- design007 Magazine
Latest IssuesCurrent Issue
Rigid-flex: Designing in 3D
In this month’s issue, our expert contributors share their best tips, tricks and techniques for designing rigid-flex circuits. If you’re a rigid board designer considering moving into the 3D world of rigid-flex, this issue is just what the doctor ordered!
Simulation, Analysis, and AI
Getting today’s designs “right the first time” is critical, especially with costly advanced PCBs. Simulation and analysis software tools can help you in the fight to eliminate respins. They’re not magical, but they can predict the future of your design.
Advanced, Complex & Emerging Designs
This month, our contributors focus on designing PCBs with advanced, complex and emerging technologies. We investigate design strategies for boards that are on the cutting edge of technology, or crazily complex, or so new that designers are still writing the rules as they go.
- Events||| MENU
- design007 Magazine
Designing Additive and Semi-Additive PCBsApril 26, 2022 | Cherie Litson, CID+, Litson1 Consulting
Estimated reading time: 1 minute
With components getting smaller and electronic devices becoming more compact, we are reaching the physical limits of the typical etched fabrication processes. To address these limits, new additive and semi-additive processes are being developed to fit into the current fabricators’ production lines without too much disruption or extra cost.
That leaves the design engineer with a few questions: Will additive and semi-additive processes really reduce layer count and sizes? Are there signal integrity and impedance advantages and disadvantages? When does it makes sense to switch to additive or semi-additive? Are my DFMs going to be any different?
Answers to these questions and many more are still being developed. However, I’ve found a few answers that I’m happy to share with you.
First, let’s look at liquid metal ink. LMI is ultra-thin and ultra-dense, conforms to any 3D surface, works with different pure metals and their alloys (copper, gold, silver, palladium, platinum, etc.), and is non-aqueous, which enables low-cost manufacturing.
Here are some fundamentals for these very small features. Figure 1 depicts some examples of the additive processes used to create fine copper traces on a printed circuit board. One of the first things you’ll notice are the shapes of the traces: They are not trapezoidal.
To read this entire article, which appeared in the April 2022 issue of Design007 Magazine, click here.
There has always been pressure to reduce line and space as we have seen the bleeding edge technology go from 8 mils to 5 mils and then to 3 mils. The difference between “then” and “now” is that the prior advancements, for the most part, used the same processes, chemistry and equipment going from 8 mils to 3 mils. But going from 3 mil to sub 1 mil trace and space is a quantum leap in printed circuit board (PCB) technology that requires a whole new set of processes and materials.
In a previous column, the critical process of desmear and its necessity to ensure a clean copper surface connection was presented. Now, my discussion will focus on obtaining a void-free and tightly adherent copper plating deposit on these surfaces. After the desmear process, the task is to insure a continuous, conductive, and void-free deposit on the via walls and capture pad. Today, there are several processes that can be utilized to render vias conductive.
Panasonic’s Darren Hitchcock spoke with the I-Connect007 Editorial Team on the complexities of moving toward ultra HDI manufacturing. As we learn in this conversation, the number of shifting constraints relative to traditional PCB fabrication is quite large and can sometimes conflict with each other.
MKS’ Atotech, a leading surface finishing brand of MKS Instruments, will participate in the upcoming IPCA Expo at Bangalore International Exhibition Centre (BIEC) and showcase its latest PCB manufacturing solutions from September 13 – 15.
Flexible circuit applications can be as basic as furnishing electrical interconnect between two conventional circuit board assemblies, or to prove a platform for placing and interconnecting electronic components. During the planning and pre-design phase of the flexible circuit, there will be several material and process related questions that need to be addressed. Most flexible circuit fabricators welcome the opportunity to discuss their customers’ flexible circuit objectives prior to beginning the actual design process.