FR4 PCB SMD contact material

[acbalbason]

Hi All,

I have a simple inquiry. I have an FR4 board which is to be tested at around 48GHz. Now we are soldering an SMD chip to the board and yeah there are silver contacts for which we can solder the chip. I just want to know what kind of metal was used for that? I am guessing it is Aluminum. Can anyone confirm this?

Thanks.
Al

 

[jiripolivka]

SMD integrated circuits- if encapsulated, the contacts are ready for soldering by PbSn solder, or by lead-less solder.
'
If your MMIC is a die, the silvery dots are aluminum and should be connected by ultrasonic /thermal welding gold wire or tape according to chip instructions.

FR4 is then used mainly for "live" 50-Ohm lines; copper foil also can be contacted with golden wires or ribbons.