What Is BGA?

BGA is short for Ball Grid Array, a form of surface mount technology (SMT) is widely used in integrated circuits, especially for small size integrated circuit (IC) chip, which can eventually achieve increased packaging I/O density. BGA package uses underside for connection and have a more robust and convenient package for the high density of PCBs and high performance of electronic products.

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Advantages Of BGA

Improvement in connectivity

The pins are placed in a grid pattern (hence the name a ball grid array) on the lower surface of the chip carrier. In addition, instead of using pins to provide connections, solder ball pads are used as the connection method. On a printed circuit board, a set of matching copper pads are placed on the PCB on which the BGA device is to be mounted to provide the desired connection.

Use PCB space efficiently

Using a BGA package means less component involvement and a smaller footprint also helps save space on custom PCBs, both of which greatly increase the effectiveness of PCB space.
Improve thermal and electrical performance.

Due to the small size of the PCB based on the BGA package, it is easier to dissipate heat. When the silicon wafer is mounted on top, most of the heat can be transferred down to the ball grid. When the silicon wafer is mounted on the bottom, the back side of the silicon wafer is attached to the top of the package, which is considered to be one of the best ways to dissipate heat. The BGA package has no pins that can be bent and broken, which makes it stable enough to ensure electrical performance on a large scale.

Cause Less Damage and Offer Higher Level Performance

The BGA leads consist of solid solder balls that are not easily damaged during operation. The conductor on the underside of the chip carrier means that the leads within the chip are shorter. Therefore, the level of unwanted lead inductance is low, and in this way, the ball grid array device can provide a higher level of performance than its QFP counterpart.
Traditional four-flat package packages have very thin, closely spaced pins that are easily damaged even in a controlled environment. In addition, they need to control the welding process very tightly, otherwise the level of welded bridges and bad joints will rise. From a design perspective, pin density can be congested in certain areas. The BGA package overcomes these problems and improves the reliability of the solder joint.

Improved manufacturing yield based on welding.

Most BGA package pads are relatively large, which makes soldering on a large area easier and more convenient, resulting in faster PCB manufacturing speeds while increasing manufacturing throughput. In addition, larger pads can be used to easily re-solder.

Types of BGA

MAPBGA – Moulded Array Process Ball Grid Array

MAPBGAThe BGA package targets low to medium performance devices and requires a low-inductance package for easy surface mount. It offers a low cost option with a small footprint and high reliability.

PBGA – Plastic Ball Grid Array

Usually, a BT resin/glass laminate is used as a substrate, and a plastic is used as a packaging material. Solder balls can be divided into lead and lead-free solder. The solder balls are not connected to the package and require no additional solder.

The BGA package is suitable for medium and high performance devices that require low inductance, easy surface mount, and relatively low cost while maintaining a high level of reliability. It has some extra copper layers in the substrate that can handle higher power levels.

TEPBGA – Thermally Enhanced Plastic Ball Grid Array

This package provides a higher level of heat dissipation. It uses a thick copper plane in the substrate to absorb heat from the chip onto the customer’s board.

TBGA – Tape Ball Grid ArrayTBGA

TBGA is a structure with a cavity. There are two types of interconnection between the chip and the substrate: reverse soldering and wire bonding. It is a mid- to high-end solution for applications that require high thermal performance without the need for an external heat sink.

MicroBGA:

As the name implies, this BGA package is smaller than the standard BGA package. There are three common spacings in the industry: 0.65, 0.75 and 0.8 mm.

CBGA – Ceramic Ball Grid Array

CBGA has the longest history among the three types of BGAs. The substrate material is a multilayer ceramic. The metal cap is soldered to the substrate by encapsulating solder to protect the chip, leads and pads. High temperature eutectic solder is used as a material for solder balls.
More type please visit :wikipedia.org ( https://en.wikipedia.org/wiki/Ball_grid_array )

BGA Assembly

During the soldering process, the solder balls have a very precise amount of solder and the solder melts as it heats up during the soldering process. The surface tension causes the molten solder to maintain proper alignment of the package with the board while the solder cools and solidifies. Carefully select the composition of the solder alloy and the soldering temperature so that the solder does not melt completely, but remains semi-liquid, leaving each solder ball separate from its adjacent solder balls.

Heat distribution is critical in the BGA asseBGAmbly process. We will carefully review your PCB files and BGA data sheets to provide an optimized heat distribution for your BGA assembly process. We will consider the BGA size, BGA ball material composition (lead or lead free) for effective heat distribution. When the physical dimensions of the BGA are large, we will optimize the heat distribution to locate the heating on the internal BGA; otherwise it will cause inefficiency. Lead-free BGAs will use a special lead-free thermal profile to avoid leaking balls due to lower temperatures. Lead-containing BGAs will use a proprietary lead-containing process to prevent pin-outs caused by higher temperatures. When we receive your order, we will review your BGA PCB design and DFM (manufacturability design) review, including inspection of board materials, surface finish, maximum warpage requirements.

Related Post: How To Solder BGA on PCB Board?

BGA Inspection

X-ray inspection is widely used to check the quality of BGA. Based on X-rays, it detects hidden features of a target object or product. The following are the four main test parameters obtained by X-ray tomography:

• Location of the solder joint center: The relative position of the solder joint center can reflect the position of the electronic components on the PCB pad.

• Solder Joint Radius: The solder joint radius measurement shows the amount of solder on the solder joint on a particular layer. The radius measurement on the mat indicates any changes caused during the paste screening process and pad contamination. Radius measurements on the horizontal layer of the ball indicate a problem of joint coplanarity over the component or PCB.

• Solder thickness on each loop centered on the solder joint: The loop thickness measurement represents the distribution of solder in the solder joint. This parameter is used to determine the presence of humidity and voids.

• Deviate from the round table. It represents a uniform distribution of solder around the solder joints, automatic registration and humidity.
We use X-ray machines to detect various defects that may occur during BGA assembly. By X-ray inspection, we can eliminate soldering problems on the board, such as solder paste bridging and insufficient ball melting. In addition, our X-ray support software calculates the gap size in the ball to ensure it meets the standard.