Inhibit W is a proprietary continuous plating process that combines custom-designed, continuous plating lines with the best of chemical solutions to inhibit both crystalline growth and surface oxidation on pure tin deposits.

The drive to eliminate lead from electronics has resulted in the use of pure tin (SN) finishes as an economical lead-free plating option. The use of pure tin, however, poses significant risk for electronic systems with the propensity of crystalline growth “tin whiskers” and resulting failure risk.

The whiskers are elongated crystals typically 1mm or less in length and 103 microns in diameter that grow spontaneously. Their growth is unpredictable and may begin soon after plating or years later, producing significant concerns for the reliable operation of electron systems. Short circuits in low voltage, high impedance circuits, and contamination in sophisticated micro-electromechanical products, such as MEMS, from crystalline debris are major concern.

There are no industry-accepted, accelerated test methods designed to judge a particular processes propensity to grow whiskers, resulting with reliance on extensive test and accelerated field trials by major electronic and interconnect companies. Several years ago, successful results by chemical process manufacturers and extensive industry testing has brought process approvals leading to the Inhibit W addition to MSI’s continuous process capability.

Inhibit W is comprised of a combination of unique, state-of-the-art continuous process plating lines with chemical stations designed to both significantly reduce whisker growth tendencies and discoloration through oxidation of the tin deposit after thermal exposure. Inhibit W is typically combined with Nickel and Copper under-plating and with selective Gold and Palladium-Nickel selective finishes.