Method for precision drying surfaces

• US 5,715,612 A
• Filed: 09/26/1996
• Issued: 02/10/1998
• Est. Priority Date: 08/17/1995
• Status: Expired due to Fees

• Current Assignee: Robert S. Schwenkler
• Original Assignee: Robert S. Schwenkler
• Inventors: Schwenkler, Robert S.
• Primary Examiner(s): Bennett, Henry A.
• Assistant Examiner(s): GRAVINI, STEPHEN MICHAEL
• Application Number:
  US08/721,353
• Time in Patent Office: 502 Days
• Field of Search: 34/469, 34/470, 34/471, 34/493, 34/73, 34/74, 34/75, 34/76, 34/78, 134/21, 134/902, 134/19
• US Class Current: 34/470
• CPC Class Codes: F26B 21/145 Condensing the vapour onto the surface of the materials to be dried using condensing steam F26B3/00; using chemical liquids F26B5/005
• CPC Class Codes: H01L 21/67028 for cleaning followed by drying, rinsing, stripping, blasting or the like
• CPC Class Codes: H01L 2224/16 of an individual bump connector

Abstract

This invention pertains to a substrate cleaner and dryer or a dryer alone, and in particular, to an improved method of isopropyl alcohol (IPA) vapor drying having "closed loop" processing and capability to process extremely large substrates. The invention uses an inert gas, typically nitrogen (N₂) or argon (Ar), as a process gas for carrying the vapor of a drying fluid in a "closed loop" cycle through a process vessel. The carrier gas and is pumped through a vapor generator and the process vessel in a rapid "closed loop" manner with extremely pure IPA vapor. Various embodiments employ the invention including two different vapor drying methods, a water rinse and vapor dry method and a solvent clean and vapor dry method. In either the water rinse and vapor dry method and a solvent clean and vapor dry method rinse water or cleaning fluid is rapidly drained in an unimpeded manner from the vessel while the process vessel is vented.

Claims

1. A method for drying objects in a vapor dryer having a process vessel, a vapor generator, a process gas storage vessel, an inert gas source and a liquid storage vessel, comprising the steps of:

purging the process vessel with an inert gas;

loading objects to be dried into the process vessel;

sealing the process vessel;

recirculating a vapor of a drying fluid, generated in the vapor generator, with an inert carrier gas, through the process vessel for a predetermined time;

evacuating the vapor of the drying fluid from the process vessel and depositing it in the process gas storage vessel for vapor condensation; and

removing the objects from the process vessel.

2. The method of claim 1 further comprising:

evacuating the vapor of the drying fluid from the process vessel under a vacuum; and

backfilling the process vessel with an inert gas to return the process vessel to atmospheric pressure.