Immersion Gold / Electroless Palladium / Immersion Gold (IGEPIG)
Uyemura Japan has conducted extensive R&D on the IGEPIG process, focusing on wire bonding (WBR), solder joint reliability (SJR), fine pattern reliability and electrical loss. Each characteristic has been evaluated to determine the optimum thickness for each IGEPIG layer.
IGEPIG is a palladium activator-free process involving 4 key steps: pretreatment, 1st EL-Au layer, 2nd EL-Pd layer and 3rd EL-Au layer.
- Detailed findings can be made available; below are 7 key performance metrics:
- IGEPIG’s unique chemistry prevents palladium over-plating.
- IGEPIG has high WBR (according to wire pull and bump shear tests) and SJR (according to ball pull and high-speed shear tests).
- The WBR of IGEPIG improves after high temperature stress.
- AES wide scan analysis shows that neither Cu nor Pd diffuse to the surface of IGEPIG.
- IGEPIG’s fine pattern ability is superior to standard or thin nickel ENEPIG, ENIG and EPIG.
- IGEPIG signal loss is lower than ENIG because there is no EN layer in the IGEPIG deposit.
- IGEPIG has excellent SJR for multi-reflow at 240° C: it is equal to ENEPIG.
Nanomover LPG-12 Gold Remover
Nanomover LPG-12 is used following the first immersion gold and prior to electroless palladium in the IGEPIG process. It removes all traces of adsorbed gold from the laminate / solder mask, preventing gold contamination in the EP bath.
Altarea TPG-13 Pure Electroless Palladium Bath
Altarea TPG-13 is used in the deposition of the IGEPIG final finish. The finish has excellent fine pattern capability, and solderability with lead-free solder. It is wire-bondable for PWB and IC package applications.
Gobright TFS-10 Reduction-assisted Immersion Gold
Gobright TFS-10 RAIG solution plates on copper and palladium substrates. It is ideally suited to the IGEPIG surface finish. The finish provides excellent fine pattern capability, wire bond reliability and solder joint reliability when used with lead-free solder. TFS-10 allows deposition of both gold layers from the same solution.