Technical Library | 2023-01-17 17:27:13.0
Reflow profile has significant impact on solder joint performance because it influences wetting and microstructure of the solder joint. The degree of wetting, the microstructure (in particular the intermetallic layer), and the inherent strength of the solder all factor into the reliability of the solder joint. This paper presents experimental results on the effect of reflow profile on both 63%Sn 37%Pb (SnPb) and 96.5%Sn 3.0%Ag 0.5%Cu (SAC 305) solder joint shear force. Specifically, the effect of the reflow peak temperature and time above solder liquidus temperature are studied. Nine reflow profiles for SAC 305 and nine reflow profiles for SnPb have been developed with three levels of peak temperature (230 o C, 240 o C, and 250 o C for SAC 305; and 195 o C, 205 o C, and 215 o C for SnPb) and three levels of time above solder liquidus temperature (30 sec., 60 sec., and 90 sec.). The shear force data of four different sizes of chip resistors (1206, 0805, 0603, and 0402) are compared across the different profiles. The shear force of the resistors is measured at time 0 (right after assembly). The fracture surfaces have been studied using a scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS)
Technical Library | 1999-08-27 09:29:49.0
Contract packaging houses have to contend with a large mix of die types and products. Flexibility and quick turnaround of package types is a must in this industry. Traditional methods of die encapsulation, (i.e., use of transfer-molding techniques), are only cost effective when producing a large number of components. Liquid encapsulants now provide similar levels of reliability1, and are cost effective...
Technical Library | 2019-07-27 07:13:16.0
Carrier Tape refers to a strip product used in the field of electronic packaging, which has a specific thickness, and equidistantly distributes holes (also called pockets) for holding electronic components in the longitudinal direction thereof. Positioning hole for index positioning.
Technical Library | 2022-04-26 03:27:56.0
The naming of the chip capacitor: The parameters included in the name of the chip capacitor include the size of the chip capacitor, the material used for this chip capacitor, the required accuracy, the required voltage, the required capacity, the requirements of the terminal and packaging requirements. Generally, the parameters to be provided for ordering a chip capacitor should be the size, the required accuracy, the voltage requirement, the capacity value, and the required brand.
Technical Library | 2009-03-27 22:22:40.0
The Sn-Ag-Cu (SAC) alloys have been considered promising replacements for the lead-containing solders for the microelectronics applications. However, due to the rigidity of the SAC alloys, compared with the Pb-containing alloys, more failures have been found in the drop and high impact applications for the portable electronic devices, such as the personal data assistant (PDA), cellular phone, notebook computer..etc
Technical Library | 2021-07-27 14:49:16.0
Conductive anodic filament (CAF) formation, a failure mode in printed wiring boards (PWBs) that are exposed to high humidity and voltage gradients, has caused catastrophic field failures. CAF is an electrochemical migration failure mechanism in PWBs. In this article, we discuss CAF, the factors that enhance it, and the necessary conditions for its occurrence. Published studies are discussed, and the results of historical mean time to failure models are summarized. Potential reasons for CAF enhancement solutions are discussed, and possible directions in which to develop anti-CAF materials are proposed.
Technical Library | 2018-07-03 12:27:02.0
It is becoming increasingly more important to provide a low-cost point-of-care diagnostic device with the ability to detect and monitor various biological and chemical compounds. Traditional laboratories can be time-consuming and very costly. Through the combination of well-established materials and fabrication methods, it is possible to produce devices that meet the needs of many patients, healthcare and medical professionals, and environmental specialists. Existing research has demonstrated that inkjet-printed and paper-based electrochemical sensors are suitable for this application due to advantages provided by the carefully selected materials and fabrication method. Inkjet printing provides a low cost fabrication method with incredible control over the material deposition process, while paper-based substrates enable pump-free microfluidic devices due to their natural wicking ability. Furthermore, electrochemical sensing is incredibly selective and provides accurate and repeatable quantitative results without expensive measurement equipment. By merging each of these favorable techniques and materials and continuing to innovate, the production of low-cost point-of-care sensors is certainly within reach
Technical Library | 2022-04-27 01:34:43.0
SMD capacitors and resistors have small sizes and many models. Some manufacturers buy a lot of products and do not use them up in time. The problem of storage is always a headache. So how should chip capacitors and resistors be stored? There are also precautions when using chip capacitors. Please see the following information and hope it will help you.
Technical Library | 2013-03-27 23:43:40.0
Vapor phase, once cast to the annals’ of history is making a comeback. Why? Reflow technology is well developed and has served the industry for many years, it is simple and it is consistent. All points are true – when dealing with the centre section of the bell curve. Today’s PCB manufacturers are faced with many designs which no longer fall into that polite category but rather test the process engineering groups with heavier and larger panels, large ground planes located in tricky places, component mass densities which are poorly distributed, ever changing Pb Free alloys and higher process temperatures. All the time the costs for the panels increase, availability of “process trial” boards diminishes and yields are expected to be extremely high with zero scrap rates. The final process in the assembly line has the capacity to secure all the value of the assembly or destroy it. If a panel is poorly soldered due to poor Oven setup or incorrect programming of the profile the recovery of the panel is at best expensive, at worst a loss. For these challenges people are turning to Vapor Phase.
Technical Library | 2019-08-14 08:27:46.0
There are five forms of carrier tape sealing cracking. In particular, it is more important to seal products such as IC components (IC tape carriers) and lighter and thinner LED components (LED tape carriers).
