TY - GEN
T1 - Bismuth-Based Transient Liquid Phase (TLP) Bonding as High-Temperature Lead-Free Solder Alternatives
AU - Cho, Junghyun
AU - Sheikhi, Roozbeh
AU - Mallampati, Sandeep
AU - Yin, Liang
AU - Shaddock, David
N1 - Publisher Copyright: © 2017 IEEE.
PY - 2017/8/1
Y1 - 2017/8/1
N2 - Predominant high melting point solders for high temperature electronics contain lead (Pb), which will soon be banned by environmental regulations as in most of consumer electronics. In an effort to replace the Pb-based solders with a new high-temperature capable material, we developed a transient liquid phase (TLP) bonding of bismuth (Bi) and nickel (Ni). A molten Bi (m.p. of 271°C) strongly reacts with Ni to form a Bi3Ni or BiNi intermetallic layer, both of which can withstand over 400°C. To study microstructural developments and their influences on reliability performance, the die attached coupons were assembled using Bi-Ni TLP bonds. It was shown that Bi3Ni is the first phase to form, after which the diffusion of Bi controls the growth kinetics of this intermetallic phase with the activation energy of 65.5 kJ/mol for the temperature range from 160 to 240°C. The solid-state transformation of Bi3Ni to BiNi follows, which is a slower process and only occurs at a long-term aging (activation energy of 17.8 kJ/mol, for the temperature range from 260 to 300°C). When tested at high temperatures (up to 350°C) or exposed under long-term storage at 200°C over 1000 hours, such bonds showed no degradation in die shear strength. It indicates the potential of the Bi-Ni TLB bonds as a Pb-free alternative to replace high-Pb solders for high temperature electronics that operate at 200°C or higher.
AB - Predominant high melting point solders for high temperature electronics contain lead (Pb), which will soon be banned by environmental regulations as in most of consumer electronics. In an effort to replace the Pb-based solders with a new high-temperature capable material, we developed a transient liquid phase (TLP) bonding of bismuth (Bi) and nickel (Ni). A molten Bi (m.p. of 271°C) strongly reacts with Ni to form a Bi3Ni or BiNi intermetallic layer, both of which can withstand over 400°C. To study microstructural developments and their influences on reliability performance, the die attached coupons were assembled using Bi-Ni TLP bonds. It was shown that Bi3Ni is the first phase to form, after which the diffusion of Bi controls the growth kinetics of this intermetallic phase with the activation energy of 65.5 kJ/mol for the temperature range from 160 to 240°C. The solid-state transformation of Bi3Ni to BiNi follows, which is a slower process and only occurs at a long-term aging (activation energy of 17.8 kJ/mol, for the temperature range from 260 to 300°C). When tested at high temperatures (up to 350°C) or exposed under long-term storage at 200°C over 1000 hours, such bonds showed no degradation in die shear strength. It indicates the potential of the Bi-Ni TLB bonds as a Pb-free alternative to replace high-Pb solders for high temperature electronics that operate at 200°C or higher.
KW - Bi3Ni
KW - BiNi
KW - Die attach
KW - High-temperature electronics
KW - Pb-free
KW - Transient liquid phase (TLP) bond
UR - https://www.scopus.com/pages/publications/85028030694
U2 - 10.1109/ECTC.2017.184
DO - 10.1109/ECTC.2017.184
M3 - Conference contribution
T3 - Proceedings - Electronic Components and Technology Conference
SP - 1553
EP - 1559
BT - Proceedings - IEEE 67th Electronic Components and Technology Conference, ECTC 2017
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 67th IEEE Electronic Components and Technology Conference, ECTC 2017
Y2 - 30 May 2017 through 2 June 2017
ER -