Issue link: https://iconnect007.uberflip.com/i/1539283
56 DESIGN007 MAGAZINE I SEPTEMBER 2025 C O N N ECT T H E D OTS als, intricacy, and cost. Designers can't simply pile one on top of another to reach the desired level of functionality. Additional layers create increased complexity and additional considerations, including signal integrity, heat, increased materials cost, and overall manufacturability. I encourage designers to carefully consider the optimum number for their design and focus on key design elements that can ensure an effective lamination process, control costs, and produce a reliable board: • Avoid designs with excessive layers that increase costs without improving performance • Design a symmetrical layer stack, paying attention to copper distribution and the thick- ness of non-conductive (dielectric) materials • Accurately align the drill holes to the cop- per pads across multiple layers of the board, ensuring the through-holes align and con- nect the intended paths without creating an unreliable connection or short-circuits • Stop me if you've heard me talk about this before: Design traces with consistent widths and spacing to maintain impedance control • Another one you might be familiar with, if you regularly read my articles: Avoid unnecessary blind or buried vias that can create problems during production and increase cost • Collaborate with your manufacturing partner about your stackup and material properties to prevent costly reworks Designing for the Reality of UHDI PCBs These design strategies will become more important as electronic devices increasingly rely on the most advanced boards. You can find ultra high density interconnect (UHDI) PCBs inside your phone, wearable, and PC. They enable more advanced products like medical devices and driver-assist systems in automobiles. Cutting-edge UHDI technology pushes the limits of fabrication capabili- ties for PCBs and challenges designers to reduce both the footprint and thick- ness of their board designs. UHDI's advanced miniaturization and integration pack a transformative amount of functionality in a small footprint. Though not new technology, the proliferation of UHDI into a broader array of devices represents a quantum leap for our industry. It is changing the fundamental method of manufacturing boards and creating the need for new manufacturing methods, equipment, chemistry, materials, and inspection capabilities. Designing for the reality of manufacturing UHDI PCBs represents a new challenge for many of us. There will be a wide range of design considerations related to new, more advanced fabrication tech- niques, higher-performance materials, 3D integration methodologies, leading-edge thermal management solutions, and ultramodern simulation tools. To learn more about how UHDI is shaking up PCB design and manufacturing, check out this recent Design007 feature article. For a deeper dive into this topic, listen to this episode of On the Line with… where we also discuss the complexities of sequential lamination for high-density PCB designs. DESIGN007 Matt Stevenson is the vice president and general manager of ASC Sunstone Circuits. To read past columns, click here. Download Matt's book, The Printed Circuit Designer's Guide to… Designing for Reality and listen to the podcast here. This stage of manufacturing is where we fuse multiple layers of a PCB into a single board. The sequential lam- ination process used for multilayer boards involves lay- ering copper and substrate materials, then applying heat and pressure to bind them together. Engineers laminate individual subsets of layers separately, then bond them together in subsequent cycles. The result is an electrically connected PCB. For a more detailed breakdown of the process, listen to episode four of I-Connect007's On the Line with… podcast. A Quick Refresher on Lamination