The Use of Cobalt in Plated Copper to Inhibit the Formation of Brittle Copper-Tin Intermetallic Compounds - at the Copper-Solder Interface on Printed Circuit Boards

1971 ◽  
Author(s):  
J. E. Breen ◽  
E. Toledo ◽  
V. White
Keyword(s):  
Intermetallic Compounds ◽  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Solder Interface

Failure Analysis of No-Clean and Water-Clean Solder Joints 0.4 mm Pitch, 256-Pin Plastic Quad Flat Pack

1994 ◽  
Vol 116 (3) ◽  
pp. 184-190 ◽  
Author(s):  
R. K. Govila ◽  
Y.-H. Pao ◽  
C. Larner ◽  
J. Lau ◽  
S. Twerefour ◽  
...  
Keyword(s):  
Eutectic Composition ◽  
Printed Circuit Boards ◽  
Solder Joints ◽  
Quantitative Comparison ◽  
Circuit Boards ◽  
Micro Structure ◽  
Printed Circuit ◽  
Qualitative And Quantitative ◽  
Solder Interface ◽  
Scanning Electron

Printed circuit boards populated with twenty-five 0.4 mm pitch, 256-pin plastic quad flat packs (QFP) containing no-clean and water-clean solder joints were subjected to thermal cycling in order to induce thermal fatigue failure. QFPs failed from a minimum of 0.27 cycle to a maximum of 5310 cycles. Solder joints in both types of units were examined in the scanning electron microscope, and a relative comparison of the extent of fatigue damage is presented. The failure associated with cracking in the eutectic composition Sn/Pb solder initiated at the stress concentration sites. Crack propagation continued either along the pin-solder interface or solder-pad interface and ultimately resulted in the separation of the pin/pad junctions. In addition, a qualitative and quantitative comparison of the resulting solder micro-structure and the failure mode between the no-clean and the water-clean QFP solder joints was made and discussed.

Reliability of Fine Pitch Sn–3.8Ag–0.7Cu Flip Chip Solder Joints With Different Connection Pads on PCB

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Dezhi Li ◽  
Changqing Liu ◽  
Paul P. Conway
Keyword(s):  
Flip Chip ◽  
Printed Circuit Boards ◽  
Solder Joints ◽  
Bulk Solder ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Fine Pitch ◽  
Solder Volume ◽  
Failure Location ◽  
Solder Interface

The reliability of fine pitch Sn–3.8Ag–0.7Cu flip chip solder joints with three different pads, i.e., bare pads, pads with solder masks, and pads with microvia, on printed circuit boards (PCBs) was studied through thermal cycling. After assembly, (Au,Ni)Sn4 intermetallics (IMCs) formed both in the bulk solder and at the interfaces due to the immersion-Au finish on the PCB side. The (Au,Ni)Sn4 IMCs formed in the solder joints on the pads with microvia were more abundant than those formed in the solder joints on the pads without microvia. The results showed that the solder joints on the pads with a microvia had poor reliability due to the insufficient solder volume and the formation of large amounts of (Au,Ni)Sn4 IMCs. The main crack initiation position was the corner of solder joint at the chip side. For the pads with microvia, the main location of failure was at the (Au,Ni)Sn4/solder interface on the chip side, and for the solder joints on bare pads and pads with solder mask, the possible failure location was in the bulk solder.

Slit Effect of Common Ground Patterns in Affecting Cross-Talk Noise between Two Parallel Signal Traces on Printed Circuit Boards

2008 ◽  
Vol 128 (11) ◽  
pp. 657-662 ◽  
Author(s):  
Tsuyoshi Maeno ◽  
Yukihiko Sakurai ◽  
Takanori Unou ◽  
Kouji Ichikawa ◽  
Osamu Fujiwara
Keyword(s):  
Cross Talk ◽  
Printed Circuit Boards ◽  
Common Ground ◽  
Circuit Boards ◽  
Printed Circuit

Influence of Component Mounting Density on Oscillating Characteristics of Multilayer Printed Circuit Boards

2018 ◽  
Vol 23 (2) ◽  
pp. 141-148
Author(s):  
S.Sh. Rekhviashvili ◽  
◽  
M.O. Mamchuev ◽  
V.V. Narozhnov ◽  
M.M. Oshkhunov ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Oscillating Characteristics

Noise properties of thin-film Ni-P resistors embedded in printed circuit boards

2013 ◽  
Vol 61 (3) ◽  
pp. 731-735
Author(s):  
A.W. Stadler ◽  
Z. Zawiślak ◽  
W. Stęplewski ◽  
A. Dziedzic
Keyword(s):  
Thin Film ◽  
Printed Circuit Boards ◽  
Circuit Boards ◽  
Noise Component ◽  
Printed Circuit ◽  
Resistance Bridge ◽  
Different Types ◽  
Signal Path ◽  
Resistance Fluctuations ◽  
Made In

Abstract. Noise studies of planar thin-film Ni-P resistors made in/on Printed Circuit Boards, both covered with two different types of cladding or uncladded have been described. The resistors have been made of the resistive-conductive-material (Ohmega-Ply©) of 100 Ώ/sq. Noise of the selected pairs of samples has been measured in the DC resistance bridge with a transformer as the first stage in a signal path. 1/f noise caused by resistance fluctuations has been found to be the main noise component. Parameters describing noise properties of the resistors have been calculated and then compared with the parameters of other previously studied thin- and thick-film resistive materials.

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