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 risks for electronic systems with the propensity of crystalline growth 'tin whiskers' and resulting failure risk.

Tin whiskers are elongated crystals typically 1mm or less in length and 1-3 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 electronic systems. Short circuits in low voltage, high impedance circuits and contamination in sophisticated micro-electromechanical products, such as MEMS, from crystalline debris are a major concern.

There are no industry accepted accelerated test methods designed to judge a particular processes propensity to grow whiskers, resulting with a reliance on extensive tests and accelerated field trials by major electronic and interconnect companies. During this last year successful results by chemical process manufacturers and extensive industry testing has brought process approvals leading to the inhibit-W addition to msi continuous process capability.

inhibit-W comprises 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.

Typical Process Combinations

> Tin over Nickel
> Selective Gold & Tin over Nickel
> Selective Gold & Tin over Nickel, over Copper
> Selective Palladium-Nickel & Tin over Nickel.

Process Trials

msi will process sample reels for customer evaluation. PPAP procedures are available as required for initial process runs.

processes

	continuous reel to reel
	automated barrel
	barrel/vibra-barrel
	rack