Maxim’s Lead Finishing Program Supplies Leaded Parts

21st October 2011

ES Admin

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Maxim Integrated Products responds to the plea of its military and aerospace customers with two programs that provide small and large quantities of lead (SnPb) finished ICs. Market demand for lead-free finishes led Maxim to modify the finish of its ICs to conform to the RoHS initiative. The company offers three lead-free finishes: a matte tin (100% Sn) finish, a nickel palladium gold (NiPdAu) for some products, and 100% gold on ceramic leadless chip carrier packages. The lead-free offering from Maxim is predominately matte tin. Subsequently, it has become increasingly difficult for mil/aero customers to find lead finished parts. In some cases the lead finish is just no longer available, and in other cases the minimum order quantity (MOQ) is substantially higher than the customer’s actual demand. To avoid the high MOQ, the customer was forced either to buy the lead-free device and use them with lead solder, or to send the device to a refinishing house for a hot solder dip. In the latter case, the dipping voids the Maxim warranty.

As part of the company’s sustained focus on customer support, two new programs now provide lead finished devices to mil/aero customers in a timely and cost-effective manner. For small quantities with a lead finish, the MOQ is 50. Lead-free parts from existing inventory or from parts just coming off the line are sent to the company’s military-qualified refinishing house. The same service is used for the gold finished mil spec parts that customers want refinished with lead. The company’s refinisher processes the parts, refinishes them with hot solder, and then marks them with an orange epoxy dot on the package per the GEIA-STD-0006, which pertains to refinishing parts with hot solder. The original marking remains visible and the orange dot is added to avoid confusion with counterfeiters who coat the top with black epoxy and remark with white ink.

Maxim retests 100% of the refinished parts at room temperature following the same QCI test program used for production parts. A final QA visual inspection is made and the parts are shipped to the customer. The full Maxim® warranty applies. Also, an X-ray fluorescence (XRF) report showing that no pure tin remains on any portion of the leads is available by request. The cycle time for this process averages about six weeks, provided that inventory is available.

A second refinishing program is designed for lead-finished parts in larger quantities. Packaged part inventory is not needed, only an inventory of wafers. While the term “large quantity” is relative, a single wafer can typically provide from 1000 to 10,000 or more die. Consequently, Maxim will advise the MOQ for these orders.

Once a production wafer is pulled from inventory, it is built on the original lead-finish flow, just as before the RoHS initiative. Building it on the lead finish flow means that the part will be solder electroplated with 85/15 SnPb. It is marked with the standard marking (no orange dot) and tested, again using the standard QCI test program. After QA, it is then shipped to the customer and the full warranty applies.