Analysis of Catastrophic Field Failures Due to Conductive Anodic Filament (CAF) Formation

1998 ◽  
Vol 515 ◽  
Author(s):  
W. J. Ready ◽  
B.A. Smith ◽  
L.J. Turbini ◽  
S.R. Stock
Keyword(s):  
Ground Plane ◽  
Water Soluble ◽  
Potential Difference ◽  
Voltage Gradient ◽  
Printed Wiring Boards ◽  
Copper Salts ◽  
Electronic Products ◽  
Hot Air ◽  
Hostile Environments ◽  
Through Hole

ABSTRACTUnder certain environmental conditions, printed wiring boards (PWB) respond to applied voltages by developing subsurface deposits of copper salts extending from anode to cathode along separated fiber / epoxy interfaces. The formation of these deposits, termed conductive anodic filaments (CAF) require high humidity (80%RH) and high voltage gradient (5V/mil). The humidity exposure during the storage environment may cause the failure in the use environment. CAF formation is enhanced by the use of certain hot air solder leveling (HASL) fluids and / or water soluble flux constituents.In this work, two catastrophic field failures were analyzed. Both failures were related to boards produced in a manufacturing process, which included HASL. One CAF failure occurred between a component through-hole and power plane held at a potential difference of 40V with a 0.005″ nominal spacing. The other occurred on an inner layer of a multi-layer board (MLB) between a via and ground plane held at a potential difference of 320V with 0.015” nominal spacing. The nature of the CAF was analyzed using scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). Ion chromatography (IC) was used to identify residue extracted from a failed board. The failure phenomena known as CAF poses serious longterm reliability concerns in electronic products exposed to adverse and hostile environments, especially those with closely spaced conductors.

Quality Control of Micro-Drilled Hole Wall of PWBs Using Data-Mining

2005 ◽  
Author(s):  
Eiichi Aoyama ◽  
Toshiki Hirogaki ◽  
Keiji Ogawa ◽  
Tsuyoshi Otsuka ◽  
Katsutoshi Yamauchi
Keyword(s):  
Data Mining ◽  
Surface Roughness ◽  
Present Report ◽  
Weft Yarn ◽  
Hole Drilling ◽  
Printed Wiring Boards ◽  
Factors Affecting ◽  
Hole Wall ◽  
Using Data ◽  
Through Hole

In the manufacturing of printed wiring boards (PWBs), various methods have been developed in order to improve the circuit packaging density. Micro-drills are generally used to make smaller diameter through-holes in PWBs, which are desired for the miniaturization of equipment. However, a problem has emerged in that copper plating degraded by hole drilling can reduce the reliability of the electrical connection between layers. The surface roughness of drilled hole wall is one of the important factors affecting the plating quality. The purpose of the present report is to apply data-mining to the surface roughness data of drilled through-hole walls, and to elucidate the factors required to control the drilled hole quality. The following conclusions were obtained. (1) The data-mining aided by a computer was found to be effective to control the drilled hole wall quality in the PWBs manufacturing. (2) It was clear that the surface roughness of drilled hole walls depended on three factors: the drill temperature, cutting distance, and the width of the fiber bundle of weft yarn.

The Effect of Cooking and Drying on the Water-Soluble Vitamins Content of Bulgur

2007 ◽  
Vol 13 (5) ◽  
pp. 349-354 ◽  
Author(s):  
Ç. Kadakal ◽  
R. Ekinci ◽  
A. Yapar
Keyword(s):  
Water Soluble ◽  
Vitamin B ◽  
Oven Drying ◽  
Sun Drying ◽  
Whole Wheat ◽  
Hot Air ◽  
Cooking Temperature ◽  
Wheat Product

Bulgur is a whole-wheat product cooked, dried, cracked, and sifted for sizing. This paper, evaluated the effect of cooking in beaker (90 and 100°C) and in autoclave at 121°C for 17min and drying in a hot-air oven (60, 70, and 80°C) or sun-drying in open air, on the content of several water-soluble vitamins [thiamin (vitamin B 1), niacin, panthothenic acid (vitamin B5), pyridoxine (vitamin B6), and riboflavin (vitamin B2)]. The content of water-soluble vitamins was analyzed by HPLC. Both cooking and drying had a significant effect ( p<0.05) on the content of water-soluble vitamins of bulgur. The cooking in autoclave resulted in a more significant decrease on the thiamin, niacin, panthothenic acid, pyridoxine, and riboflavin content of the samples, when compared with cooking at 90 and 100°C. As the cooking temperature increases, the concentrations of water-soluble vitamins in the samples decreased. The decrease in water-soluble vitamins was higher with open-air sun drying than with hot-air oven drying at 60, 70, and 80°C.

scholarly journals Drying characteristics and some quality parameters of whole jujube (Zizyphus jujuba Mill.) during hot air drying

2021 ◽  
Vol 33 (1) ◽  
pp. 1-15
Author(s):  
Begüm Tepe ◽  
Raci Ekinci
Keyword(s):  
Degradation Kinetics ◽  
Quality Parameters ◽  
Water Soluble ◽  
Total Phenolic ◽  
Order Kinetic ◽  
Drying Time ◽  
Drying Temperature ◽  
Hot Air ◽  
Zizyphus Jujuba ◽  
Kinetics Of

Drying kinetics, water-soluble vitamins, total phenolic content (TPC), antioxidant capacity (AC) of the jujube fruits dried at 50, 60, and 70°C, and degradation kinetics of the quality parameters were investigated. The models fitted to drying were determined as Page at 50 and 70°C, Parabolic at 60°C. Increment in the drying temperature increased the drying rate and decreased the drying time. Water-soluble vitamins, TPC, and AC were significantly reduced by the drying process. Degradation of water-soluble vitamins increased with the drying temperature, although TPC and AC were not significantly affected by temperature. Thermal degradations of quality parameters were fitted to first-order kinetic.

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