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1 – 10 of 63Lijuan Huang, Zhenghu Zhu, Hiarui Wu and Xu Long
Vapor phase soldering (VPS), also known as condense soldering, is capable of improving the mechanical reliability of solder joints in electronic packaging structures. The paper…
Abstract
Purpose
Vapor phase soldering (VPS), also known as condense soldering, is capable of improving the mechanical reliability of solder joints in electronic packaging structures. The paper aims to discuss this issue.
Design/methodology/approach
In the present study, VPS is utilized to assemble two typical packaging types (i.e. ceramic column grid array (CCGA) and BGA) for electronic devices with lead-containing and lead-free solders. By applying the peak soldering temperatures of 215°C and 235°C with and without vacuum condition, the void formation and intermetallic compound (IMC) thickness are compared for different packaging structures with lead-containing and lead-free solder alloys.
Findings
It is found that at the soldering temperature of 215°C, CCGA under a vacuum condition has fewer voids but BGA without vacuum environment has fewer voids despite of the existence of lead in solder alloy. In light of contradictory phenomenon about void formation at 215°C, a similar CCGA device is soldered via VPS at the temperature of 235°C. Compared with the size of voids formed at 215°C, no obvious void is found for CCGA with vacuum at the soldering temperature of 235°C. No matter what soldering temperature and vacuum condition are applied, the IMC thickness of CCGA and BGA can satisfy the requirement of 1.0–3.0 µm. Therefore, it can be concluded that the soldering temperature of 235°C in vacuum is the optimal VPS condition for void elimination. In addition, shear tests at the rate of 10 mm/min are performed to examine the load resistance and potential failure mode. In terms of failure mode observed in shear tests, interfacial shear failure occurs between PCB and bulk solder and also within bulk solder for CCGA soldered at temperatures of 215°C and 235°C. This means that an acceptable thicker IMC thickness between CCGA solder and device provides greater interfacial strength between CCGA and device.
Originality/value
Due to its high I/O capacity and satisfactory reliability in electrical and thermal performance, CCGA electronic devices have been widely adopted in the military and aerospace fields. In the present study, the authors utilized VPS to assemble a typical type of CCGA with the control package of conventional BGA to investigate the relation between essential condition (i.e. soldering temperature and vacuum) to void formation.
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Balázs Illés, Attila Géczy, Bálint Medgyes and Gábor Harsányi
This paper aims to present a review of the recent developments in vapour phase soldering (VPS) technology. This study focuses on the following topics: recent developments of the…
Abstract
Purpose
This paper aims to present a review of the recent developments in vapour phase soldering (VPS) technology. This study focuses on the following topics: recent developments of the technology, i.e. soft and vacuum VPS; measurement and characterization methods of vapour space, i.e. temperature and pressure; numerical simulation of the VPS soldering process, i.e. condensate layer and solder joint formation; and quality and reliability studies of the solder joints prepared by VPS, i.e. void content and microstructure of the solder joints.
Design/methodology/approach
This study was written according to the results of a wide literature review about the substantial previous works in the past decade and according to the authors’ own results.
Findings
Up to now, a part of the electronics industry believes that the reflow soldering with VPS method is a significant alternative of convection and infrared technologies. The summarized results of the field in this study support this idea.
Research limitations/implications
This literature review provides engineers and researchers with understanding of the limitations and application possibilities of the VPS technology and the current challenges in soldering technology.
Originality/value
This paper summarizes the most important advantages and disadvantages of VPS technology compared to the other reflow soldering methods, as well as points out the necessary further developments and possible research directions.
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Beata Kinga Synkiewicz, Agata Skwarek and Krzysztof Witek
The main advantages of vapour phase soldering are a non-oxygen environment, the elimination of overheating and the possibility of the vacuum application, which can guarantee…
Abstract
Purpose
The main advantages of vapour phase soldering are a non-oxygen environment, the elimination of overheating and the possibility of the vacuum application, which can guarantee undeniably higher quality of solder joints, especially as regards void formation. These features are less affected by the alloy composition. The paper aims to discuss these issues.
Design/methodology/approach
The quality of solder joints made in two VPS options (with and without vacuum) was investigated in terms of voids formation. Solder alloys of 37%Pb63%Sn (PbSn) and 96%Sn3.5%Ag0.5%Cu (SAC 305) were applied to an etched Cu layer on a glass-epoxy substrate using the screen-printing method. 1206 SMD resistors were placed on the solder pads with a Quadra pick-and place machine. For the inspection of joint structure and void identification, 3D X-ray images of samples were taken using a computed tomography system with a 180 kV/15 W nanofocus. For comparison, traditional cross-sections of the samples were performed using a metallographic polisher. The cross-section analysis was done in a scanning electron microscope (SEM). To confirm the relevance of these data, a statistical analysis was carried out.
Findings
The paper shows that alloy composition has less impact on the quality of joints as regards void formation. The tendency for a different arrangement of voids in a junction depending on the distance SMD element and the thickness of the solder layer was investigated using X-ray computed tomography.
Originality/value
The use of 3D computed tomography for void investigation gives full information about the internal structure of the joint and allows for precise void identification. Vacuum application during the soldering allows significant voids elimination.
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Agata Skwarek, Balázs Illés, Krzysztof Witek, Tamás Hurtony, Jacek Tarasiuk, Sebastian Wronski and Beata Kinga Synkiewicz
This paper aims to investigate the quality and reliability of solder joints prepared from Pb-free alloys on direct bounded Cu (DBC) substrates. Two types of solder alloys were…
Abstract
Purpose
This paper aims to investigate the quality and reliability of solder joints prepared from Pb-free alloys on direct bounded Cu (DBC) substrates. Two types of solder alloys were studied: Sn90.95Ag3.8Cu0.7Sb1.4Ni0.15Bi3.0, with a high melting point of 225°C, and Sn42Bi58, with low a melting point of 138°C.
Design/methodology/approach
Capacitor components of size 1806 were soldered on DBC substrates by using convection reflow soldering and vacuum vapor-phase soldering technologies. A part of the samples was subjected to the thermal shock test. The structure of the solder joints and the content of the voids were investigated using three-dimensional X-ray tomography. The mechanical strength of the joints was evaluated using the shear force test, and the microstructure of the joints was studied on metallographic cross sections by using scanning electron microscopy.
Findings
It was found that the number of voids is not related directly to the mechanical strength of the solder joints. The mechanical strength of the solder joints depends more on the amount of Ag3Sn precipitation, Au precipitation and the intermetallic layer in the solder joints. In some cases, the thermal shock test caused micro-cracks around the Au precipitation because of a mismatch of Au, AuSn4 and Sn in terms of coefficients of thermal expansion.
Originality/value
DBC substrates are usually used for power electronics, where the quality of the solder joints is even more important than in the case of commercial electronics.
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Balázs Illés, Agata Skwarek, Attila Géczy, László Jakab, David Bušek and Karel Dušek
The vacuum vapour phase soldering method was investigated by numerical simulations. The purpose of this study was to examine the temperature changes of the solder joints during…
Abstract
Purpose
The vacuum vapour phase soldering method was investigated by numerical simulations. The purpose of this study was to examine the temperature changes of the solder joints during the vapour suctioning process. A low pressure is used to enhance the outgassing of the trapped gas within the solder joints, which otherwise could form voids. However, the system loses heat near the suction pipe during the suctioning process, and it can result in preliminary solidification of the solder joints before the gas could escape.
Design/methodology/approach
A three-dimensional numerical flow model based on the Reynolds averaged Navier–Stokes equations with the standard k-e turbulence method was developed. The effect of the vapour suctioning on the convective heat transfer mechanism was described by the model. Temperature change of the solder joints was studied at the mostly used substrate and component combinations, as well as at different system settings.
Findings
In the function of the substrate thickness and the component size, the solder joints can lose large amount of heat during the void reduction process, which leads to preliminary solidification before the entrapped gas voids could be removed.
Research limitations/implications
The results provide setting information of vacuum vapour phase technology for appropriate and optimal applications.
Originality/value
The relationship between low pressure generation and convective heat transfer mechanism during vacuum vapour phase soldering has not been studied yet. The possible negative effects of the vapour suctioning process on the solder joint temperature are unknown.
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Attila Geczy, Daniel Nagy, Balazs Illes, Laszlo Fazekas, Oliver Krammer and David Busek
The paper aims to present an investigation of heating during vapour phase soldering (VPS) on inclined printed circuit board (PCB) substrates. The PCB is a horizontal rectangular…
Abstract
Purpose
The paper aims to present an investigation of heating during vapour phase soldering (VPS) on inclined printed circuit board (PCB) substrates. The PCB is a horizontal rectangular plate from the aspect of filmwise condensation with a given inclination setting.
Design/methodology/approach
The paper focuses on the measurement of temperature distribution on the PCBs with a novel setup immersed in the saturated vapour space. The measuring instrumentation is optimized to avoid and minimize vapour perturbing effects.
Findings
The inhomogeneity of the heating is presented according to the lateral dimensions of the PCB. The inclination improves temperature uniformity, improves heat transfer efficiency; however, a minor misalignment may affect the flow and result in uneven heating.
Practical implications
The results can be implemented for practical improvements in industrial ovens with the use of intended inclination. The improvements may consequently point to more efficient production and better joint quality.
Originality/value
The novel method can be used for deeper investigation of inclination during and can be complemented with numerical calculations. The results highlight the importance of precise PCB holding instrumentation in VPS ovens.
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J. Landa, I. Illarramendi, N. Kelling, M. Woydt, A. Skopp and M. Hartelt
This paper aims to focus on the potential for substituting molybdenum‐based piston ring coatings, which are recognized as “allrounder” by other candidate metallurgies. Another…
Abstract
Purpose
This paper aims to focus on the potential for substituting molybdenum‐based piston ring coatings, which are recognized as “allrounder” by other candidate metallurgies. Another purpose is the tribological interaction of molybdenum‐based and new triboactive/reactive piston ring coatings with low SAP, polymer‐ and metal‐free as well as bionotox engine oils with high‐viscosity indices.
Design/methodology/approach
Substoichiometric titanium dioxide composed of the Magnéli‐types phases Ti4O7 (∼17 per cent), Ti5O9 (∼66 per cent), Ti6O11 (∼17 per cent) deposited by plasma spraying, a vacuum sprayed TiO1,93 and a plasma‐sprayed titanium‐molybdenum carbo‐nitride coated piston rings were compared to a state‐of‐the‐art molybdenum‐based piston ring. They were tribologically characterized by means of BAM and SRV tests lubed under mixed/boundary lubrication by factory fill engine oils, engine oils as blends of hydro‐carbons with esters as well as prototype engine oils based on esters and polyglycols.
Findings
Overall, the molybdenum‐ and titanium‐based ring coatings wore in the same order of magnitude. The ranking depends on the test used. The BAM test favours MKP81A (PL72) more, whereas the SRV methods favour the TinO2n−1 more. The different bionotox and low‐ash prototype engine oils with reduced additive contents displayed isoperformance regarding the tribological behaviour of common and triboreactive materials. They presented no visible weakness in wear resistance, coefficient of friction and extreme pressure properties.
Research limitations/implications
The next steps have to confirm functional properties by different engine and endurance tests.
Practical implications
Titanium‐based piston ring coatings are overall more attractive, as they are primarily refined from titania, which is cheap and not rated at stock exchanges, and they present at least an isoperformance when compared with molybdenum‐based ring coatings.
Originality/value
This supplier report displays the complete methodology in order to substitute molybdenum‐ by titanium‐based piston ring coatings as well as illuminating the beneficial interaction with alternative engine oils in existing engine architectures.
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Agata Skwarek, Beata Synkiewicz, Jan Kulawik, Piotr Guzdek, Krzysztof Witek and Jacek Tarasiuk
The purpose of this paper is to assess the reliability of thermoelectric generators after ageing at elevated temperature and to determine the influence of the technology used…
Abstract
Purpose
The purpose of this paper is to assess the reliability of thermoelectric generators after ageing at elevated temperature and to determine the influence of the technology used (i.e. type of thermoelectric material, type of substrate and soldering technology) for thermogenerator (TGE) assembly.
Design/methodology/approach
In this paper, the Seebeck coefficient and the current voltage were measured for lead telluride doped with either manganese (PMT), germanium (PGT) or sulfur (PST) TGEs. The Seebeck coefficient measurements were taken at temperatures between 230 and 630 K.
Findings
The Seebeck coefficient determined for PMT, PGT and PST TGEs increases approximately linearly with increasing temperature and is greater by about 40 per cent for PST and about 30 per cent for PMT than in commercially available PbTe TGEs. The best outcome in terms of stability after long-term ageing was that of PMT material.
Originality/value
The choice of proper technology (i.e. thermoelectric materials, type of substrate and soldering technology) for the TGE assembly is essential for their functioning overtime and reliability.
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Manpreet Kaur, Harpreet Singh and Satya Prakash
This paper seeks to summarise the results of available research on the use of high velocity oxy‐fuel (HVOF) thermal‐spray technique to provide protection against high temperature…
Abstract
Purpose
This paper seeks to summarise the results of available research on the use of high velocity oxy‐fuel (HVOF) thermal‐spray technique to provide protection against high temperature corrosion and erosion‐corrosion of materials.
Design/methodology/approach
This paper describes one of the recent thermal‐spray processes, namely HVOF thermal‐spray technology and presents a survey of the studies on the use of this technique to provide protection against corrosion and erosion‐corrosion of high temperature alloys, with a special emphasis on boiler steels.
Findings
High temperature corrosion and erosion‐corrosion are serious problems observed in steam‐powered electricity generation plants, gas turbines, internal combustion engines, fluidized bed combustors, industrial waste incinerators and recovery boilers in paper and pulp industries. These problems can be prevented by changing the material or altering the environment, or by separating the component surface from the environment. Corrosion prevention by the use of coatings for separating materials from the environment is gaining importance in surface engineering. Amongst various surface modifying techniques, thermal spraying has developed relatively rapidly due to the use of advanced coating formulations and improvements in coating application technology. One of the variants of thermal spraying, namely HVOF has gained popularity in recent times due to its flexibility for in‐situ applications and superior coating properties.
Research limitations/implications
This review covers mainly information that has been reported previously in the open literature, international journals and some well‐known textbooks.
Practical implications
The paper presents a concise summary of information for scientists and academics, planning to start their research work in the area of surface engineering.
Originality/value
This paper fulfils an identified information/resources need and offers practical help to an individual starting out on a career in the area of surface engineering for erosion‐corrosion and wear.
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