Final Report: Hard Gold Plating for Electronics Applications from a Non-Cyanide Bath

EPA Contract Number: EPD15028
Title: Hard Gold Plating for Electronics Applications from a Non-Cyanide Bath
Investigators: Garich, Holly
Small Business: Faraday Technology, Inc.
EPA Contact: Manager, SBIR Program
Phase: I
Project Period: September 1, 2015 through February 29, 2016
Project Amount: $100,000
RFA: Small Business Innovation Research (SBIR) - Phase I (2015) RFA Text |  Recipients Lists
Research Category: Small Business Innovation Research (SBIR) , SBIR - Manufacturing

Description:

The proposed effort seeks to utilize a non-toxic sulfite-based plating bath typically used for soft gold applications, and by introduction of FARADAYIC® Electrodeposition principles of pulse and pulse reverse process mediation, develop a fast, efficient non-toxic, hard gold plating process that achieves the required functional deposit properties. The FARADAYIC® Electrodeposition approach utilizes an asymmetrical waveform to control the deposition process directly at the substrate/bath interface, i.e., electric field mediation of the process, rather than chemical mediation. Optimization of the waveform parameters enables enhanced performance in environmentally benign chemistries, as the electric field control at the interface controls the deposition processes that require toxic chemistries in conventional DC processes. Compared to conventional direct current (DC) plating from an alkaline gold sulfite bath, the FARADAYIC® Electrodeposition process will 1) achieve or preferably exceed the same high plating rates as acid gold cyanide baths, 2) improve the current efficiency compared to the acid gold cyanide bath, 3) reduce the grain size, by favoring grain nucleation over grain growth, thereby increasing hardness and wear resistance and eliminating the need for nickel and cobalt, 4) improve bath life by operating in an acidic pH range, and 5) run in a pH range which is compatible with photoresists used in printed circuit board fabrication.  If these functional properties and performance metrics can be achieved, gold sulfite could be substituted for hard acid gold cyanide baths, resulting in a substantial environmental benefit, as well as a cost benefit associated with reduced air, water and waste treatment requirements. 

In this SBIR program, Faraday has engaged two industrial partners to aid in development of the technology as well as aid in commercialization of the technology.  Coventya is a chemical formulator and supplier to the finishing industry, including supply of gold plating baths to the printed circuit boards industry.  Coventya develops and supplies specialty chemicals for surface finishing in over forty countries and four continents, and their customers include both captive surface treatment and job shop platers. In addition to its U.S. presence, Coventya has a significant presence in Europe and is well aware of the regulatory issues associated with REACH.  Coventya will closely monitor the technical progress, provide consultation on evaluation protocols and supply base cyanide-free gold plating chemistry for pulse/pulse reverse development activities.  Faraday’s second industrial partner for the development of the technology is TTM Technologies, formerly Viasystems Group, a leading provider of PCBs and Electro-Mechanical Solutions to the global electronics industry.  Viasystems’ currently conducts a significant amount of gold plating from cyanide based plating solutions, and would like to replace the cyanide plating bath with an environmentally friendly and worker friendly gold plating process. Viasystems represents a strong and commercially relevant strategic partner for commercialization of the FARADAYIC® Electrodeposition technology for hard gold plating, specifically for electronic connectors.

Summary of Findings:

In this Phase I program, Faraday Technology demonstrated the ability to plate gold deposits from non-cyanide, sulfite based electrolyte using the FARADAYIC® Electrodeposition process.  Use of the FARADAYIC® Electrodeposition process enabled gold deposits to be plated at higher applied current densities than corresponding DC processes, which will promote higher throughput in a manufacturing environment, translating to reduced operating costs for PCB manufacturers.  Gold deposits plated onto copper coupons using the FARADAYIC® Electrodeposition process showed smoother deposits than corresponding DC deposits; it has been demonstrated for the patented FARADAYIC® Trivalent Chromium Plating process that an increase wear resistance is observed with decreasing surface roughness.  Faraday demonstrated gold deposits plated from a sulfite-based bath using the FARADAYIC® Electrodeposition process with hardness properties on the high-end of the soft gold range.  Faraday anticipates that fine-tuning of the waveform as well as incorporation of non-nickel or –cobalt additives (such as the CIRRUS dopant) will enable development of a process that provides gold deposits with the desired hardness and wear properties while maintaining enhanced through-put over conventional DC, cyanide-based processes.

Conclusions:

In conclusion, the work conducted under this SBIR funding shows great promise for the development of an industrial gold plating process based on FARADAYIC® Electrodeposition in sulfite-based plating baths.  Use of the FARADAYIC® Electrodeposition process enables plating at higher average current densities, which lowers the operating costs associated with that step of PCB manufacture.  In addition, gold deposits plated with the FARADAYIC® Electrodeposition process showed equivalent or better properties (in terms of surface roughness, hardness and observed density) when compared to operation under DC conditions at the same average current density.  Development of a gold plating process from a sulfite-based bath that delivers the desired “hard” gold deposit properties would enable the elimination of cyanide-based plating baths which offers benefits in terms of cost as well as worker and environmental safety considerations, with the added benefits of improving perceived company stewardship. 

Publications:

There were no publications resulting from this Phase I program.

Commercialization:

Faraday has engaged two partners to aid in the commercialization of the technology developed under this SBIR grant: TTM Technologies and Coventya.  TTM Technologies is a leading provider of PCBs and Electro-Mechanical (E-M) Solutions to the global electronics industry with combined net sales of $1.33B (PCBs representing ~85% of their net sales and E-M Solutions ~15%). TTM Technologies currently conducts a significant amount of gold plating from cyanide based plating solutions, and would like to replace the cyanide plating bath with an environmentally friendly and worker friendly gold plating process. Coventya is a chemical formulator and supplier to the finishing industry, including supply of gold plating baths to the printed circuit boards industry.  Coventya develops and supplies specialty chemicals for surface finishing in over 40 countries and 4 continents, and their customers include both captive surface treatment and job shop platers. In addition to its U.S. presence, Coventya has a significant presence in Europe and is well aware of the regulatory issues associated with REACH.

From our discussions with TTM Technologies and Coventya, the desire is for a drop-in technology to replace cyanide-based hard gold plating. FARADAYIC® Hard Gold Plating fits the desired requirements for a replacement technology. Faraday’s key commercialization challenge is establishing distribution channels for the FARADAYIC® Hard Gold plating process, and our strategy is to partner with chemical formulators and chemical vendors, such as Coventya, to distribute FARADAYIC® Hard Gold Plating through their existing channels. Coventya is currently supplying decorative and functional gold plating chemicals and services to the plating and surface finishing industries. In addition to its U.S. presence, Coventya has a significant presence in Europe and is well aware of the environmental and regulatory issues associated with REACH. Faraday’s current plan is to work with Coventya to distribute the chemistry developed in this program and associated FARADAYIC® Hard Gold process via Coventya on a non-exclusive royalty basis. In addition, Faraday would collaborate with other plating chemical vendors to develop a pulse reverse process tuned to their plating chemistry. In this manner, if end users have a preferred chemical supplier they would not be forced to purchase solely from Coventya. Faraday’s remuneration would be on a non-exclusive royalty basis.