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The Total Solution Exhibition for Electronic Equipment 2024 (June 12 - 14)


The Total Solution Exhibition for Electronic Equipment 2024
Topics about wiring manufacturing process have been proposed

June 12 - 14th, The Total Solution Exhibition for Electronic Equipment 2024 was held in Tokyo Big Sight. Main topics are picked up.


Atsugi Micro exhibited Soar's PM-OLED


Pic.2 3.4-inch multicolor PM-OLED

Pic.1 Transparent PM-OLED
As regards display module, patterning maker "Atsugi Micro" exhibited Soar's passive matrix-OLEDs. Atsugi Micro has patterned ITO anode line and bus metal electrode on the glass substrate, and then, Soar has manufactured OLE device on the substrate with ITO and metal electrodes. In the booth, transparent 1.4-inch panel (45 segment) and 3.4-inch multicolor panel (256 × 64 dots) were demonstrated. As picture 1, in the former, it's possible to see background because of high transmittance same as 75 %.

Specific Cu series powder can be sintered at low temperature in atmosphere

As concerns flexible device such as FPC, Mitsui Metal introduced a specific Cu series powder, is sintered at low temperature in atmosphere. It's composed of pure Cu powder and specific additive agent. After printing this Cu series paste on the substrate, Cu grain is covered with additive agent in annealing process at 200 ℃. For this reason, this film is not oxidized at film state, and then, its specific resistance is relatively low same as 10-5 Ω･cm order. The company supplies this Cu series power to paste makers.

Wiring electrode with 3D shape is formed by polyaniline + plating Cu


Pic.3 3D form wiring sample using polyaniline
On the other hand, Yamagata University proposed polyaniline + plating Cu wiring as 3D shape wiring for 3D shape structure. Solvent soluble type polyaniline is printed on a plastic sheet by the screen printing method and cured at 130 - 140 ℃, and then, this substrate is cast by heating. Subsequently, a commercial Cu plating solution is selectively plated on polyaniline wiring. As a result, flexible wiring is completed.

As you can image easily, polyaniline is good correspondence with stretch, as a result, breaking don't occur. Furthermore, initially specific resistance same as 10-6 Ω･cm is kept after stretch because of deposition of Cu after fixed polyaniline wiring. However, printing resolution is 100 μm order at the present moment because of non-optimization of printing process.

MEC appealed Cu selective roughening etchant and selective etchant


Fig.1 Image of selective roughening wet-etching
And also, MEC Company appealed Cu selective roughening etchant "CZ-8500" and Cu selective etchant "SF-5405".

As figure 1, if the former is used in wet-etching process, Cu film only is roughed, and other metals such as Ni, Sn, Ag, Au are not roughed because of great difference of wet-etching ratio. On the other hand, the latter is used in case of mixed environment of Cu/Al film and Ni film, Cu seed only is etched. In fact, typical etching ratio of Cu is 0.41 μm/min, on the other hand, Co is 0.05 μm/min, Mo is 0.02 μm/min, In is 0.02 μm/min, Ag is 0.01 μm/min, and those of Ni, Al, Ti, Ta, Nb, W, Bi, Au, ITO, Pt, Si are almost 0 μm/min.

Backlight of Mini-LED is manufactured by laser direct drawing system


Pic.4 Backlight sample for Mini-LED
With respect to manufacturing system, SCREEN Group demonstrated laser direct drawing system "LeVina/Ledia series" , and then, proposed a patterned backlight for Mini-LED by "Ledia weiss", which is correspondent with thick photoresist. Concretely, a solder resist is coated on the glass substrate, and then, it's patterned with hole shape array by laser direct drawing system. LED chips are mounted on these holes. Thickness of solder resist is very thick same as 55 μm. Therefore, solder resist should be coated by 2 times. However, it's exposed by 1 time of laser drawing.

REMARK
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Stella's repair system“Repair Vision” is suitable for repair use of electrode and so on. Also, it's possible to directly pattern ITO, metal, CNT (Carbon Nano Tube) films by use of this system, too.