Substrates Resistor Material Metallization Options Mounting Options Filled and Plated Vias Thick Copper Plating Sputtered AuSn Cutouts and Special Shapes Sidewall Patterning
For many types of passive components (e.g.through hole or surface mount) the mounting operation creates both an electrical and mechanical connection; however, with most wirebondable components the physical mounting only creates a mechanical connection and the electrical connection is made through wirebonds.
The exception to this is back contact resistors (BCR and IGBR) and thin film capacitors (NCx and CBx) where the backside of the component is also one terminal of the device. The method of attaching the die to the substrate influences whether and what kind of metal to have on the back of the die.
Mounting Options Chip Attachment Contact Type Back Metal Non-conductive epoxy Mechanical Non required Conductive epoxy Mechanical only for top contact; also electrical for capacitors back contact resistors Au back for caps, BCR, IGBR, none for attachment only Solder Mechanical for top contact Ni/Au back Electrical and mechanical for flip chip None, Solder terminations required Sintering Mechanical only for top contact; also electrical for capacitors back contact resistors Ni/Au or Pd/Au Mechanical only for top contact; also electrical for capacitors back contact resistors Au back