacks. That is, it is difficult to control the cleanliness of the cleaning liquid by the immersion method of the above (1). Further, in the cleaning method of the above (2), the injection time of the cleaning liquid onto the silicon wafer and the pressure distribution are not constant. Furthermore, each of the above cleaning methods causes contamination by the particulate matter dispersed in the cleaning liquid. Therefore, none of the cleaning methods can uniformly etch the entire surface of the silicon wafer and cause secondary contamination by the particulate matter, so that the entire surface of the silicon wafer cannot be uniformly cleaned with high cleanliness.

The present invention has been made in order to solve the above-mentioned conventional problems, and is a method of uniformly cleaning the entire front and back surfaces of a silicon wafer with high cleanliness, and cleaning with such uniform and high cleanliness. It is intended to provide a feasible device.

[0005]

SUMMARY OF THE INVENTION A method of cleaning a silicon wafer according to the present invention comprises a high-frequency shaker attached to a fog generating chamber.
A step of generating a mist of an aqueous solution of hydrofluoric acid by a moving nozzle; a step of transporting the mist of the aqueous solution of hydrofluoric acid into a processing chamber and exposing a silicon wafer standing upright in the processing chamber to the atmosphere of the mist to perform etching. And rinsing both surfaces of the wafer by injecting pure water along the surface of the wafer to the silicon wafer exposed to the atmosphere of the fog. As the hydrofluoric acid aqueous solution,
For example, it is desirable to use one having a hydrofluoric acid concentration of 0.1 to 50%.

Further, the silicon wafer cleaning apparatus according to the present invention is provided with a fog generating chamber provided with a high frequency vibrating nozzle for injecting a hydrofluoric acid aqueous solution, a processing chamber connected to the fog generating chamber, and the fog generating chamber. A shutter arranged in a communicating portion between the chamber and the processing chamber, a transport means for transporting a storage member in which a plurality of silicon wafers are stood up and stored in the processing chamber, and the processing located above the storage member A pure water spray nozzle for spraying pure water along the surface of each silicon wafer of the storage member is provided in the chamber.

The high-frequency vibrating nozzle preferably has a structure in which a high-frequency oscillator supplies a high-frequency wave to a vibrator provided in the main body, and a diaphragm attached to the vibrator generates a high frequency of 1 to 4 MHz. Such a high frequency vibrating nozzle,
It may be provided on the side wall, the bottom surface, or both of the fog generating chamber. In particular, it is desirable that the high-frequency vibrating nozzle provided on the bottom surface of the mist generating chamber is arranged so that its nozzle port is located below the water surface of the hydrofluoric acid aqueous solution filled near the bottom of the mist generating chamber.

In the cleaning apparatus according to the present invention, the rectangular transportation path is penetrated through the partition between the mist generating chamber and the processing chamber, and both ends of the transportation path are projected into each chamber, and the mist is formed. A shutter is arranged at the end of the transportation path located on the side of the generation chamber, and further air or an inert gas (for example, nitrogen gas, argon gas, etc.) having high cleanliness is injected to the processing path toward the processing chamber. You may provide the nozzle for doing.

[0009]

According to the method of the present invention, by applying high frequency vibration to the hydrofluoric acid aqueous solution in the fog generating chamber, it is possible to generate a mist of micron to submicron order, and to generate the mist of the order and the fog in the generating chamber. By the retention, it is possible to separate the particulate matter which is a secondary pollution source in the hydrofluoric acid aqueous solution. By transporting the mist of the hydrofluoric acid aqueous solution into the processing chamber and exposing the silicon wafer standing upright in the processing chamber to the mist atmosphere, the entire front and back surfaces of the wafer can be uniformly etched by the hydrofluoric acid. Then, pure water is sprayed along the wafer surface onto the silicon wafer exposed to the atmosphere of the mist, so that both surfaces of the wafer can be favorably rinsed. In addition, during the etching and rinsing treatment, since the fine particles can be exposed to a mist of a highly clean hydrofluoric acid aqueous solution, secondary contamination by the fine particles can be prevented. Further, by performing the etching and rinsing processes in a closed processing chamber, that is, by performing continuous processes in a closed state, it is possible to avoid oxidation of the active front and back surfaces of the wafer after etching. Therefore, the entire front and back surfaces of the silicon wafer can be cleaned uniformly and with high cleanliness.

Further, according to the present invention, a fog generating chamber provided with a high-frequency vibrating nozzle for hydrofluoric acid aqueous solution, a processing chamber connected to the fog generating chamber, and a communicating portion between the fog generating chamber and the processing chamber. Is provided in the processing chamber located above the storage member, and a shutter arranged in the processing chamber, a transfer means for transferring a storage member in which a plurality of silicon wafers are stood up in the processing chamber and stored. With the configuration including the pure water spray nozzle for spraying along the surface of each silicon wafer of the storage member, it is possible to realize a cleaning device capable of uniformly cleaning the entire front and back surfaces of the silicon wafer with high cleanliness.

Further, in the cleaning device, a rectangular cylindrical transportation path is penetrated through the partition wall of the mist generating chamber and the processing chamber, and both ends of the transportation path are projected into the respective chambers, and the mist generating chamber side. By disposing a shutter at the end of the transportation path located at, and further by providing a nozzle for injecting highly clean air or inert gas toward the processing chamber side in the transportation path, the fog generation chamber The mist of the aqueous solution of hydrofluoric acid can be efficiently transported into the processing chamber, and the etching and rinsing of the front and back surfaces of the silicon wafer can be performed in a short time.

Furthermore, if high-frequency vibrating nozzles are provided on the side wall and the bottom surface of the mist generating chamber in the cleaning device, the mist generating chamber can be filled with mist of hydrofluoric acid aqueous solution in a short time.
By transporting the mist to the processing chamber, it becomes possible to perform etching and rinsing on the front and back surfaces of the silicon wafer in a short time.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view of a cleaning apparatus showing an embodiment of the present invention. In FIG. 1, 1 is a fog generating chamber, and 2 is a processing chamber arranged adjacent to the generating chamber 1. The chambers 1 and 2 are partitioned by a partition wall 3. A bar type high frequency vibrating nozzle 4 for spraying an aqueous solution of hydrofluoric acid is provided on a side wall of the fog generating chamber 1 facing the partition wall 3. The nozzle 4 is composed of a main body 4b having an elongated nozzle opening 4a extending in the direction of the paper surface of FIG. 1, and a vibration plate (not shown) built in the main body 4b and having a vibrator attached thereto. ing. A cable 6 of a high-frequency oscillator 5 is connected to the vibrator of the nozzle 4, and the diaphragm attached to the vibrator generates a high frequency of 1 to 4 MHz by supplying a high frequency to the vibrator. Has become. The main body 4b portion of the nozzle 4 located between the vibrating plate and the nozzle opening 4a has, for example, a concentration of 20%.
Supply pipe 7 for supplying the aqueous solution of hydrofluoric acid in the main body 4b
Are connected. The other end of the supply pipe 7 is immersed in a hydrofluoric acid aqueous solution 9 contained in a tank 8. The supply pipe 7
A first pump 10 is interposed in the. The fog generating chamber 1
A drain pipe 11 for returning the hydrofluoric acid aqueous solution 9 filling the bottom of the mist generating chamber 1 into the tank 8 is connected to the bottom surface of the tank. The other end of the drain pipe 11 is inserted into the tank 8. The drain pipe 11 has a second pump 12 and a filter 13 having an opening of 0.2 μm or less from the connection side of the fog generating chamber 1.
Are sequentially installed.

On the bottom surface of the fog generating chamber 1, another high frequency vibrating nozzle 14 is filled with the hydrofluoric acid residual solution 9 to fill the fog generating chamber 1.
It is provided so that it can be immersed in. This nozzle 14
A main body 14b having a round nozzle opening 14a arranged below the water surface of the hydrofluoric acid aqueous solution 9 filled in the mist generating chamber 1,
The main body 14b includes a vibrating plate (none of which is shown) to which a vibrator is attached. The vibrator of the nozzle 14 is connected to the cable of the high frequency oscillator 5.
A vibration plate attached to the vibrator is configured to generate a high frequency of 1 to 4 MHz by connecting 15 to the vibrator.

A flat rectangular tube-shaped transportation path 16 is penetrated through the partition wall 3 so that both ends thereof project into the generation chamber 1 and the processing chamber 2. A shutter 17 for opening and closing an opening of the transportation path 16 is arranged at an end of the transportation path 16 located on the side of the fog generating chamber 1. A plurality of nozzles 18 for injecting, for example, clean air from the inside of the transportation passage 16 toward the processing chamber 2 side are provided in the portion of the transportation passage 16 protruding toward the side of the fog generating chamber 1.

Further, numeral 19 in the drawing is a gate on the side wall of the processing chamber 2.
A transport member that moves between the inside and the outside of the processing chamber 2 through 20. A carrier 21 is placed on the carrying member 19 to stand and store the silicon wafer. On the upper wall of the processing chamber 2 located above the carrier 21 transported into the processing chamber 2, a plurality of pure water injection nozzles 22 are arranged in the longitudinal direction of the carrier 21 (the paper surface direction in the figure). ,
For example, a gas supply nozzle 23 for supplying clean air into the processing chamber 2 is provided. An exhaust pipe 24 for exhausting gas or the like in the processing chamber 2 is inserted into the processing chamber 2 from the bottom side of the processing chamber 2, and the exhaust pipe is
An exhaust fan 25 is provided at 24. Further, a drain 26 is provided at the bottom of the processing chamber 2. Next, a method for cleaning a silicon wafer using the above-described cleaning device will be described.

First, the carrier 21 in which a plurality of silicon wafers 27 are stood upright is placed on the transfer member 19, and then the gate is
20 is opened, the transfer member 19 is transferred into the processing chamber 2 through the gate 20, and the gate 20 is closed. Subsequently, for example, clean air is supplied into the processing chamber 2 from the gas supply nozzle 23, and the exhaust fan 25 is operated to exhaust the gas in the processing chamber 2 through the exhaust pipe 24 to clean the inside of the processing chamber 2. Replace with.

While the inside of the processing chamber 2 is being replaced with clean air, the first pump 10 is operated to operate the hydrofluoric acid solution 9 in the tank 8.
Is supplied to the bar-type high-frequency vibrating nozzle 4 through the supply pipe 7, and a high frequency is supplied from the high-frequency oscillator 5 to the vibrator of the vibrating nozzle 4, so that a vibration plate attached to the vibrator generates a high frequency of 1 to 4 MHz. Occur. Supply of the hydrofluoric acid aqueous solution to the high-frequency vibrating nozzle 4 and the vibrating plate 1
Due to the generation of the high frequency of ˜4 MHz, the fog 28 of the hydrofluoric acid aqueous solution is jetted from the nozzle port 4a of the vibrating nozzle 4. At this time, the fog 27 of micron order to submicron order is generated, and the fog generation of the order and the fog generation chamber 1 are performed.
The fine particles that were originally contained in the hydrofluoric acid aqueous solution are separated by the retention of the mist 28 in. By operating the bar type high frequency vibrating nozzle 4 and supplying high frequency from the high frequency oscillator 6 to the vibrator of another high frequency vibrating nozzle 14 provided on the bottom surface of the mist generating chamber 1 through the cable 15,
A vibration plate attached to the vibrator generates a high frequency of 1 to 4 MHz. The high frequency vibration of 1 to 4 MHz from the vibrating plate is applied to the hydrofluoric acid aqueous solution 9 at the bottom of the fog generating chamber 1, so that the fog is jetted into the fog generating chamber 1 from the water surface of the hydrofluoric acid aqueous solution 9. By using such another high frequency vibrating nozzle 14 in combination, the fog 28 can be filled in the fog generating chamber 1 in a short time. The hydrofluoric acid aqueous solution 9 filled in the bottom of the fog generating chamber 1 is introduced into the drain pipe 11 by the operation of the second pump 12 in order to remove the particulate matter accumulated in the aqueous solution 9 to the outside of the system. Filter installed in drainage pipe 11
After the particulate matter is removed by 13, it is returned to the tank 8 as an aqueous solution of hydrofluoric acid having high cleanliness.

After the mist generating chamber 1 is filled with a sufficient amount of mist 28, the operation of the bar type high frequency vibrating nozzle 4 is stopped (when another high frequency vibrating nozzle 14 is operated, The operation is also stopped), and the shutter 17 arranged on the transportation path 16 is opened. At the same time, for example, clean air is jetted toward the processing chamber 2 side from a plurality of nozzles 18 provided in the transportation path 16, and at the same time, the exhaust fan 25 is operated. By such an operation, the mist 28 of the hydrofluoric acid aqueous solution in the mist generating chamber 1 rides on the clean air sprayed from the nozzles 18 in the transportation path 16 and is accelerated toward the processing chamber 2 side, so that the inside of the processing chamber 2 is accelerated. And the inside of the processing chamber 2 becomes the atmosphere of the mist. When the processing chamber 2 becomes the mist atmosphere, the mist of the hydrofluoric acid aqueous solution comes into contact with the plurality of silicon wafers 27 in the carrier 21 transported into the processing chamber 2, and the front and back surfaces of each wafer 27 are etched.

Next, after etching for a predetermined time, the shutter 17 is closed and the injection of clean air from the nozzle 18 is stopped. Continuing, the carrier
Pure water is jetted from a plurality of pure water jet nozzles 22 arranged above 21. At this time, the pure water is sprayed along the front and back surfaces of the plurality of wafers 27 that are stood up in the carrier 21 to rinse the front and back surfaces of each wafer 27.
In such a rinsing process, in order to prevent the mist of the hydrofluoric acid solution from reattaching to the silicon wafer 27, it is desirable to operate the exhaust fan 25 in the latter stage of the rinsing to discharge the mist through the exhaust pipe 24.

Next, after the pure water jetting nozzle 22 stops the pure water jetting, clean air is supplied from the gas supply nozzle 23 into the processing chamber 2 and the exhaust fan 25 is operated to operate the gas in the processing chamber 2. By exhausting mist and mist through the exhaust pipe 24, the inside of the processing chamber 2 is replaced with clean air. After that, the gate 20 is opened, and etching is performed by the transport member 19,
The carrier 21 containing the wafer 27 after the rinsing process is transferred to the outside of the processing chamber 2 through the gate 20.

According to the cleaning method described above, the mist of the hydrofluoric acid aqueous solution of the micron order to the submicron order generated in the mist generating chamber 1 is transported into the processing chamber 2 and the silicon wafer 27 is arranged. By making the processing chamber 2 a mist atmosphere, the entire front and back surfaces of the wafer 27 can be uniformly etched by the mist of the hydrofluoric acid aqueous solution. In addition, thereafter, pure water is sprayed from the pure water spray nozzle 22 onto the silicon wafer 27 exposed to the mist atmosphere, so that both surfaces of the wafer 27 can be rinsed well. Also, during the etching and rinsing processing, the wafer
Since 27 can be exposed to the mist of the aqueous solution of hydrofluoric acid having a high degree of cleanliness in which the particulate matter has already been separated in the fog generation chamber 1, secondary contamination by the particulate matter can be prevented, and etching and etching with a high degree of cleanliness can be performed. Can be rinsed. Furthermore,
By performing the etching and rinsing processes in the closed processing chamber 2, that is, by continuously performing the process in the closed state, it is possible to avoid oxidation of the front and back surfaces of the active wafer 27 after etching. Therefore, the entire front and back surfaces of the silicon wafer 27 can be cleaned uniformly and with high cleanliness.

In the above embodiment, a bar type high frequency vibrating nozzle provided in the fog generating chamber was used, but the present invention is not limited to this, and a normal high frequency vibrating nozzle may be used. .

In the above embodiment, only the high frequency is supplied to the vibrator as the high frequency vibration nozzle provided on the bottom surface of the fog generating chamber,
A structure was used in which the aqueous solution of hydrofluoric acid filling the bottom of the fog generating chamber was subjected to high frequency vibration to spray the aqueous solution of hydrofluoric acid.
It is not limited to this. For example, a high frequency vibrating nozzle having a structure similar to that of the high frequency vibrating nozzle provided on the side wall of the mist generating chamber, that is, a structure of supplying a hydrofluoric acid aqueous solution to the main body portion between the nozzle opening and the vibrating plate may be provided on the bottom surface of the mist generating chamber. .

In the above embodiment, pure water was sprayed onto the silicon wafer exposed to the mist atmosphere, but the present invention is not limited to this. For example, after exhausting the mist in the processing chamber and supplying an inert gas such as argon from the gas supply nozzle into the processing chamber to replace the inside of the processing chamber with the inert gas, the rinse treatment is performed by spraying pure water on the silicon wafer. You can go.

[0026]

As described in detail above, according to the present invention, a method of uniformly cleaning the entire front and back surfaces of a silicon wafer with high cleanliness, and cleaning of the silicon wafer with such uniform and high cleanliness can be realized. A device can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a cleaning apparatus according to an embodiment of the present invention. 1 ... Fog generation chamber, 2 ... Processing chamber, 4 ... High frequency vibration nozzle, 5
... high frequency oscillator, 8 ... tank, 9 ... hydrofluoric acid aqueous solution, 14 ... high frequency vibration nozzle, 16 ... transport path, 17 ... shutter, 18 ... nozzle,
19 ... Transport member, 20 ... Gate, 21 ... Carrier, 22 ... Pure water injection nozzle, 25 ... Exhaust fan, 27 ... Silicon wafer, 28 ...
fog.

 ─────────────────────────────────────────────────── ───Continued from the front page (72) Inventor, Kaiki Kagayaki, Ur Klang Free Trade Zone, Selangor, Malaysia, Rolong Engang 35, Lot Number 2 SHE Malaysia Malaysia In Sendilien Bellhat (72) Inventor Yasuyuki Harada 5-37-2-3 Tsurumaki, Tama-shi, Tokyo (72) Inventor Hiroshi Amano 962-8 Kawai, Shizuoka-shi, Shizuoka 301 (56) Reference JP-A-2 -194527 (JP, A) JP-A-59-115763 (JP, A) JP-A-2-284423 (JP, A)

Claims (5)

(57) [Claims] 1. A high frequency vibration nozzle attached to a fog generating chamber.
Generating a mist of the hydrofluoric acid aqueous solution by means of a vacuum, a step of transporting the mist of the hydrofluoric acid aqueous solution into the processing chamber, and exposing the silicon wafer standing upright in the processing chamber to the atmosphere of the mist to perform etching, And a step of rinsing both sides of the wafer by injecting pure water along the wafer surface onto the silicon wafer exposed to the mist atmosphere. 2. A mist generating chamber provided with a high-frequency vibrating nozzle for injecting a hydrofluoric acid aqueous solution , a processing chamber connected to the mist generating chamber, and a communicating portion between the mist generating chamber and the processing chamber. A shutter disposed, a transfer means for transferring a storage member that stands and stores a plurality of silicon wafers in the processing chamber, and a processing chamber located above the storage member, the pure water is stored in the processing chamber. A cleaning apparatus for a silicon wafer, comprising: a pure water spray nozzle for spraying along each silicon wafer surface of a member. 3. A rectangular tubular transport path is made to penetrate through the partition between the fog generating chamber and the processing chamber, and both ends of the transport path are projected into the respective chambers and are located on the fog generating chamber side. 3. A shutter is arranged at an end of the transportation path, and a nozzle for injecting highly clean air or an inert gas toward the processing chamber is provided on the transportation path. The silicon wafer cleaning apparatus described. 4. The high frequency vibrating nozzle is provided on a side wall and a bottom surface of the fog generating chamber.
The silicon wafer cleaning apparatus described. 5. The bottom of the fog generating chamber is filled with an aqueous solution of hydrofluoric acid, and the nozzle opening of the high-frequency vibrating nozzle provided on the bottom of the fog producing chamber is located below the water surface of the aqueous solution of hydrofluoric acid. The cleaning apparatus for a silicon wafer according to claim 2, wherein