JP2012238649A - Substrate case cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate case cleaning device which can be cleaned even when an object to be cleaned has a complicated shape in executing dry cleaning of the substrate case.SOLUTION: A cleaning device 1 of a door part 2 of a substrate case includes: the door part 2 which holds a substrate which is vulnerable to adhesion of foreign matters, such as a silicon wafer and a photo mask; a cover part for preventing the foreign matters from being adhered to the substrate held by shielding the door part 2 from a surrounding atmosphere; and packings 5 which are provided at the door part 2 and used for tightly sealing the door part 2 and the cover part. A substrate case cleaning device 1 includes: a turn unit 3 for placing at least the door part thereon and rotating it; and a gas jet nozzle 4 which jets cleaning gas toward the door part 2.

Description

The present invention relates to SMIF-POD (Standard of Mechanical Interface-POD, a sealed container for semiconductor manufacture for transporting silicon wafers and reticles) and FOUP (Front Opening Unified POD, SEMI standards) used in semiconductor manufacturing processes and photomask manufacturing processes. The present invention relates to a substrate case cleaning apparatus used for cleaning a substrate case such as a compliant 300 mm wafer front opening type transfer / storage sealed container).

  In the semiconductor manufacturing process and the photomask manufacturing process, a clean room called a clean room (a state where particles floating in the air are removed as much as possible by using an air filter such as a HEPA filter) in order to suppress adhesion of foreign matters to the product is used. It is installed in the room. A silicon wafer or a photomask, which is an article to be processed, is transported between processes to the next process when the process in the previous process is completed. By repeating these steps, wafer processing (semiconductor pre-process) and photomask manufacturing are performed.

  In recent years, substrate cases such as SMIF-POD and FOUP (conveying cases that contain silicon wafers and photomasks and suppress the adhesion of foreign matter during transportation) for the purpose of further reducing foreign matter adhesion. Are beginning to be used.

  The SMIF-POD is one type of sealed wafer container that can store a plurality of wafers used in wafer processing, for example, and has an opening / closing mechanism on the bottom surface of the container. FOUP is a sealed wafer container in which a carrier capable of storing multiple wafers and a container are integrated, and has an opening / closing mechanism on the front surface of the container, and has an interface function with semiconductor manufacturing equipment in each process. It is a feature.

  These substrate cases such as SMIF-POD and FOUP are composed of a part called a cover part for isolating a silicon wafer and photomask from the surrounding space and a part called a door part for holding the wafer and photomask. A packing made of fluorine-based rubber is provided on the door portion side of the contact portion between the cover portion and the door portion, and can be sealed. Further, a lock mechanism for locking the cover portion and the door portion is provided.

  Substrate cases such as SMIF-POD and FOUP have a problem of generating dust from the packing that enables sealing, and cleaning is performed in order to suppress the influence. When cleaning is performed, the cover portion and the door portion are separated and cleaned separately.

Conventional cleaning methods include a method in which the cover part and the door part are separated and then washed by immersing them in pure water or chemicals (round washing) and a method in which pure water is sprayed and washed without being immersed (spraying washing). .
In round washing, pure water or chemicals enter the packing part or parts with complicated structures, so it is difficult to dry or wash away chemicals, so the metal parts corrode and eventually from the corroded parts. There are problems such as dust generation and generation of gas that leads to defects.

Spray cleaning involves cleaning only the inside of the door packing to prevent the entry of pure water or chemicals into the door packing and lock mechanism. There is a problem that foreign matter adhering to the end surface portion of the substrate case which cannot be cleaned and adhered to the door portion packing or the contact portion between the cover portion and the door portion cannot be removed. Such foreign matter is generated when the photomask substrate is taken out from the substrate case or stored in the photomask manufacturing process, and is scattered and reattached to the inside of the substrate case. Cause.

  In Patent Document 1, as a method of dry cleaning of organic foreign matter, ionic foreign matter, or ionic crystalline foreign matter physically adsorbed on a substrate case, a temperature range from room temperature to 80 ° C. in a stream of clean air or inert gas. Discloses a method of detaching and removing the foreign matter. However, this method has a problem that desorption and removal are difficult unless the flow rate of clean air or inert gas exceeds a certain value, and a sufficient cleaning effect cannot be expected for an object to be cleaned containing a complicated shape. Have

JP 2008-053392 A

  An object of the present invention is to provide a substrate case cleaning apparatus capable of cleaning even when the object to be cleaned includes a complicated shape when the substrate case is dry-cleaned.

As a means for solving the above-mentioned problems, the invention according to claim 1 of the present invention is characterized in that a door portion for holding a substrate which does not like adhesion of foreign substances such as a silicon wafer and a photomask, and the door portion is shielded from the surrounding atmosphere A cover part for preventing foreign matter from adhering to the substrate held by the packing, and a packing provided on the door part for sealing the door part and the cover part, A cleaning device for the door part of the substrate case comprising:
A turn unit for placing and rotating at least the door portion;
A substrate case cleaning apparatus comprising: a gas ejection nozzle that ejects a cleaning gas toward the door portion.

  Further, the invention according to claim 2 is a foreign matter adhering to the object to be cleaned by physical adsorption and floating in the internal space of the cover part generated by being blown away by the gas ejected from the gas ejection nozzle. The cleaning apparatus according to claim 1, further comprising a suction unit.

  The invention according to claim 3 is characterized in that the cleaning gas is composed of at least one of nitrogen gas, clean air having an ultra-low dew point, and clean air containing dry ice particles. The cleaning apparatus according to claim 1.

  With the cleaning device of the present invention, the cleaning liquid can be prevented from entering the packing and locking mechanism of the door portion, and at the same time, foreign matters adhering to the periphery of the packing and the case end surface portion which is a contact portion between the cover portion and the door portion can be removed. Became.

The conceptual diagram which shows an example of the washing | cleaning apparatus of this invention SMIF-POD conceptual diagram

In FIG. 1, the SMIF-POD is taken as an example, and a conceptual diagram of a state in which the door portion 2 is placed on the turn unit 3 of the cleaning device 1 of the present invention is shown. The SMIF-POD door is provided with a packing 5 for keeping airtightness in close contact with a cover (not shown).
FIG. 2 shows a conceptual diagram of SMIF-POD. The SMIF-POD is composed of a door portion 2 and a cover portion 6. After a silicon wafer or photomask is placed on the door portion 2, the cover portion 6 is brought into close contact with the packing 5, and a lock mechanism not shown in the figure. Locked and transported.

  The cleaning apparatus 1 includes a gas ejection nozzle 4 from which a clean gas that is dry and free of fine particles such as nitrogen gas and ultra-low dew point clean air (clean air dried to the limit) is ejected. Thus, cleaning is performed by blowing off foreign matter and dust that are physically adsorbed on the door portion 3 and the packing 5.

It is necessary to take measures to prevent re-adhesion so that the adhered matter blown off does not re-adhere.
The simplest method is to provide a suction port (not shown in FIG. 1) downstream of the air flow for blowing off the deposits. A suitable method is to suck the same amount of gas as the amount of gas ejected from the gas ejection nozzle 4. When the amount of gas sucked from the suction port is larger than the amount of gas ejected from the gas ejection nozzle 4, dust floating from the surrounding space (originally floating dust or ejected gas is blown away) Floating deposits etc. will be attracted. In addition, when the suction amount is small, the deposits blown off by the ejected gas cannot be sufficiently removed, so that dust and the like (gas that causes dust and defects) increase.

  Instead of the gas suction port, the apparatus may be configured to suck gas from the entire periphery of the turn unit 3. Also in that case, it is desirable that the amount of the gas ejected from the gas ejection nozzle 4 and the amount of the sucked gas coincide. When the amount of gas to be sucked is small, a part of the dust that has not been sucked in continues to float. This is because if the amount of gas to be sucked is too large, dust and the like are attracted from the surrounding space.

Further, a mechanism for removing dust using the same principle as that of the electrostatic precipitator may be provided downstream of the air flow for blowing off the deposits.

  In addition, it is effective to add an ionizer around the gas ejection nozzle 4 and the turn unit in order to prevent the adhered matter blown off from being charged and reattached. Reattachment is suppressed by suppressing the electrification of the blown-off deposits and the door portion 2 to be cleaned.

  Further, instead of cleaning by jetting gas from the gas jet nozzle 4, dry ice blast cleaning (fine particles of dry ice are jetted together with gas, and the dry ice that is solid on the deposit on the surface of the object to be cleaned is used. The same principle as in the case of colliding fine particles) may be used. In this method, since the dry ice particles contained in the gas collide with the deposit, it can be removed even if the particles adhere more firmly, and the dry ice particles sublimate. Therefore, it is not necessary to dry. Naturally, clean air or clean nitrogen gas is used as the gas. In the case of dry ice blast cleaning, since there are dry ice particles, it is particularly easy to be charged, and it is desirable to provide an antistatic mechanism with an ionizer.

  Further, in FIG. 1, the gas ejection nozzle 4 is shown as being fixed around the turn unit, but it is not necessary to be fixed, for example, the gas ejection nozzle 4 can be freely moved spatially, A robot that can freely control the direction of the gas ejection nozzle 4 may also be used. By providing such a mechanism, it becomes possible to carry out cleaning of necessary portions without excess or deficiency.

  Hereinafter, examples of the substrate case cleaning apparatus of the present invention will be described in more detail.

On the outer periphery of the SMIF-POD door portion 2 disassembled on the turn unit 3, a gas jet nozzle having a jet port with an opening diameter of 3 mm is provided.
The gas ejection nozzle is ejected in a conical shape with the center of the opening as the apex, and the gas is ejected in a range of an angle of 90 degrees or more and ejected in a range of an ejection angle of less than 180 degrees. In particular, it is desirable that the jet angle is around 135 degrees because jetting can be performed uniformly.

From the gas jet nozzle, nitrogen gas pressure-adjusted by a regulator is jetted at a pressure of 0.10 MPa for 10 seconds to the SMIF-POD door portion 2 decomposed on the turn unit 3.
In the dust collection mechanism, suction is performed at a pressure equivalent to the pressure of the gas ejection nozzle, and dust is collected for the same time in synchronization with the gas ejection.
The gas ejection time is not fixed at 10 seconds, but is appropriately set depending on the gas type and ejection pressure.
As for the dust collection time, it is efficient to collect dust that floats in a time range equivalent to the gas ejection time or about twice as long.

When the pressure of the gas ejection nozzle is less than 0.05 MPa, it is difficult to remove dust adhering to the SMIF-POD. And when it is the pressure of the gas ejection nozzle exceeding 0.50 MPa, the case fixed on the turn unit may be levitated, which may cause a failure of the apparatus.
Therefore, the jet gas pressure is set to an arbitrary pressure value of 0.05 MPa or more and 0.50 MPa or less, and it is preferable to collect dust at the same pressure in the dust collection mechanism, and a pressure sensor or the like is provided for these pressures. Therefore, it is desirable to detect it.

In addition, when the case is used for case cleaning, the type of gas to be ejected is a gas that is inert in the atmosphere in which the SMIF-POD is installed and has a high degree of cleanliness in which particles and oil mist derived from a compressor are not mixed. Is desirable.
Note that the type of gas to be ejected is not limited, and in addition to the exemplified nitrogen gas, there is no problem even if ultra-low dew point clean air (CDA, Clean Dry Air) or other highly clean gas is employed. There is no.

DESCRIPTION OF SYMBOLS 1 ... Cleaning apparatus 2 ... Door part 3 ... Turn unit 4 ... Gas ejection nozzle 5 ... Packing 6 ... Cover part 7 ... Substrate case

Claims (3)

A door portion for holding a substrate that is not suitable for adhesion of foreign matter such as a silicon wafer or a photomask; and a cover portion for preventing foreign matter from adhering to the held substrate by blocking the door portion from the surrounding atmosphere. A cleaning device for the door portion of the substrate case, comprising: a packing provided on the door portion, the seal for sealing the door portion and the cover portion,
A turn unit for placing and rotating at least the door portion;
A substrate case cleaning apparatus, comprising: a gas ejection nozzle that ejects a cleaning gas toward the door portion.   It has a means for sucking in foreign matter that has adhered to the object to be cleaned by physical adsorption and that floats in the internal space of the cover part that is generated by being blown away by the gas ejected from the gas ejection nozzle. The substrate case cleaning apparatus according to claim 1.   3. The substrate case cleaning apparatus according to claim 1, wherein the cleaning gas includes at least one of nitrogen gas, clean air having an ultra-low dew point, and clean air containing dry ice particles.