Technical Guidance: BGA Design Rules

With the advancement of the electronics industry, chip integration continues to increase, the number of IO pins quickly rises, and power consumption grows accordingly, leading to stricter requirements for integrated circuit packaging. To meet the demands of this progress, Ball Grid Array (BGA) packaging technology is introduced. This technology involves the creation of an array of solder balls on the bottom of the package substrate as the I/O interface for the circuit, connecting it to the printed circuit board (PCB). Devices packaged using this technology are one type of surface-mount components.

Applications of BGA Packages:

However, some issues have arisen. Let's take a look at the illustrations below:

1. BGA pads trimmed for clearance

2. BGA pads with open vias

BGA Capabilities When Using Conventional Plugged Vias:

BGA capabilities using high-end regular/copper epoxy-filled via-in-pad:

The application of epoxy filled or copper paste filled vias makes via-in-pad the best choice for BGA routing. At the same time, advancements in multi-layer board manufacturing equipment enable the creation of more precise BGA pads.

Tips:

Vias inside pads cannot be plugged; instead, you can use epoxy or copper paste (copper paste offers better thermal and electrical conductivity), and then plate over the filled vias.

For designs using the above process for filled vias, aim to have the via (inner diameter) at 0.2 mm or larger and the pad (outer diameter) designed at 0.35 mm or larger. Click PCB Manufacturing & Assembly Capabilities for details.

On multi-layer boards, it is acceptable to have a few traces as narrow as 0.076 mm (3 mil); however please make traces at least 0.09 mm wide wherever possible.