STELLA NEWS SITE is managed by Stella Corporation Inc.

Innovation Japan 2020 - Online (September 28 - November 30)


Innovation Japan 2020 - Online
New manufacturing processes for electronics device are easy to notice

September 28th, Innovation Japan 2020 - Online has started by the online method. Many demonstrations are disclosed until November 30th by a specific homepage. Topics for electronics device are closed up based on the homepage.

Cu electrode with high work function is gained by dipping treatment

Kyushu Institute of Technology proposed low-cost organic electronic devices with Cu electrodes.


Figure 1. Image of manufacturing process
Concretely, Cu electrode was formed on the substrate by various deposition and patterning methods, and then, the substrate was dipped into sodium thiocyanic acid liquid at RT environment for a few minutes. As figure 1, Cu and thiocyanic acid ion in the liquid were reactive; as a result, CuSCN was generated from Cu surface toward inside. Therefore, work function of Cu electrode becomes to be high by surface treatment. In short, metal electrode with high work function is easily obtained. Of course, pattern form of Cu film keeps, and high work function pattern is generated selectively.

Effective application is organic transistor with bottom gate/bottom contact structure. In fact, an organic transistor was pilot-manufactured by making use of this technology as source/drain electrode (L&S = 100 μm/20 μm). Organic transistor with low contact resistance could be formed by low cost. Beyond that, it's effective for anode and hole transport layer of OLED and organic solar cell.

Ultra-fine Ag pattern is formed by direct laser irradiation


Figure 3. Pilot-manufactured samples


Figure 2. Process image by laser irradiation method
On the other hand, Shizuoka University announced fabrication technique for ultra-fine metal structure by laser irradiation. It's a laser patterning technology of fine metal wiring on a flexible polymer film. Ultra-fine line same as a few dozen nm can be obtained.

As figure 2, a femtosecond pulse laser is irradiated with a polymer film with dissolved Ag ion. In this time, carboxyl group in polymer absorbs light. As a result, an electron is emitted. Ag ion catches this electron; as a result, it's precipitated by reduction. Metal is precipitated to laser irradiated area only because of light reduction. In short, fine pattern can be obtained at will by laser scanning.

Figure 3 shows microscope image of Ag line and nanosized Ag ring. In short, it's possible to obtain ultra-fine line such as a few dozen nm easily.

Nano-silicon is crystalized at RT by irradiation of flash light

University of Hyogo introduced a photo-crystallizing nano-silicon inks. It's crystallization technology of nanosized silicon ink by light irradiation treatment instead of conventional anneal treatment. This technology can be adopted for low thermal resistance substrate such as various plastic films.


Figure 4. Production process of silicon nanocrystal films from silicon nanocolloid
In this experiment, first of all, silicon nanosized colloid with water solvent was coated on the glass substrate, and then dried at RT. Average diameter of nanosized grain in the silicon film was 14 nm, but crystal size was approximate 4 nm. This film was treated at RT environment by irradiation of flash light; as a result, crystal size was almost same as average diameter of nanosized grain. In fact, effect of this flash light treatment (1 time) was confirmed to be approximately same value of anneal treatment at 700 ℃ and over.

It's possible to enhance crystalline nature of Ag grain for low thermal resistance substrate such as plastic films because of RT environment process. In fact, substrate temperature in this process was 40 ℃ and under.

REMARK
STELLA NEWS SITE is a free news site of FPD and PCB by Stella Corporation Inc.(This company does not release these FPD and PCB related products.)

Assembly system of emulsion film mask“LCGM”
Novel system was released as manufacturing system of emulsion film mask.