Issue link: https://iconnect007.uberflip.com/i/1126810
20 DESIGN007 MAGAZINE I JUNE 2019 permitting, hoping that we end up booking the business. And when the standard rules are too tight to meet requirements, then we may loosen the rules to more advanced capabilities, which increase cost. Shaughnessy: What are some of the guidelines that you give these designers? Ellis: We provide design presentations for dif- ferent requirements, including BGA and DFM design guidelines and technology capabilities for each TTM fab site. After I've reviewed all the design inputs for specific projects, the site- approved information I provided the customer includes: • Stack-up graphic showing Cu layers, dielectrics, and drill structures • Controlled impedance table, if required • Mechanical and laser via hole min drill/pad diameters • Min. lines/spaces for plated/unplated layers based on starting Cu foil thickness • Design rules for special requirements, as necessary Nolan Johnson: You're saying that you start with a qualification process to figure out what that design team's intent is with the board. How often do you find that they don't know, or are they mostly clear on that by the time they come to you? Ellis: Approximately 80% of my work is with ongoing customers that I have a good relation- ship with, so I'm their first call for the stack- up, DFM guidelines, and sometimes to help with best PCB or array dimensions for panel optimization. Other customers mostly know where their business is going. We support a lot of new development custom- ers, so if one happens to be in the electric vehi- cle or medical space, it's a fair assumption that their PCB assemblies will eventually be manu- factured somewhere in a high-volume region off- shore. When I confirm Asia production intent on a new stack-up, I verify it with TTM China be- fore sending it for customer review. Sometimes, though, engineers need to test their electronic design. They're in a hurry, and they're very lim- ited for space, so they'll use the prototype guide- lines to quickly check functionality. And other designs are limited quantity test boards that will never go into full production. Johnson: For the 20% of your customers that are new to you, do they tend to be as well pre- pared? Ellis: Not necessarily, although a lot of new "customers" are actually familiar friends who moved from a previous customer. Most design- ers I work with already have some experience working with a fabricator, and the ones who haven't are normally glad to have the opportu- nity to learn. Dan Feinberg: The customer can come to you for the entire package and get assistance, ideas, or recommendations regarding help with the ini- tial part of the design. Ellis: Yes. TTM has a design center in Stafford, Connecticut, where we can provide new elec- tronic designs, redesigns, PCB layout, and elec- tro-mechanical designs. Our Anaren division designs and manufactures high-frequency RF and microwave microelectronics, components, and assemblies for the space, defense, and telecom sectors. Our EMS sites in China do full turn-key PCB assemblies and box-builds. We also work with a lot of good design bureaus and can provide referrals to reputable outside resources for work we don't do. Feinberg: Regarding designers working with others in expanding collaboration, what's hap- pening with the designers working with the suppliers? I know that it didn't used to be the case, but it has become more of the case over the last number of years. For example, if a dry- film supplier comes up with a way to do lines and spaces with straight sidewalls with 0.5- mm lines and spaces, would you then go to a photoresist supplier in today's and work with them to discern if they can develop the mate- rial that would be congruent with your design?