A Guide To Ball Grid Arrays
Printed circuit boards (PCBs) are used in most electronic devices to drive circuits and connect different electronic components. The performance of every circuit board depends on how it is structured and the layout, which will differ depending on the arrangement of the components.
One such arrangement that has grown in popularity is ball grid arrays (BGAs) thanks to the many beneficial features and these are most frequently used in PCBs that demand high-density connections.
In the guide below, we’re going to take a more in-depth look at ball grid arrays, the pros and cons of these packages and how they are assembled.
What is a ball grid array and how is it assembled?
A ball grid array (BGA) is a Surface Mount Device (SMD) used for integrated circuits. These packages use a pattern, also referred to as an array, of solder pads on the bottom side. Attached to these pads are small balls of solder, replacing the need for leads to connect the different components to the PCB.
A BGA can have a huge number of interconnections to the PCB than other types of packages. Once the solder balls are in place, they can be attached to the PCB with stencil printing and solder paste.
BGA has become the standard in recent years and as such, this assembly method is easy to adopt as an electronics manufacturer.
The key benefits of BGAs
There are several reasons why ball grid arrays have become so popular and these include:
- Assemblies can be much thinner, which means the packaging is reduced and you can make sleeker products
- Thanks to the placement of the solder balls, high-density connections can be made. This leads to better performance at higher speeds
- The connection of solder balls to the solder pads means the construction is stronger and more reliable
- As the solder balls are melted during the heating process, they attach better to the circuit board. This reduces the risk of component damage
- The thermal channels in BGAs help to reduce the heat in the circuit boards and therefore, they also reduce the chance of overheating
The disadvantages of BGAs
Unfortunately, as with most things in life, ball grid arrays also come with some downsides and it’s about weighing these up to see if this is the solution for you. These disadvantages include:
- The equipment used to solder BGA packages is expensive, therefore, the packages are more expensive
- These packages are harder to inspect as they are so small and compact, this can make soldering faults difficult to detect. That said, this can be overcome with an X-ray machine
- Flexural stress from PCBs can cause solder balls to fracture and packages to bend, which can lead to reliability issues
What are the different types of BGA and what are they used for?
Now we’ve looked at the benefits of using BGAs, let’s take a look at the different types of arrays and the materials they are made from. We’ll also look at what each type of BGA is better suited to.
Plastic Ball Grid Array (PBGA)
PBGA is a ball grid array package in which the components are made from a plastic substrate material. This can be a more affordable solution and as it can house a larger number of connections, this is one of the top-performing packages.
As a result, PBGA is commonly used in consumer electronics, telecommunications and automotive electronics.
Ceramic Ball Grid Array (CBGA)
As the name suggests, CBGA packages use a ceramic substrate material. Ceramic offers better thermal conductivity, making this a great material for more high-performance applications. Not only that, but CBGAs can be far more durable and reliable.
For this reason, ceramic components are often used in the military, aerospace and medical industries.
Tape Ball Grid Array (TBGA)
TBGA stands for tape ball grid array and uses a tape-based packaging technology. This is another low-cost solution, that is flexible and perfect for smaller applications where space is limited. For example, it is commonly used in smartphones and tablets.
Enhanced Ball Grid Array (EBGA)
Enhanced ball grid array uses a mixture of ceramic and organic materials for the packaging. This combination of the two materials allows for better thermal conductivity and electrical performance. That is why they are used in high-performance applications like server systems, networking equipment and high-end gaming systems.
Metal Ball Grid Array (MBGA)
Finally, we have metal ball grid arrays. In this case, metal solder balls are used instead of the usual tin-lead balls. This has a higher melting point so it is more effective in high-temperature processing to create products for automotive and industrial applications.