Solid-State Interfacial Reaction between Eutectic Au-Ge Solder and Cu/Ni（P）/Au Metalized Ceramic Substrate and Its Suppression
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2015年第5期
论文作者：F.Q.Lang H.Yamaguchi H.Nakagawa H.Sato
文章页码：445 - 452
摘 要：Eutectic Au-12 Ge solder was employed to bond the SiC power devices to a Si3N4/Cu/Ni（P）/Au multilayered substrate.The high-temperature reliability of the bond was investigated in detail at 200,250,300 and 330 ℃,respectively.NiGe and Ni5Ge3 intermetallic compounds（IMCs） were identified at the Au-12Ge/Ni（P） interface by micro X-ray diffraction（μXRD） and scanning electron microscopy（SEM）equipped with energy dispersive X-ray analysis（EDX）.The growth of the Ni-Ge IMCs was dominated by Ni5Ge3 layer,which formed at the Ni5Ge3/NiGe interface by outward diffusion of Ni from the Ni（P） layer.The activation energy of the total Ni-Ge IMCs growth was 66 kJ/mol.The shear strength of the bond was tested at both 25 ℃ and the aging temperatures,respectively.The shear strength decreased slightly after aging at 200 and 250 ℃.The shear strength tested at 250 ℃ was 46 MPa after aging at 250 ℃ for 3000 h.The shear strength aged at 300 and 330 ℃ rapidly decreased with aging time due to the rapid growth of the Ni5Ge3 IMC.To slow down the interfacial reaction between the high temperature solder and the Ni（P）layer,an approximately 200 nm-thick Ta/TaN/Ta new diffusion barrier（DB） was deposited on the substrate.Analysis by transmission electron microscopy（TEM） equipped with EDX,reveals that the Ta/TaN/Ta DB was bonded well to the Ni（P） layer and the solder.High temperature storage test at 330 ℃ for1500 h reveals that the bond of the SiC devices maintained its high shear strength of approximately56 MPa without decrease.The new DB effectively suppressed the interfacial reaction between the Au-12 Ge solder and the Ni（P） layer of the substrate.
F.Q.Lang，H.Yamaguchi，H.Nakagawa，H.Sato
Advanced Power Electronics Research Center(ADPERC),National Institute of Advanced Industrial Science and Technology(AIST).Central 2,1-1-1,Umezono,Tsukuba,Ibaraki 305-8568.Japan
摘 要：Eutectic Au-12 Ge solder was employed to bond the SiC power devices to a Si3N4/Cu/Ni（P）/Au multilayered substrate.The high-temperature reliability of the bond was investigated in detail at 200,250,300 and 330 ℃,respectively.NiGe and Ni5Ge3 intermetallic compounds（IMCs） were identified at the Au-12Ge/Ni（P） interface by micro X-ray diffraction（μXRD） and scanning electron microscopy（SEM）equipped with energy dispersive X-ray analysis（EDX）.The growth of the Ni-Ge IMCs was dominated by Ni5Ge3 layer,which formed at the Ni5Ge3/NiGe interface by outward diffusion of Ni from the Ni（P） layer.The activation energy of the total Ni-Ge IMCs growth was 66 kJ/mol.The shear strength of the bond was tested at both 25 ℃ and the aging temperatures,respectively.The shear strength decreased slightly after aging at 200 and 250 ℃.The shear strength tested at 250 ℃ was 46 MPa after aging at 250 ℃ for 3000 h.The shear strength aged at 300 and 330 ℃ rapidly decreased with aging time due to the rapid growth of the Ni5Ge3 IMC.To slow down the interfacial reaction between the high temperature solder and the Ni（P）layer,an approximately 200 nm-thick Ta/TaN/Ta new diffusion barrier（DB） was deposited on the substrate.Analysis by transmission electron microscopy（TEM） equipped with EDX,reveals that the Ta/TaN/Ta DB was bonded well to the Ni（P） layer and the solder.High temperature storage test at 330 ℃ for1500 h reveals that the bond of the SiC devices maintained its high shear strength of approximately56 MPa without decrease.The new DB effectively suppressed the interfacial reaction between the Au-12 Ge solder and the Ni（P） layer of the substrate.
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