Application of Robert Duva

387 F.2d 402, 55 C.C.P.A. 829
CourtCourt of Customs and Patent Appeals
DecidedDecember 14, 1967
DocketPatent Appeal 7833
StatusPublished
Cited by2 cases

This text of 387 F.2d 402 (Application of Robert Duva) is published on Counsel Stack Legal Research, covering Court of Customs and Patent Appeals primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
Application of Robert Duva, 387 F.2d 402, 55 C.C.P.A. 829 (ccpa 1967).

Opinion

SMITH, Judge.

The sole issue to be determined in this appeal is whether the invention as a whole as claimed in the appealed claims of appellant’s application 1 would have been obvious at the time it was made. The examiner based the rejection on 35 U.S.C. § 103 and this rejection was affirmed by the Patent Office Board of Appeals. 2

While the appealed claims are couched in terms of “composition” and “process,” it is appellant’s basic position that all of the appealed claims relate to a single invention, i. e., the chemical, as distinguished from the electrolytic, deposition of gold plate on what the art terms the “basis” metal.

The decision of the board, adhered to on reconsideration, affirmed the examiner’s rejection of the claims on appeal as relating only to obvious differences over the composition of the bath and the process of a single reference. 3

Appellant’s Invention

Appellant’s claimed bath composition and process for the deposition of gold upon a basis metal are asserted to be patentable improvements in what is known as the “electroless” deposition of gold. The invention, like the known electroless processes, does not require or utilize the techniques of electroplating baths and processes. Appellant’s invention differs therefrom in that no electrical current is required; hence no anode or cathode is used, and appellant’s bath is not used as an electrolyte. Appellant achieves the deposition of gold solely by a chemical reduction process.

By way of background information, appellant’s brief here describes three general processes for depositing gold from an aqueous bath; namely, (1) the electroplating method, generally described in the single reference patent before us, (2) the electroless process, with which the application here on appeal is primarily concerned, and (3) the immersion or replacement process. In his specification, appellant asserts that, in the immersion process, it is possible to obtain deposit thicknesses of no more than % to *4 of a micron, but only on basis metals less noble than the metal being plated out from the bath.

As to the known prior chemical reduction, or electroless, processes, appellant’s specification notes that the metal will be continually deposited by chemical reduction to substantial thicknesses, although deposition generally is limited to certain “catalytic” basis metals which effectively accept the deposit.

Appellant’s invention is based on his asserted discovery that gold will deposit from a gold-containing solution in the presence of palladium ions. According to appellant’s specification, an advantage of the invention resides in the deposit of gold at the rate of 2 to 2% microns per hour at a temperature substantially below that ordinarily used for either immersion or electroless gold plating. Appellant’s invention is also predicated on his observation that unless the excess of free cyanide (CN) ions is controlled in the bath composition below stated limits, no electroless deposition of gold will occur. 4 Ap *404 pellant theorizes that this is due to the formation of a very stable palladium complex with cyanide ions which does not provide the palladium (Pd++) ions upon whose action appellant depends to secure the plating out of the gold. Thus, appellant’s specification states:

* * * The ratio of the Pd salt to free CN— ions should therefore be maintained high enough to provide Pd++ ions which are necessary for the deposition of the gold. An exact measurement of the working ratio of Pd salt/CN— is not possible but it is very simple to test a given solution to see if gold deposits therefrom. It is understood that the palladium of the “P” salt and of disodium palladium tetrachloride provides Pd ++ ions in the gold cyanide bath. 5

Appellant’s brief summarizes, as the essence of appellant’s invention, his discovery that:

* * * multilayers of gold could be deposited by the electroless process provided (1) the bath contained a small but effective amount of palladous salt and (2) the bath 1 contained insufficient (CN) — ions to poison the effect produced by the presence of said palladous salt. * * *

The Appealed Claims

We agree with the board that appealed claims 1 and 10 are representative of the claims on appeal. They are:

1. As a composition for chemically depositing gold an aqueous solution consisting essentially of 0.5-30 g/1 of a soluble gold cyanide, 0.01 to 30 g/1 of a soluble palladous salt, absent sufficient CN ions to prevent deposition induced by said palladous salt, and sufficient alkali to provide a pH of 8-11.
10. A process for depositing gold on a workpiece having a conducting surface comprising immersing the workpiece in an aqueous solution consisting essentially of 0.5-30 g/1 of a soluble gold cyanide, sufficient alkali to provide a pH of 8-11, in the presence of 0.01 to 30 g/1 of a soluble palladous salt, and in the absence of sufficient CN ions to prevent deposition induced by said palladous salt whereupon gold is deposited on said conducting surface by the chemical reduction process.

Claims 1, 2, 4 and 5 on appeal, which are directed to the composition of the bath according to the invention, differ in certain particulars. Independent claim 2 further calls for an alkali salt of certain weak acids and a certain weak acid per se, which, appellant explains, improve the stability of the bath. Claims 4 and 5 are dependent upon claim 2, but are directed to specific palladous salts. Process claims 7 through 9 refer to and include independent claim 10 and define a particular source of the palladous ions.

Reference Relied Upon

The sole reference upon which the rejection is predicated discloses a process and bath for electrodepositing a codeposit of gold and palladium in the form of a gold-palladium alloy. This reference discloses an electroplating process and bath which contains, in solution, salts of the various metals which are simultaneously deposited to provide the desired gold alloy plate. It preferably employs a palladium anode and a potential must be established between it and the cathode to be plated. The plating solution disclosed includes salts of gold, palladium and one or more of the metals nickel, copper and cadmium. The reference specifically states that gold and palladium are compatible, precious, acid-resistant metals which may be coelectrodeposited from an electrolyte under suitable conditions. The electrolyte or plating bath disclosed as preferable includes, in solu *405 tion, specific amounts of gold cyanide; palladium chloride; cyanides of nickel, cadmium, copper, and potassium; sodium chloride and potassium hydroxide. 6

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387 F.2d 402, 55 C.C.P.A. 829, Counsel Stack Legal Research, https://law.counselstack.com/opinion/application-of-robert-duva-ccpa-1967.