An Inside Look: 3D AOI of Electronic Assemblies Seminar

Reading time ( words)

The prestigious Manufacturing Technology Centre in Coventry, UK, was an appropriate venue for SMART Group’s seminar on 3-Dimensional Automated Optical Inspection of electronic assemblies, “3D AOI." The event brought together experts from leading AOI suppliers, to discuss and explain different approaches to three-dimensional inspection and to present the latest in technology to an attentive audience of engineers from the electronics manufacturing industry with a collective interest in yield improvement, process control, and quality assurance. All were welcomed by SMART Group Chairman Keith Bryant, who introduced the speakers and moderated the panel discussions.

Andy_Bonner.jpg“Putting 3D into Perspective” was the scene-setting theme of the first presentation, from Andy Bonner, managing director of NordsonYestech Europe, who demonstrated how AOI technology had evolved from the mid-1990s to the present day. “Test and Inspection--who needs it?” was a rhetorical question as he described how AOI began to take the place of in-circuit testing once confidence in the quality of integrated circuits had improved to the point where their functionality could be consistently expected. The weaknesses of early AOI machines were low data processing power, limited lighting capability and analogue top-down cameras. Systems were used to check for component presence and orientation, and the presence of solder.

Lighting progressed from plain white through added coaxial red light, which could show up tombstoning, to RGB phased lighting with arrays of different-coloured LEDs at different angles which gave some information on topography, for example the shape of a solder joint. The next step into the third dimension was to use a series of angled high-resolution cameras, which could for example look at IC packages from the side and see leads and solder joints out-of-sight of the top-down camera. A typical configuration for the inspection of assemblies had five cameras with resolution from 25 down to 8 microns and simultaneous image capture. To measure the height of components and features accurately, the options were laser or moiré optical techniques, or a combination of both. Now, with clever software, “Real 3D” was possible--3D systems could be integrated with 2D applications and optimised for speed and repeatability, with fast programming and easy updates for component changes during production.

So what could be achieved with AOI other than just funding faults? Bonner listed yield improvement through feedback to the line, historical data, production statistics, and designer and supplier feedback.

Gary_Leong.jpgGary Leong, director of business development with ViTrox, remarkably bright-eyed after a 14-hour flight from his base in Malaysia, gave an informative presentation entitled “Capturing lifted lead, coplanarity and missing component defects effectively with 3D AOI.” Reflecting on his early career as a post-reflow inspector, he was concerned for his future when the company invested $300,000 in an AOI machine. In fact his job was just the same--his boss saw him as an insurance policy--because placing the machine post-reflow still left the opportunity for many in-process defects and the machine, with top-down cameras, gave too many false calls and missed defects such as lifted leads, missing components, coplanarity and foreign material in unpopulated areas. Fifteen years on, today’s 2D + 3D combination systems were capable of consistently detecting these defects, the 2D functions revealing missing, offset, skewed, wrong part, wrong polarity, billboard and tombstone components, lifted or bent leads, excess or insufficient solder, and solder bridging, complemented by the 3D functions measuring package height and coplanarity to an accuracy of 2 microns.


Suggested Items

CyberOptics: New Partnership Shows Promise for Semiconductor Industry

12/28/2022 | Nolan Johnson, I-Connect007
Nolan Johnson checks in with Sean Langbridge, European sales director for CyberOptics, at electronica to discuss details of the recent merger between CyberOptics and Nordson and the partnership’s potential benefits for customers, especially regarding solutions geared toward enhancing the accuracy of test and inspection in advanced packaging. The company’s unique optical technologies, including its MRS sensors and AI² software, are already saving customers hours on the line; with Nordson’s X-ray capabilities in the mix, CyberOptics sees some very compelling technological solutions on the horizon.

Essemtec: Manufacturing Moves In-house

12/28/2022 | Pete Starkey, I-Connect007
Pete Starkey talks with Kevin Domancich at Essemtec at electronica 2022 about the company integration within Nano Dimension and how the two companies have pioneered an exciting new end-to-end manufacturing solution that helps customers speed up production, cut costs, and keep their proprietary materials secure. In a world where time to market has become a priority consideration, this universal system has the potential to revolutionize the industry.

The ‘Intel’ on Advanced Packaging Options

11/29/2022 | Nolan Johnson, I-Connect007
Dr. Tom Rucker is vice president in technology development at Intel and was a keynote speaker at the IPC Advanced Packaging Symposium, which helped set the table for the rest of the agenda. Tom understands this “radical and seismic” shift in terms of technology and breaks down what it means for the semiconductor and PCB fab industries. There’s absolutely a place at the table for PCB fabricators, but what are the first steps?

Copyright © 2023 I-Connect007 | IPC Publishing Group Inc. All rights reserved.