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The Total Solution Exhibition for Electronic Equipment 2023 (May 31 - June 2)


The Total Solution Exhibition for Electronic Equipment 2023
Device manufacturing process is greatly reduced by new materials and equipment

May 31 - June 2, The Total Solution Exhibition for Electronic Equipment 2023 was held in Tokyo Big Sight. Main topics of display category are picked up.

Manufacturing process is simplified by selective adhesion process using new material, is adhered to nitride film only

In this time, most impressive product was considered to be a water solution include of secret Nano component, which was exhibited by Daicel.


Fig.2 Comparison of wet-etching ratio of SiN film


Fig.1 Image of selective adhesion process
As figure 1, this solution is coated on nitride film such as SiN film by various coating methods, and then, dried and cured, as a result, it is selectively adhered to nitride film only. Its mechanism was not disclosed because of strong relationship with its composition.

In the experiment, if this solution is coated on SiOx film, it's not adhered to SiOx film, as a result, its wet-etching ratio was not changed. On the other hand, as figure 2, wet-etching ratio of SiNx film was greatly decreased by 1/4 - 1/5 compared to reference (without coating). For this reason, in case of layer structure of figure 1, SiOx film can be etched without photoresist process-free by coating this solution only. As a result, total manufacturing process cost can be greatly reduced.

Furthermore, it’s possible to thin nitride film and enlarge process margin in nitride film etching process as small merits, too.

New values are obtained by fine concavity and convexity fabrication of glass surface


Fig.3 3D image of fine concavity and convexity plane

Pic.1 Demonstration of enhanced adhesion
Nippon Electric Glass (NEG) proposed a high added value glass substrate with fine concavity and convexity surface. Fine concavity and convexity structure is formed on surface of glass by blast etching process using abrasive. Fabrication pitch and depth can be controlled at 350 μm and under and a few dozen nm respectively. In short, it's possible to modify surface as keeping transparent property of initial value.

Its applications are very superior. In the booth, three applications were proposed. First application is a touch-panel. If this glass is used as a substrate, wring feeling of pen output is changed. Concretely, writing slipping is reduced, as a result, writing feeling becomes to be almost same as that of writing on a paper. Of course, it's not only pen output but also finger output.

Second application is effect of enhanced adhesion. Picture 1 shows its demonstrated sample. Third effects is enhancement of hydrophobic property. Its contact angle is enlarged from 30 - 70°to 110°.

Printing resolution is enhanced by use of porous PI film


Pic.2 SEM image of porous structure of PI film
Tokyo Ohka Kogyo exhibited an unique porous polyimide (PI) film. In PI film, fine holes same as 30 nm - 1 μm diameter are formed on surface. Its airspace ratio can be controlled at 60 - 80 %.

In this time, this PI film was confirmed to be effective for enhancement of printing resolution. Figure 4 shows result of Ink-Jet (IJ) printing using a metal ink. In case of using this PI film, printing resolution was greatly enhanced compared to that of using flat PI film. Of course, this is reason why printing bleeding is suppressed because of penetration of ink into fine hole. For this reason, it's effective for not only enhancement of printing resolution, but also, unnecessity of surface modification, such as insert of buffer layer, hydrophobic or hydrophilic treatment of surface, and etc.

By the way, basic characteristics such as thermal resistance and solvent resistance are almost same as that of the conventional PI film, however, mechanical strength same as tensile strength is low because of its structure.


Fig.4 Result of IJ printing


Nano Cu paste for spray coating is developed


Pic.3 Spray-coated sample of Nano Cu paste
Ishihara Sangyo Kaisha introduced a Nano Cu paste for spray coating method as new material of Nano Cu paste and ink series. It's mainly useful for coating only without pattern. Its anneal temperature is relative low same as 150 ℃, however, high conductivity same as 10-5-10-6Ω･cm is obtained. Of course, its film can be etched by use of the conventional acid series etchant, however, as picture 2, is effective for coating on 3D structure because of coating mechanism.

Anneal time is greatly reduced by NIR

As regards manufacturing system, Yamagata University and Komori Corporation suggested a breakthrough anneal system. It's possible to anneal Nano Ag paste for mere 1.5 - 4.5 min by use of NIR with 780 - 100 nm wavelength. Anneal time can be greatly reduced compared to the conventional oven system (30 - 60 min). NIR is absorbed into metal, however, is not absorbed into a plastic film because of its irradiation mechanism. In short, thermal damage against plastic substrate is not generated. As table 1, film characteristic for example specific resistance are almost same as that of case of using oven system.

It's suitable not only Nano Ag paste and ink, but also, Nano Cu paste and solder resist ink, too. In the booth, film samples with 7 layers inclusive Ag wiring and organic insulation films were exhibited. This method was indicated to be optimum for plastic film device.

By the way, NIR anneal system will be released by Komori Corporation in the near future.

Paste
Cure dry time (sec))
Specific resistance (Ω･cm) Color
Oven
 NIR Oven NIR Before After
Ag
Flexible 3600 87  2.4×10-4 1.6×10-4 Silver yellow Silver yellow
Nano
1800
 144 4.2×10-6 7.3×10-6  Black White
Bendable nano
1800
 130 1.2×10-5 8.3×10-6 Silver Silver
Ag/C Bendable 3600 87  3.0×10-5
 5.2×10-5 Silver gray Gray
Ag/Cu Ag coated Cu 1800 260 6.9×10-6 4.8×10-6 Silver copper Silver copper
Isolation Flexible 1800 289 - - White Translucent or White

Table 1. Result of annealing process

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