High-speed Interconnect Demands Require Lower-Cost PCB Material

When analysis and also examining the plethora of viewpoints available in articles and also on the web, it’s easy to assume that there is consensus among those well-informed that the days of making use of conventional low-priced PCB materials for next-generation high-speed layout are dead as well as gone. After that there is this notion that the demands of modern-day technologies such as PCIe 5.0 and also past have pressed the boundaries of board layout and also manufacture toward the verge.

Taking a better consider the materials as well as approaches involved, however, provides brand-new hope that although we are undoubtedly sprinting ever before closer to the brink, there are some essential modifications that we can make, which might allow us to stop short of crossing it, at the very least in the meantime.

Next-generation PCB products at a cost

While it holds true that using next-generation products will enable less complicated incorporation of new technologies right into layouts, this rise in capability as well as efficiency comes with an actual price: it is far more pricey to make a PCB utilizing unique materials. The rise is likely to be in the area of 100% (2 ×) and even more, depending on the layout specifics.

Some firms are extra going to make this breakthrough because their systems and layouts can fit using unique materials and take in the additional costs connected with their use. Nevertheless, there are many others who are subject to tighter style as well as monetary restraints, which would certainly make the transition more difficult.

For this reason, Intel engineers have striven to examine the different elements included as well as offer a number of strategies that will enable developers to construct next-generation innovation into their designs using reduced cost, current-generation PCB products and also processes.

Expense is not the only factor to consider

When including next-generation modern technology right into your layouts, some rise in making expenses is inevitable. Our study has determined, though, that there are a variety of variables that can be managed to keep the boost to just 30%.

Following are a few of the extra conveniently appropriate insights that have been obtained from the study that we performed. As you check out, though, it is important to keep in mind that this strategy is not a cure all– there are compromises to think about at every level, and also while overall cost is necessary, it is only one of the variables that has to be taken into consideration.

Style variables

When manufacturing PCBs, there are any kind of number of variables that need to be considered. However, our initiatives have figured out that one of the most profit originates from focusing on 4 of these style variables particularly: dielectric product, surface area roughness of the copper, oxidation procedure, and optimization of the stackup. For every style variable, we likewise list the options that the sector can put efforts in, and also provide cost-effective services.

1. Dielectric material

Typical FR4 dielectric materials make use of an epoxy-based resin with E-glass support system to keep the cost down. Unique dielectric products commonly require using an extra costly PPE/PPO-based resin system and/or low-Dk glass for much better performance, enhancing the total manufacturing price.

Alternative: Newer manufacturing approaches have been created which integrate epoxy with the PPE/PPO-based resin, resulting in a finished board with performance attributes that can satisfy the efficiency demand but at a lower production expense.

2. Surface area ruggedness of copper

In a perfect circumstance, high-speed signals would pass through courses made from copper that have no surface roughness. Sadly, in the real world, utilizing ‘smooth’ copper is not a possibility as various other products will certainly have difficulty adhering to it and also the PCB will flake and also crumble. For this reason, some level of roughness is intrinsic to every one of the copper made use of in PCB production. For boards with higher electric performance and also lower loss needs, suppliers utilize copper with a reduced (smoother) profile. The drawback is that these materials are more expensive.

Figure 1 Greater copper roughness impedes present flow, resulting in higher losses. Source: Intel

Alternative: Making use of a newer kind of copper aluminum foil, commonly referred to as RTF2, is gaining appeal in the market. RTF2 is a copper foil with a non-uniform roughness profile whose efficiency is close to active really reduced profile (HVLP) copper foil but can be manufactured at a reduced price. The future generation of RTF2 copper aluminum foil is also being examined to achieve HVLP-like efficiency with minimal boost.

3. Oxidation process

In PCB production, a surface area oxidation procedure is usually called for to promote attachment in between core and also prepreg layers for optimal bonding. An exact balance must be struck throughout this procedure because while raising the surface area roughness of copper foil will certainly aid to improve attachment, it can have a substantial negative effect on the copper account and thus on signal stability. An inaccurate or unnecessarily hostile oxidation process can squash the improvements gotten by spending for better-performing, lower-profile copper aluminum foils by over-roughening them prior to bonding.

Option: Low-etch oxidation chemistry and bond marketers– which decrease the need for roughing up of the copper surface while maintaining the desired bonding toughness of the PCB– are being established and embraced by the sector. Less surface oxidation likewise reduces the possible adverse impact on signal integrity, making this method a win-win.

4. Stackup optimization

In some ways, proper resolution of the PCB stackup is the low-hanging fruit of the efficiency optimization as well as price reduction process because, well, thickness matters.

Number 2 Loss is a feature of stack-up choice, where 3/9 indicates a 3 mil core and 9 mil pre-preg building and construction for stripline. Resource: Intel

Option: When taking a cautious check out the signal loss characteristics of the more common core/prepreg layer density choices, it becomes clear that losses can be minimized merely by taking the time to establish the ideal stackup. In one test executed by Intel engineers, it was found that, when gauging signal loss, a 5/6 stackup– 5 mil core density and 6 mil prepreg thickness– surpassed a 3/9 stackup by more than 15% making use of the exact same substrate and also copper profile.

Obviously, this method is not a bang dunk, as modifications to the stackup can have an unfavorable impact on transmitting density and also sound combining. Nevertheless, it does offer to emphasize that careful option of the stackup and also its signal honesty implications are a crucial step in the efficiency as well as price optimization process.

Partnership with academia

As pointed out over, Intel has undertaken this study initiative as a way to provide alternatives for business which might find it hard– or perhaps difficult– to develop the next-generation products into their systems and styles. Yet despite having the amount of resources that Intel has, there are gaps in the r & d that we just can not fill up on our own.

So, academia has to be involved in these initiatives in any way degrees. Numerous evolutionary advances have actually been made in this field by sector specialists and academicians interacting with the usual objective of recognizing, researching, as well as addressing the issues that afflict PCB manufacturing. This joint strategy is crucial to making sure that our sector continues to introduce and also expand years into the future, just as it does today.