Why Do Cypress Cu (Copper) Lead Frame Products Use Matte Sn (Tin) Plating Despite Concerns Regarding Whisker Growth? - KBA203668

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Question:

Why do Cypress Cu (Copper) lead frame products use matte Sn (Tin) plating in spite of concerns regarding whisker growth? 

 

Answer:

Matte Sn plating has been chosen for Cu lead frame Cypress Pb-free (lead-free) memory products for the following reasons:

  1. Matte Sn is compatible with existing SnPb and Pb-free board assembly processes.
  2. Matte Sn has a higher melting point than other Pb-free alternatives, which makes it acceptable for automotive and high temperature applications. All Matte Sn finishes are qualified according to stringent JEDEC standards. To date, no failures related to whisker growth have been observed for the matte Sn plating chemistry qualified for Cypress memory products.