Finishes

Finishes

Tin-Lead

Applied by Hot Air Solder Level. Composition 60/40 or 63/37. Industry standard for years. Disadvantages - flatness and environmental concerns over lead.

Immersion Tin

Omikron Process deposits a minimum of 65 microns of "white tin". Advantages are 1) a flat surface, 2) processing temperatures are low causing less stress on the flex and, 3) a shelf life of 12 - 24 months. Some industry concerns over multiple heat cycles.

Electroplated Gold

Specification is to MIL-G-45204. Hardness can be Grades A, B or C. The Nickel specification is to QQ-N-290A. For gold wire bonding the specification would read as follows: Electroplated Gold to MIL-G-45204 Type III, Grade A, Class 00 minimum over 100 microinches of Nickel to QQ-N-290A. This specification would give 20 microinches of 99.9 % soft gold (knoop < 90).

Immersion Gold / Electroless Nickel

Gold is Type III, Grade A, 3 to 8 microinches thick over the requested Nickel thickness to AMS 24049. Advantages are: 1) flat pads and, 2) is suitable for aluminum wedge bonding.