Ki Yong Song

Photochemical Deposition of Ni – Cu Patterns onto Conducting Substrates Employing TiO2 – Pd2 + Layers

The metal photopatterning process employing a thin film of amorphous TiO 2 doped with Pd 2+ and oxalic acid has been developed. The exposure of this photolayer to UV light is believed to yield Pd(I) stabilized in a titanium oxide matrix, while subsequent washing results in formation of Pd nanoparticles through disproportionation. The Pd centers at the exposed areas are capable of inducing electroless nickel plating yielding the adhesive nickel pattern. The electroless copper deposition over patterned Ni allows generation of metal patterns with a resistivity of 4-12 μΩ cm and a resolution of 7 μm on the conducting substrates (indium-tin oxide glass, Si).

Low-Temperature Fabrication of Zinc Oxide Micropatterns Using Selective Electroless Deposition

Zinc oxide ZnO micropatterns were synthesized site-selectively on photocatalytically activated regions of TiO2 in an aqueous solution of zinc nitrate and dimethylamine-borane at 55°C by an electroless deposition process. The as-deposited ZnO micropatterns showed a polycrystalline wurtzite structure with a thickness of approximately 0.1 m. The ZnO micropatterns emitted ultraviolet light at 380 nm due to the recombination of bound excitons and broad visible-light luminescence 500-800 nm .

Selective Electroless Deposition Using Photoinduced Oxidation of Sn(II) Compounds on Surface-Modified Polyimide Layers

This paper describes an electroless deposition method for fabricating microscale metal patterns on polyimide surfaces. This method uses the selective deposition of catalytic Pd seeds via the photoinduced oxidation of Sn(II) compounds. The preparation process requires three steps: a first step in which the adsorption of Sn(II) compounds occurs on the surface of the polyimide film through ion exchange reactions, a second step in which the photoinduced oxidation of the Sn(II) compounds with atmospheric oxygen occurs in ultraviolet light (UV) irradiated areas, and a third step comprising the deposition of Pd 2+ ions in nonirradiated areas, which are simultaneously reduced.

Microscale Metal Patterning Using Photosensitive Silver Organometallic Compounds

We report a simple method for realizing the direct lithographic patterning of metallic silver and its alloy from amorphous films of photosensitive silver organometallic compounds. In this process, ultraviolet (UV) light was used to selectively activate organometallic compounds, converting organometallic compounds to metallic states in illuminated regions. The photolysis process was monitored by FTIR spectroscopy and the products were analyzed by UV–visible light spectrometry, X-ray photoelectron spectroscopy (XPS), and X-ray diffraction analysis (XRD). A feature size of 5 µm was demonstrated through the process.

Half-Buried Structure Cu Bus Line in TFT LCD

As we know, we normally used stacked aluminum bus line as the Gate or Source/Drain layer in LCD now, but the next general LCD needs larger display area, higher resolution, and faster response time, so we need develop the new TFT bus line structure and select the appropriate metallization materials to decrease the resistance of bus line. There are many new kinds of structure and material were used, for example copper, silver and their alloys, pure copper have some advantages among them because of its low electric resistance and cost, but it is restricted by the problem of pure copper’s lifting and etching. In this paper, we not only use electroless copper plating to decrease the resistance and cost of bus line but also use the half-buried structure to increase the thickness of bus line, it can combine these two new technologies well in LCD. We use the half-buried structure copper bus line to make some panel samples, it can decrease the delay of RC greatly (it is lower than 1/4 of normal aluminum bus line panel in the same size).

Photodefined Metal Pattern Formation and Its Electromagnetic Interference Shielding Effect

This paper proposes a electromagnetic interference (EMI) shielding effect of Cu mesh patterns which were formed by a novel, low-cost, photodefined metal pattern using a bilayer thin film of amorphous titanium dioxide (TiO2) and hole-scavenger-containing poly(vinyl alcohol) (PVA). Via UV-irradiation through a photomask on the bilayer film, the photodefined image of photoelectrons can be easily produced, resulting in selective palladium (Pd) catalyst deposition by reduction. In the bilayer thin film, the hole-scavenger-containing PVA layer scavenge the holes in the valence band of UV-irradiated TiO2 thin film, this retarding the recombination of the photoexcited electron-hole pairs for a few minutes. These long-surviving photoelectrons in the bilayer structure can reduce the Pd ions on only the photodefined region. Successive Ni electroless plating on Pd catalysts and Cu electroplating on an electroless plated pattern are possible. The electromagnetic interference shielding effects of selective nickel and copper mesh patterns were investigated.