Low Temperature Deposition of Materials from Supercritical Fluid Solution
A novel process by which high-purity metals are deposited from supercritical carbon dioxide solution by the chemical or thermal reduction of soluble organometallic compounds. The process is demonstrated by deposition of ultra-high purity platinum and palladium thin films onto silicon wafers. The same method could be used to deposit a wide variety of metal and semiconductor thin films.
Principle application is the deposition of high purity metal films suitable for microelectronic devices. The invention overcomes two significant deficiencies of the current state of the art, chemical vapor deposition. The invention can also be used for the metallation of porous inorganic solids for use as supported catalysts where conventional approaches such as metal ion exchange are ineffective. Water purification and hydrocarbon processing could be two target markets
The principal benefits are three-fold: Combined with US patents 6,992,018 and 6,689,700 it enables the conformal deposition of pure films in very high aspect ratio features. Conformal deposition is possible because of high precursor concentrations that yield surface reaction rate-limited depositions. Because transport occurs in supercritical solution, precursor volatility constraints are eliminated.
US Patent 5,789,027 issued