The I/O terminals of the BGA package are distributed under the package in the form of circular or columnar solder joints in the form of arrays. The advantage of BGA technology is that the number of pins increases, but the pin spacing does not decrease but increases, thus increasing the assembly yield. Although its power consumption increases, BGA can be welded by controllable collapse chip method, which can improve its electrothermal performance;The thickness and weight are reduced compared with the previous packaging technology; the parasitic parameters are reduced, the signal transmission delay is small, and the frequency of use is greatly improved; the assembly can be welded in coplanar welding with high reliability
Structural characteristics PBGA (Plasma BGA) carrier is a common printed board substrate, generally a multilayer board composed of 2~4 layers of organic materials. The chip is connected to the upper surface of the carrier by wire compression welding, and the surface of plastic molded carrier is connected with eutectic solder ball array.This encapsulation is used by PemtiumII、III、IV processors in Intel series of CPU, for example. Another CDPBGA (Carity Down PBGA), refers to the central packaging has a square low-trapped chip area (also known as: cavity area)。Advantages: relatively low packaging cost; not easy to be damaged by machinery compared with QFP; suitable for mass electronic assembly; the font is the same as the PCB substrate, the thermal expansion coefficient is almost the same, and the stress on the correspondence is very small during welding. The reliability of solder joint is also less.Disadvantages: easy to absorb moisture. CBGA (Ceramic BGA) carrier is multilayer ceramic. The connection between chip and ceramic carrier can take two forms: wire pressing welding and flip chip technology. This encapsulation is used by PemtiumI、II、PemtiumI Pro processors in Intel series of CPU.Advantages: excellent electrical and thermal properties; good sealing; not easy to be damaged by machinery compared with QFP; suitable for electronic assembly with I/O number greater than 250. Disadvantages: compared with the PCB, the thermal expansion coefficient is different, and when the package size is large, the thermal cycle power failure is caused.FCBGA (Filp Chip BGA) adopts hard multilayer substrate. CCGA CCGA is another form when the CBGA size is larger than at 32*32 mm, the difference is to use solder post instead of solder ball. The solder column is fixed to the bottom of the ceramic by eutectic solder connection or direct pouring.
The advantages and disadvantages are roughly the same as the CCGA, the difference is that the solder column can withstand the stress caused by different CTE and can be applied to large size packaging. TBGA carrier adopts bimetallic layer belt, chip connection is realized by inversion technology. Advantages: can achieve lighter and smaller packaging; suitable for the number of I/O can be more packaging; good electrical properties; suitable for batch electronic assembly; high reliability of solder joints. Disadvantages: easy to absorb moisture; high packaging cost.
 
The principle of common rework SMD rework system: hot gas flow is used to gather on the pins and pads of surface assembly devices (SMD) to melt solder joints or reflow solder paste to complete disassembly and welding functions.Different manufacturers repair the system is mainly different in the heating source, or different hot air flow mode, some nozzles make hot air above the SMD. The flow of air around the PCB should be selected from the point of view of the protective device. In order to prevent PCB warpage, the rework system with the function of preheating the PCB should be selected.
 
BGA quality detection after mount, we can use AOI optical detector for location detection, character detection, mount direction detection, if there is a functional problem, we can use the X light machine for internal perspective detection