Stocker for semiconductor substrates, storage method therefor and fabrication method for semiconductor device using the stocker

Abstract

A stocker for semiconductor substrates comprises a container that is for containing the semiconductor substrates and composed of a casing having an open side and a removable lid for sealing the casing at the open side, an atmosphere control unit having a cavity through which a clean gas is passed to keep the inside pressure higher than the outside atmospheric pressure and a gas supply system for supplying the gas to the cavity, and a loadport for connecting the cavity with the container to prevent outside air from entering into the inside of the container. The loadport comprises a port door and a lid placement/removing unit. The lid placement/removing unit is configured to remove the lid from the container into communication between the cavity and the container, thereby allowing the inside of the container to have the same atmosphere as the cavity.

1 . A stocker for semiconductor substrates, comprising: 
 a container for containing the semiconductor substrates at which semiconductor devices are to be formed, said container being composed of a casing having an open side and a removable lid for sealing the casing at the open side;    an atmosphere control unit having a cavity through which a clean gas is passed to keep the inside pressure higher than the outside atmospheric pressure and a gas supply system for supplying the gas to the cavity; and    a loadport for connecting the cavity with the container to prevent outside air from entering into the container,    wherein the loadport comprises a port door that can be brought into close face-to-face contact with one surface of the lid of the container and a lid placement/removing unit for placing the lid on the container and removing the lid from the container brought into close face-to-face contact with the port door, and    the lid placement/removing unit is configured to remove the lid from the container into communication between the cavity and the container, thereby allowing the inside of the container to have the same atmosphere as the cavity.    
   
   
       2 . The stocker of  claim 1 , wherein 
 a pressure in the cavity is 1.5 through 3 times higher than the outside atmospheric pressure.    
   
   
       3 . The stocker of  claim 1 , wherein 
 the gas has a moisture concentration of 2% or less and contains three or less 0.12-μm-or-more-diameter foreign particles per one cubic foot.    
   
   
       4 . The stocker of  claim 3 , wherein 
 the gas is a nitrogen gas, an argon gas, a helium gas, or air.    
   
   
       5 . The stocker of  claim 1 , wherein 
 the gas supply system has a moisture remover for reducing the moisture concentration in the gas to 2% or less.    
   
   
       6 . The stocker of  claim 5 , further comprising 
 a gas recovery line for recovering a gas exhausted from the cavity and returning the gas to the gas supply system.    
   
   
       7 . The stocker of  claim 1 , wherein 
 the gas supply system has at least one of a particle-removing filter for removing particles from the gas by filtering the gas and a chemical filter for removing a chemical substance from the gas by filtering the gas.    
   
   
       8 . The stocker of  claim 7 , further comprising 
 a gas recovery line for recovering a gas exhausted from the cavity and returning the gas to the gas supply system.    
   
   
       9 . The stocker of  claim 1 , further comprising: 
 a sensor for measuring the concentration of at least one of moisture, an organic chemical component and an inorganic chemical component in the cavity; and    a flow rate control unit for increasing the gas flow rate in the cavity when the measurement result of the sensor is above a predetermined value.    
   
   
       10 . The stocker of  claim 1 , further comprising: 
 a defect inspection unit for inspecting the surfaces of the semiconductor substrates for defects; and    a semiconductor substrate transport system for taking the semiconductor substrates from the container and transferring the semiconductor substrates to the defect inspection unit.    
   
   
       11 . The stocker of  claim 1 , wherein 
 the loadport further comprises an extendable delivery table for receiving/delivering the container from/to the outside.    
   
   
       12 . The stocker of  claim 1 , further comprising: 
 a lid storage section for storing a lid removed from the container by the lid placement/removing unit; and    a lid transport unit for bidirectionally transferring the removed lid between the lid placement/removing unit and the lid storage section.    
   
   
       13 . The stocker of  claim 12 , wherein 
 the loadport comprises a plurality of loadports.    
   
   
       14 . The stocker of  claim 13  further comprising a recognition unit for, when the lid is removed from the casing, recognizing a combination of the lid and the casing such that the removed lid can again be fitted to the associated casing.  
   
   
       15 . The stocker of  claim 1 , wherein 
 the container is a front opening unified pod.    
   
   
       16 . A storage method for semiconductor substrates, comprising the steps of: 
 containing semiconductor substrates at which semiconductor devices are to be formed inside a stocker having a cavity through which a clean gas is passed to keep the inside pressure higher than the outside atmospheric pressure,    connecting the stocker with a container composed of a casing having an open side and a removable lid for sealing the casing at the open side;    opening the lid while preventing outside air from entering into the container, thereby communicating the cavity with the container; and    storing the semiconductor substrates while replacing a gas inside the container with a gas with which the cavity is filled.    
   
   
       17 . The method of  claim 16 , wherein 
 a pressure in the cavity is 1.5 through 3 times higher than the outside atmospheric pressure.    
   
   
       18 . The method of  claim 16 , wherein 
 the cavity is filled with a gas having a moisture concentration of 2% or less and containing three or less 0.12-μm-or-more-diameter foreign particles per one cubic foot.    
   
   
       19 . The method of  claim 18 , wherein 
 the gas is a nitrogen gas, an argon gas, a helium gas, or air.    
   
   
       20 . The method of  claim 18 , wherein 
 a gas exhausted from the cavity is used while being circulated by returning the gas to the cavity.    
   
   
       21 . The method of  claim 16 , further comprising the step of connecting the cavity to the container through a loadport comprising a port door that can be brought into close face-to-face contact with one surface of the lid of the container and a lid placement/removing unit for placing the lid on the container and removing the lid from the container brought into close face-to-face contact with the port door, said loadport being placed in the cavity.  
   
   
       22 . The method of  claim 16 , further comprising the steps of: 
 measuring the concentration of at least one of moisture, organic chemical components and inorganic chemical components in the cavity; and    increasing the flow rate of a gas supplied to the cavity when the result obtained by measuring the concentration thereof is above a predetermined value.    
   
   
       23 . A fabrication method for a semiconductor device, said method comprising 
 a plurality of process steps for forming a semiconductor device at a semiconductor substrate and    a storage step carried out between any two of the plurality of process steps,    wherein in the storage step, a stocker to which a container is connected is used, said container containing the semiconductor substrate and being composed of a casing having an open side and a removable lid for sealing the casing at the open side,    the stocker comprises:    an atmosphere control unit having a cavity through which a gas having a moisture concentration of 2% or less and containing three or less 0.12-μm-or-more-diameter ambient foreign particles per one cubic foot is passed to keep the inside pressure at a positive pressure that is 1.5 through 3 times higher than the outside atmospheric pressure, and a gas supply system for supplying the gas to the cavity; and    a loadport for connecting the cavity with the container to prevent outside air from entering into the container,    wherein the loadport comprises a port door that can be brought into close face-to-face contact with one surface of the lid of the container and a lid placement/removing unit for placing the lid on the container and removing the lid from the container brought into close face-to-face contact with the port door, and    the lid is removed from the container by the lid placement/removing unit so that the cavity is communicated with the container to allow the inside of the container to have the same atmosphere as the cavity.