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Volume: 22 | Article ID: art00014_3
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Variable Droplet Size Molten Solder Ejection Tool for Microelectronics Packaging
Hiroshi Fukumoto
Yoshinori Yokoyama
Kazuyo Endo
Yoshio Fujii
Munehisa Takeda
  DOI :  10.2352/ISSN.2169-4451.2006.22.2.art00014_3  Published Online :  January 2006
Abstract

A unique piezo-drive diaphragm type head, which enables molten solder droplets to be ejected over a wide range of diameters, has been developed in order to apply the solder droplet deposition method for various applications in microelectronics packaging. The features of this method are a mask-less process and lead-free soldering without soldering flux, therefore a flexible and eco-friendly operation can be realized in contrast to conventional plating or screen-printing methods. The prototype head can continuously adjust the droplet diameter from 35 μm to 200 μm.In this paper, a simple analytical model of the droplet formation process is proposed and an empirical formula, which estimates the droplet diameter affected by the nozzle diameter and the piezo-drive period, is derived from the experimental investigation. It is also confirmed that the estimated values agree with the results by Flow-3D fluid dynamics simulation software.Using the prototype head and formula, it becomes easier to adjust the droplet size suitable for each application. We also show application examples such as a solder sealed vacuum package fabricated with the droplet diameter of 200 μm, and a solder filled through-hole with one of 40 μm.

Journal Title : NIP & Digital Fabrication Conference
Publisher Name : Society of Imaging Science and Technology
Publisher Location : 7003 Kilworth Lane, Springfield, VA 22151, USA
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 DOI 10.2352/ISSN.2169-4451.2006.22.2.art00014_3
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Hiroshi Fukumoto, Yoshinori Yokoyama, Kazuyo Endo, Yoshio Fujii, Munehisa Takeda, "Variable Droplet Size Molten Solder Ejection Tool for Microelectronics Packaging"  in Proc. IS&T Digital Fabrication Conf.,  2006,  pp 38 - 41,  https://doi.org/10.2352/ISSN.2169-4451.2006.22.2.art00014_3

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Copyright © Society for Imaging Science and Technology 2006
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NIP & Digital Fabrication Conference
nip digi fabric conf
2169-4451
Society of Imaging Science and Technology
7003 Kilworth Lane, Springfield, VA 22151, USA
2169-4451(20060101)2006:3L.38;1-
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Articles
Variable Droplet Size Molten Solder Ejection Tool for Microelectronics Packaging
FukumotoHiroshi
YokoyamaYoshinori
EndoKazuyo
FujiiYoshio
TakedaMunehisa
01012006
2006
3
38
41
2006
A unique piezo-drive diaphragm type head, which enables molten solder droplets to be ejected over a wide range of diameters, has been developed in order to apply the solder droplet deposition method for various applications in microelectronics packaging. The features of this method are a mask-less process and lead-free soldering without soldering flux, therefore a flexible and eco-friendly operation can be realized in contrast to conventional plating or screen-printing methods. The prototype head can continuously adjust the droplet diameter from 35 μm to 200 μm.In this paper, a simple analytical model of the droplet formation process is proposed and an empirical formula, which estimates the droplet diameter affected by the nozzle diameter and the piezo-drive period, is derived from the experimental investigation. It is also confirmed that the estimated values agree with the results by Flow-3D fluid dynamics simulation software.Using the prototype head and formula, it becomes easier to adjust the droplet size suitable for each application. We also show application examples such as a solder sealed vacuum package fabricated with the droplet diameter of 200 μm, and a solder filled through-hole with one of 40 μm.