Ball Grid Array
A ball grid array (BGA) is a type of surface-mount packaging (a chip carrier) used for integrated circuits. BGA packages are used to permanently mount devices such as microprocessors. A BGA can provide more interconnection pins than can be put on a dual in-line or flat package. The whole bottom surface of the device can be used, instead of just the perimeter. The leads are also on average shorter than with a perimeter-only type, leading to better performance at high speeds.
Description
The BGA is descended from the pin grid array (PGA), which is a package with one face covered (or partly covered) with pins in a grid pattern which, in operation, conduct electrical signals between the integrated circuit and the printed circuit board (PCB) on which it is placed. In a BGA the pins are replaced by pads on the bottom of the package, each initially with a tiny ball of solder stuck to it. These solder spheres can be placed manually or by automated equipment, and are held in place with a tacky flux.The device is placed on a PCB with copper pads in a pattern that matches the solder balls. The assembly is then heated, either in a reflow oven or by an infrared heater, melting the balls. Surface tension causes the molten solder to hold the package in alignment with the circuit board, at the correct separation distance, while the solder cools and solidifies, forming soldered connections between the device and the PCB.
Reballing Ball Grid Array (BGA) Chips in mobile phones manually by hand
Reballing BGA chips tends to need and have a good steady hand, since most cellphone technician applied it manually by hands. It also requires good practice and experimentation before proceeding to reball any chips in mobile phones, because there are chips in mobile phones that can be easily damaged if you are not so familiar of doing it as well. like the CPU's and the Application processor chips are very vulnerable and can be easily damaged when applying unrecommended heat on it. I advice that spending much time to practice it with non working PC board and chips is a good way to start. To put thing straight up, in real life there are technician that are good re-baller and some have poor skills on it. that is what I observe mostly when attending many forums on the Internet. The truth is by practicing doing it is the key to enhance re-balling chips skills.
Re-balling Chips Methods
Prepare the proper Tools -You need to prepare also proper reballing kits and a cleaning kits for further cleaning the PC board.
A good and controlled hot air temperature, You need to refer to manufacturers manual for proper temperature settings.
Reballing BGA chips manually by hand skill, this tutorial video courtesy of onadbballais
Some technician used IRDA or Infrared Reworks Station and other reballing kit available on the market today. Practice by doing it everyday I assure you can do it yourself within just a few days.
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