Abstract: The present invention provides a vapor processing apparatus in which the vapor is generated in a region adjacent to the vapor processing area. This is generally done in a batch process and a limited volume of processing vapor is generated for each batch. The separation of the vapor generation from the processing avoids the contamination of the vapor source and the inadvertent cooling of the vapor generating area. In the preferred embodiment, two vessels are disposed one inside the other such that a vapor generating region is provided in the annular space between vessels. The vapor is injected into the processing region through channels formed in the annular space. In a preferred embodiment, the vapor is isopropyl alcohol and the substrates for processing are silicon wafers.