Void formation on PCB surface finish during reflow soldering

2011 ◽  
Author(s):  
Thomas D. Ewald ◽  
Norbert Holle ◽  
Klaus-Jurgen Wolter
Keyword(s):  
Surface Finish ◽  
Void Formation ◽  
Reflow Soldering

Reflow soldering and isothermal solid-state aging of Sn-Ag eutectic solder on Au/Ni surface finish

2001 ◽  
Vol 30 (9) ◽  
pp. 1152-1156 ◽  
Author(s):  
C. M. Liu ◽  
C. E. Ho ◽  
W. T. Chen ◽  
C. R. Kao
Keyword(s):  
Solid State ◽  
Surface Finish ◽  
Reflow Soldering ◽  
Eutectic Solder

scholarly journals Analysis of Void Formation Mechanism in the Vacuum Reflow Soldering Process of Semiconductor Laser Diode

2021 ◽  
Author(s):  
Peidong Xu ◽  
Bin Wang ◽  
Yong Wang ◽  
Xiantao Wang
Keyword(s):  
Semiconductor Laser ◽  
Formation Mechanism ◽  
Laser Diodes ◽  
Void Formation ◽  
Reflow Soldering ◽  
Soldering Process ◽  
Semiconductor Laser Diode ◽  
Soldering Technology ◽  
Semiconductor Laser Diodes ◽  
Selection Of

In this paper, the vacuum reflow soldering technology for semiconductor laser chips in optoelectronic devices was studied and analyzed in a systematic manner. Through the study on the key elements in the reflow soldering process, such as the selection of solders, <a>chamber</a> vacuum, flux, and the pressure applied by the fixture on the chip, this paper focused on exploring the formation mechanism of voids in the solder layer when the device was resoldered. Also, the change in the movement of gas bubbles in the voids with changing reflow oven chamber conditions and its underlying law were analyzed, by preparing 200 C-package semiconductor laser diodes and verifying the reliability and stability of the theoretical analysis through inspection and test aging. which could provide a theoretical basis for the use of the vacuum reflow soldering technology to reduce the void rate in the soldering process of devices.

scholarly journals The Effect Of Void Formation On The Reliability Of ED-XRF Measurements In Lead-Free Reflow Soldering

2015 ◽  
Vol 60 (2) ◽  
pp. 1445-1448 ◽  
Author(s):  
D. Koncz-Horváth ◽  
G. Gergely ◽  
Z. Gácsi
Keyword(s):  
Standard Deviation ◽  
Void Formation ◽  
Lead Free ◽  
Practical Implementation ◽  
Reflow Soldering ◽  
Eu Directive ◽  
Chemical Coating ◽  
Coating Methods ◽  
Heating Profiles

Abstract In lead-free reflow soldering, the presence of voids should be taken into account. For this reason, the effect of the applied heating profiles was examined via the characterization of voids in galvanic and immersion Sn coatings. According to EU Directive 2002/95/EC, the screening of Pb element of reflow soldering (i.e. of electrical and electronic equipment) is necessary; and the practical implementation of this measurement is largely affected by the characteristics of the solder (i.e. the presence of voids and the inhomogeneity of the solder). Comparing the results of the above two coating methods, it was found that by chemical coating more voids were formed and the detected lead content was higher than for galvanic Sn. The standard deviation of Ag and Cu concentrations was mainly influenced by the appearance of large compounds in the second case, while with chemical coating, no large compounds were formed due to the elevated number of voids.

Transmission electron microscopy studies of interfacial reactions and void formation in lead-free solders with minor elements

2010 ◽  
Vol 25 (7) ◽  
pp. 1304-1311 ◽  
Author(s):  
Y.T. Chin ◽  
P.K. Lam ◽  
H.K. Yow ◽  
T.Y. Tou
Keyword(s):  
Surface Finish ◽  
Intermetallic Layer ◽  
Void Formation ◽  
Electroless Nickel ◽  
Interfacial Reactions ◽  
Lead Free ◽  
Form Complex ◽  
Minor Elements ◽  
Transmission Electron ◽  
Lead Free Solders

Electroless nickel (Ni–P) is a common surface finish used in the ball grid array (BGA) package and interfacial reactions between its surface finish and lead-free solders can form complex intermetallic compound (IMC) layers. The presence of minor elements in lead-free solders either intentionally added or due to impurity contamination during solder manufacturing, can affect the solder-joint performance. In this work, interfacial reactions between Ni–P surface finish and the Sn–Ag–Cu solders were modified by varying Ag and Cu contents and also by adding a small amount of minor elements such as phosphorus (P), indium (In), and germanium (Ge). A transmission electron microscope was used to determine the intermetallic layer phases, compositions, crystal structures, and void defects. Varying the solder alloy elements led to the modulation of voids formation.

scholarly journals Analysis of Void Formation Mechanism in the Vacuum Reflow Soldering Process of Semiconductor Laser Diode

2021 ◽  
Author(s):  
Peidong Xu ◽  
Bin Wang ◽  
Yong Wang ◽  
Xiantao Wang
Keyword(s):  
Semiconductor Laser ◽  
Formation Mechanism ◽  
Laser Diodes ◽  
Void Formation ◽  
Reflow Soldering ◽  
Soldering Process ◽  
Semiconductor Laser Diode ◽  
Soldering Technology ◽  
Semiconductor Laser Diodes ◽  
Selection Of

In this paper, the vacuum reflow soldering technology for semiconductor laser chips in optoelectronic devices was studied and analyzed in a systematic manner. Through the study on the key elements in the reflow soldering process, such as the selection of solders, <a>chamber</a> vacuum, flux, and the pressure applied by the fixture on the chip, this paper focused on exploring the formation mechanism of voids in the solder layer when the device was resoldered. Also, the change in the movement of gas bubbles in the voids with changing reflow oven chamber conditions and its underlying law were analyzed, by preparing 200 C-package semiconductor laser diodes and verifying the reliability and stability of the theoretical analysis through inspection and test aging. which could provide a theoretical basis for the use of the vacuum reflow soldering technology to reduce the void rate in the soldering process of devices.

scholarly journals Influence of Flux and Related Factors on Intermetallic Layer Growth within SAC305 Solder Joints

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7909
Author(s):  
Karel Dušek ◽  
Petr Veselý ◽  
David Bušek ◽  
Adam Petráč ◽  
Attila Géczy ◽  
...  
Keyword(s):  
Image Analysis ◽  
Layer Thickness ◽  
Surface Finish ◽  
Intermetallic Layer ◽  
Layer Growth ◽  
Solder Paste ◽  
Sac305 Solder ◽  
Related Factors ◽  
Reflow Soldering ◽  
Solder Mask

Flux contained in solder paste significantly affects the process of solder joint creation during reflow soldering, including the creation of an intermetallic layer (IML). This work investigates the dependence of intermetallic layer thickness on ROL0/ROL1 flux classification, glossy or matt solder mask, and OSP/HASL/ENIG soldering pad surface finish. Two original SAC305 solder pastes differing only in the used flux were chosen for the experiment. The influence of multiple reflows was also observed. The intermetallic layer thicknesses were obtained by the image analysis of micro-section images. The flux type proved to have a significant impact on the intermetallic layer thickness. The solder paste with ROL1 caused an increase in IML thickness by up to 40% in comparison to an identical paste with ROL0 flux. Furthermore, doubling the roughness of the solder mask has increased the resulting IML thickness by 37% at HASL surface finish and by an average of 22%.

Intermetallic growth and shear strength of SAC305/EN-Boron

2016 ◽  
Vol 28 (3) ◽  
pp. 141-148
Author(s):  
Hardinnawirda Kahar ◽  
Zetty Akhtar Abd Malek ◽  
Siti Rabiatull Aisha Idris ◽  
Mahadzir Ishak
Keyword(s):  
Shear Strength ◽  
Solder Joint ◽  
Surface Finish ◽  
Air Cooling ◽  
Slow Cooling ◽  
Reflow Soldering ◽  
Content Type ◽  
Cu Substrate ◽  
Lap Shear ◽  
Scanning Electron

Purpose This paper aims to study the effect of aging and cooling rate on the reliability of the solder joint using electroless nickel boron (EN-Boron) as a surface finish in the electronic packaging area. Design/methodology/approach EN-Boron was plated on a Cu substrate through electroless plating method. This process was followed by reflow soldering of Sn–3.0Ag–0.5Cu solder alloy on metallized Cu substrate to form a joining. Then, the specimens were cooled using different cooling mediums such as air (slow cooling) with 15.7 °C/min and water (fast cooling) with 110.5 °C/min. After that, the specimens were subjected to isothermal aging at 150°C for 0, 250 and 1,000 h. Finally, they went through a lap shear test following ASTM D1002. Optical microscope and scanning electron microscopy were used for intermetallic compound (IMC) characterization. The type of IMC formed was confirmed by field emission scanning electron microscope-energy-dispersive X-ray spectroscopy (FESEM-EDX). Findings The results showed that the IMC type changed from the combination of Ni3Sn4 and (Ni, Cu)3Sn4 after reflow soldering into fully (Ni, Cu)3Sn4 when aged for 1,000 h. The formation of (Ni, Cu)3Sn4 and Cu3Sn underneath the IMC layer played a role in reducing the shear strength of joining. Overall, water cooling was reported to provide higher shear strength of solder joint compared to air cooling medium. Originality/value The shear strength when using EN-Boron as the surface finish is comparable to the surface finish conventionally used.

The Effect of Bismuth on Intermetallics Growth between Lead-Free Solders and Electroless Nickel Immersion Silver (ENIMAG) Surface Finish

2019 ◽  
Vol 796 ◽  
pp. 183-188
Author(s):  
Jaidi Zolhafizi ◽  
Osman Saliza Azlina
Keyword(s):  
Grain Size ◽  
Intermetallic Compound ◽  
Surface Finish ◽  
Aging Treatment ◽  
Electroless Nickel ◽  
Optical Microscope ◽  
Circuit Board ◽  
Lead Free ◽  
Reflow Soldering ◽  
Immersion Silver

Surface finish is coating layer plated on a bare copper board of printed circuit board (PCB). Among PCB surface finishes, Electroless Nickel/Immersion Gold (ENIG) finish is a top choice among electronic packaging manufacturer due to its excellent properties for PCB. However, the use of gold element in ENIG is very high cost and the black pad issue have not been resolved. Thus, by introducing an Electroless Nickel/Immersion Silver (ENImAg) as alternative surface finish hopefully can reduce the cost and offer better properties. The aim of this study is to investigate the effect of bismuth on interfacial reaction during reflow soldering between Sn-2.5Ag (SA25), Sn-3.4Ag-4.8Bi (SAB3448) and ENIMAG surface finish. Solder balls with sizes of 500μm diameters were used. The characteristics of intermetallic compound (IMC) were analyzed by using scanning electron microscopy (SEM), optical microscope and energy dispersive x-ray (EDX). After reflow soldering, the result revealed that only the irregular circle-shape of (Cu,Ni)6Sn5IMC layer was formed at the interface and change to an irregular rod-like shape meanwhile the irregular needle-shape (Ni,Cu)3Sn4was appeared after aging treatment. The result also indicated that, the grain size and thickness of IMC for SAB3448 is smaller and thinner compared to the SA25. The IMC thickness is proportional to the aging duration and IMC morphology for both solder are became thicker, larger and coarser after isothermal aging. No bismuth particle has been detected on SAB3448 solder during top surface examination. In addition, the Bi has been observed can reduce the grain size and the growth rate of IMC. Keywords: ENIMAG, reflow soldering, lead-free solder, intermetallic compound, bismuth

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