Water-based high-volume stress-free ultra-thin powder-chip method

Noda, Hideyuki; Usami, M.; Sato, Akira; Terasaki, Satoshi; Ishizaka, Hironori

doi:10.1109/ectc.2009.5074212

Cited by 3 publications

(4 citation statements)

References 18 publications

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“…A micropipette with inner-and outer diameters of 41 and 87 μm was used to pick up a single chip from a 1.0-ml 30% methanol solution filled with chips. The details of the capture conditions were described in previous reports [6,7]. After the pick-up process, the pipette was moved above a preformed liquid droplet.…”

Section: Single Chip Pick-up and Manipulatementioning

confidence: 99%

“…Au-sputtering was used to form 50-μm-square electrodes on both surfaces of the chip. After finishing the chip fabrication on a wafer scale, the chips on the support sheet were put into a resiststripping solution and then released [6,7]. For the subsequent pick-up process, the chips were removed from the stripping solution and put into a 30% methanol liquid solution.…”

Section: Powder Chipsmentioning

confidence: 99%

“…Our UH apparatus was used to manipulate a single chip [6,7]. A micropipette with inner-and outer diameters of 41 and 87 μm was used to pick up a single chip from a 1.0-ml 30% methanol solution filled with chips.…”

Section: Single Chip Pick-up and Manipulatementioning

confidence: 99%

“…We have recently developed an ultra-small and ultra-thin RFID chip (75757.5-μm powder chip) handling technique, called UH [6,7]. The technique uses double-surface-electrode chips and water-based single-chip micropipette manipulation.…”

Section: Introductionmentioning

confidence: 99%

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Self-aligned positioning technology to connect ultra-small RFID powder-chip to an antenna

Noda

Usami

Sato

et al. 2011

2011 IEEE 61st Electronic Components and Technology Conference (ECTC)

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We propose a process of stress-free self-alignment of an ultra-small, ultra-thin (75755 μm) radio frequency identification (RFID) chip (called a "powder chip") on an antenna film. The process consists of only two simple steps: dispensing a micro-liter liquid droplet with a semispherical diameter of about 1 mm onto a hydrophilic/hydrophobic patterned surface on the antenna film and then releasing a single powder chip onto the droplet. In this method, the dispensed droplet is several tens of times larger than the chip. The hydrophilic surface domain, functioning as an electrode, exists inside the hydrophobic domain. First, the chip released onto the liquid droplet is captured on the liquid/atmosphere interface and is kept floating on the droplet. The droplet gradually shrinks due to evaporation, and the liquid on the hydrophobic domain moves toward the hydrophilic domain. In other words, the liquid that captured the chip is drawn into the hydrophilic electrode domain. When the droplet has completely evaporated, the chip is self-aligned on the hydrophilic electrode domain under stress-free conditions. The key to this technique is determining the balance between the chip size and the liquid droplet size that is necessary to keep the chip afloat. First, the feasibility of the floating condition of the chip on the liquid droplet was determined by calculating isostasy and Laplace pressure force equations. Next, in order to select an appropriate hydrophobic surface, changes in the receding contact angles during the motion of liquid droplet shrinkage on various hydrophobic patterned surface substrates were investigated. On a fluorocarbon-based hydrophobic surface, a greater hydrophobic contact angle of more than 90˚ was kept stable, even for a droplet size with a substrate contact width of 0.7 mm. Furthermore, a receding contact angle of about 20˚ was obtained even after the droplet had shrunk to a diameter of 0.2 mm. In these conditions, the powder chip was able to move together with the droplet edge, and was positioned in the predefined 150-μm-square hydrophilic domain. The combination of our double-surfaceelectrode chip and the liquid droplet self-aligned process makes it possible to place a chip on a predetermined area on an antenna film without high-accuracy positioning requiring high-end robotics.

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Section: Single Chip Pick-up and Manipulatementioning

confidence: 99%

Section: Powder Chipsmentioning

confidence: 99%

Section: Single Chip Pick-up and Manipulatementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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