Abstract:Recently, the polymeric micro-fluidic biochip, often called LOC (lab-on-a-chip), has been focused as a cheap, rapid and simplified method to replace the existing biochemical laboratory works. It becomes possible to form miniaturized lab functionalities on a chip with the development of MEMS technologies. The micro-fluidic chips contain many micro-channels for the flow of sample and reagents, mixing, and detection tasks. Typical substrate materials for the chip are glass and polymers. Typical techniques for micro-fluidic chip fabrication are utilizing various micro pattern forming methods, such as wet-etching, micro-contact printing, and hot-embossing, micro injection molding, LIGA, and micro powder blasting processes, etc. In this study, to establish the basis of the micro pattern fabrication and mass production of polymeric micro-fluidic chips using injection molding process, micro machining method was applied to form micro-channels on the LOC molds. In the research, a series of machining experiments using micro end-mills were performed to determine optimum machining conditions to improve surface roughness and shape accuracy of designed simplified micro-channels. Obtained conditions were used to machine required mold inserts for micro-channels using micro end-mills. Test injection processes using machined molds and COC polymer were performed, and then the results were investigated.

The effects of geometrical parameters on the electrical characteristics of network-channel low-temperature polycrystalline silicon (LTPS) thin-film transistors (TFTs) were investigated. The grain boundary and interface trap densities were also extracted using parameters such as hole-to-hole distance, hole-branch top width, effective channel width, and area filling factor (AF). It was found that the electrical characteristics were largely dependent on AF, mainly owing to reduced trap densities. However, excessive hole formation in the network-channel structure was found to increase channel resistance and decrease drain current. These results suggest that, for a given footprint device area, denser hole patterns are preferred for achieving better electrical characteristics in novel network-channel LTPS TFTs.

The extraction of nitride trap density (Nt) filled with electrons emitted by thermal emission (TE) in the charge-trapping layer of 3-D NAND flash memory is demonstrated. The intercell program (IP) pattern was adopted to intentionally inject electrons into the intercell region to minimize the influence of lateral migration (LM) on the trap profiles. This was confirmed by the retention characteristics observed at 120 °C, where the charge loss is mainly caused by the TE of the trapped electrons in the nitride layer. The extracted peak value of Nt at EC-ET value of 1.20 eV using the IP pattern was as low as 1.01×10 19 cm -3 eV -1 , in the scan range of 0.96 eV to 1.27 eV. This value was 17% lower than that from the conventional adjacent cell program (P-P-P) pattern. Therefore, the IP pattern can be used in extracting trap profiles in the SiN layer in scaled 3-D NAND memories. INDEX TERMS 3D NAND flash memory, data retention, lateral migration, trap profilingThis work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.

The quantitative characteristics of traps created in the bandgap-engineered tunneling oxide (BE-TOX) layer and block layer after program/erase (P/E) stress-cycling in a 3D NAND flash memory were investigated. The trap spectroscopy by charge injection and sensing technique was used to obtain the distribution of traps in these layers. In the BE-TOX layer, significant traps were generated at 1.3 eV in the nitrogen-doped layer (N1) and increased by 48% in the fresh cell after P/E stress-cycling. The H bonds in the N1 are more likely to break during the stress-cycling and create neutral ≡ SiO • traps. In the block layer, however, trap generation was negligible after stress-cycling.INDEX TERMS 3D NAND flash memory, bandgap-engineered tunneling, program/erase cycling, trap profile, TSCIS

The polymeric biochip has been focused as a cheap, rapid and simplified method to replace the existing biochemical laboratory works. This biochip is formed miniaturized lab functionalities on a chip with the development of MEMS technology. This has many micro-fluidic channels for the flow of sample and reagents, mixing and detection task. Existing technologies for the biochip fabrication are utilizing various micro pattern forming methods, such as etching, LIGA, and micro-imprinting etc. In this study, an injection molding process with micro mold was applied to the mass production of polymeric biochip which contains micro-fluidic channel. Micro cutting process was applied to fabricate the core feature for molding micro-fluidic channel. Therefore, a series of micro cutting experiments using micro endmill were performed to determine optimum cutting conditions. Besides, the low temperature micro-cutting experiments using micro endmills were performed to improve the quality of micro mold core by reducing the burr and surface roughness. After the verification of low temperature micro-cutting process efficiency, this process was used to fabricate required mold core for micro feature. Finally, test injection molding process using manufactured micro mold and COC polymer were performed, and then the results were investigated.