A method and an apparatus for drying semiconductor wafers by using an IPA drying apparatus. The present invention uses a vapor generator to generate an IPA vapor. The IPA vapor is generated and saved in a closed surrounding and then transferred in a porous hollow plate in the dryer tank by using a quartz pipe. The IPA vapor is diffused evenly from the porous hollow plate. Furthermore, the present invention increases the safety of the process and can easily control the input amount of the IPA vapor.