Teflon coated metal tweezers cannot be used to load clean furnaces or epi!!!

maurice stevens maurice at stanford.edu
Sun Dec 11 16:32:48 PST 2011


A reminder:

Metal tweezers cannot be used to load  clean furnaces or epi!

Metal tweezers with green teflon tips cannot be used to load clean furnaces or epi.

You must use delrin (plastic) tweezers for loading clean systems (if you cannot use the quartz wand).


More info at the link below


http://snf.stanford.edu/Process/WetProcessing/TweezerCln.html


Tweezer types and catagories:


Dirty Nonmetal:
These are teflon coated stainless steel tweezers. They are for handling NONMETAL wafers (wafers that are either Si, SiGe or Quartz that do not and never have had metal on them). They may be used at any time EXCEPT for wafers that have had a prediffusion clean and are ready to be loaded into a furnace or deposition system.

Clean Nonmetal:
These are for loading wafers into the furnaces (if you cannot use the quartz wand). They must be Delrin (plastic) not metal and they must have been cleaned according to the procedure below. They may only be used to handle wafers which have been through the full prediffusion clean at wbdiff and are ready to load into one of the Tylan furnaces or LPCVD's. Exceptions are the metal side of the LTO and tylanfga where it is assumed that the wafers have metal on them.

Clean Nonmetal/LTO:
These are teflon coated stainless steel tweezers and are the best choice for loading the nonmetal side of the LTO boat. They MAY NOT be used for loading oxidation tubes, nitride or poly LPCVD's. Use the quartz wand or CLEAN NONMETAL Delrin tweezers for that.

Clean Metal:
These are used for loading wafers into tylan7 or tylanfga (if you cannot use the quartz wand, i.e. the wand is broken or you are using double polished wafers). They must be Delrin and they must be cleaned according to the procedure below. They are only to be used to handle wafers which have been through the complete cleaning procedure at wbsilicide or wbmetal and are ready to load.

Clean Metal/LTO:
These are teflon coated stainless steel tweezers and are the best choice for loading the metal side of the LTO boat. They MAY NOT be used for loading tylan7 or tylanfga (use the quartz wands or CLEAN METAL Delrin tweezers for that).

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