FlexTech Alliance Hosts Printed Electronics Metrology Status and Needs Workshop at NIST
Sep 24, 2012
Industry Gathering Produces Approaches to Advance Manufacturing Strategies
FlexTech Alliance, a trade association and R&D consortium representing the emerging flexible, printed electronics industry, hosted a metrology workshop on September 12-13, 2013 at the National Institute of Standards and Technology (NIST) in Gaithersburg, MD. The purpose of the workshop was to examine current requirements and identify future needs for flexible, printed electronics (FPE) manufacturing. Insights from both the integrated circuit (IC) and flat panel display (FPD) industries were presented.
Chris Soles of NIST opened the workshop with an agency overview, noting multiple industry partnerships and that NIST wants to engage with the FPE industry on manufacturing metrology issues. He was followed by Marc Carter of IPC – Association Connecting Electronic Industries, who provided a history of FPE, stating that the technology was developed 70 years ago to address fuzing issues related to WWII munitions. Carter explained that IPC is part of a worldwide standards organization which is presently balloting 4 key topics including guidelines for printed electronics, base materials, functional materials, and assemblies.
Corning, Orbotech and Imprint Energy reviewed the challenges of obtaining measurements on a flexible substrate, such as plastic or flexible glass. These specifically relate to the differences in material characteristics including mechanical reliability, thermal effects such as expansion and contraction, and processing on a fast moving web as opposed to plate to plate or wafer to wafer. Other challenges being addressed include taking measurements on small, high-resolution displays, and reflective and often optically transparent material. These challenges require that new measurement methods be developed. According to Daniel Toet of Orbotech, position accuracy will be key if film measurements in FPE are to achieve the precision of those current being obtained in FPD manufacturing.
Speakers from Northfield Automation, JA Woollam, NVision, and DarkField Technologies related various, current methods to perform FPE metrology functions and the pros and cons of each. Essentially, these methods can include but are not limited to multiple forms of automated optical inspection (AOI), spectroscopic ellipsometry, conventional and dynamic interferometry, and solid state laser reflection. Jay Provine of Stanford University, who is working in the field of atomic layer deposition (ALD), reviewed several types of measuring techniques for thin films. He concluded that these methods offer insight in different ways and, taken together, provide a more complete measurement picture. However, the time and cost of multiple techniques have to be considered.
Malcolm Thompson, Chief Technical Advisor to FlexTech Alliance, summed up the workshop by stating “Metrology is at the core of yield management and the development of new manufacturing processes. There is much the FPE industry can learn from the IC and FPD manufacturing industries with respect to developing and implementing effective metrology strategies. The door is open to innovative tool and process developers seeking a growing market opportunity.”