Within wafer non-uniformity (WIWNU), which significantly affects the yield of chip products, is mainly caused by non-uniform chemical mechanical polishing (CMP) at the wafer’s edge. This study ...investigates the origins of the non-uniformity and presents a process that uses an edge profile control ring (EPC ring) to solve the problem. The EPC ring is designed to be positioned between the wafer and the retaining ring and pressed at the same pressure as the wafer by a flexible membrane to reduce the pressure discontinuity between the center region and the edge region of the wafer. Experimental results show that for a WIWNU of 2%, the EPC ring makes it possible to shrink the edge exclusion region from 15 mm to 2 mm without any change in process conditions. This result suggests that the EPC ring is applicable to real fabrication.
Alzheimer’s disease is a progressive neurodegenerative disease that is characterized by the presence of extracellular amyloid plaques and intraneuronal neurofibrillary tangles within the brain. ...Biochemical analysis of amyloid plaques have revealed that the main constituents are fibrillary aggregates of 39-42 peptide residues referred to as the amyloid-
β
protein (A
β
). Here, we examined the consecutive aggregation stages of the A
β
-42 peptide, as well as the fibril formation stages on a mica substrate by using atomic force microscopy. These results offer new tools for an analysis of the mechanisms of A
β
aggregation.
Prediction of Real Contact Area from Microtopography on CMP Pad JEONG, Hobin; LEE, Hyunseop; CHOI, Sungha ...
Journal of Advanced Mechanical Design, Systems, and Manufacturing,
2012, 2012-00-00, 20120101, 2012-01-01, Letnik:
6, Številka:
1
Journal Article
Recenzirano
Odprti dostop
A simplified model related to microtopography on CMP pad and prediction of real contact area between the pad and wafers is presented in this paper. The model has been developed on the basis of the ...analysis of the pad surface roughness and contact mechanics. The bearing area curve, representing tribological properties of the surface, is used to formulate the model. The pad microtopography which is expressed in the model is uniform and simple. Particularly, the important characteristics of the pad microtopography for the CMP process are emphasized in the model. It provides more convenient way to perceive the situation of the pad surface during the CMP process. The progress of the pad surface wear and the real contact area can be easily taken and connected each other by using the model. The model is also verified by comparing the tendency of actual removal rates with those theoretically anticipated. Finally, authors could get the efficient link between the pad surface wear and the real contact area, which results in a strong tool to understand the fundamental CMP mechanism of material removal.
High‐rate nanoscale offset printing using a newly developed reusable template enables the assembly of nanomaterials into nanostructures followed by their transfer onto a flexible substrate in a few ...minutes. The developed template can potentially be reused more than 100 times in the offset printing process without any additional functionalization. This approach provides a new way for the printing of flexible devices with nanoscale patterns.
A new high-rate directed assembly based nanomanufacturing process has been developed at the NSF Center for High-rate Nanomanufacturing to print electronics and sensors on flexible nano-enabled ...devices using reusable templates. These ‘damascene templates’ are designed to achieve not only a flat topographical surface consisting of conductive patterns and insulated areas but also multi-scale (macro/micro/nano) size conductive patterns having the same electric potential during electrophoretic assembly, thereby allowing uniform assembly and high yield transfer of nanomaterials. The governing parameters for this printing process, such as the surface energy of damascene templates, applied potential during electrophoretic assembly, temperature and pressure for transferring nanomaterials have been investigated. We have also demonstrated that Offset Printing using damascene templates is highly compatible with various nanomaterials such as carbon nanotubes (CNT), silica nanoparticles, and numerous polymers. There are many challenges to making such a scalable template based nanoscale printing process. First, damascene templates must be large scale and have multi-scale (macro/micro/nano) conductive patterns on a perfectly flat surface. A flat surface is essential to obtaining high yield transfer, and a CMP (Chemical Mechanical Polishing) process is used to achieve it. Unfortunately, CMP processes are not suitable for large scale templates and multi scale conductive patterns because they are limited by wafer size and have inherent defects, ‘dishing’ and ‘erosion’, which happen when the template has different sized patterns with different materials. Developing new fabrication processes for damascene templates could overcome these problems by replacement of CMP with more suitable techniques. A multi-layer transfer printing process for printing different devices using various nanomaterials has been developed. This is important for developing printed applications using Offset Printing such as flexible transistors, antennas, chemical and biological sensors, and metal circuit printing. This work enables high-rate manufacturing of nanomaterial devices in various fields such as a mobile product, flexible displays, biosensor, and energy harvesting.
Direct electrochemical (EC) monitoring in a cell culture medium without electron transporter as called mediator is attractive topic in vitro organoid based on chip with frequently and long-time ...monitoring since it can avoid to its disadvantage as stability, toxicity. Here, direct monitoring with nonmediator is demonstrated based on impedance spectroscopy under the culture medium in order to overcome the limitation of mediator. The applicability of EC monitoring is shown by detecting alpha-1-anti trypsin (A1AT) which is known as biomarkers for cardiac damage and is widely chosen in organoid cardiac cell-based chip. The validity of presented EC monitoring is proved by observing signal processing and transduction in medium, mediator, medium-mediator complex. After the observation of electron behavior, A1AT as target analyte is immobilized on the electrode and detected using antibody-antigen interaction. As a result, the result indicates limit of detection is 10 ng mL
and linearity for the 10-1000 ng mL
range, with a sensitivity of 3980 nF (log g mL)
retaining specificity. This EC monitoring is based on label-free and reagentless detection, will pave the way to use for continuous and simple monitoring of in vitro organoid platform.
Polyvinyl chloride (PVC) has been used as a general-purpose polymer because of its lower cost, good durability and mechanical properties compared to other materials. However, PVC is vulnerable to ...heat deformation and generates a toxic gas like hydrogen chloride. Therefore, it is important to delay or prevent the flame retardancy and thermal degradation of the PVC during the processing. It was reported that aluminum trihydroxide (ATH) improved flame retardancy as well as smoke inhibition of the virgin polymer. In this study, PVC composites by addition of ATH were compounded in a modular intermeshing co-rotating twin screw extruder. The PVC composites with different concentrations of ATH (0~5 phr) were analyzed. Flame retardancy of the PVC composite significantly increased depending on the ATH concentration. LOI of the composite also increased with the concentration of ATH. There were no significant differences for the thermal properties of the PVC composites with ATH.
In this study, the reclaimed polypropylene (RPP) and waste ground rubber tire (WGRT) were used to simulate the thermoplastic vulcanizate (TPV) for cost reduction and resources recycling. Also, we ...examined the effects of dicumyl peroxide (DCP) and 2,5-dimethyl-2,5-di-(tert-butylperoxy)-hexane (DTBPH) as peroxide type cross-linking agents to enhance the properties of TPV`s. The components of RPP and WGRT were fixed at 30 and 70 wt%, and DCP and DTBPH were added in the concentrations from 0.5 to 1.5 phr, respectively. RPP/WGRT composites with different contents of DCP and DTBPH were prepared by a modular intermeshing co-rotating twin screw extruder. The Young`s modulus of composites were decreased with increasing peroxides contents. On the other hand, tensile strength, elongation at break, and impact strength of the composites were increased with peroxide contents. We also confirmed that interfacial adhesion between RPP and WGRT was considerably improved by adding the peroxides. Taken together, DTBPH added RPP/WGRT composites exhibited better mechanical properties rather than those of DCP added composites.
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