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Post-CMP cleaning is a crucial step to eliminate the residual particles, organic residues, foreign materials, metallic impurities, etc., from the wafer surfaces. As post-CMP cleaning technology has grown by leaps and bounds over the past several decades, traditional cleaning solutions (SC-1, SC-2, SPM, and DHF) have been modified to meet the stringent requirements for the level of acceptable defects, and many alternatives have been developed so far. Recent developments of post-CMP cleaning solutions for FEOL, MOL, and BEOL applications are summarized in this chapter. The challenges and future research directions related to post-CMP cleaning solutions and the experimental techniques to evaluate post-CMP cleaning formulations are highlighted.

This paper presents a method to measure the threshold voltage degradation ΔVth along the channel direction due to electrical stress in MOSFETs. This method uses ΔVths measured after electrical stress at different drain bias Vds, and calculated the depletion length Ldep into the channel for each condition under which ΔVth is measured. By substituting ΔVth and Ldep into the proposed equation, the amount of degradation generated in each region of the MOSFET channel can be calculated. The ΔVth profiles of OFF-state stress and negative bias temperature instability in pMOSFET and hot carrier injection in nMOSFET were extracted using the proposed method. The degradation profiles correspond well with each stress characteristic.

GPa-grade steels which possess the ultimate tensile strength over 1000 MPa and higher elongation have been thoroughly researched to replace conventional high-strength steels in automobile industry to enhance fuel efficiency without sacrificing crashworthiness. However, high strength of GPa-grade steel does not only induce punching pin buckling due to high contact pressure, but also abrasive wear on the mold surface due to the unstable contact that results from the large amount of springback, which tend to impede widespread usage of GPa-grade steels. In this research, design criteria for an optimal aspect ratio of the punching pin preventing buckling failure has been proposed by linking with experimental and numerical analyses, which is validated with the analytic solutions. Furthermore, in order to prevent stripping failure, it is highly recommended that one of the main factors, a blank holder force (BHF), over 1.5 MPa has to be maintained during the withdrawal process to minimize the effect of springback in stamped panels applying GPa-grade steel, which is able to extend the tool life of the side punching pin about 100,000 cycles.

In this study, a response surface methodology (RSM) coupled with a face center cube design (FCD) was used to optimize the three principal components (i.e., Fe(NO3)3, H2O2, and SiO2 abrasives) in polishing slurries for a W barrier chemical mechanical planarization (CMP) process. The experimental ranges of the three components were 10–50 ppm of Fe(NO3)3, 0.3–0.9 wt% of H2O2, and 1–5 wt% of SiO2 abrasives. Based on the experimental data from the FCD, the second-order models for the material removal rate (MRR) of the W and Oxide films were fitted; these were determined to be statistically valid and reliable. We have achieved the optimal conditions for the three components where the MRR is maximized and the selectivity between the W and Oxide MRRs is ~1. The predicted MRR and selectivity at the optimal conditions were well correlated with the results of a confirmation run, which was conducted by using the W barrier CMP process with W-patterned wafers. In addition, we employed a particular RSM called dual-response optimization in order to investigate the tradeoff between the MRR and selectivity. Based on the tradeoff information, process engineers can conduct the optimization of the three components more flexibly. Keywords: Chemical mechanical planarization, Optimization, Response surface methodology, Slurries, Semiconductor manufacturing process

Semiconductors are fabricated through unit processes including photolithography, etching, diffusion, ion implantation, deposition, and planarization processes. Chemical mechanical planarization, which is essential in advanced semiconductor manufacturing processes, aims to achieve high planarity across the wafer surface. This paper presents a case study in which the optimal blend of mixture slurry was obtained to improve the two response variables material loss and roughness at the same time. The mixture slurry consists of several pure slurries; when all of the abrasive particles within the slurry are of the same size, the slurry is referred to as a pure slurry. The optimal blend was obtained by applying a multiresponse surface optimization method. In particular, the recently developed posterior approach to dual response surface optimization was employed, which allows the chemical mechanical planarization process engineer to investigate tradeoffs between the two response variables. The two responses were better with the obtained blend than the existing blend. Copyright © 2016 John Wiley & Sons, Ltd.

We report on thin film transistors (TFTs) based on spinel ZnGa2O4 (ZGO) that was recently spotlighted as an ultra-wide bandgap oxide semiconductor. The ZGO layers were grown in a spinel structure by pulsed laser deposition on the cubic spinel MgAl2O4 (MAO) as well as on cubic MgO substrates while changing the Zn/Ga ratio. The compressive strained epitaxial growth of ZGO on MgAl2O4 (100) and the tensile strained epitaxial growth of ZGO on MgO (100) without any misfit or threading dislocations were confirmed by the reciprocal space map and cross-sectional transmission electron microscopy. The electrical transport properties were demonstrated through TFTs based on ZGO as the channel layer, Al2O3 as the gate oxide, and Sn-doped In2O3 as the source, drain, and gate electrodes. When the Zn/Ga ratio is slightly lower than the ideal value of 0.5 on MgO substrates, the ZGO TFT showed the highest mobility of 5.4 cm2/V s. The ION/IOFF ratio and subthreshold swing (S) value are 4.5 × 108 and 0.19 V/dec, respectively.

With the success of image classification problems, deep learning is expanding its application areas. In this paper, we apply deep learning to decode a polar code. As an initial step for memoryless additive Gaussian noise channel, we consider a deep feed-forward neural network and investigate its decoding performances with respect to numerous configurations: the number of hidden layers, the number of nodes for each layer, and activation functions. Generally, the higher complex network yields a better performance. Comparing the performances of regular list decoding, we provide a guideline for the configuration parameters. Although the training of deep learning may require high computational complexity, it should be noted that the field application of trained networks can be accomplished at a low level complexity. Considering the level of performance and complexity, we believe that deep learning is a competitive decoding tool.

Bluetooth Low Energy (BLE) evolved from classical Bluetooth technologies for enabling short-range communication in different services and systems. BLE has many advantages over classical Bluetooth technologies, including low-cost deployment and low-power consumption. Recently, a very few number of research studies have been conducted to improve device discovery process of BLE. But, these studies have still some limitations. Prior studies have assumed that advertising PDUs are immediately processed as long as they are received successfully by a scanner. Practically, however, BLE devices may experience lots of collisions due to contention among neighbors, particularly in a crowded environment. With increasing number of BLE devices, delays of both device discovery and connection setup keep exponential growth, which could influence user experience in terms of either time or energy consumption. In this paper, an enhanced mechanism is proposed to enable BLE advertisers and scanners to learn the network contention and adjust their parameters accordingly, so as to achieve fast discovery latency. Through extensive simulations, the proposed mechanism has shown its effectiveness to reduce unexpected long latency in crowded BLE networks.

Bluetooth Low Energy (BLE) is a short-range wireless communication technology aiming at low-cost and low-power communication. The performance evaluation of classical Bluetooth device discovery have been intensively studied using analytical modeling and simulative methods, but these techniques are not applicable to BLE, since BLE has a fundamental change in the design of the discovery mechanism, including the usage of three advertising channels. Recently, there several works have analyzed the topic of BLE device discovery, but these studies are still far from thorough. It is thus necessary to develop a new, accurate model for the BLE discovery process. In particular, the wide range settings of the parameters introduce lots of potential for BLE devices to customize their discovery performance. This motivates our study of modeling the BLE discovery process and performing intensive simulation. This paper is focused on building an analytical model to investigate the discovery probability, as well as the expected discovery latency, which are then validated via extensive experiments. Our analysis considers both continuous and discontinuous scanning modes. We analyze the sensitivity of these performance metrics to parameter settings to quantitatively examine to what extent parameters influence the performance metric of the discovery processes.

We have demonstrated a highly efficient blue phosphorescent organic light emitting diodes (PHOLED) using iridium (111) bis[(4,6-di-fluoropheny)-pyridinato-N,C2] picolinate doped in double emitting layers (D-EML), N,N-dicarbazolyl-3,5-benzene (mCP) and p-bis (triphenylsilyly)benzene (UGH2). D-EML layers were employed to broaden the exciton formation zone and confine excitons. The optimized blue PHOLEDs having mCP/UGH2 as D-EML with a thickness of 200/100 A, exhibited a peak external quantum efficiency of 11.44%, power efficiency of 16.8 Im/W, luminous efficiency of 23.14 cd/A, and Commission Internationale de l'Eclairage coordinates of (0.17, 0.33).

The authors have demonstrated the various characteristics of hybrid white organic light-emitting diodes (HWOLED) using fluorescent blue and phosphorescent red emitters. We also demonstrated that two devices showed different characteristics in accordance with thickness of the 4,4′-N,N′-dicarbazole-biphenyl (CBP) spacer (CS) inserted between the blue and the red emitting layer. It was found that the device with a CS thickness of 70 A showed a current efficiency 2.5 times higher than that of the control device with a CS thickness of 30 A by preventing the triplet Dexter energy transfer from the red to the blue emitting layer. The HWOLED with the CS thickness of 70 A exhibited a maximum luminance of 24500 cd/m, a maximum current efficiency of 42.9 cd/A, a power efficiency of 37.5 lm/W, and Commission Internationale de I'Eclairage coordinates of (0.37, 0.42). [DOI: 10.4313/TEEM.2009.10.6.208]

We report on white organic light‐emitting diodes (WOLEDs) based on single white dopants, Ir(pq)2(F2‐ppy) and Ir(F2‐ppy)2(pq), where F2‐ppy and pq are 2‐(2,4‐difluorophenyl) pyridine and 2‐phenylquinoline, respectively. The similar phosphorescent lifetime of two ligands lead to luminescence emission in two ligands simultaneously. However, the emission color of the devices was reddish, because the energy was not transferred efficiently from the 4,4,N,N‘‐dicarbazolebiphenyl (CBP) to the F2‐ppy ligand, due to the small band gap of the CBP. Accordingly, we used 1,4‐phenylenesis(triphenylsilane) (UGH2) with a large band gap, instead of CBP as the host material. As a result, it was possible to adjust the emission color by the host material. The luminous efficiency of the device with Ir(F2‐ppy)2(pq) doped in UGH2 was about 11 cd/A at 0.06 cd/m2.

The original version of this article unfortunately contained a mistake. Figure 9 was originally published with an incorrect image. The correct version of this figure is provided here and the original article was corrected.

Wireless mesh networking is emerging as an important architecture for the future generation of wireless communications systems. The challenging issue in WMNs is providing Quality of Service (QoS). So, this paper proposes a multiple-metric routing scheme for QoS in WMNs using a system of active networks. The Active Network paradigm offers the attractive capability of being able to carry executable payloads that can change the characteristics of a given platform. In other words, network nodes not only forward packets, but also perform customized computation on the packets flowing through them. It provides a programmable interface to the user.

A series of red emitters 1-3 based on modified DCM were synthesized and their electroluminescent properties were investigated. A device employing red emitter 2 as a dopant exhibited efficient red emission with maximum luminous efficiency of 1.87 cd/A, maximum power efficiency of 0.78 lm/W, maximum external quantum efficiency of 1.52%, and CIE coordinates of (0.65, 0.35) at 7.0 V.

Multilayered organic light-emitting diodes (OLEDs) were fabricated by using the new fluorine derivatives end-capped with arylaminofluorenylethylenes as dopant materials. The device structure was ITO/NPB/15% blue dopants doped in MADN/Bphen/Liq/Al. Among those, a device shows the maximum luminance of 40800 cd/m(2) at 12 V, the luminous efficiency of 12.8 cd/A at 20 mA/cm(2), power efficiency of 9.13 lm/W at 20 mA/cm(2) and CIE(x,y) coordinates of (x = 0.188, y = 0.372) at 8 V.

We demonstrated hybrid white organic light-emitting diodes (HWOLEDs) using 1,4-bis{2-[7-N-diphenyamino-2-(9,9-diethyl-9H-fluoren-2-yl)]vinyl} benzene as the fluorescent blue emitter and iridium(III) bis(2-phenylquinoline) acetylacetonate as the phosphorescent red emitter. We also investigated the codoped spacer ratio (CSR) effects of 4,4',4''-tris(N-carbazolyl)-triphenylamine (TCTA) and 2,2',2''-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBI) on the electroluminescence characteristics of HWOLEDs. The optimized HWOLED with a CSR of 1:3 (TCTA:TPBI) exhibited a lower efficiency roll-off of 32% than the control device (67%) with a CSR of 1:1 (TCTA:TPBI). The HWOLED also showed a current efficiency of 12.76 cd/A, an external quantum efficiency of 6.95%, and Commission Internationale de I'Eclairage coordinates of (0.38,0.39) at 1000 cd/m2.

The authors have demonstrated hybrid white organic light-emitting diodes (HWOLEDs) with reduced efficiency roll-off. It was shown that HWOLEDs fabricated with {9,9-dimethyl-7-[10-(naphthalen-2-yl)anthracen-9-yl]-9H-fluoren-2-yl} triphenylsilane (ANFTPS) as the blue host have the maximum external quantum efficiency of 9.92%, power efficiency of 14.51 lm/W, and reduced efficiency roll-off 2.0 times that of the control white device. The deep highest occupied molecular orbital of ANFTPS of the optimized white device adequately brocks holes and confines excitons in emitting layers. The white device also exhibited a more stable color shift from low to high current density than did the control white device.

We have demonstrated high-efficiency phosphorescent white organic light-emitting diodes (PHWOLEDs) using iridium(III) bis[(4,6-difluorophenyl)-pyridinato-N,C 2] picolinate and iridium(III) bis[1-phenyl(quinolinato-N,C 2')]acetylacetonate doped in N,N '-dicarbazolyl-3,5-benzene as a single-host system. As the position of the doped red emitter changed from near the anode to the cathode, the PHWOLED exhibited reduced exciton loss and greater color stability. The optimized PHWOLED exhibited a peak external quantum efficiency of 13.49%, a power efficiency of 20.59 lm/W, a current efficiency of 26.20 cd/A, and Commission Internationale de l'Eclairage coordinates of (0.37, 0.35). The red emitter near the cathode includes efficient triplet energy confinement in the emitting layers.

The authors have demonstrated hybrid white organic light-emitting diodes (WOLEDs) using 1,4-bis[2-(7-N-diphenyamino-2-(9,9-diethyl-9H-fluoren-2-yl))vinyl] benzene as a fluorescent blue emitter and iridium(III) bis(2-phenylquinoline) acetylacetonate as a phosphorescent red emitter. As the spacer ratio of 4,4',4''-tris-(N-carbazolyl) triphenylamine to 4,7-diphenyl-1,10-phenanthroline changed from 1:1 to 1:3, WOLEDs showed changes from cold to warm electroluminescent characteristics. The optimized WOLEDs of 1:3 spacer ratio showed an external quantum efficiency of 7.40%, a luminous efficiency of 14.79 cd/A, and Commission Internationale de I'Eclairage coordinates of (0.43, 0.39) at 1000 cd/m2.

We have demonstrated high-efficiency white organic light-emitting diodes (WOLEDs) using codoped blue-emitting layers with three light emitters, 4''-(2,2-diphenylvinyl)-1-[4-(N,N-diphenylamino)-styryl]-terphenyl, fac-tris(2-phenypyridine) iridium(III), and bis(5-benzoyl-2-phenylpyridinato-C,N)iridium(III) (acetylacetonate). Blue-emitting layers (BEMLs) were codoped with the different functional materials, N,N'-bis(1-naphyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine and 4,7-diphenyl-1,10-phenanthroline, which are used as charge-transporting materials in OLEDs. An optimized device with centralized carriers in emitting layers showed a maximum luminance of 19 710 cd/m2 at 12 V, a maximum luminous efficiency of 23.20 cd/A at 0.14 mA/cm2, and an external quantum efficiency of 10.20% at 32.19 cd/m2.