Technical Library | 2010-05-27 22:12:10.0
The quad flat pack no lead or quad flat non-leaded (QFN) is one of the fastest growing package types in the electronics industry today. While the advantages of QFNs are well documented, concerns arise with its reliability and manufacturability. Acceptance of this package, especially in long-life, severe-environment, high-reliability applications, is currently limited. One of the most common drivers for reliability failures is inappropriate adoption of new technologies, such as the case with QFN. In this presentation, we will review and discuss QFN related reliability concerns and challenges, and propose Physics-of-Failure (PoF) based approaches to allow the confident introduction of QFN components into electronics products.
Technical Library | 2019-07-23 22:33:47.0
The Quad Flat Pack No Leads (QFN) style of leadless packaging [also known as a Land Grid Array (LGA)] is rapidly increasing in us e for wireless, automotive, telecom and many other areas becaus e of its low cost, low stand-off height and excellent thermal and electri cal properties. With the implementation of any new package type, there is always a learning curve for its use in design and processing as well as for the Process and Quality Engineers who have to get to grips with the challenges that these packages bring. Therefore, this paper will provide examples of the common process defects that can be seen with QFNs /LGAs when using optical and x-ray inspection as part of manufacturing quality control. Results of trials conducted on four PCB finishes and using vapour phase and convection reflow will be discussed.
Technical Library | 2019-06-18 03:23:42.0
After-sale service Climatest Symor® strictly controls every production procedure,our main after-sale service procedure is as follow: 1) Email Climatest Symor® about the fault description(Pictures or video is preferred) 2) Within 1 working days, Climatest Symor® gives feedback or solution (If Climatest Symor® needs customer to take pictures about some parts of the machine, customer should cooperate accordingly to settle issues. 3) If checked that some parts(except glass nozzle) is possible broken by non-artificial reason, If necessary, customer deliver the broken part to Climatest Symor®, later Climatest Symor® send the repaired part or new part to customer. If unnecessary, Climatest Symor® will make delivery for the new part to customer directly. Remark:During warranty, Climatest Symor® is responsible for delivery fees both ways and parts fees.After warranty, Customer is responsible for the delivery fees both ways,Climatest Symor® will provide the parts to customer by cost price.
Technical Library | 2021-09-29 13:35:21.0
In PCB circuit assemblies the trend is moving to more SMD components with finer pitch connections. The majority of the assemblies still have a small amount of through hole (THT) components. Some of them can't withstand high reflow temperatures, while others are there because of their mechanical robustness. In automotive applications these THT components are also present. Many products for cars, including steering units, radio and navigation, and air compressors also use THT technology to connect board-to-board, PCB's to metal shields or housings out of plastic or even aluminium. This is not a simple 2D plain soldering technology, as it requires handling, efficient thermal heating and handling of heavy (up to 10 kg) parts. Soldering technology becomes more 3D where connections have to be made on different levels. For this technology robots using solder wire fail because of the spattering of the flux in the wires and the long cycle time. In wave soldering using pallets the wave height is limited and pin in paste reflow is only a 2D application with space limitations. Selective soldering using dedicated plates with nozzles on the solder area is the preferred way to make these connections. All joints can be soldered in one dip resulting in short cycle times. Additional soldering on a small select nozzle can make the system even more flexible. The soldering can only be successful when there is enough thermal heat in the assembly before the solder touches the board. A forced convection preheat is a must for many applications to bring enough heat into the metal and board materials. The challenge in a dip soldering process is to get a sufficient hole fill without bridging and minimize the number of solder balls. A new cover was designed to improve the nitrogen environment. Reducing oxygen levels benefits the wetting, but increases the risk for solder balling. Previous investigations showed that solder balling can be minimized by selecting proper materials for solder resist and flux.
Technical Library | 2024-07-24 01:04:35.0
Quad Flat No Leads (QFN) package designs receive more and more attention in electronic industry recently. This package offers a number of benefits including (1) small size, such as a near die size footprint, thin profile, and light weight; (2) easy PCB trace routing due to the use of perimeter I/O pads; (3) reduced lead inductance; and (4) good thermal and electrical performance due to the adoption of exposed copper die-pad technology. These features make the QFN an ideal choice for many new applications where size, weight, electrical, and thermal properties are important. However, adoption of QFN often runs into voiding issue at SMT assembly. Upon reflow, outgassing of solder paste flux at the large thermal pad has difficulty escaping and inevitably results in voiding. It is well known that the presence of voids will affect the mechanical properties of joints and deteriorate the strength, ductility, creep, and fatigue life. In addition, voids could also produce spot overheating, lessening the reliability of the joints.
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