Method of reducing water spotting and oxide growth on a semiconductor structure

#Field of the Invention: The present invention relates to drying semiconductor structures. More particularly, the present invention relates to the minimization of water spotting and of oxide growth that are experienced on semiconductor structures during chemical treatment steps, deionized (DI) water rinse steps, and drying steps. Examples of minimization of water spotting and of oxide growth are given for an HF rinse process in which the steps of DI water rinsing and drying are combined.

#State of the Art: Producing a substantially impurity-free semiconductor structure is an ongoing challenge during fabrication of operable integrated circuits and other microelectronic devices. During fabrication, several operations are completed with a chemical treatment such as a polysilicon etching, a photoresist stripping, an RCA cleaning, or a buffered oxide etching (BOE). Following a chemical treatment, rinsing the structure to remove treatment chemicals is required.

#Following a chemical treatment such as an HF rinse cleaning, a semiconductor structure is typically transferred to a vessel for a DI water rinse and then to a dryer to be dried. With each transfer of the semiconductor structure during fabrication between processing vessels, the possibility of contamination increases and, with that, also the likelihood of lower process yield. In chemical treatments of semiconductor structures that result in exposed hydrophobic surfaces, the possibility of oxidation and particle contamination is high.

#In order to obtain the above-recited and other advantages of the invention, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not, therefore, to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

#FIG. 1 is a cross-sectional elevational view of a glove valve that can be installed in a Marangoni dryer, a spray/dump rinser, and other wet processing vessels in order to practice the method of the present invention;

#FIG. 2 is a cross-sectional elevational view of a check valve that can be installed in a Marangoni dryer, a spray/dump rinser, and other wet processing vessels in order to practice the method of the present invention;

#The present invention relates to a method of cleaning and drying semiconductor structures. The present invention also relates to a method of using a conventional gas etch/rinse vessel, or a conventional dryer, or a conventional rinser in conjunction with the inventive method. The present invention also relates to an apparatus that accomplishes the inventive method. The present invention reduces the likelihood of oxide contamination or the like, as well as the incidence of water spotting.

#Rinsing by the method of the present invention is usually carried out with DI water. Other rinsing solutions may be used such as aqueous hydrogen peroxide. Drying by the method of the present invention comprises forming a substantially continuous layer of a drying liquid upon the upper surface of a DI water bath in which the semiconductor structure is submerged. Following formation of the substantially continuous layer of the drying liquid, the semiconductor structure is drawn through the substantially continuous layer of the drying liquid. Both the DI water and contaminants therein are entrained beneath the substantially continuous layer of the drying liquid in the DI water bath and are, therefore, substantially removed from the semiconductor structure.

#The drying liquid comprises a volatile liquid such as IPA. Other drying liquids are contemplated to be, but need not be, derived from an anhydrous organic vapor, such as acetone, chloroform, methanol, carbon tetrachloride, benzene, ethanol, ethyl acetate, hexane, 1-propanol, and 2-propanol, and equivalents. By reading the disclosure of the present invention and by practicing the present invention, one of ordinary skill in the art will recognize that anhydrous organic liquids or the like may be used in the method of the present invention. The skilled practitioner will recognize that, although a water-miscible drying liquid such as IPA may be used, such liquids are preferred to be more volatile than the DI water used for rinsing, and such liquids are preferred in that they are not prone to cause deleterious chemical effects upon the semiconductor structure.