Elementary Mr. Watson: Navigating RF—A Glide Path Approach to Design Success
Designers Notebook: Layer Stackup Planning for RF Circuit Boards
Connect the Dots: Involving Manufacturers Earlier Prevents Downstream Issues
BGA Fanout Routing Overview
September 4, 2018 | Christian Keller, AltiumEstimated reading time: 1 minute
PCB developers are deluged with new challenges caused by increasing density and smaller components. Ball grid arrays (BGAs) create particular challenges during layout, with hundreds of connections in just a few square centimeters. Fortunately, designers now have options for addressing these issues.
Fanout and Escape Routing
Because of the density and distance from the connection points, only the two outermost rows of a BGA can be connected directly to surface circuit traces. All other terminals of the BGA cannot be connected in a direct path on the surface.
Fanout and escape routing is integrated in many PCB design systems to enable further connections. In fanout and escape routing, the two outermost rows, and all other rows of a BGA, are automatically connected to the center of the terminals via a short circuit trace that is executed at a 45° angle. This provides a blind via that forms a direct connection to the next signal layer. Routing can be executed on the next signal layer.
Using via-in-pad eliminates the need for the additional trace to the center of the connections, thereby creating additional space for circuit traces. Therefore, with via-in-pad, the through contact can be placed directly at the terminal of the BGA.
During circuit board manufacturing, these through contacts will be filled with a non-conducting medium and cured. Later, the ends are metallized, planarized, and also over-contacted. This makes the surface of the via flat and can be used the contacts of the BGA. This solution can be used for both stacked and staggered microvias and/or blind vias. IPC-4761 describes how via-in-pads, for example filled and capped vias (IPC-4761 Type VII), are prepared. Despite the higher manufacturing costs, via in pads will always be preferred, because of the higher integration density of BGAs and their lower inductance at high frequencies (signal quality).
To read this entire article, which appeared in the August 2018 issue of Design007 Magazine, click here.
Share on:
Suggested Items
Real Time with... IPC APEX EXPO 2025: Empowering IPC North Asia—Leadership and Future Goals
04/24/2025 | Real Time with...IPC APEX EXPONolan Johnson catches up with Sydney Xiao, the IPC North Asia President, who leads a team covering China, Taiwan, Japan, and Korea. IPC's North Asia regions 800 members are focusing on standards, training, and advocacy to enhance quality and profitability. The adoption of IPC standards by Toyota in 2021 highlights this increased regional engagement. IPC prioritizes workforce development, with over 7,000 professionals in certification programs and school partnerships.
Recognizing the IPC Committee Volunteer Awards in 2025
04/24/2025 | Patty Goldman, I-Connect007In 2023, IPC created two new awards to honor standards development committee volunteers: The Hillman-Lambert Award for Volunteer of the Year and the Kessler-Goldman Award for Committee Leader of the Year. The awards were named after Hall of Fame members whose service to standards development is well-known and who have demonstrated the skills and principles that the awardees should also have.
IPC Rising Star Award: Young-Ho Hwang, Guru E&E
04/23/2025 | Nolan Johnson, I-Connect007Since 2022, IPC has made significant progress for its Korean members. Young-Ho Hwang has been instrumental in driving these developments. As a core advisory committee member and chair of the 610 RTG, he has played a key role in guiding IPC Korea’s strategic direction, championed the development and adoption of IPC standards across industries, and fostered strong collaborations with stakeholders.
Real Time with... IPC APEX EXPO 2025: IPC's Growth and Future in India's Manufacturing Sector
04/23/2025 | Real Time with...IPC APEX EXPOGaurab Majumdar, VP for IPC in SE Asia and India, highlights IPC's impressive growth in India, with certification numbers rising significantly. The Indian manufacturing sector is projected to reach a $300 billion market, alongside a $10 billion investment in semiconductors. IPC is addressing industry demands through standards development and a new workforce project aimed at training students for job placements.
Real Time with... IPC APEX EXPO 2025: DuPont Electronics Materials and Innovations
04/23/2025 | Real Time with...IPC APEX EXPODuPont is many things to many markets, but DuPont Electronics Materials is, perhaps, a bit out of the DuPont "norm," developing specialized electronic materials that are particularly focused on challenging areas such as flex circuits, high power PCBs and products that must withstand harsh environments. At IPC APEX EXPO, Marcy LaRont sat down with Shannon Dugan from DuPont Electronics Materials to discuss some big news. They are being spun off into an independent entity with a new CEO having just been announced as the show wrapped.