Manufacturing / Production Technology, Hardware & Services


Via-in-pad PCB design tips

8 October 2014 Manufacturing / Production Technology, Hardware & Services

So what’s all the hype regarding via-in-pad? When should one evaluate the cost versus benefit for this technology before adding it to a design? And when is it a must-have tool?

The benefits of via-in-pad designs are well documented. From reduction of inductance to increased density, it has become an essential tool for designers when navigating the routing challenges of fine-pitch array packages that have become mainstays in today’s bills of materials. But there are trade-offs that must be considered.

The basic concept is elegant: the via-in-pad design methodology allows the designer to place the via right beneath the component contact pad; hence the reduction of inductance plus the added benefit of improved routing density, which can lead to higher density per layer. The net result is more routing in less space and a smaller printed circuit board (PCB) footprint. It is another miniaturisation tool that can drive cost down.

However, there are trade-offs when implementing via-in-pad technology, such as increased PCB cost. The reason is that the via-in-pad technique requires both additional process steps and extra materials. Added costs are found in both the extra materials used, including epoxy or metal-based via fill materials and copper cap plating processes, as well as added process steps like vacuum via fill, curing, planarisation and secondary plating operations. There is also the general challenge that results from producing a higher-density PCB.

On the design side there are numerous benefits that can be exploited through via-in-pad technology. If via fill is done with thermally conductive materials such as copper or silver epoxy pastes, the design can also be used to provide a site-specific thermal management solution. Copper pastes, for example, have a 10 – 15 W/mK thermal conductivity compared to solder mask fill at 0,25 W/mK.

For high-speed designs, the lower intrinsic inductance created by proximity is ideal to improve signal speeds regardless of material selection. Design-for-assembly (DFA) benefits include excellent planar via plugging that results in improved ionic cleanliness, as well as a more planer surface that is ideal for low-profile components.

Not all designs need via-in-pad. There are some added benefits such as in thermal management and high-speed designs where the advantages should be weighed against the costs. However, when considering via-in-pad as an option for improving routing for high I/O count in packages below 0,8 mm pitch, it can become a highly valuable go-to tool.



Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

High-performance acrylic conformal coating
29 April 2020, Vepac Electronics , Manufacturing / Production Technology, Hardware & Services
Electrolube’s HPA high-performance acrylic conformal coating is specifically designed to meet the demanding requirements of applications such as the defence and aerospace industries. It is fast drying ...

Read more...
High-performance acrylic conformal coating
29 May 2020, Vepac Electronics , Manufacturing / Production Technology, Hardware & Services
Electrolube’s HPA high-performance acrylic conformal coating is specifically designed to meet the demanding requirements of applications such as the defence and aerospace industries. It is fast drying ...

Read more...
Embedding a 3D STEP model in a footprint
29 April 2020, EDA Technologies , Design Automation
Integrating mechanical design workflows into electrical design tools has become a necessary component of today’s successful PCB design processes. But transferring inaccurate design data back and forth ...

Read more...
New range of thermal gap fillers
29 May 2020, Vepac Electronics , Manufacturing / Production Technology, Hardware & Services
Global electro-chemicals manufacturer, Electrolube, has introduced a versatile new range of gap-filling products with excellent thermal performance. GF400 is a two-part, liquid silicone-based gap filler, ...

Read more...
Company profile: SMTech
25 March 2020, SMTech , Manufacturing / Production Technology, Hardware & Services
It also provides a full turnkey solution, should its customers require this type of service. The company has a very modern manufacturing facility with high-speed SMT lines, automatic optical inspection, ...

Read more...
RFiber adds specialist PCB manufacturer to its stable
25 March 2020, RFiber Solutions , Manufacturing / Production Technology, Hardware & Services
RFiber Solutions recently announced the addition of Transline Technologies Inc. (TTI) to its growing portfolio of electronics and RF/microwave suppliers. “The addition of TTI adds a competitive and very ...

Read more...
Tip-heater cartridge soldering iron
25 March 2020, MyKay Tronics , Manufacturing / Production Technology, Hardware & Services
PACE Worldwide’s new TD-100A ergonomic soldering iron maintains the comfort and feel of the original TD-100 handpiece yet contains many enhancements. The TD-100A’s Cool Touch design features all-aluminium ...

Read more...
BTU supports Hermes standard
25 March 2020, MyKay Tronics , Manufacturing / Production Technology, Hardware & Services
BTU International announced that it now supports the Hermes standard, officially referred to as IPC-HERMES-9852. Hermes links individual machines together with a direct form of horizontal communication. The ...

Read more...
Soldering iron tester
25 March 2020, Vepac Electronics , Manufacturing / Production Technology, Hardware & Services
Hakko’s FG-101B is a soldering iron tester for measurement of tip temperature, leak voltage, and tip to ground resistance, for daily maintenance of a soldering station. Control of tip temperature, leak ...

Read more...
All good things come to an end
25 March 2020, Microtronix Manufacturing , Manufacturing / Production Technology, Hardware & Services
“Contract manufacturing is not for the fainthearted and my respected colleagues and competitors will attest to this.” – Mike Goodyer.

Read more...