The Safe Operation Of The Backplane
Backplane has been a specialized product of PCB manufacturing. Backplane is more conventional PCB board thick and heavy, corresponding to its heat capacity is also larger. In view of the slow cooling of the backplane, the length of the reflow oven should be lengthened. Back Plate There is also a need for forced air cooling at the exit to reduce the backplane temperature to a safe operating level.
Users of the core layer is thinner, the number of layers more need to bring the back of the conveyor system on the contrary two requirements. When a large power application card is inserted into the backplane, the thickness of the copper layer must be moderate in order to provide the required current to ensure that the card is working properly. All of these factors have led to an increase in the average weight of the backplane, Back Plate which requires that the conveyor belt and other conveyor systems must not only be able to safely transfer large-sized raw material plates, but must also take into account their weight gain. As the backplane is thicker than the conventional PCB, and the number of holes is much more, it is easy to cause the flow of processing fluid. It is important to use a high pressure flush and air blower method to clean the borehole in order to minimize the amount of liquid and to remove any residual impurities from the holes.
As the user application requires more and more layers, the interlayer alignment becomes very important. The interlayer alignment requires tolerance convergence. Back Plate The size of the board makes this convergence more demanding. All layout processes are generated in a controlled temperature and humidity environment. Exposure equipment in the same environment, the entire area before and after the figure on the tolerance to be maintained at 0.0125mm CCD camera to be used before and after the completion of the layout. After etching, the inner plate is perforated using a four-bore system. Perforation through the core plate, the position accuracy is maintained at 0.025mm, repeatability is 0.0125mm. And then inserted into the perforation with the needle pin, the inner layer after etching, while the inner layer together. The use of this etching method can fully ensure that the drilling and etching copper plate alignment, Back Plate the formation of a solid ring design structure. However, with the user in the PCB routing requirements in a smaller area to lay more and more lines, in order to keep the board fixed cost unchanged, the requirements of etching copper plate size smaller, which requires a better alignment between the layers of copper. Fixtures and conveyors must be able to deliver both large and heavy plates at the same time.
In addition to the uniform thickness of the coating required for the drilling, the backplane designers generally have different requirements for copper uniformity on the outer surface. Some designs have little signal lines on the outer layer. On the other hand, in the face of high-speed data rates and impedance control circuit requirements, the external layer of near-solid copper foil will become very necessary for EMC shielding. Because the user requires more layers, it is important to ensure that the inner layer is subjected to defect identification and isolation before bonding. In order to achieve effective and repeatable control of the backplane impedance, Back Plate the etch line width, thickness and tolerances are critical. In this case, the AOI method can be used to ensure that the etched copper pattern matches the design data. Using the impedance model, the line width tolerance is set by the AOI to determine and control the sensitivity of the impedance to line width variation.
Traditionally, for reliability reasons, it is desirable to use passive components on the backplane. However, in order to maintain the fixed cost of active boards, BGA and other active devices are increasingly designed to the backplane. The component mounting device must be able to accommodate not only smaller capacitors and resistors, but also the ability to operate additional silicon packaging components. In addition, the large size of the backplane requires the installation of the equipment to be large, and the counterweight can also be displaced with fine position tolerances.