Ball grid array (BGA) is a common surface mount package derived from pin grid array (PGA) technology. It uses a grid of solder balls or leads to conduct electrical signals from the integrated circuit board. BGA packages are popular in modern PCB designs because they offer several advantages over other types of IC packages.
BGA is also known as Ball Grid Array, which is a type of surface mount technology (SMT) that is used for packaging 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.
Instead of pins like the PGA, the BGA uses solder balls that are placed on the printed circuit board (PCB). By using conductive printed wires, the PCB supports and connects electronic components.
There are different requirements for different equipment and assembly types. This is why there are many different and useful variants of the ball grid array, which are produced in order to meet the necessary requirements. There are several types of BGA packages commonly used in PCB design:
Micro BGA: Micro BGA is small, which makes them ideal for small high-tech products. Also, its pins are few, and it's the main component of high storage devices. Here, three pitches are prevalent: 0.8, 0.65, and 0.75mm.
Plastic BGA (PBGA): PBGA is useful devices of mid to high performance, which requires surface mounting ease, low inductance, and low cost. However, it still retains high reliability levels. This PBGA package features extra copper layers which is useful for improving the ability of power dissipation.
Tape BGA (TBGA): The TBGA package is used in middle and high-end solution for applications which need high thermal performance without an external heatsink. The only disadvantage of TBGA is that this always costs higher than PBGA.
Thermally Enhanced Plastic BGA (TEPBGA): The MAPBGA package is used in low-performance to mid-performance devices that require packaging with low inductance, ease of surface mounting. It provides a low cost option with a small footprint and high level of reliability.
Molded Array Process BGA (MAPBGA): The MAPBGA package uses semiconductor grade materials, making it sturdy for long-term processes and flexible design constraints. It is mainly for enhanced SMT capacity, improved thermal processes, and low inductance devices.
Package on Package (PoP): The POP ball grid array package is useful in applications in which space is a real premium. This permits the stacking of a memory package on the top of your base device.
Efficiently PCB Space Usage in BGA Package: By using BGA package, we could use fewer PCB components and smaller footprint in PCBs, and such package can also be used in custom PCBs which could make the PCB space more effective.
Excellent Performance at High Speeds: In BGA, the solder balls are placed near to each other, which enables a close bond among components, strengthens interconnections, and reduce signal distortions during high-speed work. This means the system offers higher electrical performance at high speeds.
Less Component Damage: Unlike PGA, the solder balls of BGA are melted by the heating process, which allows them to adhere to the circuit board. This helps in reducing the chances of component damage.
Reducing PCB Assembly Cost: Efficiently PCB space using, improved features, quick manufacturing speed and less damage danger, all of these would definitely help reduce the PCB assembly cost when we are using BGA package.
Reliable Construction: The pins used in the PGA packages are thin and fragile. Thus, these pins are easily damaged or bent. However, this does not happen with BGA packages. In BGA, solder pads are connected to solder balls that make the system more reliable.
Excessively Expensive: A BGA is nothing but a small piece of material on which the manufacturer places an integrated circuit die. As the BGAs are tiny in size, it is difficult to inspect the solder joints through visual observation. However, this problem can be solved using special microscopes and X-ray machines.
Difficult to Inspect: In BGA, the solder balls are placed near to each other, which enables a close bond among components, strengthens interconnections, and reduce signal distortions during high-speed work. This means the system offers higher electrical performance at high speeds.
Prone to Stress: Due to the flexural stress from the circuit boards, BGAs are prone to stress that lead to reliability issues.
The more complex the BGA parts that you are working with, the more you will have to plan ahead in order to successfully route each pin to its associated net. High pin-count BGAs with their pins on a 0.5mm pitch will need careful planning to design escape routing patterns for all of their nets. This will take a lot of forethought in component placement long before you get into routing your traces.
As always, start your placement floorplanning with the fixed components such as connectors, switches, and other IO devices first. You will also want to keep the thermal considerations of the board in mind to ensure that your hot-running BGAs will have the airflow they need to stay cool. Processor and memory chips need to be close enough to their off-board connectors so that they don’t have to run long trace lengths throughout the board. At the same time, you must provide enough room for all of the parts of the signal path to cleanly fit without their traces having to wander too far to reach them.
As you begin your placement, remember to give your BGA parts enough room for all of their routing around them. These parts should have a lot of bypass capacitors associated with them, and they need to be placed directly next to the pins that they are connected to. Next, the components that are part of the signal paths need to be placed sequentially between the source and load of the signals. This may require altering large portions of your placement in order to fit these parts in, so be prepared for interactive work to finalize the placement.
BGA Reballing: This process involves changing all the old soldered balls on a grid array assembly to new balls. Engineers employ this process on PC motherboards, gaming consoles, or laptops that have issues with their VGA cards.
BGA Soldering: Manufacturers engage in BGA soldering by applying the solder reflow process with the help of a reflow oven. The BGA solder balls melt into the reflow oven during the BGA soldering process.
BGA Rework: The BGA rework process involves an electronic component getting heated in a dedicated BGA rework station. And it has a vacuum device that boosts the package. It also has an infrared burner and a thermocouple that checks the temperature.
The most advanced inspection method for BGAs is X-ray inspection. X-rays work by emitting X-ray energy from an X-ray tube onto the board. X-rays pass through the board at differing amounts, with more X-rays trapped in dense areas such as solder joints.
Electrical testing of BGAs is another inspection process that tests the board’s electrical properties. This is different from mechanical testing, which is a destructive process that subjects the BGA to shock and shear tests to evaluate the quality of solder joints under stress.
Optical inspection, also referred to as visual inspection, is the use of optics technology to view a BGA and its connections. This technique historically used the naked eye or microscopes, which delivered limited results. However, introducing the endoscope has proven particularly valuable for this inspection technique.
Place the BGA package on a conductive pad and use a litter solder paste on the surface of it.
By using the solder wire and soldering iron, we need to carefully remove the ball from the BGA. Use the soldering iron to heat the absorbent wire and melt the tin ball before you swipe the wash line over the BGA surface.
Clean the BGA surface immediately with industrial alcohol. Use friction motion to remove solder aid on BGA surface.
By using the microscope to examine the clean pads, damaged pads, and unremoved tin balls.
Using deionized water and brush to scrub the BGA surface carefully.
Let the BGA dry in the air and double-check the BGA surface.
BGA packages will be more and more popular in the electrical and electronic product markets in the future. BGA PCBs are used in a variety of electronic devices, including computers, cell phones, and gaming consoles, due to their high pin count and low profile. The high pin count allows for more connections to be made between the device and the PCB, while the low profile allows for a more compact design.
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