| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 544871 | Microelectronics Reliability | 2014 | 8 Pages |
•Insulated Cu wire forms spherical and organic free residue FAB using forming gas.•Insulated Cu wire needs lower energy to form a FAB compared to Cu wire.•Insulated Cu and bare Cu FABs demonstrate tapering effect at higher EFO settings.•Insulated Cu wire demonstrates comparable ball bond strength to Cu wire.
Insulated Cu wire technology has immense potential for fine pitch wire bonding interconnection. Understanding the behavior of the insulated Cu free air ball (FAB) formation is crucial for wire bonding process. The FAB formation, size, shape and cleanliness under different conditions for 20 μm insulated Cu wire were investigated using SEM, FESEM and FTIR surface analysis. The results were compared with that of bare Cu wire. Consistently spherical residue free FAB of insulated Cu wire were formed using forming gas. The samples with insulated Cu wire consistently produced larger FAB than that of bare Cu wire, indicating that the energy required for free air ball formation is lower. Basic bonding performances in terms of ball bond strength, intermetallic (IMC) coverage growth and stitch bond strength of insulated Cu wire at time zero are also discussed in the paper.
