Surface passivation of Cu cone bump by self-assembled-monolayer for room temperature Cu-Cu bonding

Cu-Cu room temperature bonding is investigated using Cu cone bumps with SAM passivation. Effect of the SAM passivation for preventing the Cu oxidation is confirmed by AES and water contact angle measurements. The contact resistance at the bump interconnection is kept small even with 24 hours storage in air after the SAM passivation. Also, the die shear strength of the bonded chip is enough high to satisfy the criterion of MIL-STD. According to these findings, we can conclude that the Cu cone bump with the SAM passivation is promising candidate for room temperature Cu-Cu bump interconnections.