Versatile and economical specimen heater for ultrahigh vacuum applications

Bryant, K.W.; Bozack, M. J.

doi:10.1116/1.582005

Cited by 3 publications

(2 citation statements)

References 25 publications

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“…9,10 Heater power and thermocouple connections were routed by a UHV power connector flanged to the chamber wall of the SEM. The board finish was mechanically held to the heater element by Ta sheet clips that were screwed into the Teflon and the solder paste was supported by gravity on the finish surface.…”

Section: Methodsmentioning

confidence: 99%

Real-time scanning electron microscopy and auger spectroscopy of wetting in Sn-3.3Ag-4.8Bi solder paste wetted to Ni-Au

Bozack

Johnson

2005

Journal of Elec Materi

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Surface and thin film techniques reveal an immediate and intense surface reaction during wetting of Sn-3.3Ag-4.8Bi solder paste to Ni-Au board finishes. Rutherford backscattering spectroscopy (RBS) shows that a typical, vendorsupplied Ni-Au board finish consists of ϳ750 Å of Au above the Ni. Stylus profilometry indicates that the finish surface is rough with average vertical height variations of ϳ1-2 µm. The board finish seen by the solder alloy during wetting contains a large ϳ45% atom fraction of adventitious surface C observed by Auger spectroscopy (AES). The AES and energy-dispersive x-ray spectroscopy (EDX) indicates that Ni has fully intermixed throughout the alloy within seconds of wetting. Dissolution of the Au cap layer into the alloy and Bi and Ag surface segregation is observed. Auger point analysis and maps at the leading edge of the wetting front show no evidence of flux advance ahead of the alloy. Bismuth does not move out with the spreading wetting front. A unique feature of this work is the acquisition of real-time, in-situ electron microscopic observations of the spreading Sn-3.3Ag-4.8Bi alloy front across the Ni-Au substrate during wetting. The observations have been recorded on videotape and converted into computer files accessible on the World Wide Web with standard media players (ftp: //131.204.44.20).

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Section: Methodsmentioning

confidence: 99%

Real-time scanning electron microscopy and auger spectroscopy of wetting in Sn-3.3Ag-4.8Bi solder paste wetted to Ni-Au

Bozack

Johnson

2005

Journal of Elec Materi

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“…5,6 Teflon was used because it is inexpensive, chemically inert at ϳ200-300°C, and easy to machine. 5,6 Teflon was used because it is inexpensive, chemically inert at ϳ200-300°C, and easy to machine.…”

Section: Methodsmentioning

confidence: 99%

Real-time wetting dynamics and interfacial chemistry in low-melting 57Bi–42Sn–1Ag solder paste on Ni–Au

Bozack

2004

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Electron microscopy study of interfacial reaction between eutectic SnPb and Cu/Ni(V)/Al thin film metallizationWe report the observation of real-time, in situ, wetting and spreading dynamics for 57Bi-42Sn-1Ag solder paste on Ni-Au surfaces during melting in a scanning electron microscope. The 57Bi-42Sn-1Ag is a low melting ͑139°C͒ Pb-free eutectic alloy currently under consideration by automobile manufacturers for use in instrument displays. We find that, while there is excellent wetting of 57Bi-42Sn-1Ag solder paste on Ni-Au, there is almost no spreading. A large amount of Bi segregates to the surface of 57Bi-42Sn-1Ag solder balls during the sintering process. At melting, excessive flux outgassing and pooling are observed, several melted solder balls float on top of the flux, and substantial elemental segregation occurs during the first minutes of wetting. Neither Ni nor Au fully intermixes throughout the alloy at the interface within seconds of wetting. Bi does not move outward with the expanding alloy front. This combination of detrimental effects forms voids in the solder paste, contributes to low reliability of solder joints, and complicates the materials science at the solder-substrate interface as shown by Auger electron spectroscopy. Reliability work in progress (3000 cycles) shows that 57Bi-42Sn-1Ag on Ni-Au is less reliable than eutectic Sn-37Pb on Ni-Au for 2512 chip resistors cycled from −40 to 125°C.

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Note: Heated sample platform for in situ temperature-programmed XPS

Samokhvalov

Tatarchuk

2011

Review of Scientific Instruments

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We present the design, fabrication, and performance of the multi-specimen heated platform for linear in situ heating during the Temperature-Programmed XPS (TPXPS). The platform is versatile, compatible with high vacuum (HV) and bakeout. The heater platform is tested under in situ linear heating of typical high surface area sorbent∕catalyst support--nanoporous TiO(2). The platform allows the TPXPS of multiple samples located on specimen disk that can be transferred in and out of the TPXPS chamber. Electric characteristics, temperature and pressure curves are provided. Heating power supply, PID temperature controller, data-logging hardware and software are described.

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Versatile and economical specimen heater for ultrahigh vacuum applications

Cited by 3 publications

References 25 publications

Real-time scanning electron microscopy and auger spectroscopy of wetting in Sn-3.3Ag-4.8Bi solder paste wetted to Ni-Au

Real-time scanning electron microscopy and auger spectroscopy of wetting in Sn-3.3Ag-4.8Bi solder paste wetted to Ni-Au

Real-time wetting dynamics and interfacial chemistry in low-melting 57Bi–42Sn–1Ag solder paste on Ni–Au

Note: Heated sample platform for in situ temperature-programmed XPS

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