APEX focuses on test and inspection

03/01/2002

SAN DIEGO, CALIF. - Test and inspection equipment of all kinds could be found all over the show floor at the IPC's APEX conference and exhibition in January. Many of the manufacturers of X-ray systems seemed to have some new twist on their offerings, and there were some more revolutionary approaches to test and inspection challenges as well.

On the inspection side, one of the most interesting capabilities demonstrated was an X-ray video of the evolution of a void in a solder ball located above a via in a printed circuit board (PCB). Phoenix X-ray Systems showed that, as well as its system that fills the space between high-resolution failure analysis and high-speed in-line inspection. An interesting comment from Adrian Wilson, president of Phoenix, was that a back-end tool such as an X-ray system was finding applications in the front end of wafer processing. The resolution of such equipment has reached the point where it can see defects in silicon or interconnect in power devices, for example. FeinFocus also introduced an X-ray inspection system with sub-micron defect detection capability.

Photon Dynamics and Viscom both had equipment with a combination of optical and X-ray inspection. Paul Handler, VP of North American operations at Viscom, said that they are the only two suppliers this versatile tool, and Viscom also had a system for inspecting and analyzing wire bond sweep. Bruce Delmore, president of the electronics division of Photon Dynamics, described the "adaptive learning system" of their system, in which true defects are "remembered" by the system to help eliminate false identification of defects.

In an interesting example of advanced packaging technology pushing the equipment capabilities, Stuart Wright of X-TEK Systems described its computerized tomography approach for creating 3-D X-ray images of any slice of a structure. This was initially developed for an application involving stacked packages.

At the entry level, Metcal introduced a simple and elegant system for inspecting BGA ball attachment. The miniature optical system can see under packages with a 50 µm stand-off, so it works for many chip scale packages (CSP) and micro-surface mount devices.

Agilent Technologies had a clever - and patented - technique for identifying non-wetted solder balls. With packages and PCBs being unavoidably warped, it is difficult to specify how tall a solder ball needs to be to be in contact with both. Instead of imposing global limits, Agilent reduces false negatives by using an algorithm that compares the solder ball height to its near neighbors; this allows a true anomaly to stand out.

Another intriguing product used infrared imaging for a combination of inspection and test. Advanced Research Technologies (ART) has an infrared imaging system that views a board or component while it is operating, and by comparing the image to stored images of known-good devices, it is essentially able to test the unit.

Services, Software and Opto

Some of the larger companies at APEX presented offerings that matched their size. Siemens Dematic Electronic Assembly

Systems, for example, announced that they will now guarantee not just throughput for users of their production equipment, but also yield, time to market, time to volume, and production cost. Siemens calls this its Enterprise Partner Program, and it is similar to the guarantees of Applied Materials in the front end of semiconductor manufacturing, according to Patrick Trippel, president of Siemens Dematic.

Teradyne, another large exhibitor at APEX, had some new software packages that help to orchestrate a whole suite of test equipment. With a floor full of optical inspection, X-ray inspection, in-circuit test and functional test equipment, it would be easy to suffer from the pitfalls of inefficient usage of the equipment. Teradyne's software optimizes the flow of parts through the system to maximize yield, throughput, asset usage and fault coverage.

There were some interesting assembly capabilities on display, as well. Neil MacRaild of DEK described the successes of its wafer-level ball placement machine. It can put 100,000 solder balls on an 8-inch wafer in one pass with 100 percent yield, for example. The system is flexible, with the ability to handle tiled substrates (not just wafers) with the appropriate tooling.

Optoelectronic assembly was, of course, represented, although they hype was diminished compared to trade shows during the past year or two. Adept Technology had a new product for automated fiber alignment, although Joseph Campbell, VP of marketing at Adept, noted that true automation is not possible until standards for the physical components are in place. When this point is reached, then the corresponding automatic handling systems can be integrated, resulting in true optoelectronic assembly automation.

Photonics West

Interestingly, at The International Society for Optical Engineering's Photonics West, a simultaneous event in San Jose, Calif., some volume production approaches to optoelectronic assembly began to emerge. Newport had several pieces of equipment that looked like something from a production floor rather than a research lab, with their new offering being a laser diode characterization system for testing of bare laser diode chips. Because the packaging of such devices is still quite an expensive endeavor, it is especially beneficial to be able to test them before they are packaged.

In a related discussion at Photonics West, Chris Gracie, the chief executive of the Scottish Optoelectronics Association (SOA), told Advanced Packaging that optoelectronics assembly needs more real production solutions. The SOA has been helping Scottish start-ups find funding for several years, but it is now setting up an optoelectronic packaging center in Scotland to help the start-ups take the next step. They will help to create production capabilities for cost-effective manufacturing.