Surface and Interface Modifications of Aluminum Thin Films on Silica Glass Substrate Using 157 nm F₂ Laser for Selective Metallization

Abstract

A 157 nm F2 laser induced strong oxidation of an Al thin film surface, allowing it to show chemical resistance to KOH aqueous solution used for selective metallization on silica glass or native oxide Si substrate. The strong oxidation reactions on the surface and in the depth direction were confirmed by X-ray photoelectron spectroscopy. A high adhesion strength of 663 kgf/cm2 between Al and silica glass was also obtained for the F2-laser-irradiated sample, compared with that of the nonirradiated sample, 16 kgf/cm2. The suitable thickness of Al thin films for the F2-laser-irradiated surface and interface modifications was examined to be approximately 20 nm. The mechanism of the F2-laser-induced interface modification was discussed regarding the dependence of substrate material and the analyses of the chemical bonding state of silica glass underneath Al thin films.

F2-laser-induced surface modification of iron thin films to obtain corrosion resistance

“…When we used a 193 nm ArF excimer laser (Coherent COMPexPro 110) for a complimentary experiment, instead of the F 2 laser, the Fe 3 O 4 layer was not formed on iron thin films. The same as in the case of silicone rubber and aluminum thin film, [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] to produce O( 1 D) atoms by the photodecomposition of O 2 molecules in air with the F 2 laser is essential for the present surface modification of iron thin film.…”

“…Instead of silicone rubber, in recent years, we have also employed aluminum thin films to modify the surface into Al 2 O 3 by the F 2 laser. [27][28][29] In this case, the surface of aluminum thin films was strongly oxidized by F 2 laser photons and shows high chemical resistance to KOH aqueous solution.…”

Surface modification of iron thin films into corrosion resistant property by F<inf>2</inf> laser

“…Previously, we used the F 2 laser for the surface modification of aluminum thin films into Al 2 O 3 resistant to KOH aqueous solution [1][2][3]. In this work, instead of aluminum, iron (Fe) thin films were photochemically modified into Fe 3 O 4 by the F 2 laser for developing a corrosion resistant Fe thin film.…”

F2-Laser-Induced Modification of Aluminum Thin Films into Transparent Aluminum Oxide

“…[3][4][5][6] Previously, we used a vacuum-UV (VUV) F 2 laser of 157 nm wavelength for the surface and interface modifications of Al thin films on silica glass for micropatterning. 7,8) In this case, the Al thin film surface was strongly oxidized by the F 2 laser photons to realize high resistance to the potassium hydroxide (KOH) aqueous solution used to etch the nonirradiated Al thin films for selective metallization. In addition, high adhesion between Al and silica glass was achieved by the F 2 laser irradiation.…”