High temperature thermogenerators made on DBC substrate using vapour phase soldering

Skwarek, Agata; Synkiewicz, Beata; Kulawik, J.; Guzdek, P.; Witek, Krzysztof; Tarasiuk, Jacek

doi:10.1108/ssmt-04-2015-0017

Cited by 21 publications

(14 citation statements)

References 9 publications

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“…Various methods are used for the fabrication of modern thermoelectric microsensors (e.g., temperature [12,13], heat flux [14,15], thermal insolation [15,16,17], laser power [1,18,19], Seebeck nanoantennas for solar energy harvesting [20] or calorimeters [21]) and microgenerators [1,2,3,4,5,6,7,10,22,23,24,25,26,27]—classical semiconductor technology and silicon micromachining [1], volume micromachining [1,5,6,9,25] (where, for example, vapor phase soldering is used to improve solder joint quality and reliability of the various microgenerator parts [28]), plasma spraying and laser patterning [29,30], thin-film deposition (evaporation, magnetron sputtering, electrochemical deposition) [3,8,24,25,31], thick-film technology (planar, 3D, on flexible substrates, alumina or LTCC ones) [2,4,6,7,10,11,12,13,22,26,32,33,34,35]. …”

Section: Introductionmentioning

confidence: 99%

Thermoelectric Mixed Thick-/Thin Film Microgenerators Based on Constantan/Silver

2018

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This paper describes the design, manufacturing and characterization of newly developed mixed thick-/thin film thermoelectric microgenerators based on magnetron sputtered constantan (copper-nickel alloy) and screen-printed silver layers. The thermoelectric microgenerator consists of sixteen thermocouples made on a 34.2 × 27.5 × 0.25 mm3 alumina substrate. One of thermocouple arms was made of magnetron-sputtered constantan (Cu-Ni alloy), the second was a Ag-based screen-printed film. The length of each thermocouple arm was equal to 27 mm, and their width 0.3 mm. The distance between the arms was equal to 0.3 mm. In the first step, a pattern mask with thermocouples was designed and fabricated. Then, a constantan layer was magnetron sputtered over the whole substrate, and a photolithography process was used to prepare the first thermocouple arms. The second arms were screen-printed onto the substrate using a low-temperature silver paste (Heraeus C8829A or ElectroScience Laboratories ESL 599-E). To avoid oxidation of constantan, they were fired in a belt furnace in a nitrogen atmosphere at 550/450 °C peak firing temperature. Thermoelectric and electrical measurements were performed using the self-made measuring system. Two pyrometers included into the system were used for temperature measurement of hot and cold junctions. The estimated Seebeck coefficient, α was from the range 35 − 41 µV/K, whereas the total internal resistances R were between 250 and 3200 ohms, depending on magnetron sputtering time and kind of silver ink (the resistance of a single thermocouple was between 15.5 and 200 ohms).

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Section: Introductionmentioning

confidence: 99%

Thermoelectric Mixed Thick-/Thin Film Microgenerators Based on Constantan/Silver

2018

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“…The thermal profile setting is a significant variable that affects the quality of joints, because an inappropriate reflow thermal profile can cause problems with reliability and many soldering defects (Koncz-Horváth et al, 2015;Krammer, 2014;Skwarek et al, 2015;Chen et al, 2016). The following paper details the possibility of applying VPS to the reflow of solder alloys in power electronics modules based on direct bonded copper (DBC) substrates.…”

Section: Introductionmentioning

confidence: 99%

Real-time profiling of reflow process in VPS chamber

Livovský

Pietriková

2017

SSMT

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Purpose This paper aims to present a new method of real-time monitoring of thermal profiles applied in vapour phase soldering (VPS) reflow processes. The thermal profile setting is a significant variable that affects the quality of joints. The method allows rapid achievement of a required thermal profile based on software control that brings new efficiency to the reflow process and enhanced joint quality, especially for power electronics. Design/methodology/approach A real-time monitoring system based on computerized heat control was realized in a newly developed laboratory VPS chamber using a proportional integral derivation controller within the soldering process. The principle lies in the strictly accurate monitoring of the real defined reflow profile as a reference. Findings Very accurate maintenance of the required reflow profile temperature was achieved with high accuracy (± 2°C). The new method of monitoring and control of the reflow real-time profiling was verified at various maximal reflow temperatures (230°C, 240°C and 260°C). The method is feasible for reflowing three-dimensional (3D) power modules that use various types of solders. The real-time monitoring system based on computerised heat control helped to achieve various heights of vapour zone. Originality/value The paper describes construction of a newly developed laboratory-scale VPS chamber, including novel real-time profiling of the reflow process based on intelligent continuously measured temperatures at various horizontal positions. Real-time profiling in the laboratory VPS chamber allowed reflow soldering on 3D power modules (of greater dimensions) by applying various flux-less solder materials.

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“…The most common assembly method for connecting electronic components to printed circuit boards (PCB) is reflow soldering technology. Depositing solder paste by stencil printing (Lau et al , 2016) onto the solder pads of the PCB (Chung and Kwak, 2015) is one of the most crucial steps of this technology (Skwarek et al , 2015); almost 60 per cent of soldering failures can be traced back to the printing process (Tsai, 2008). The process of stencil printing can be divided into two main parts: the print stroke of the solder paste and the time-gap between the strokes.…”

Section: Introductionmentioning

confidence: 99%

Investigating the thixotropic behaviour of Type 4 solder paste during stencil printing

Krammer

Szilágyi

Storcz

et al. 2017

SSMT

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Purpose A measurement method has been developed to reveal the viscosity change of solder pastes during stencil printing. This paper aimed to investigate thixotropic behaviour, the viscosity change of a lead-free solder paste (Type 4). Design/methodology/approach The viscosity change of the solder paste during stencil printing cycles was characterised in such a way that the time-gap between the printing cycles was modelled with a rest period between every rheological measurement. This period was set as 15, 30 and 60 s during the research. The Cross model was fitted to the measurement results, and the η0 parameter was used to characterise the viscosity change. The number of printing cycles necessary for reaching a stationary state in viscosity was determined for various rest periods. Findings It was found that the decrease in zero-shear viscosity is significant (25 per cent) in the first cycles, and it starts to become stationary at the sixth-seventh cycles. This means a printing process can provide the appropriate deposits only after the 7th cycle with the investigated Type 4 solder paste. Originality/value Time-dependent rheological behaviour of solder pastes was studied in the literature, but only the viscosity change over continuous time at constant shear rates was examined. The time-gap between stencil printing cycles was not considered, and thixotropic behaviour of solder pastes was also neglected. Therefore, the authors developed a measurement set which is able to model the effect of time-gap between printing cycles on the viscosity change of solder pastes.

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High temperature thermogenerators made on DBC substrate using vapour phase soldering

Cited by 21 publications

References 9 publications

Thermoelectric Mixed Thick-/Thin Film Microgenerators Based on Constantan/Silver

Thermoelectric Mixed Thick-/Thin Film Microgenerators Based on Constantan/Silver

Real-time profiling of reflow process in VPS chamber

Investigating the thixotropic behaviour of Type 4 solder paste during stencil printing

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