Issue link: https://iconnect007.uberflip.com/i/1531384
JANUARY 2025 I DESIGN007 MAGAZINE 55 To enable the fabrication of fine-line semi- additive circuits, suppliers will commonly use dielectric materials with very thin Cu foil or use the base materials prepared for the semi- additive copper plating process. Process refine- ment for HDI PCB manufacturing includes implementing more efficient imaging capabil- ity and greater use of alternative hole-forming techniques, applying more advanced etching and plating chemistry, and sophisticated lami- nation methods. When possible, establish periodic meet- ings to review the design with the circuit board supplier as it progresses. This will avoid delays that can affect the product's introduction to the market. The issues to be resolved are the key attributes, land pattern geometr y, and line width and spaces that must be updated to comply with the circuit board fabricators' capability. This is where the circuit board design specialist should have a pre-release discussion with the sup- plier to clarify process capability. Circuit board manufacturers commonly give design- ers practical guidance to help ensure fabri- cation process efficiency, maximize yield, and minimize costs. Manufacturers have developed these guidelines from experi- ence, and when followed, the circuit board is more likely to be processed without com- plications. The circuit board designer will be faced with several challenges: component quantity and complexity, limited surface area, and meeting the circuit board's cost target. Before releasing the design package for a prototype run, ask the fabricator to per- form a fabrication process evaluation. Note that a wide range of PCB design and simulation soware tools are available to help the designer avoid potential system fail- ure because of thermal and mechanical load- ing from growing power dissipation. is is a concern, particularly with smaller board sizes. Analyzing the electrical, thermal, and mechan- ical characteristics of the board will determine whether the semiconductor package(s) and overall board temperatures remain within safe operating limits and will calculate overall stress conditions that could potentially affect end-product reliability. DESIGN007 Appearances Vern Solberg will conduct a half-day Professional Development Course, "PCB Design Engineers Intro- duction to High-Density Semiconductor Package Technologies: 2D, 2.5D, and 3D System-in-Packag- ing and Ultra High Density Interposer Development," on March 17 at IPC APEX EXPO 2025. Vern Solberg is an independent technical consultant, specializ- ing in SMT and microelectronics design and manufacturing tech- nology. To read past columns, click here. Table 1: Establishing HDI interconnect complexity levels. (Source: IPC-2226)