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SEMICON Japan 2021 (December 15-17)


SEMICON Japan 2021 Materials such as stretchable paste for flexible device were remarkable

December 15-17, SEMICON Japan 2021 was held in Tokyo Big Site. Main topics of display in this exhibition are picked up.


Stretchable conductive paste with good launderability was exhibited


Picture 1. Printed sample of stretchable paste
As concerns materials, Toyobo appealed stretchable conductive pastes, were commercially adopted for high-end sportswear. Ag paste and carbon paste for the screen printing have been resealed yet. Specific resistance of the former is 1.0 - 2.0×10-4Ω･cm. Of course, if printed wiring is elongated, contorted and bended, it is not broken, and also, electric characteristics are not almost changed. Concretely, increase of specific resistance at 50 % extension is mere 4 %, and also, after 100 time laundry, it is mere 3 %, too.

Fine pattern same as a few dozen μm is obtained by IJ printing + laser trimming

Elephantech, a start-up company (established in 2016) introduced an original FPC "P-Flex", which was produced by ink jet printed Nano Ag and plated Cu selectively. The company announced that P-Flex has been commercially adopted at semi-mass production.


Picture 2. Patterned metal wiring by IJ printing + laser trimming
Furthermore, newly fine patterning technology was introduced. In this process, firstly Ag ink is printed by the IJ printing method, and then, its printed wiring is finely patterned by the laser trimming method (wavelength 550 nm), finally Cu film is selectively deposited by the plating method. As a result, patterning resolution was fined from L&S = 200μm/200μm to L&S = 100μm/100μm.

Moreover, as picture 2, ultra-fine pattern same as L&S = 21μm/13μm was obtained recently. By the way, manufacturing process cost of this new method is lower than that of the conventional wet-etching method.

Highly crystalline film is deposited at low damage by pressure gradient type sputtering system

With respect to manufacturing system, Kenix appealed a pressure gradient type sputtering system. In this system, work distance was spread from general value (50 ㎜) to 150 ㎜ in 6 inch system, as a result, highly dense plasma is generated neighborhood of sputtering target only. And also, it's possible to keep neighborhood of target at high vacuum state such as 10-2Pa. For this reason, it's easy to deposit highly crystalline film, and also, deposit at low damage against the substrate and under layer.

It's useful for not only nitride and oxide film, but also, various films on organic underlayer. In fact, substrate temperature in oxide film deposition was 95 ℃ and under. In short, it's verified that it was effective for sensitively organic device.

REMARK
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