Behavior of palladium and its impact on intermetallic growth in palladium-coated Cu wire bonding

Xu, Huining; Qin, Ivy; Clauberg, Horst; Chylak, Bob; Acoff, Viola L.

doi:10.1016/j.actamat.2012.09.030

Cited by 60 publications

(18 citation statements)

References 10 publications

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“…Heraues wire vendor compares Pd distribution in both Pd-doped and Pd-coated Cu wires and found uniform Pd distribution is observed within RelCu Free Air Ball (FAB) on melting the wire [23] . Hui X et al [24] , [25] reported when a Pd coated copper wire is being heated and melted to form a FAB, the Pd layer does not completely dissolve into copper ball to form a total solid solution according to solid solubility of the two metals. This is because in actual melting process of the wire, the duration of heating is too short to allow complete dissolution of Pd into copper core material before cooling and the solidification rate is too fast in the FAB formation process due to the short electric flame off (EFO) firing time to melt the tip of wire and the use of process gas such as nitrogen/hydrogen (95%/5%) mixture or pure nitrogen to protect the ball from oxidation before bonding onto the IC pad.…”

Section: Discussionmentioning

confidence: 99%

Comparative Reliability Studies and Analysis of Au, Pd-Coated Cu and Pd-Doped Cu Wire in Microelectronics Packaging

Gan

Hashim

2013

PLoS ONE

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This paper compares and discusses the wearout reliability and analysis of Gold (Au), Palladium (Pd) coated Cu and Pd-doped Cu wires used in fineline Ball Grid Array (BGA) package. Intermetallic compound (IMC) thickness measurement has been carried out to estimate the coefficient of diffusion (Do) under various aging conditions of different bonding wires. Wire pull and ball bond shear strengths have been analyzed and we found smaller variation in Pd-doped Cu wire compared to Au and Pd-doped Cu wire. Au bonds were identified to have faster IMC formation, compared to slower IMC growth of Cu. The obtained weibull slope, β of three bonding wires are greater than 1.0 and belong to wearout reliability data point. Pd-doped Cu wire exhibits larger time-to-failure and cycles-to-failure in both wearout reliability tests in Highly Accelerated Temperature and Humidity (HAST) and Temperature Cycling (TC) tests. This proves Pd-doped Cu wire has a greater potential and higher reliability margin compared to Au and Pd-coated Cu wires.

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Section: Discussionmentioning

confidence: 99%

Comparative Reliability Studies and Analysis of Au, Pd-Coated Cu and Pd-Doped Cu Wire in Microelectronics Packaging

Gan

Hashim

2013

PLoS ONE

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“…However, bare Cu wire is easily oxidized, and thus Cu ribbon may need special care like reduction gas, or coatings for bonding. 7) The hardness and modulus of Cu higher than those of Al are drawback in bonding process leading to higher risk of chip fracture. 7) In the present study, we hence adopted Al ribbon to achieve sufficient joint reliability by ultrasonic bonding.…”

Section: Introductionmentioning

confidence: 99%

Mechanical stabilities of ultrasonic Al ribbon bonding on electroless nickel immersion gold finished Cu substrates

Park¹,

Nagao²,

Sugahara³

et al. 2014

Jpn. J. Appl. Phys.

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Metal ribbon wiring attracts much attention for next-generation power-electronics interconnection technology, which requires wider capacity of electrical current in smaller package. The bonding methods of metal ribbons are to be optimized suitable for the larger bonding area than conventional thin string wires. We here use ultrasonic bonding for Al ribbon (1500 × 200 µm2) on to electroless nickel immersion gold (ENIG) finished copper substrate, and optimize the bonding process parameters to minimize the heat damage with sufficient bonding strength. The effect of the process parameters of ultrasonic power, bonding time and normal bonding force on bond formation at ambient temperatures have been investigated with field emission-scanning electron microscopy (FE-SEM) and energy-dispersive spectroscopy (EDS) analysis. Au–Al interfaces were characterized by FE-SEM following pull- and shear-test to effect separation of the bond joints. Bond stabilities were evaluated by lift-off phenomenon and fracture morphology after pull- and shear-test. The highest bonding strength indicated at 20 W (ultrasonic power), 1.8 s (bonding time), and 800 mN (normal bonding force). In this bonding condition, relative motion was occurred from center of gross sliding area over 60%. Based on those result, we confirmed the excellent ribbon bonding conditions and investigated bonding mechanism involved in relative motion.

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“…Many microscopic testings were involved in 3-D electronic packaging. Li et al [21] explored the impact of palladium on the wire bonding process and Li et al [22] did the state detection of bond wires in insulated gate bipolar transistor modules. There are also some testings available for the thermal management of LED packaging [23], [24].…”

Section: Introductionmentioning

confidence: 99%

A Measurement Method on Nanoscale Thickness of the Ti Barrier Layer of TSV Structure for 3-D IC

Tian

et al. 2016

IEEE Trans. Compon., Packag. Manufact. Technol.

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As the characteristic dimension of an integrated circuit (IC) continuously scales down, together with the requirements of low power consumption, multiple functionality, and cost effectiveness, the conventional IC transforms into a 3-D IC. Through-silicon via (TSV) is a promising and preferred way to realize the reliable interconnection for a 3-D IC. Thus, accurate measurement of the critical structural parameters plays an important role in securing the integrity and reliability of TSV. In this paper, a novel image-processing-based measurement method is proposed to measure the barrier layer thickness and step coverage of TSV. Since the thickness of the barrier layer is generally less than 100 nm, which is a drawback of the conventional SEM method, we used the material information from SEM as well as structural prior of TSV to infer the barrier layer thickness on nanoscale. In addition, we further achieved the step coverage of thin films in TSV using the proposed measurement method.Index Terms-Barrier layer thickness, image processing, step coverage, through-silicon via (TSV).

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Behavior of palladium and its impact on intermetallic growth in palladium-coated Cu wire bonding

Cited by 60 publications

References 10 publications

Comparative Reliability Studies and Analysis of Au, Pd-Coated Cu and Pd-Doped Cu Wire in Microelectronics Packaging

Comparative Reliability Studies and Analysis of Au, Pd-Coated Cu and Pd-Doped Cu Wire in Microelectronics Packaging

Mechanical stabilities of ultrasonic Al ribbon bonding on electroless nickel immersion gold finished Cu substrates

A Measurement Method on Nanoscale Thickness of the Ti Barrier Layer of TSV Structure for 3-D IC

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