Beyond Design: High-speed Rules of Thumb
Global PCB Connections: A Technical Overview of Long-flex Printed Circuit Boards
The Shaughnessy Report: A Handy Look at Rules of Thumb
Reassessing Surface Finish Performance for Next-gen Technology, Part 1
June 26, 2023 | Frank Xu, PhD and Martin Bunce of MacDermid Alpha, and John Coonrod of Rogers Corp.Estimated reading time: 1 minute
Introduction
Over the years, various surface finishes have been successfully utilized, namely organic solderability preservative (OSP), immersion silver (ImAg), immersion tin (ImSn), electroless nickel immersion gold (ENIG), and electroless nickel electroless palladium immersion gold (ENEPIG), as solderable finishes for PCB and package substrates. All these surface finishes have their pros and cons, with no single finish being suited to all applications.
As system designers continue to respond to new performance demands, it can be noted that ENIG/ENEPIG finishes have endured as a leading choice in many advanced applications where reliability is prioritized over cost.
Electroless nickel (EN) deposits have served well as a barrier layer, preventing copper migration to the outer gold or palladium-gold surfaces, and enabling the robust solderability performance of ENIG and ENEPIG finishes. However, the introduction of the 5G mobile network creates a growing demand for smartphones, networking, and wireless connections, all requiring increased “data flow.” The need to reduce the signal loss at higher frequency bandwidth is becoming vitally important. The low conductivity and magnetic properties of EN affect electrical signals as they travel along a conductor’s outer surfaces leading to insertion losses at higher frequencies.
As a result, designers and fabricators are looking for newer-generation surface finishes to meet their performance criteria. EPIG (electroless palladium immersion gold with no EN), silver-gold (Ag-Au), and reducing the EN thickness from traditional ENEPIG, have all gained attention. What follows is a review that compares the performance attributes of the leading candidates for a high-frequency alternative surface finish.
MacDermid Alpha Electronic Solutions has worked in partnership with Rogers Corporation to evaluate the effect of various surface finishes on signal loss with increasing frequency. Together, we subsequently worked to understand and compare other critical-to-quality performance metrics that will guide application-based surface finish selection.
Work Program
We first set out to evaluate the effect of surface finish on signal losses up to 110 GHz using the microstrip test method and a vector network analyzer, with the support of Rogers.
To read this entire article, which appeared in the June 2023 issue of Design007 Magazine, click here.
Share on:
Suggested Items
Unlocking Advanced Circuitry Through Liquid Metal Ink
10/31/2024 | I-Connect007 Editorial TeamPCB UHDI technologist John Johnson of American Standard Circuits discusses the evolving landscape of electronics manufacturing and the critical role of innovation, specifically liquid metal ink technology, as an alternate process to traditional metallization in PCB fabrication to achieve ever finer features and tighter tolerances. The discussion highlights the benefits of reliability, efficiency, and yields as a tradeoff to any increased cost to run the process. As this technology becomes better understood and accepted, even sought out by customers and designers, John says there is a move toward mainstream incorporation.
Fresh PCB Concepts: The Critical Nature of Copper Thickness on PCBs
10/31/2024 | Team NCAB -- Column: Fresh PCB ConceptsPCBs are the backbone of modern electronics and the copper layers within these boards serve as the primary pathways for electrical signals. When designing and manufacturing PCBs, copper thickness is one of the most critical factors and significantly affects the board’s performance and durability. The IPC-6012F specification, the industry standard for the performance and qualification of rigid PCBs, sets clear guidelines on copper thickness to ensure reliability in different environments and applications.
Book Excerpt: The Printed Circuit Designer’s Guide to... DFM Essentials, Ch. 1
10/25/2024 | I-Connect007The guidelines offered in this book are based on both ASC recommendations and IPC standards with the understanding that some may require adjustment based on the material set, fabricator processes, and other design constraints. This chapter details high-frequency materials, copper foil types, metal core PCBs, and the benefits of embedded capacitance and resistor materials in multilayer PCBs.
The Cost-Benefit Analysis of Direct Metallization
10/21/2024 | Carmichael Gugliotti, MacDermid AlphaCarmichael Gugliotti of MacDermid Alpha discusses the innovative realm of direct metallization technology, its numerous applications, and significant advantages over traditional processes. Carmichael offers an in-depth look at how direct metallization, through developments such as Blackhole and Shadow, is revolutionizing PCB manufacturing by enhancing efficiency, sustainability, and cost-effectiveness. From its origins in the 1980s to its application in cutting-edge, high-density interconnects and its pivotal role in sustainability, this discussion sheds light on how direct metallization shapes the future of PCB manufacturing across various industries, including automotive, consumer electronics, and beyond.
Connect the Dots: Designing for Reality—Pattern Plating
10/16/2024 | Matt Stevenson -- Column: Connect the DotsIn the previous episode of I-Connect007’s On the Line with… podcast, we painted the picture of the outer layer imaging process. Now we are ready for pattern plating, where fabrication can get tricky. The board is now ready to receive the copper traces, pads, and other elements specified in the original CAD design. This article will lay out the pattern plating process and discuss constraints in the chemistries that must be properly managed to meet the customer's exacting manufacturing tolerances.