MIL-PRF-38535K
APPENDIX A
A.3.5.6.3.5 Tin-lead plate. Tin-lead plate may be fused after plating before or after burn-in by heating above its
liquidus temperature. Tin-lead plate shall be visually inspected after fusing and shall exhibit a dense, homogeneous,
and continuous coating. The visual inspection after fusing shall be conducted on a sample basis by the manufacturer
as an in-process control. Visual inspection of the fusing shall be performed at a frequency sufficient to assure
continuous compliance with these requirements on the finished product. The manufacturer shall monitor the tin-lead
content of the leads to assure a minimum of 3 percent lead by weight.
A.3.5.7 Die plating and mounting. Pure glass shall not be used for microcircuit die mounting. Metal glass die
mounting and Silver Cyanate Ester (see Rome Labs letter 31 May 1994 for guidelines) are acceptable with QA
approval. (Contact the preparing activity for the Rome Labs letter.) Electroplated and electroless plated gold backing
on dice shall not be used, with the exception of gallium arsenide (GaAs) dice which may use electroplated gold
backing.
TABLE A-II. Lead finish systems.
Applied over
Gold plate
Required underplate
Electroless nickel 1/
Electroplated
nickel
Finish
None
X
Hot solder dip 2/
Hot solder dip 2/
Hot solder dip 2/
Hot solder dip 2/
Hot solder dip 2/
X
X
X
X
X
X
Tin-lead plate 3/
Tin-lead plate 3/
Tin-lead plate 3/
X
X
X
X
X
Gold plate
Gold plate
Palladium
X
X
Gold flash palladium
1/ Electroless nickel shall not be used as the undercoat on flexible or semi-flexible leads (see 3.3.1 and 3.3.2 of
TM 2004 of MIL-STD-883) and shall be permitted only on rigid leads or package elements other than leads.
2/ Hot solder dip shall be applied in accordance with A.3.5.6.3.4.
3/ Fusing of tin-lead plating is permitted in accordance with A.3.5.6.3.5.
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ACTEL [ Actel Corporation ]
