-
- News
- Books
Featured Books
- design007 Magazine
Latest Issues
Current IssueMechatronics
Our expert contributors discuss the advent of mechatronics in PCB design, the challenges and opportunities this creates for circuit board designers, and the benefits—to the employee and the company—of becoming a mechatronics engineer.
Creating a Culture of Collaboration
PCB designers could learn quite a bit from NASA and the private companies that develop spacecraft: Every one of these vehicles is a testament to the value of collaboration among disparate stakeholders. Without a collaborative culture, the rocket might never get off the ground.
Breaking High-speed Material Constraints
Do you need specialty materials for your high-speed designs? Maybe not. Improvements in resins mean designers of high-speed boards can sometimes use traditional laminate systems. Learn more in this issue.
- Articles
- Columns
Search Console
- Links
- Events
||| MENU - design007 Magazine
HDI, A-SAP and mSAP: A Designer’s Point of View
October 26, 2022 | Cherie Litson, CID+, Litson1 ConsultingEstimated reading time: 1 minute
![](https://iconnect007.com/application/files/2916/9086/4363/cherie_litson__250.jpg)
HDI—high-density interconnect—designs require some different thinking on the part of the designer. One of the first things to consider is whether you need HDI, and if so, how much. The HDI option comes into play as soon as you purchase any components with 0.5 mm pin pitch.
The number of these components and other specifications of your design will determine the amount of HDI you will need. Each option brings choices that will affect fabrication and assembly, so a little research is needed before making these choices. Here’s a quick list of HDI options:
- Smaller vias
- Smaller traces
- Thinner dielectrics
- Tighter solder mask clearances
- Controlled paste mask construction
I’m only going to explore the first two, as these often determine which fabrication process you want to use.
Smaller Vias
A variety of options are available here:
Blind vias with through vias
This is the optimal choice. It adds a little expense while giving you the ability to place components on both sides of the board without having to be confined by opposing pad with different nets.
Blind and buried vias with through vias
This option gives you the most routing control; however, it also adds the most cost.
Through vias only
While this can cut fabrication costs, it limits breakout, routing, via size, and component placement. Smaller vias are dependent upon the aspect ratio of the board. Keep the board thin and most fabricators can produce smaller vias, down to 6 mils (1.5 mm) if your board measures 50 mils of thickness or less, without additional costs.
Both the A-SAP and mSAP processes can be used to plate holes. Again, the aspect ratio will make a difference. Also, how much plating do you need? Are you plugging the vias with conductive or non-conductive material?
Smaller Traces
How small you will go depends on the fabrication process you select and how small the component pin pitch is.
It’s important to understand the differences between A-SAP and mSAP before you commit to a process. Standard subtractive etch processes start with very thin copper foils, etch a pattern, and then add copper for the finished traces and copper features.
To read this entire article, which appeared in the October 2022 issue of Design007 Magazine, click here.
Suggested Items
Altus Highlights Success of Essemtec's I2S in the UK and Ireland Market
07/23/2024 | Altus GroupAltus Group, a leading distributor of capital equipment for the electronics industry in the UK and Ireland, is pleased to highlight the success of Essemtec's Integrated Inspection System (I2S).
Automatic Paste Transfer and Quick Change Squeegee for ASMPT Printers
07/23/2024 | ASMPTASMPT, the market and innovation leader in SMT manufacturing technology, has added two new features to its proven DEK printing platforms that automate solder paste transfers and simplify squeegee changes.
New Breakthrough in Double-Sided Reflow Part Retention from Alltemated
07/19/2024 | AlltematedAlltemated's PLACE-N-BOND™ underfilm passed testing and was implemented in volume production to aid in component retention during the second pass reflow of printed circuit assemblies. This successful testing and implementation occurred in various applications with components such as capacitors, inductors, transformers, connectors, and larger ICs.
Book Excerpt: The Printed Circuit Assembler’s Guide to... Factory Analytics, Chapter 2
07/17/2024 | I-Connect007 Editorial TeamIn this chapter, we’ll focus on the most important analytics at the forefront of SMT, from the solder paste machine to placement machines, and breakdown these metrics from the perspectives of the different decision makers involved in the process. The lead SMT shift manager isn’t going to have the same concerns as a quality manager, so it’s important to look at how each machine and operation contains valuable KPIs for each role.
SMTA Heartland Chapter Announces Rescheduled Date for High Reliability: Virtual STAR Forum
07/10/2024 | SMTAThe SMTA Heartland Chapter announces the rescheduled date for the High Reliability: Virtual STAR Forum, following the overwhelming success of our May event. Join us on Tuesday, July 30, 2024, for an afternoon of engaging discussions and expert insights into high-reliability manufacturing.