scholarly journals Aluminium Wires Have the Free Air Balls (FABs): Electronic Flame-Off, Fracture Strength, Electrical Properties, and Bonding Characteristics of Nano Zn Film Al–Si Bonding Wires

Metals ◽  
2017 ◽  
Vol 7 (5) ◽  
pp. 152 ◽  
Author(s):  
Fei-Yi Hung ◽  
Truan-Sheng Lui ◽  
Kuan-Ming Chu ◽  
Yi-Wei Tseng
2015 ◽  
Vol 2015 (1) ◽  
pp. 000394-000398
Author(s):  
William G. Crockett

Since around 2008, the shift from Gold (Au) bonding wire to Copper (Cu) bonding wire has been taking place, full scale, with the aim of reducing costs. When compared with Au, Cu wire presents challenges in reliability and repeatable bonding characteristics in terms of chemical stability, which is required in high reliability applications. Therefore Cu wire adoption in automotive and industrial semiconductors has been limited. Conventionally the market for Cu bonding wires has been divided into two types: bare Cu wires (high purity) and Palladium coated copper (PCC) bonding wires. These wires have yet to satisfy the required characteristics for high reliability products such as industrial and automotive electronics. A new breed of alternative bonding wires has been developed to offer performance advantages for high reliability applications compared to bare copper wire and PCC wire. Cu alloy wire and Ag alloy wires continue their market introduction for advanced bonding applications, where bare Cu and PCC wires have known limitations.


2014 ◽  
Vol 2014 (1) ◽  
pp. 000272-000277
Author(s):  
Noritoshi Araki ◽  
Yasutomo Ichiyama ◽  
Ryo Oishi ◽  
Teruo Haibara ◽  
Takashi Yamada

The Free Air Ball (FAB) formation processes of fine diameter Cu wires were observed, and the effects of process parameters were studied on the basis of high-speed camera observation. It was revealed that the FAB formation process is characterized by preheating before melting, melting that accompanies ball rising, and solidification periods. The relationships between the electronic flame-off (EFO) condition and the FAB formation were summarized for both bare Cu and palladium-coated Cu wires. Further study was performed on the changes in FAB shape with different EFO conditions, wire types, and FAB sizes. Off-centered FABs were observed in the bare Cu wire whereas they were rarely observed in the Pd-coated Cu wire. The off-center tended to be affected by shielding gas condition, EFO torch gap, and FAB size. The mechanisms of the off-centered FAB formation were proposed through the high speed camera observations. The optimization of process parameters to achieve defect-free, consistent FAB is discussed based on these findings, which is useful for the next generation high density packaging.


2015 ◽  
Vol 12 (2) ◽  
pp. 98-103
Author(s):  
Noritoshi Araki ◽  
Yasutomo Ichiyama ◽  
Ryo Oishi ◽  
Teruo Haibara ◽  
Takashi Yamada

The free air ball (FAB) formation processes of fine diameter Cu wires were observed, and the effects of process parameters were studied on the basis of high-speed camera observation. It was revealed that the FAB formation process is characterized by preheating before melting, melting that accompanies ball rising, and solidification periods. The relationships between the electronic flame-off (EFO) condition and the FAB formation were summarized for both bare Cu and palladium-coated Cu (PCC) wires. Further study was performed on the changes in FAB shape with different EFO conditions, wire types, and FAB sizes. Off-centered FABs were observed in the bare Cu wire whereas they were rarely observed in the PCC wire. The off-center tended to be affected by shielding gas condition, EFO torch gap, and FAB size. The mechanisms of the off-centered FAB formation were proposed through the high-speed camera observations. The optimization of process parameters to achieve defect-free, consistent FAB is discussed based on these findings, which is useful for the next generation high-density packaging.


Author(s):  
Fei-Yi Hung ◽  
Truan-Sheng Lui ◽  
Kuan-Ming Chu ◽  
Yi-Wei Tseng

Aluminum wire is a common material for wire bonding due to its resistance to oxidation and low price. It does not melt when becoming a free air ball (FAB) during the electronic flame-off (EFO) process with wettability, and is applied by wedge bonding. This study used 20μm Zn-Coated Al-0.5wt.%Si (ZAS) wires to improve the FAB shape after the EFO process, while maintaining stability of the mechanical properties, including the interface bonding strength and hardness. In order to test circuit stability after ball bonding, the current-tensile test was performed. During the experiment, it was found that 80nm ZAS with wire bonding has lower resistance and higher fusing current. For the bias tensile test, the thicker Zn film diffused into the Al-Si matrix easily, after which the strength was reduced. The ball-bond interfaces had no change in their condition before and after the bias. Accordingly, ZAS could be a promising candidate for ball bonding in the future.


Author(s):  
C. J. Hang ◽  
I. Lum ◽  
J. Lee ◽  
M. Mayer ◽  
Y. Zhou ◽  
...  

In order to eliminate the chip cratering for copper wire applications in IC packaging, it is worthwhile to develop new Cu wire chemistries to obtain a soft copper wire with a soft free-air ball (FAB). The conventional hardness characterization of a new bonding wire is a labour intensive, time-consuming work. Therefore an on-line hardness characterization method is presented that enables the hardness comparison of a larger number of different wires within a shorter time. The influences of capillary change, bonding substrate metallization and temperature on this method is quantified. It is found these influences need to be held constant during a hardness comparison study. With this method, the wire and FAB hardness comparison of nine novel 2-mil copper bonding wires, Cu 1 to Cu 9, and one 2-mil Au wire are performed. The wire hardness (wireside) and FAB hardness are characterized. It is found that the Cu 4 and Cu 5 have the softest wireside hardness and FAB hardness.


Author(s):  
F. M. Ross ◽  
R. Hull ◽  
D. Bahnck ◽  
J. C. Bean ◽  
L. J. Peticolas ◽  
...  

We describe an investigation of the electrical properties of interfacial dislocations in strained layer heterostructures. We have been measuring both the structural and electrical characteristics of strained layer p-n junction diodes simultaneously in a transmission electron microscope, enabling us to correlate changes in the electrical characteristics of a device with the formation of dislocations.The presence of dislocations within an electronic device is known to degrade the device performance. This degradation is of increasing significance in the design and processing of novel strained layer devices which may require layer thicknesses above the critical thickness (hc), where it is energetically favourable for the layers to relax by the formation of misfit dislocations at the strained interfaces. In order to quantify how device performance is affected when relaxation occurs we have therefore been investigating the electrical properties of dislocations at the p-n junction in Si/GeSi diodes.


Author(s):  
A.M. Letsoalo ◽  
M.E. Lee ◽  
E.O. de Neijs

Semiconductor devices require metal contacts for efficient collection of electrical charge. The physics of these metal/semiconductor contacts assumes perfect, abrupt and continuous interfaces between the layers. However, in practice these layers are neither continuous nor abrupt due to poor nucleation conditions and the formation of interfacial layers. The effects of layer thickness, deposition rate and substrate stoichiometry have been previously reported. In this work we will compare the effects of a single deposition technique and multiple depositions on the morphology of indium layers grown on (100) CdTe substrates. The electrical characteristics and specific resistivities of the indium contacts were measured, and their relationships with indium layer morphologies were established.Semi-insulating (100) CdTe samples were cut from Bridgman grown single crystal ingots. The surface of the as-cut slices were mechanically polished using 5μm, 3μm, 1μm and 0,25μm diamond abrasive respectively. This was followed by two minutes immersion in a 5% bromine-methanol solution.


Author(s):  
J.P.S. Hanjra

Tin mono selenide (SnSe) with an energy gap of about 1 eV is a potential material for photovoltaic applications. Various authors have studied the structure, electronic and photoelectronic properties of thin films of SnSe grown by various deposition techniques. However, for practical photovoltaic junctions the electrical properties of SnSe films need improvement. We have carried out investigations into the properties of flash evaporated SnSe films. In this paper we report our results on the structure, which plays a dominant role on the electrical properties of thin films by TEM, SEM, and electron diffraction (ED).Thin films of SnSe were deposited by flash evaporation of SnSe fine powder prepared from high purity Sn and Se, onto glass, mica and KCl substrates in a vacuum of 2Ø micro Torr. A 15% HF + 2Ø% HNO3 solution was used to detach SnSe film from the glass and mica substrates whereas the film deposited on KCl substrate was floated over an ethanol water mixture by dissolution of KCl. The floating films were picked up on the grids for their EM analysis.


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