MIL-PRF-38535K
APPENDIX A
TABLE A-IV. Package element (other than leads/terminals) finish systems.
Finish
Applied over
Gold plate
Required underplate
Electroplated
nickel 1/
Electroless
nickel 1/
Nickel cladding
1/
None
X
Hot solder dip
Hot solder dip
Hot solder dip
Hot solder dip
Hot solder dip
Hot solder dip
Hot solder dip
X
X
X
X
X
X
X
X
X
Tin-lead plate 2/
Tin-lead plate 2/
Tin-lead plate 2/
Tin-lead plate 2/
X
X
X
X
X
X
X
Gold plate 3/
Gold plate 3/
Gold plate 3/
Electroplated nickel 1/
Electroless nickel 1/
Nickel cladding 1/
X
X
X
Palladium
X
X
Gold flash palladium
1/ Combinations of electroplated nickel and electroless nickel and nickel cladding are permitted.
2/ Fusing of tin-lead plate is permitted in accordance with A.3.5.6.3.5.
3/ Multilayer gold and nickel finish structures are acceptable provided the outer gold layer meets a minimum
thickness of 25 microinches (0.635 micrometer), the total of the gold layers meet a minimum thickness of 50
microinches (1.27 micrometers), and each of the nickel undercoats meet the thickness requirements of table
A-III with the total nickel thickness not to exceed 450 microinches (11.43 micrometers). For multilayer finish
structures, nickel plate, nickel cladding, or gold plate are permitted on the base metal.
A.3.5.8 Glassivation. All microcircuits shall be coated with a transparent glass or other approved coating, except
where glassivation is omitted by documented design rules (e.g., probe opening, fuse pads, etc.) The minimum
glassivation thickness shall be 6,000 Å (600 nm) for Si02, 2,000 Å (200 nm) for Si3N4, or approved thicknesses for
approved coatings. The composition and minimum thickness of other approved coatings are subject to approval by
the QA, and must be included in the manufacturer’s QM plan. The glassivation/nitridation shall cover all electrical
conductors except the bonding or test pads. NOTE: For GaAs microwave microcircuits, the glassivation or nitride
dielectric shall cover the semiconductor regions (e.g., field effect transistor (FET)) of the device and planar thin film
resistors as a minimum. Furthermore; for class level S devices, the glassivation or nitride dielectric shall cover
regions where conductors are separated by less than the minimum 1 mil particle size detectable by a PIND test. For
RF/microwave GaAs microcircuits, the manufacturer shall define appropriate glassivation thickness requirements for
the technology in the internal baseline documentation.
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ACTEL [ Actel Corporation ]
