Simultaneous Laser Soldering by the Use of Multi-Beam Optics

The analysis of material composition by ion-beam analysis (IBA) is becoming a standard method, similar to electron microscopy. A pool of IBA methods exists, from which the combination of particle-induced-X-ray emission (PIXE), particle induced gamma-ray analysis (PIGE), nuclear-reaction-analysis (NRA), and Rutherford-backscattering-spectrometry (RBS) provides the most complete analysis over the whole periodic table in a single measurement. Yet, for a highly resolved and accurate IBA analysis, a sophisticated technical setup is required integrating the detectors, beam optics, and sample arrangement. A new end-station developed and installed in Forschungszentrum Jülich provides these capabilities in combination with high sample throughput and result accuracy. Mechanical tolerances limit the device accuracy to 3% for RBS. Continuous pumping enables 5*10−8 mbar base pressure with vibration amplitudes < 0.1 µm. The beam optics achieves a demagnification of 24–34, suitable for µ-beam analysis. An in-vacuum manipulator enables scanning 50 × 50 mm² sample areas with 10 nm accuracy. The setup features the above-mentioned IBA detectors, enabling a broad range of analysis applications such as the operando analysis of batteries or the post-mortem analysis of plasma-exposed samples with up to 3000 discrete points per day. Custom apertures and energy resolutions down to 11 keV enable separation of Fe and Cr in RBS. This work presents the technical solutions together with the quantification of these challenges and their success in the form of a technical reference.

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Interfacial Reactions and Mechanical Properties of Sn–58Bi Solder Joints with Ag Nanoparticles Prepared Using Ultra-Fast Laser Bonding

Materials ◽

10.3390/ma14020335 ◽

2021 ◽

Vol 14 (2) ◽

pp. 335

Author(s):

Gyuwon Jeong ◽

Dong-Yurl Yu ◽

Seongju Baek ◽

Junghwan Bang ◽

Tae-Ik Lee ◽

...

Keyword(s):

Mechanical Properties ◽

Low Temperature ◽

Printed Circuit Boards ◽

Solder Joints ◽

Interfacial Reactions ◽

Circuit Boards ◽

Ag Nps ◽

Laser Bonding ◽

Laser Soldering ◽

Low Temperature Bonding

The effects of Ag nanoparticle (Ag NP) addition on interfacial reaction and mechanical properties of Sn–58Bi solder joints using ultra-fast laser soldering were investigated. Laser-assisted low-temperature bonding was used to solder Sn–58Bi based pastes, with different Ag NP contents, onto organic surface preservative-finished Cu pads of printed circuit boards. The solder joints after laser bonding were examined to determine the effects of Ag NPs on interfacial reactions and intermetallic compounds (IMCs) and high-temperature storage tests performed to investigate its effects on the long-term reliabilities of solder joints. Their mechanical properties were also assessed using shear tests. Although the bonding time of the laser process was shorter than that of a conventional reflow process, Cu–Sn IMCs, such as Cu6Sn5 and Cu3Sn, were well formed at the interface of the solder joint. The addition of Ag NPs also improved the mechanical properties of the solder joints by reducing brittle fracture and suppressing IMC growth. However, excessive addition of Ag NPs degraded the mechanical properties due to coarsened Ag3Sn IMCs. Thus, this research predicts that the laser bonding process can be applied to low-temperature bonding to reduce thermal damage and improve the mechanical properties of Sn–58Bi solders, whose microstructure and related mechanical properties can be improved by adding optimal amounts of Ag NPs.

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Study of a Laser Soldering Process for Fine-Pitch Leads (3rd Report)

Journal of the Japan Society for Precision Engineering ◽

10.2493/jjspe.60.1806 ◽

1994 ◽

Vol 60 (12) ◽

pp. 1806-1810 ◽

Cited By ~ 1

Author(s):

Kohei MURAKAMI ◽

Akira ADACHI ◽

Jitsuho HIROTA ◽

Masaharu YOSHIDA ◽

Osamu HAYASHI ◽

...

Keyword(s):

Soldering Process ◽

Fine Pitch ◽

Laser Soldering

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