Process and apparatus for contacting a precision surface with liquid or supercritical carbon dioxide

#1. Field of the Invention

#The present invention is directed to a process and apparatus for contacting a precision surface with liquid or supercritical carbon dioxide. More specifically, the present invention is directed to a process and apparatus for contacting a precision surface with liquid or supercritical carbon dioxide accompanied by sound waves.

#2. Background of the Prior Art

#The present invention may be better understood by reference to the accompanying drawings of which:

#FIG. 1 is a schematic diagram of an apparatus employed in the instant invention for the processing of a precision surface;

#FIG. 2 is a schematic representation of an element of the apparatus of FIG. 1; and

#The apparatus of the present invention includes a process chamber 12 having a sample zone 14 therein for the disposition of a precision surface, denoted by reference numeral 16. The term “precision surface” is used herein to denote a material which contains a surface that has cavities, trenches and/or channels incorporated therein. Suitable precision surfaces that may be employed in the present invention include, but are not limited to, semiconductor samples, metals such as Al, Si, W, Ti, Ta, Pt, Pd, Ir, Cr, Cu and Ag, polymers, such as polyimides, polyamides and the like, and insulators. Of the “precision surfaces” employed in the apparatus and process of the present invention semiconductor samples, e.g. semiconductor wafers, are particularly appropriate for use therein.

#The process chamber 12 is surrounded by a heater jacket 18 and contains sonic generating means 20. Sonic generating means 20 are described in detail in the discussion of FIGS. 2 and 3 below. Additionally, the process chamber includes inlet line 22, outduct 24 and thermocouple 26. The inlet line 22 includes a high pressure pumping system 28 which is connected to a cylinder 30 for supplying liquid or supercritical carbon dioxide to process chamber 12. Cylinder 30 contains pressurized carbon dioxide that enters process chamber 12 as liquid or supercritical carbon dioxide. Thermocouple 26 is connected to heat controller 32 which is utilized for controlling and monitoring the temperature in process chamber 12.

#Additional processing equipment that may be provided in the apparatus is depicted in the drawings. Thus, the apparatus may include a reservoir 34 for collecting and/or purifying liquid or supercritical carbon dioxide that exits process chamber 12 through outduct 24. This material may then be recycled into process chamber 12 through duct 35.