Browsing by Author "Cheng, DS"

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Low-temperature synthesis of transition metal nanoparticles from metal complexes and organopolysilane oligomers
(2002-10-01)
Chang, YH
;
Wang, HW
;
Chiu, CW
;
Cheng, DS
;
Yen, MY
Mo, W, and Cu nanoparticles (5-50 nm) are synthesized from reactions employing a metal complex, such as MoO2Cl2(DME), MoCl5, WCl6, ((CuOBu)-Bu-t)(4), or CuCl2, and a organopolysilane oligomer Si(SiMe3)(4) or (SiMe2)(6) either in a hexane solution (343 K) or in a sealed tube (473-673 K). Oxo- and chlorophilicities of the silyl groups provide for an energetically favored reaction route to reduce the metal complexes. The reaction byproducts are removed easily either by evaporation or dissolution into hydrocarbon solvents. It is proposed that the homogeneous mixing of the reactants in vapor and solution phases allows the association and growth of molecules into small clusters, then into nanosized metal particles.
Monitoring lithographic focus and tilting performance by off-line overlay measurement tools
(2001-09-01)
Ku, CY
;
Lei, TF
;
Cheng, DS
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
In this work we present a novel bar-in-bar (BIB) pattern to monitor the focus and tilting of exposure tools and production wafers. The inner and outer bars contain various hole sizes. When defocused, the shrinkage of the smaller patterns is more significant than that of the larger ones, thus causing the center of gravity to shift. Through the organization of the bar patterns, the centers of inner and outer bars shift in opposite directions when defocused. An overlay measurement tool can be used to easily measure the shift between the centers of inner and outer bars. Therefore, a second-order polynomial equation can precisely fit the measured BIB shift. In addition, an accurate and reliable focus value can be obtained with a maximum error of less than 0.05 mum by simply differentiating the fitting equation. The novel BIB has many applications, such as measuring field curvatures for exposure tools and determining best focus related information for production wafers. (C) 2001 American Vacuum Society.