Interaction of intermetallic compound formation in Cu/SnAgCu/NiAu sandwich solder joints

Xia, Yanghua; Lu, C. T.; Chang, Junling; Xie, Xiaoming

doi:10.1007/bf02692545

Cited by 14 publications

(17 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…7,[14][15][16][17][18] The Cu-Ni interaction continued but at a relatively low rate during subsequent solid-state annealing. 2,[7][8][9][10][11] It is clear that cross-interaction refers to an up-hill diffusion process wherein both Cu and Ni diffuse from regions of low concentration to those of high concentration. The driving force for the process is the chemical potential gradient or the chemical force.…”

Section: Introductionmentioning

confidence: 99%

“…One of these reliability concerns results from the so-called crossinteraction between Cu and Ni. [1][2][3][4][5][6][7][8][9][10][11] It was recently reported that both Cu and Ni atoms can diffuse across the entire solder (hundreds of microns) to opposite sides of the sandwich structure in a very short time (a few seconds) during soldering. [1][2][3][4][5][6][7][8] The diffusion of Cu to the Ni-side can form a single layer of (Cu,Ni) 6 Sn 5 or a bilayer of (Cu,Ni) 6 Sn 5 and (Ni,Cu) 3 Sn 4 over the Ni pad, 1-8 resulting in a brittle solder/pad interface.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Influence of Current Direction on the Cu-Ni Cross-Interaction in Cu/Sn/Ni Diffusion Couples

Chung

Chen

et al. 2009

Journal of Elec Materi

View full text Add to dashboard Cite

The influence of current direction on the Cu-Ni cross-interaction in the Cu/Sn/Ni joint configuration was investigated in this study. During current stressing, an electric current towards or away from the Ni-side of Cu/Sn/Ni was imposed at 150°C. It was observed that the (Cu,Ni) 6 Sn 5 ternary compound was the dominant reaction product at both interfaces, and its growth at the Ni-side strongly depended upon the direction and magnitude of the electron flow. When the electron flow was towards the Ni-side, more Cu was found to be driven to the Ni-side, resulting in an increase in the thickness of (Cu,Ni) 6 Sn 5 . This is due to the chemical-potential-induced Cu flux (J Cu chem ) that was enhanced by the electromigration (J Cu em ). In the case of electron flow away from the Ni-side, the supply of Cu to the Ni-side was retarded due to the fact that J Cu em was in the opposite direction to J Cu chem : The results of this study revealed that the Ni-side (Cu,Ni) 6 Sn 5 thickness remained almost unchanged under current stressing of 10 4 A/cm 2 at 150°C, which suggests the inward Cu flux is approximately equal to the outward flux, i.e., J Cu chem % J Cu em :

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The Influence of Current Direction on the Cu-Ni Cross-Interaction in Cu/Sn/Ni Diffusion Couples

Chung

Chen

et al. 2009

Journal of Elec Materi

View full text Add to dashboard Cite

show abstract

“…Surface finish used can also change the morphology of the IMC formed [17,18]. Tseng and Duh [19] investigated the interfacial reaction of Sn-3.0Ag-0.5Cu solder jointed with ENIG and electroless Ni-P/electroless Pd/immersion Au (ENEPIG).…”

Section: Interfacial Reaction Of Solder Alloy and Surface Finishmentioning

confidence: 99%

A review on the effect of surface finish and cooling rate on solder joint reliability

Kahar¹,

Akhtar²,

Idris³

et al. 2016

WIT Transactions on the Built Environment

View full text Add to dashboard Cite

With increasing environmental concern over the toxicity of lead (Pb) combined with strict regulations, the use of lead-based solders provides an inevitable driving force for the development of lead-free solder alloys. Many studies have been conducted for the evaluation of the solder joint reliability with respect to solder alloys and surface finishes. However, as the demand of electronic devices is increasing, there is a need to improve the mechanical properties of the solder joint in order to keep up with the current evolution of electronic devices' technology. In this study, the effect of surface finish and cooling rate on solder joint reliability using nickel-based surface finish was summarized. The study focused on nickel based surface finish (ENIG and ENEPIG) with different cooling media, slow (furnace), medium (air) and fast (water). It was found that the type of surface finish and the cooling rate can change the morphology of the solder intermetallic compound (IMC) and directly changes the solder joint mechanical properties. A faster cooling rate was reported to provide finer IMC grains which might be translated into better solder joint strength. The findings presented here may provide a better understanding for further study and facilitate improvements in terms of solder joint reliability.

show abstract

“…8,12 The cross-diffusion of Cu to the opposite Ni is known as an up-hill diffusion process, in which Cu diffuses from a region with lower Cu concentration (C Cu ) (less than 0.1 wt.% for solid solder at 150°C 13 ) to one with higher C Cu [more than 20 wt.% for the (Cu,Ni) 6 Sn 5 phase formed on the Ni side]. [2][3][4][5][6][7][8][9][10][11]14 Such a process can occur within hours at elevated temperature, e.g., 150°C, because Cu is a well-known ''fast diffuser'' in tin-based alloys. 15 The driving force is the chemical potential gradient between the Cu 6 Sn 5 with a lower Ni content (Cu side) and that with a higher Ni content (Ni side).…”

Section: Introductionmentioning

confidence: 99%

“…During joint structure fabrication or subsequent operation, an appreciable amount of Cu can diffuse through the entire solder to the Ni side, [1][2][3][4][5][6][7][8][9][10][11] where it nucleates as a very brittle (Cu,Ni) 6 Sn 5 /(Ni,Cu) 3 Sn 4 bilayer structure. 8,12 The cross-diffusion of Cu to the opposite Ni is known as an up-hill diffusion process, in which Cu diffuses from a region with lower Cu concentration (C Cu ) (less than 0.1 wt.% for solid solder at 150°C 13 ) to one with higher C Cu [more than 20 wt.% for the (Cu,Ni) 6 Sn 5 phase formed on the Ni side]. [2][3][4][5][6][7][8][9][10][11]14 Such a process can occur within hours at elevated temperature, e.g., 150°C, because Cu is a well-known ''fast diffuser'' in tin-based alloys.…”

Section: Introductionmentioning

confidence: 99%

Critical Current Density for Inhibiting (Cu,Ni)6Sn5 Formation on the Ni Side of Cu/Solder/Ni Joints

Chung

Chen

et al. 2010

Journal of Elec Materi

View full text Add to dashboard Cite

The Cu/solder/Ni structure is a common joint configuration used in microelectronic packages today. In high-temperature operation of this joint structure, an appreciable amount of Cu can readily diffuse across the entire solder to the Ni side, where it might grow into a brittle bilayer structure of (Cu,Ni) 6 Sn 5 /(Ni,Cu) 3 Sn 4 . The driving force for Cu diffusion is the chemical potential gradient. To counterbalance this chemical-force-induced Cu flux (J chem Cu ), an attempt to apply a reverse electric current into a Cu/Sn(50 lm)/Ni structure was made in this study. Ten current densities (j = 0 A/cm 2 to 2 9 10 4 A/cm 2 ) were examined at 150°C upon current stressing. The results indicated that, under current stressing of <10 4 A/cm 2 , Cu atoms were still driven to the Ni side, resulting in noticeable increase in the amount of Cu (N Cu ) or (Cu,Ni) 6 Sn 5 at the Sn/Ni interface. In contrast, N Cu decreased significantly, and the (Cu,Ni) 6 Sn 5 was further converted into another lowCu-content phase, (Ni,Cu) 3 Sn 4 , when j exceeded 1.25 9 10 4 A/cm 2 . Under $10 4 A/cm 2 , the (Cu,Ni) 6 Sn 5 thickness and N Cu remained relatively unchanged over time, suggesting that 10 4 A/cm 2 is close to the critical current density (j crit ) that can counterbalance J chem Cu . Growth of (Cu,Ni) 6 Sn 5 and (Ni,Cu) 3 Sn 4 under the conditions (I) j < j crit , (II) j > j crit , and (III) j % j crit were also examined in this study.

show abstract

Interaction of intermetallic compound formation in Cu/SnAgCu/NiAu sandwich solder joints

Cited by 14 publications

References 23 publications

The Influence of Current Direction on the Cu-Ni Cross-Interaction in Cu/Sn/Ni Diffusion Couples

The Influence of Current Direction on the Cu-Ni Cross-Interaction in Cu/Sn/Ni Diffusion Couples

A review on the effect of surface finish and cooling rate on solder joint reliability

Critical Current Density for Inhibiting (Cu,Ni)6Sn5 Formation on the Ni Side of Cu/Solder/Ni Joints

Contact Info

Product

Resources

About