Browsing by Author "Ko, CJ"

Now showing 1 - 5 of 5

Characterization of imprinting polymeric temperature variation with fluorescent Rhodamine B molecule
(2006-04-01)
Ko, FH
;
Weng, LY
;
Ko, CJ
;
Chu, TC
;
材料科學與工程學系奈米科技碩博班
The method to measure the imprint temperature variation of resist film with fluorescence probe technique was established. The maximal Rhodamine B concentration was 8 X 10(-4) M to achieve higher sensitivity and avoid precipitation problem. The temperature effect was a critical parameter on the temperature sensing, while imprinting pressure was not. The fluorescence intensity of Rhodamine B linearly decayed with time at various temperatures due to the formation of lactone-containing molecule during thermal stressing. The usual imprint time of less than 20 min was not affected by the signal decay effect due to limited percentage of signal variation during 100200 degrees C. The technique based on fluorescence probe method was successfully applied to measure the resist temperature variation of the imprint on the resist film of 6-in. wafer. (c) 2006 Elsevier B.V. All rights reserved.
Organic selective-area patterning method for microlens array fabrication
(2006-04-01)
Huang, WK
;
Ko, CJ
;
Chen, FC
;
光電工程學系
;
顯示科技研究所
Refractive microlens arrays (MLAs) are widely used in many electro-optical devices due to their high performance and low optical loss. To fabricate a microlens array effectively, we have proposed a novel fabrication method based on a selective-area patterning method. The surface properties of glass substrates were defined as either hydrophilic or hydrophobic regions by microcontact printing of self-assembled monolayers (SAMs). Consequently, the microlens arrays were self-organized on the hydrophilic regions after the lens materials were nozzle-spread followed by UV curing. As a result, we have demonstrated microlenses with 50, 75, and 100 Pm footprints, and f numbers as low as 5.4. The focused spot size of the 50 mu m lens was 9.82 mu m, which is near the diffraction limit. The optical measurement shows excellent light collecting efficiency of a microlens array, which is suitable for many electro-optical applications. Furthermore, all fabrication steps can be accomplished in ambient environment and at room temperature. It is anticipated that the present proposed method has great potential for mass production. (c) 2006 Elsevier B.V. All rights reserved.
Probing the microwave degradation mechanism of phenol-containing polymeric compounds by sample pretreatment and GC-MS analysis
(2004-11-22)
Chang, YC
;
Ko, FH
;
Ko, CJ
;
Chu, TC
;
材料科學與工程學系奈米科技碩博班
We have detected the volatile organic species obtained after microwave digestion of poly(hydroxystyrene) with nitric acid in closed vessels at various reaction temperatures by using headspace solid-phase microextraction (HS-SPME) and gas chromatography/mass spectrometry (GC-MS). We probed the digestion reaction by measuring the response of the detectable species - we detected a total of 20 volatile organic compounds - with respect to the temperature over the range from room temperature to 80 degreesC. These compounds can be classified into alkane, alkanol, and aromatic species. The alkane species decreased monotonically, whereas the alkanol and aromatic compounds first increased and then decreased, as the digestion temperature increased. We have established the degradation mechanisms, which involve bond scission, recombination, adduct formation, and ring opening, on the basis of product analyses and bond length simulations. (C) 2004 Elsevier B.V. All rights reserved.
Purification of multi-walled carbon nanotubes through microwave heating of nitric acid in a closed vessel
(2005)
Ko, FH
;
Lee, CY
;
Ko, CJ
;
Chu, TC
;
材料科學與工程學系奈米科技碩博班
We demonstrate that microwave-assisted heating in 5mL of nitric acid eliminates impurities, such as amorphous carbon, carbon nanoparticles, and metals, from multi-walled carbon nanotubes (MWNTs). Heating the closed reaction vessel under microwave irradiation at 160degreesC for 30min is a very effective means of purifying the MWNTs. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images confirm that these reaction conditions are beneficial for removing the impurities and ensuring that the MWNTs remain intact. In contrast, a purification temperature of 180degreesC provides too strongly oxidizing conditions that destroy the MWNTs. The ratio of the G and D bands in the Raman spectra also confirms that a temperature of 160degreesC. is optimal. The defect peak that we observed in the differential thermogravimetry (DTG) analysis of the raw material was not present after microwave purification. The presence of metal impurities in the MWNTs can be reduced significantly when using this method. (C) 2004 Elsevier Ltd. All rights reserved.
Synthesis and characteristics of polyimide/siloxane hybrid films for reliability adhesion
(2006-02-24)
Tsai, MH
;
Chiang, PC
;
Whang, WT
;
Ko, CJ
;
Huang, SL
Polyimide/siloxane (PISi) hybrid films from 2,2'-bis[4-(3-aminodiphenoxy)phenyl]sulfone (in-BAPS), 3,3'-oxydiphthatic anhydride (ODPA) and p-aminopropyltrimethoxysilane (APrTS) have been successfully fabricated by an in-situ sol-gel process. The APrTS is used to introduce siloxane structure and to be the end-capped agent to control the polymer block chain length in the range of 5000-20000 g/mol. The network structure of the PISi hybrid film is formed through the hydrolysis and condensation reactions. The PISi hybrid films with various polyimide block chain lengths are characterized with regard to the structure effect, mechanical properties, adhesion strength, adhesive melting flow and thermal stability. The result indicates that the more APrTS is contained, the shorter of the polyimide block chain length is formed and thus the lower inherent viscosity of APrTS-PAA is obtained. It is also suggested that the cross-linked density of the PISi hybrid film increases with the increase in the amount of APrTS. The network structure of the hybrid film reinforces the pure PI and makes the coefficient of thermal expansion (CTE) as well as adhesive melting flow decrease. Based on the dynamic mechanical analyses (DMA), the hybrid film with higher cross-linked density possesses superior mechanical property at elevated temperature. In addition, the introduction of APrTS causes an increase in thermal stability due to the network structure of hybrid film and the filler effect of the siloxane. (c) 2005 Elsevier B.V. All rights reserved.