This paper presents a handheld mechanical cell lysis chip with ultra-sharp nano-blade arrays fabricated by simple and cost effective crystalline wet etching of (110) silicon. The ultra-sharp nano-blade array is simply formed by the undercutting of (110) silicon during the crystalline wet etching process. Cells can be easily disrupted by the silicon nano-blade array without the help of additional reagents or electrical sources. Based on the bench-top test of the proposed device, a handheld mechanical cell lysis chip with the nano-blade arrays is designed and fabricated for direct connection to a commercial syringe. The direct connection to a syringe provides rapid cell lysis, easy handling, and minimization of the lysate dead volume. The protein concentration in the cell lysate obtained by the proposed lysis chip is quantitatively comparable to the one prepared by a conventional chemical lysis method.
This paper presents a micromachined in-plane tunable optical filter using the thermo-optic effect of crystalline silicon. The device was fabricated by a silicon deep reactive ion etching process with a silicon-on-insulator wafer and thermal oxide removal to improve the sidewall smoothness. Optical fibers could be horizontally aligned on the fabricated TOF device by exploiting in-plane device structures, which enable TOFs to easily connect with other optical components. Tunability of the TOFs was experimentally achieved through thermal modulation of optical path length by heating the silicon etalon. As the input voltage increases, a notch in the reflectance spectrum shifts to a longer wavelength with an average tuning sensitivity of 0.9 nm K−1 and a best bandwidth of 1.1 nm. The proposed device can be utilized for spectroscopy or optical communication.
This study investigated the wettability effect of polysilicon on the polishing performance and organic defect contamination during polysilicon chemical mechanical polishing ͑CMP͒. Contact angle measurement was utilized to understand the nature of polysilicon surfaces. An oxidizer, H 2 O 2 , was added to the silica slurry to modify a hydrophobic polysilicon surface to a hydrophilic surface during polishing. The adhesion force was measured between a polymeric pad particle and a poly-Si wafer surface in KOH solution ͑pH 11͒ as a function of H 2 O 2 concentration. The adhesion force of the polymeric pad particle on the polysilicon decreased from 14 to 8 nN as the peroxide concentration increased to 10 vol %, at which the surface became hydrophilic. The hydrophilization of the polysilicon surface during polishing drastically reduced the organic contamination on the polysilicon wafers after polishing. The removal rate, frictional force, and pad temperature during CMP, with and without oxidizing the surface, were measured. They all decreased with the increasing concentrations of the oxidizer. The decrease was attributed to the formation of the lubrication layer of the oxide surface due to the oxidation of polysilicon.Dynamic random access memory ͑DRAM͒ process technology has become a leading semiconductor technology, with the highest production volume among very large scale integration ͑VLSI͒ semiconductor products. The density of DRAM quadrupled approximately every three years by virtue of advances in DRAM technology. 1 Because of the decrease in device feature size, the chemical mechanical polishing ͑CMP͒ process has become a necessary processing step for planarizing the surfaces during the DRAM process. 2 Poly-Si CMP is implemented to reduce the step height of a gate poly-Si in the construction of a recess channel array transistor and Fin Field Effect Transistor ͑FinFET͒ three-dimensional structures. 3 Although the CMP process is performed effectually, there are several problems that need to be overcome, such as local dishing/erosion, scratches, and abrasive and organic particle contamination. 4 After the CMP process, the wafer surface might be contaminated by the abrasive particles and polymeric residues from the pad, the retainer ring, and other consumables. The removal of organic residues from the wafer surfaces is a great challenge for the next processing step. The surface of poly-Si is hydrophobic in nature. Hence, it attracts hydrophobic organic residues, mostly pad debris, during the CMP process. These organic defects are difficult to be removed by general post-CMP cleaning methods. 5-7 Because there is much concern about organic contamination on polished polysilicon surfaces after polishing, understanding the interaction between the organic residues and the polysilicon surface is required.Therefore, this study investigated the organic contamination mechanism of polymeric residues on polished polysilicon surfaces. H 2 O 2 , as an oxidizer, was added to the silica slurry to modify the wettability of the polysil...
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