BGA (Ball Grid Array)-ball pin grid array packaging technology, high-density surface mount packaging technology. At the bottom of the package, the pins are spherical and arranged in a grid-like pattern, hence the name BGA. Motherboard control chipsets mostly use this type of packaging technology, and the material is mostly ceramic. The memory packaged with BGA technology can increase the memory capacity by two to three times without changing the volume of the memory. Compared with TSOP, BGA has a smaller volume, better heat dissipation performance and electrical performance. BGA packaging technology has greatly improved the storage capacity per square inch. With the same capacity, memory products using BGA packaging technology are only one-third of the volume of TSOP packaging; compared with traditional TSOP packaging, BGA packaging has A faster and more efficient way to dissipate heat.
As a new type of SMD, BGA evolved from PGA (Pin Grid Array) and usually consists of a core cavity, a base, a lead, a cover and a spherical pin. The attributes of BGA include:
• Higher pin count. In the SMD of the same package size, BGA can have more pins. Generally, BGA components have 400+ ball pins. For example, a BGA with an area of 32mm * 32mm can carry up to 576 pins, while a QFP with the same area can only carry 184 pins.
• Smaller assembly area. Through the number of pins, BGA can accommodate a smaller assembly area. For example, compare a QFP with 304 pins to a BGA with 313 pins. Although the latter has more pins, the area it occupies is reduced by a third.
• Lower assembly height. The assembly height of BGA is lower than the sum of package thickness and solder ball height. For example, the height of a QFP with 208 pins or 304 pins is 3.78mm, while the height of a BGA with 225 or 313 pins is only 2.13mm. In addition, the assembly height of the BGA after soldering will be reduced because the solder balls will melt during the soldering process.
• Larger pin spacing. According to the BGA physical standard issued by JEDEC, the lead pitch between BGA solder balls should be 1.5mm, 1.27mm or 1.0mm. Using the same package size and pin count, the QFP pin pitch is 0.5mm, while the BGA pin pitch is 1.5mm.
• Excellent heat dissipation performance. The temperature of the BGA package circuit is closer to the ambient temperature, and the operating temperature of the chip is lower than any other SMD.
• Compatibility with SMT. The BGA package is compatible with standard SMT. In addition, because BGA components have a larger pin pitch and excellent coplanarity, the pins will not be bent, and the corresponding assembly technology is simpler than other SMD components with leads.
• Better electrical performance. Because BGA components have shorter pins and higher assembly integrity, they have better electrical performance, and are especially suitable for higher frequency ranges.
• Reduce manufacturing costs. Because the BGA package occupies a smaller assembly area and a higher assembly density, the manufacturing cost will be reduced. Especially with the increase of BGA package output and wider application, it is obvious to reduce the manufacturing cost.
• Higher reliability and fewer quality defects. Since the solder balls on the BGA package are being soldered, the molten solder balls will automatically align due to surface tension. Even if a 50% error does occur between the solder ball and the pad, an excellent soldering effect can be obtained.
Although BGA packaging has some obvious advantages, there are some disadvantages in the SMT assembly process, including:
• It is difficult to inspect solder joints. Solder joint inspection requires X-ray inspection equipment resulting in higher costs.
• BGA rework needs to overcome more difficulties. Since the BGA components are assembled on the circuit board through solder balls distributed in the array, rework will be more difficult.
• Some BGA packages are very sensitive to humidity, so dehydration is required before application.
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