• Journal of the Korean Institute of Telematics and Electronics
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• v.17 no.6
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• pp.24-27
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• 1980

본 논문에서는 J.Klapper와 E.J. Kratt[1]III에 의하여 제안된 저지연 FM검파기의 일반적인 왜곡해석을 Taylor[2] 반수전개법에 의하여 또한 상기의 저지연 FM검파기에서 사용한 RLC Notch 필터를 동 FM 검파기의 IC화를 고려하여 Twin-Tee RC 능동필터로 대치하고 예상되는 검파신호의 지연시간을 검토하였다.

• Journal of IKEEE
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• v.3 no.1 s.4
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• pp.11-21
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• 1999

This paper has been proposed a structure composed of FIRs and IIR filters as digital interpolation filter to integrate the off-chip analog low-pass filter of audio DAC. The passband ripple (>$0.41{\times}fs$), passband attenuation(>at$0.41{\times}fs$) and stopband attenuation(<$0.59{\times}fs$) of the ${\Delta}{\Sigma}$ modulator output using the proposed digital interpolation filter had ${\pm}0.001[dB]$, -0.0025[dB] and -75[dB], respectively. Also the inband group delay was 30.07/fs[s] and the error of group delay was 0.1672%. Also, the attenuation of stopband has been increased -20[dB] approximately at 65[kHz], out-of-band. Therefore the RC products of analog low-pass filter on chip have been decreased compared with the conventional digital interpolation filter structure.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.44 no.8
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• pp.65-73
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• 2007

This paper presents a low power CMOS continuous-time $\Sigma\Delta$ (sigma-delta) modulator for UMTS receivers. The loop filter of the continuous-time $\Sigma\Delta$ modulator consists of an active-RC filter which performs high linearity characteristics and has a simple tuning circuit for low power operating system The architecture of this modulator is the $3^{rd}-order$ 4-bit single loop configuration with a 24 of OSR (Oversampling Ratio) to increase the power efficiency. The modulator includes a half delay feedback path to compensate the excess loop delay. The experimental results of the modulator are 71dB, 65dB and 74dB of the peak SNR, peak SMR and dynamic range, respectively. The continuous-time $\Sigma\Delta$ modulator is fabricated in a 0.18-um 1P4M CMOS standard process and dissipates 15mW for a single supply voltage of 1.8V.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.3
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• pp.51-59
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• 2009

This paper presents the design of continuous-time sigma-delta modulator for acoustic sensor. The feedforward structure without summing block is used to reduce power consumption of sigma-delta modulator. A high-linearity active-RC filter is used to improve resolution of sigma-delta modulator. Excess loop delay problem in conventional continuous-time sigma-delta modulators is solved by our proposed architecture. A low power, high resolution fourth-order continuous-time sigma-delta modulator with 1-bit quantization was realized in a 0.13-${\mu}m$ 1-Poly 8-metal CMOS technology, with a core area of $0.58\;mm^2$. Simulation results show that the modulator achieves 91.3-dB SNR over a 25-kHz signal bandwidth with an oversampling ratio of 64, while dissipating $290{\mu}W$ from a 3.3-V supply.

• Tribology and Lubricants
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• v.31 no.3
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• pp.79-85
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• 2015

RC delay is a critical issue for achieving high performance of ULSI devices. In order to minimize the RC delay time, we uses the CMP process to introduce high-conductivity Cu and low-k materials on the damascene. The low-k materials are generally soft and fragile, resulting in structure collapse during the conventional high-pressure CMP process. One troubleshooting method is electrochemical mechanical polishing (ECMP) which has the advantages of high removal rate, and low polishing pressure, resulting in a well-polished surface because of high removal rate, low polishing pressure, and well-polished surface, due to the electrochemical acceleration of the copper dissolution. This study analyzes an electrochemical state (active, passive, transpassive state) on a potentiodynamic curve using a three-electrode cell consisting of a working electrode (WE), counter electrode (CE), and reference electrode (RE) in a potentiostat to verify an electrochemical removal mechanism. This study also tries to find optimum conditions for ECMP through experimentation. Furthermore, during the low-pressure ECMP process, we investigate the effect of current density on surface roughness and removal rate through anodic oxidation, dissolution, and reaction with a chelating agent. In addition, according to the Faraday’s law, as the current density increases, the amount of oxidized and dissolved copper increases. Finally, we confirm that the surface roughness improves with polishing time, and the current decreases in this process.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.1
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• pp.753-759
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• 2020

A modified Chebyshev lowpass filter function with progressively diminishing ripples in the passband is proposed and analyzed in the frequency domain. Owing to the diminishing ripples, the passband magnitude characteristic of the proposed Chebyshev function has improved compared to the classical Chebyshev function. In addition, the phase characteristics of the proposed Chebyshev function were improved considerably compared to that of the Chebyshev function, and the time delay of the proposed function was much simpler and flatter. In addition, the proposed Chebyshev filter was realizable by the passive doubly terminated ladder network delivering maximum power transfer for the order n, even or odd, thus making themselves amenable to low-sensitivity active RC or switched capacitor filters through the simulation techniques. To verify the proposed Chebyshev filter characteristics, a 6th order passive doubly terminated ladder lowpass filter was designed and analyzed using the MATLAB and SPICE program. Thus, the proposed Chebyshev function can remove the drawbacks of the classical Chebyshev function and could be applicable to the design of a filter with an improved filter size, phase, and time delay characteristics for various signal processing.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.95-99
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• 2008

Cu has been used for metallic interconnects in ULSI applications because of its lower resistivity according to the scaling down of semiconductor devices. The resistivity of Cu lines will affect the RC delay and will limit signal propagation in integrated circuits. We investigated the electrolyte effects of the electroplating solution in the resistivity value of Cu films grown by electroplating deposition (EPD). The resistivity was measured with a four-point probe and the material properties were investigated with XRD (X-ray Diffraction), AFM (Atomic Force Microscope), FE-SEM (Field Emission Scanning Electron Microscope) and XPS (X-ray Photoelectron Spectroscopy). From these experimental results, we found that the electrolyte condition plays an Important role in formation of Cu film with lower resistivity by EPD.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.1-10
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• 2009

As a demand for the portable device requiring smaller size and better performance is in hike, reducing the size of conventionally used planar 2 dimensional chip cannot be a solution for the enhancement of the semiconductor chip technology due to an increase in RC delay among interconnects. To address this problem, a new technology - "3 dimensional (3D) IC chip stack" - has been emerging. For the integration of the technology, several new key unit processes (e.g., silicon through via, wafer thinning and wafer alignment and bonding) should be developed and much effort is being made to achieve the goal. As a result of such efforts, 4 and 8 chip-stacked DRAM and NAND structures and a system stacking CPU and memory chips vertically were successfully developed. In this article, basic theory, configurations and key unit processes for the 3D IC chip integration, and a current tendency of the technology are explained. Future opportunities and directions are also discussed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.1-6
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• 2019

Multicast is an efficient method for real-time transmission in many multimedia applications. It is important to recover lost packets and to manage multicast groups according to the network status in order to improve the reliability of multicast transmissions. In this paper, we propose a method that can efficiently recover lost packets in a large multicast group. In the proposed method, we create a recovery cluster (RC) using a multicast domain (MD) for recovery of lost packets. In the conventional methods, clusters send a request message for lost packets to the senders in order to recover the packets lost from many multicast applications. This increases packet delay time and overhead because of the feedback messages and retransmitted packets. In the proposed method, we improve these problems using the RC, which consists of many MDs (which have overlay multicast senders), and many cluster heads (CHs). We divide the message into blocks, and divide each block into many segments for packet recovery using the CHs. When packet loss occurs, all CHs share the segment information and recover the lost segments at the same time. Simulation results show that the proposed method could improve the packet recovery ratio by about 50% compared to the conventional methods.

• Journal of the Korea Concrete Institute
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• v.23 no.1
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• pp.109-120
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• 2011

This paper presents an experimental study results on the crack control of flexure-dominant reinforced concrete beams repaired with strain-hardening cement composite (SHCC). Five RC beams were fabricated and tested until failure. One unrepaired RC beam was a control specimen (CBN) and remaining four speciemens were repaired with SHCC materials. The test parameters included two types of SHCC matrix ductility and two types of repair method (patching and layering). Test results demonstrated that RC beams repaired with SHCC showed no concrete crushing or spalling until final failure, but numerous hair cracks were observed. The control specimen CBN failed due to crushing. It is important to note that SHCC matrix can improve crack-damage mitigation and flexural behavior of RC beams such as flexural strength, post peak ductility, and energy dissipation capacity. In the perspective of crack width, crack widths in RC beams repaired with SHCC had far smaller crack width than the control specimen CBN under the same deflection. Especially, the specimens repaired with SHCC of PVA0.75%+PE0.75% showed a high durability and ductility. The crack width indicates the residual capacity of the beam since SHCC matrix can delay residual capacity degradation of the RC beams.