Retaining box, and a feeding apparatus of a semiconductor wafer, which can feed or retain a semiconductor wafer without any contamination of the semiconductor wafer caused by a hydrocarbon in air and a hydrocarbon generated from a retaining box

A retaining box of a semiconductor wafer, includes an air supply port and an exhaust port. The air supply port has a piping joint and a first filter. Air is forcedly supplied through the air supply port. The exhaust port has a second filter. Inner air inside the retaining box is exhausted from the exhaust port. The retaining box accommodates a plurality of semiconductor wafers in an interval between each other.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. The present invention will be described below in detail on the basis of a preferable embodiment in the present invention with reference to the drawings. FIG. 3 is a side section view showing a retaining box of a semiconductor wafer according to an embodiment in the present invention. A retaining box 10 is made of polycarbonate resin material, and it has the shape of a rectangular parallelepiped with a size of about 400 mm 3 as a whole, and includes a door 11 on a front surface in order to accommodate/take out the semiconductor wafer. A piping joint 12 to be connected to a pipe through which clean air or clean gas (hereafter, referred to as clean gas, including both of them) is formed in the vicinity of a rear of a top surface of the retaining box 10 , and a ULPA filter is attached inside the piping joint 12 . A valve may be attached to the piping joint 12 . An exhaust port 13 for natural exhaust is formed in the vicinity of the front door 11 on the bottom of the retaining box 10 . The ULPA filter is attached inside the box of the exhaust port 13 . The semiconductor wafers 14 are placed on the racks, which are formed so as to be protruded from both sides inside the retaining box 10 and extended in forward and backward directions of the retaining box 10 and arrayed in a vertical direction. For example, 25 semiconductor wafers are horizontally accommodated in one retaining box 10 at one time. The retaining box 10 in the embodiment can be especially preferably used when the semiconductor wafer 14 is fed between a certain process step and a process step following it, in the process for manufacturing the semiconductor wafer. A cylinder filled with the clean gas is prepared in the feeding apparatus containing a plurality of retaining boxes 10 , and a plurality of hoses are connected to discharging plugs of the cylinder. A tip of the hose is connected to the piping joint of the air supply port 12 of each retaining box 10 . The clean gas from the cylinder may be always or intermittently supplied. The clean gas is exhausted from the exhaust port 13 by the natural exhaust. The particles stripped off from the inner wall made of the polycarbonate resin in the retaining box 10 , or the organic matter or the organic gas that is degassed from the inner wall and is floating inside the retaining box 10 is introduced by the air flow which flows downwardly from above the box and flows towards a forward direction, and it is never deposited on the surface of the semiconductor wafer 14 . Also, even a light organic matter once fallen on the surface of the semiconductor wafer 14 is moved on the surface of the wafer by the air flow, and fallen in an edge of the wafer, and then introduced into the exhaust port 13 . FIG. 4 shows the manner when the retaining box 10 in the embodiment is accommodated in a retaining warehouse 20 , by using a section view of a warehouse. A plurality of stages of floors 21 to place the retaining boxes 10 are placed inside the warehouse 20 , and each retaining box 10 is retained on a corresponding floor 21 . A clean gas pipe 22 extended in the placed direction of the retaining box 10 is fixed along each floor 21 inside the retaining warehouse 20 . A cock 23 and a hose 24 are placed correspondingly to a position of each retaining box 10 . Then, when the retaining box 10 is placed, the hose 24 is connected to the piping joint of that supply port 12 . A clean gas 25 is supplied to the clean gas pipe 22 from a clean gas supplying apparatus (not shown). The clean gas exhausted from the exhaust port 13 of each retaining box 10 is exhausted through an exhaust port 26 formed on the warehouse 20 . FIG. 5 shows the manner when the semiconductor wafer is taken out from the retaining box 10 through the load port constituting the feeding apparatus. The retaining box 10 is inserted into the vicinity of the load port 30 by a feeding carriage 27 . The load port 30 has a blower unit 31 having a fan and a HEPA filter at that top. Then, while the clean gas is introduced into the load port 30 by the fan, a wafer loader 32 is actuated to thereby take out the semiconductor wafers 14 from the retaining box 10 through a carrying inlet 33 , one by one. The semiconductor wafers 14 taken out by the wafer loader 32 are fed to a next process shown on the right side of FIG. 5 , through a carrying outlet 34 of the load port 30 , one by one. The load port 30 is designed such that before the door of the retaining box 10 is opened, the blower unit 31 is actuated to thereby introduce a clean gas 35 , and before the door is opened, the clean gas 25 is similarly introduced into the retaining box 10 from the air supply port 12 . The clean gases 25 , 35 form the air seal between the carrying inlet 33 of the load port 30 and the front surface of the retaining box 10 , and a positive pressure protects the invasion of the external particles. Also, a part of the clean gases 25 , 35 is exhausted from the exhaust port 13 at the lower portion of the retaining box 10 . After the operation for taking out the semiconductor wafers 14 from the retaining box 10 is ended and the door is closed, the introduction of the clean gas is stopped. According to the retaining box 10 , the retaining warehouse 20 and the load port (feeding apparatus) 30 of the semiconductor wafer according to the embodiment, the atmosphere in the semiconductor wafer is kept clean during the retaining and the feeding thereof. In particular, even if the organic matter from the retaining box 10 is exhausted as out gas, this out gas is exhausted from the exhaust port by the cleaned gas flow. Thus, the staying time of the out gas can be shortened to thereby protect the contamination caused by the out gas over the surface of the semiconductor wafer 14 . Also, the invasion of the external particles can be effectively protected. As mentioned above, the present invention has been explained on the basis of the preferable embodiment. However, the retaining box, the feeding apparatus, the feeding method and the retaining warehouse of the semiconductor wafer in the present invention are not limited to the configurations of the embodiment. The configurations on which the various modifications from the embodiment are performed are included in the range of the present invention. For example, the retaining box of the present invention is not limited to the example of the front door. For example, it can be also applied to a retaining box whose bottom functions as a door. Also, the retaining box of the present invention is not limited to the retaining of the semiconductor wafer. It can retain the various materials requiring the cleanliness level similar to that of the semiconductor wafer, the half-finished products and the finished products. As mentioned above, according to the retaining box of the semiconductor wafer in the present invention, the air flow can be forcedly generated always or intermittently inside the retaining box. Thus, it is possible to effectively protect the particle and the organic matter from being deposited on the surface of the semiconductor wafer. Also, the usage of the feeding apparatus, the feeding method or the retaining warehouse of the semiconductor wafer in the present invention enables the function of the retaining box to be further effectively provided.