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SEMICON Japan 2023 (December 13-15)


SEMICON Japan 2023 Toyobo & Xenomax demonstrated PI film with low-thermal expansion effectively

December 13-15, SEMICON Japan 2023 was held in Tokyo Big Site. Main topics of eclectic device in this exhibition are picked up.


First of all, Toyobo and Xenomax Japan appealed an original polyimide (PI) film with low-thermal expansion effectively. Its heat resistance is greatly high same as 500℃. Furthermore, linear coefficient of expansion is low same as 8 ppm/℃, which is almost same value of glass. In short, high robust such as that of silicon wafer and ceramics is ensured. And also, surface flatness is mere Ra = 0.5nm.


Pic.1 Rotary type MINI-LED

Pic.2 Flexible MINI-LED
In this time, both companies showed effective applications of this PI film. Firstly, it's useful for flexible display use. As picture 1 and 2, rotary type 55-inch MINI-LED display and flexible 9-inch MINI-LED display were exhibited. The both were pilot-produced by Innolux (Taiwan) using this PI film as a substrate.

In case of manufacturing display device, display maker laminates PI film on an original glass plate, and then, manufactures display device by the conventional manufacturing process for glass substrate, finally, PI film is released from the original glass plate. Adhesive strength between glass and PI film is relative low same as 0.1 - 0.2 N/cm2. For this reason, it's possible to release PI film easily by not only laser irradiation method, but also, mechanical method and wet method using medicinal solution.

This PI film is effective for TFT device, too. In the booth, a flexible double-gate structure poly-Ge-TFT (Tohoku-gakuin) was exhibited. As you know, in case of manufacturing practical Ge-TFT, it's necessary to anneal Ge at high temperature. In this time, Ge was crystallized by annealing at 385℃. As a result, world's highest carrier mobility as Ge-TFT with plastic film was obtained such as 700cm2/V･sec.

High gas barrier property and flexible property are obtained at the same time by new CVD deposition

Yamagata University introduced the project for manufacturing technology of flexible OLED by Roll to Roll process, and then, appealed an original CVD deposition method of single layer gas barrier film for OLED using plastic film.


Pic.3 Cross section of barrier film


Fig.1 Mechanism of CVD deposition
Figure 1 shows mechanism of CVD deposition system. In this system, magnetic field is formed by four magnets. Film property is changed by magnetic force. In short, Carbon-rich and Carbon-poor are mixed. HMDSO ( hexamethyldisiloxane.) is used as a precursor material. After deposition, it's grown to SiO2. As above, SiO2 with C-rich and C-poor are generated alternately. Picture 3 show cross-section. Two layers were stacked alternately. Of course, high gas barrier property in C-poor layer and flexible (low stress) property in C-rich layer are obtained. This means that crack does not almost occur.

Water vapor permeability is 6.3×10-6g/m2/day (WVTR) at 720nm thickness. This means that it's useful for OLED.

Flexible substrate is manufactured by wet-etching method


Pic.5 Wiring substrate with 20μm thickness
Micro Technology disclosed ultra-thin glasses with electrode pattern. First of all, wiring pattern is manufactured on a commercial non-alkali glass substrate by the conventional photo etching process, and then, the substrate is slimmed by wet etching treatment using acid. Minimum thickness is 20μm. For this reason, as picture 4, it's possible to bend easily. Sample size is 150 × 150㎜ at the maximum, and also, fine pattern same as 5 μm can be patterned.


Non-contact & air display is suitable for operation of glove box

Mitsui Chemical introduced a non-contact and air display. As its name, it's possible to operate air-floating touch panel by non-contact.



Pic.2 Glove box with air display unit
For example, if it's integrated into the glove box, operator can operate without glove by non-contact. And also, it's effective for wet-etching process. In this case, it's possible dissipate crud and degradation of touch panel system because of non-contact operation. In the booth, the glove box with this system was exhibited.

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