If you own a cell phone, chances are its chips passed under a HEIDENHAIN product somewhere along the way. “We like to say that every cell phone that’s out there has seen a HEIDENHAIN product,” said David Doyle, president and CEO of HEIDENHAIN U.S., which represents the German HEIDENHAIN Corporate Group in the U.S., Canada and Mexico. Doyle said nearly all inspection and metrology systems in the industry carry HEIDENHAIN technology of one kind or another, either at the encoder level or as a complete wafer stage. What’s changing, he said, is where that technology is headed. “What we’re beginning to see is the shift of front-end technology now applying in the back end as it relates to advanced packaging,” Doyle said. “The back end requires increasingly smaller dimensions. Not quite at the front end, but on the motion control side, there is a further degree of accuracy and precision required.” As chiplets and heterogeneous integration take hold, sub-50 nm precision in motion control is where packaging is headed, “and actually we’re there already.” METIS HP debuts The proof point at the show is the METIS HP from ETEL, the group’s Swiss motion systems company, a full air bearing XY stage for step-and-scan applications such as direct laser writing and high-resolution optical inspection. It supports panels up to 600 mm x 600 mm. Integrated into its axes are HEIDENHAIN multi-degree-of-freedom (mDoF) encoders, which measure position along an axis as well as rotation, giving the controller far more information than a conventional linear scale ( FIGURE 1 ). Figure 1. The ETEL METIS HP combines the motion system, motors, active vibration isolation and motion control in one platform. (Source: HEIDENHAIN/ETEL) Other features include ironless, water-cooled linear motors to pull heat out of the system (“heat, much like in the semiconductor device itself, is the enemy of performance and reliability,” Doyle noted) and a metrology frame isolated from the moving components and located close to the wafer, for a cleaner reading of where the substrate actually is. According to ETEL, the stage delivers ±150 nm accuracy over the full XY stroke after mapping, ±150 nm dynamic straightness at speeds up to 1 m/s and acceleration up to 2 m/s². Doyle put precision at 50 nm. Dynamic straightness matters for scanning applications. “Let’s say you wanted to look down a scribe lane, or you wanted to use a laser ablation-type system to singulate,” he said. “This straightness would be a critical parameter for that application.” Doyle has a personal connection to the platform. He worked with the original METIS architecture at Nanometrics, where it was introduced around 2008. “Almost 20 years later, it’s a similar overall architecture, where we’re taking all of the innovation over the last 15 years or so and building a system with these capabilities,” he said. And more is coming: HEIDENHAIN showed a technology at SEMICON Taiwan capable of roughly ±5 nm precision, though it has not yet been formally announced as a product. Settling faster, measuring better HEIDENHAIN’s pitch is integration from the floor up to the chuck: encoders, motors, vibration isolation, granite, stage and control electronics tied into a single control loop. Doyle said that approach removes about 99.9% of vibration, which lets a stage accelerate quickly and, more importantly, settle quickly. “When you stop a motion system, you typically have a certain amount of ringing,” he said. Compressing that settling time improves throughput, “and if you’re waiting to make a measurement, you can use more time to integrate and improve your signal-to-noise and your measurement uncertainty.” The group is also working with partners adapting front-end technology to panel handling, where substrate flatness is a big challenge. “We provide the motion system, they provide the chuck and the handling, and we try to get the substrate moving in the right way, in the right place,” Doyle said. Thermal compression bonding s