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Kyoto, Japan

Jeong S.,Pusan National University | Lee H.,Pusan National University | Cho H.,Pusan National University | Lee S.,Pusan National University | And 4 more authors.
Applied Surface Science | Year: 2010

High roughness and a greater number of defects were created by lithium niobate (LN; LiNbO3) processes such as traditional grinding and mechanical polishing (MP), should be decreased for manufacturing LN device. Therefore, an alternative process for gaining defect-free and smooth surface is needed. Chemical mechanical planarization (CMP) is suitable method in the LN process because it uses a combination approach consisting of chemical and mechanical effects. First of all, we investigated the LN CMP process using commercial slurry by changing various process conditions such as down pressure and relative velocity. However, the LN CMP process time using commercial slurry was long to gain a smooth surface because of lower material removal rate (MRR). So, to improve the material removal rate (MRR), the effects of additives such as oxidizer (hydrogen peroxide; H2O2) and complexing agent (citric acid; C6H8O7) in a potassium hydroxide (KOH) based slurry, were investigated. The manufactured slurry consisting of H2O2-citric acid in the KOH based slurry shows that the MRR of the H2O2 at 2 wt% and the citric acid at 0.06 M was higher than the MRR for other conditions. © 2009 Elsevier B.V. All rights reserved. Source

Jang S.,Pusan National University | Jeong H.,Pusan National University | Yuh M.,Pusan National University | Park I.,Pusan National University | Park J.,Nitta Haas Inc.
International Journal of Precision Engineering and Manufacturing - Green Technology | Year: 2016

Chemical mechanical polishing (CMP) technology has been newly applied in printed circuit board (PCB) field for satisfying requirements from miniaturization of mobile devices. This paper focuses on the complexing agent to increase the removal rate for thick Cu layer. In order to find out optimum type and concentration of the complexing agent, experiments have been done in terms of electrochemical analysis, surface roughness and removal rate. As concentration of complexing agent (glycine) in slurry increased, it was confirmed that corrosion current density increased in potentio-dynamic curve since it promoted production of new Cu ion by decreasing amount of Cu ion of chemical reaction layer. Finally, it was possible to confirm that chemical reaction had a direct correlation with removal rate through CMP evaluation. © 2016 Korean Society for Precision Engineering. Source

Jang S.,Pusan National University | Jeong H.,Pusan National University | Yuh M.,Pusan National University | Park J.,Nitta Haas Inc.
International Journal of Precision Engineering and Manufacturing - Green Technology | Year: 2015

The demand for pattern miniaturization on package substrates has been steadily increasing. One technical innovation for the package substrate manufacturing process was chemical mechanical planarization (CMP). In conventional wiring, it was possible to remove extraneous copper through only the etching process. However, etching defects occur with narrower line widths. As the package substrate has a Cu hybrid structure through Cu plating and copper clad laminate (CCL) removal, it is necessary to apply the CMP to remove excess copper. However, defects are generated by the CMP process due to mechanical and chemical effects from the slurry. This study investigated the surfactant effect on Cu dishing and erosion in patterns with approximately 10/10 μm line width and spacing. The conventional Cu slurry without a surfactant had severe erosion (0.58 μm) in Cu patterns of 4/6 μm and deep dishing (4.2 μm) in Cu patterns of 14/16 μm. However, the experimental results showed that the friction force during CMP decreased, with smaller dishing and erosion as surfactant concentration increased. Finally, globally planarized Cu patterns were realized with an erosion range of 0.22 μm to 0.35 μm and a dishing range of 0.37 μm to 0.69 μm with 3 wt.% surfactant. © 2015 Korean Society for Precision Engineering. Source

Yamao T.,Kyoto Institute of Technology | Juriy K.,Kyoto Institute of Technology | Juriy K.,Ricoh Co. | Sakaguchiz T.,Kyoto Institute of Technology | And 7 more authors.
Japanese Journal of Applied Physics | Year: 2010

We have fabricated semiconducting oligomer films composed of uniaxially-oriented crystal domains by melt molding. It is highly important to generate a temperature gradient in the lateral direction parallel to the substrate on which the said oligomer films are fabricated. As a result, the melted oligomer layer starts to solidify from parts of lower temperatures to end up as a uniaxially aligned film. The uniaxial alignment is further promoted by slowly cooling that oligomer layer. In the present studies, the temperature gradient was set at ̃0:06-0:4 °C/mm. From the polarizing microscope observations, we confirm that within this range the temperature gradient efficiently produces the uniaxial orientation. This method has been applied to fabricating organic field-effect transistors. Those devices show an effective modulation of the drain current with varying gate voltage. © 2010 The Japan Society of Applied Physics. Source

Isobe A.,Kyushu University | Ogata K.,Nitta Haas Inc. | Kurokawa S.,Kyushu University
Japanese Journal of Applied Physics | Year: 2014

A macromodel for changes in a pad surface by dressing and polishing is proposed. A polishing pad is divided into small areas and it is assumed that each area takes an ''H'' (= high) or''L'' (= low) condition. The condition is changed by dressing or polishing, and the total chemical mechanical planarization (CMP) performance is determined by the average pad condition. The results from equations are compared with experimental data, and good correspondence is confirmed. Various CMP behaviors are well explained by the equations, such as polishing rate stabilization by dummy running, the differences in the stability time and polishing rate between in situ dressing and ex situ dressing, and polishing rate behaviors for patterned wafers. This new model can be used to predict process performances, to optimize process conditions, or to indicate the direction of consumable development.© 2014 The Japan Society of Applied Physics. Source

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