Paula Doe, SEMI01.19.10
As companies start volume production of printed electronics products, they’re finding they need tighter control of specifications in their substrate and barrier films, and are looking to some possible solutions from the electronics industry to help solve the problem.
Printed electronics producers at a recent FlexTech Alliance workshop, hosted by the semiconductor manufacturing trade association SEMI in San Jose, all complained that the rolls of flexible substrates and barrier films they were receiving from suppliers were not uniform enough for producing consistent results for their devices, as subtle differences in surface chemistry both within a roll and from roll to roll turn out to have significant impact on electronic performance. Current testing methods can’t differentiate these spatial distinctions, so the films may meet the specifications macroscopically, but not be uniform across all areas.
The more than 100 attendees at the workshop took first steps towards establishing a plan to identify the necessary attributes for the critical inline inspection and failure analysis tools, and to develop standard testing protocols. Suppliers also stressed the need for workshops and roadmaps to communicate clear and common target specifications, to assure focusing development efforts on the right features for real markets.
Nanoparticle technology has made silver and now copper conductive inks easily printable, says IDTechEx CEO Raghu Das, who notes that these advances in functional inks mean that simpler, relatively low resolution electrical circuits can now be produced with existing off-the-shelf printing equipment with minor customization. But volume manufacture of higher performance electronics products, from displays to solar cells to memory, has proved a little trickier, requiring electronics-industry type metrology, quality control, and standards for materials.
“One key need is online real-time inspection tools,” says Dan Gamota, principal of startup Printovate, Inc., and formerly director of Motorola’s printed electronics effort. The group proposed starting a collaborative effort to advance understanding of failure mechanisms and yield killers in printed electronics, by specifying the common types and densities of defects that matter in its products, and then looking for what families of tools and solutions already exist to find them, whether in university labs or other industries, from semiconductors to the high speed film processing world.
“Other industries may have already looked at these issues,” notes Gamota. “And transferring solutions from other industries would probably be an easier option for bringing things over faster, since universities can sometimes take considerable time to develop tools.” Gamota and iNEMI are working with SEMI to gather input from its member suppliers of electronics industry metrology, inspection, and defect analysis to include this expertise in the large area flexible electronics section of the 2011 iNEMI electronics industry roadmap.
Though the users complained about the inconsistent quality of materials they received from suppliers, the suppliers countered that users must more clearly specify the characteristics that were most important, and must be willing to pay for obtaining uniform quality in those key areas. It was agreed that defining a few broad categories of standard material quality, as the semiconductor industry did early on, would allow suppliers to focus their limited development funds on controlling key specifications to the necessary degree for multiple customers, instead of having to do separate custom development for each customer.
Both users and suppliers stressed the need for more appropriate and more standard testing protocols, including testing after integration and processing, not just on flat lab samples, as inks on the surface and rolling through presses change performance. Testing also needs to be performed with conditions that reflect real conditions of product use, like flexing. Products for solar applications need to be tested under exposure to light and impure water spray, not just the typical heat and humidity. Participants suggested a central standard testing lab would be useful for testing films, barriers and adhesives, since different labs tend to get different results even with the same test equipment.
Realistically, too, most printed/flexible products to date involve hybrid solutions combining the new processing approaches (e.g. non-vacuum, wide-web, and solution processing) with more traditional electronics processes like lithographic patterning and vacuum thin film deposition. Thus integrated manufacturing platforms that deal with these multiple processes, as well as metrology and software controls, will be needed to enable large scale commercialization. In the “printed/flexible” solar market, for example, as there is as yet no existing flexible encapsulant to protect flexible photovoltaics from degeneration under sunlight’s ultraviolet radiation, the hybrid solutions range from vacuum deposition on flexible substrates (Unisolar/Gobal Solar), to solution-coating on flexible substrates then covered with rigid glass sheets (Nanosolar), to printing solar film on top of silicon wafers (Innovalight).
Most printed/flexible electronics production still also requires high temperature processes for at least some steps, restricting most production still to metal foil substrates. Heat resistant foils in fact will account for 84% of the substrate market in 2010, with polymers only reaching 26% even by 2013, says Nanomarkets analyst Paul Markowitz.
Companies interested in joining the collaborative efforts to move the printed electronics industry forward can attend future FlexTech Alliance’s quarterly workshops (www.Flextech.org), or join the technical working group chaired by Gamota ([email protected]) to specify development priorities for large area, flexible electronics for the 2011 edition of iNEMI electronics roadmap (www.inemi.org). The working group is planning to build upon the 2009 roadmap and expand the applications section (solar, display, RFID, and sensors) to include “Needs, Gaps, and Showstoppers” for PoP/PoS Signage, ePackaging, eLabels, and SmartPackaging products.
The more than 100 attendees at the workshop took first steps towards establishing a plan to identify the necessary attributes for the critical inline inspection and failure analysis tools, and to develop standard testing protocols. Suppliers also stressed the need for workshops and roadmaps to communicate clear and common target specifications, to assure focusing development efforts on the right features for real markets.
Nanoparticle technology has made silver and now copper conductive inks easily printable, says IDTechEx CEO Raghu Das, who notes that these advances in functional inks mean that simpler, relatively low resolution electrical circuits can now be produced with existing off-the-shelf printing equipment with minor customization. But volume manufacture of higher performance electronics products, from displays to solar cells to memory, has proved a little trickier, requiring electronics-industry type metrology, quality control, and standards for materials.
“One key need is online real-time inspection tools,” says Dan Gamota, principal of startup Printovate, Inc., and formerly director of Motorola’s printed electronics effort. The group proposed starting a collaborative effort to advance understanding of failure mechanisms and yield killers in printed electronics, by specifying the common types and densities of defects that matter in its products, and then looking for what families of tools and solutions already exist to find them, whether in university labs or other industries, from semiconductors to the high speed film processing world.
“Other industries may have already looked at these issues,” notes Gamota. “And transferring solutions from other industries would probably be an easier option for bringing things over faster, since universities can sometimes take considerable time to develop tools.” Gamota and iNEMI are working with SEMI to gather input from its member suppliers of electronics industry metrology, inspection, and defect analysis to include this expertise in the large area flexible electronics section of the 2011 iNEMI electronics industry roadmap.
Though the users complained about the inconsistent quality of materials they received from suppliers, the suppliers countered that users must more clearly specify the characteristics that were most important, and must be willing to pay for obtaining uniform quality in those key areas. It was agreed that defining a few broad categories of standard material quality, as the semiconductor industry did early on, would allow suppliers to focus their limited development funds on controlling key specifications to the necessary degree for multiple customers, instead of having to do separate custom development for each customer.
Both users and suppliers stressed the need for more appropriate and more standard testing protocols, including testing after integration and processing, not just on flat lab samples, as inks on the surface and rolling through presses change performance. Testing also needs to be performed with conditions that reflect real conditions of product use, like flexing. Products for solar applications need to be tested under exposure to light and impure water spray, not just the typical heat and humidity. Participants suggested a central standard testing lab would be useful for testing films, barriers and adhesives, since different labs tend to get different results even with the same test equipment.
Realistically, too, most printed/flexible products to date involve hybrid solutions combining the new processing approaches (e.g. non-vacuum, wide-web, and solution processing) with more traditional electronics processes like lithographic patterning and vacuum thin film deposition. Thus integrated manufacturing platforms that deal with these multiple processes, as well as metrology and software controls, will be needed to enable large scale commercialization. In the “printed/flexible” solar market, for example, as there is as yet no existing flexible encapsulant to protect flexible photovoltaics from degeneration under sunlight’s ultraviolet radiation, the hybrid solutions range from vacuum deposition on flexible substrates (Unisolar/Gobal Solar), to solution-coating on flexible substrates then covered with rigid glass sheets (Nanosolar), to printing solar film on top of silicon wafers (Innovalight).
Most printed/flexible electronics production still also requires high temperature processes for at least some steps, restricting most production still to metal foil substrates. Heat resistant foils in fact will account for 84% of the substrate market in 2010, with polymers only reaching 26% even by 2013, says Nanomarkets analyst Paul Markowitz.
Companies interested in joining the collaborative efforts to move the printed electronics industry forward can attend future FlexTech Alliance’s quarterly workshops (www.Flextech.org), or join the technical working group chaired by Gamota ([email protected]) to specify development priorities for large area, flexible electronics for the 2011 edition of iNEMI electronics roadmap (www.inemi.org). The working group is planning to build upon the 2009 roadmap and expand the applications section (solar, display, RFID, and sensors) to include “Needs, Gaps, and Showstoppers” for PoP/PoS Signage, ePackaging, eLabels, and SmartPackaging products.