Continuing our look at the SEMI 3D European Summit:
Oerlikon systems discussed PVD solutions for TSV metallization. Since sputter deposition is line-of-sight, it has been difficult for it to fill high AR features. Ionized PVD addresses this coverage in high AR issue, but significantly increases the equipment costs.
Highly ionized sputtering (HIS) is based on high power pulsed magnetron sputtering and reportedly has excellent directionality and film quality. It deposits at a higher rate that ionized PVD. They showed the following coverage for TI barrier layer in 10:1 AR TSV…
and the following data for Cu seed layers:
Eric Beyne of IMEC discussed the 3D technology maturation process and COO issues.
The std IMEC 3DIC TSV process has had 5 x 50 um TSV, but recently they have indicated that a more to 3um dia TSV may be warranted. One reason is that a reduction in the dia of the TSV correspondingly reduces the keep out zone (KOZ) requirements.
Another interesting comparison was the thermal impact of Cu/Sn intermetallic bumps vs Cu-Cu bonds, where the direct copper-copper bonding shows a significant reduction in temperature.
IMEC assessment of the cost structure for a 10 x 100 um interposer TSV vs a std 5 x 50 TSV vs the proposed 3 x 50 TSV looks like this:
Ron Huemoeller of Amkor addresses future packaging needs. He showed an interesting Prismark slide, which showed that smart phones and tablets will account for more than 50% of the Semi Ind growth through 2016.
In terms of interposers, Ron shared his views on interposer density vs application space. IFTLE has mentioned several times that the only interposer programs that have been announced are ones requiring high density interposers only available from foundries. Although this statement still holds true, Ron points to “ lower end smart phones and tablets” as potentially requiring interposers with less than 8 um l/s which could be fabricated by an OSAT RDL line.
In terms of memory supply for 2.5/3D products, Ron lists on Elpida (Micron) and Hynix as currently supplying.
For all the latest in 3DIC and advanced packaging, stay linked to IFTLE.