Mechanical effects of polishing pad in copper electrochemical mechanical deposition for planarization?

Sukhoon Jeong,Sangjik Lee,Boumyoung Park,Hyoungjae Kim,Sungryul Kim,정해도 한국물리학회 2010 Current Applied Physics Vol.10 No.1

ECMD (electrochemical mechanical deposition) process consists of a traditional ECP (electrochemical plating) mechanism and a mechanical component. That is, this technique involves both electrochemical plating and mechanical sweeping of the material surface by the polishing pad. The mechanism of the ECMD process may be achieved through two mechanisms. The first mechanism may be the electrochemical plating on the surface where mechanical sweeping of polishing pad does not reach, and the second mechanism may be that the plating rate in the area that is mechanically swept may be reduced by the polishing pad. In this study, the effects of the mechanical component were investigated through various polishing pad types and hole ratios. In comparison to various polishing pad types using the manufactured the ECMD system, the plating rate and WIWNU (within wafer non-uniformity) using the experimental non-pore polishing pad were better than those of the experiments using other polishing pads.

Mechanical effects of polishing pad in copper electrochemical mechanical deposition for planarization

Jeong, S.,Lee, S.,Park, B.,Kim, H.,Kim, S.,Jeong, H. Elsevier 2010 CURRENT APPLIED PHYSICS Vol.10 No.1

ECMD (electrochemical mechanical deposition) process consists of a traditional ECP (electrochemical plating) mechanism and a mechanical component. That is, this technique involves both electrochemical plating and mechanical sweeping of the material surface by the polishing pad. The mechanism of the ECMD process may be achieved through two mechanisms. The first mechanism may be the electrochemical plating on the surface where mechanical sweeping of polishing pad does not reach, and the second mechanism may be that the plating rate in the area that is mechanically swept may be reduced by the polishing pad. In this study, the effects of the mechanical component were investigated through various polishing pad types and hole ratios. In comparison to various polishing pad types using the manufactured the ECMD system, the plating rate and WIWNU (within wafer non-uniformity) using the experimental non-pore polishing pad were better than those of the experiments using other polishing pads.

Methodological Consideration on the Prediction of Electrochemical Mechanical Polishing Process Parameters by Monitoring of Electrochemical Characteristics of Copper Surface

Seo, Yong-Jin The Korean Electrochemical Society 2020 Journal of electrochemical science and technology Vol.11 No.4

The removal characteristics of copper (Cu) from electrochemical surface by voltage-activated reaction were reviewed to assess the applicability of electrochemical-mechanical polishing (ECMP) process in three types of electrolytes, such as HNO₃, KNO₃ and NaNO₃. Electrochemical surface conditions such as active, passive, transient and trans-passive states were monitored from its current-voltage (I-V) characteristic curves obtained by linear sweep voltammetry (LSV) method. In addition, the oxidation and reduction process of the Cu surface by repetitive input of positive and negative voltages were evaluated from the I-V curve obtained using the cyclic voltammetry (CV) method. Finally, the X-ray diffraction (XRD) patterns and energy dispersive spectroscopy (EDS) analyses were used to observe the structural surface states of a Cu electrode. The electrochemical analyses proposed in this study will help to accurately control the material removal rate (MRR) from the actual ECMP process because they are a good methodology for predicting optimal electrochemical process parameters such as current density, operating voltage, and operating time before performing the ECMP process.

Correlation between Process Parameters and Electrochemical Surface State for Electrochemical-mechanical Polishing Application of Copper in Acid- and Alkali-based Electrolyte

이영균,서용진,Jun-Won Yang,김형호,Yeongbong Park,정해도 대한금속·재료학회 2012 ELECTRONIC MATERIALS LETTERS Vol.8 No.1

We examine the correlation between process parameters and electrochemical surface state for electrochemical-mechanical polishing (ECMP) application of copper (Cu) in alkali-based NaNO3 and acid-based HNO3 elec-trolyte. First, the effects of electrolyte concentration on the electrochemical surface reaction of Cu electrode were evaluated from the current-voltage (I-V) curve obtained by linear sweep voltammetry (LSV) method. Second, we fundamentally studied the chemical states and element composition of the Cu surface according to the concentration of the electrolyte and the potential variation using scanning electron spectroscopy (SEM)and X-ray diffraction (XRD) patterns. The proposed mechanism and analyses were a good methodology in finding suitable electrochemical process parameter for ECMP application.

Voltage-Dependent Electrochemical Removal of Copper in KNO3 Electrolytes for Electrochemical-Mechanical Polishing Applications

서용진,한상준,이우선 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

In this paper, the voltage-activated electrochemical reactions of Cu for electrochemical- mechanical polishing (ECMP) applications were investigated for dierent concentrations of the KNO3 electrolyte. The electrochemical characteristics of Cu, such as active, passive, transient and transpassive states, were evaluated from the current-voltage (I-V ) curve obtained by using linear sweep voltammetry (LSV) and cyclic voltammetry (CV). Finally, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diraction (XRD) analyses were utilized to observe the structural surface states of a Cu disk. The proposed mechanism and analyses were a good methodology for finding suitable electrochemical process parameters for ECMP applications.

열전지용 황철석(FeS₂) 입자크기 변화에 따른 전기화학반응 메커니즘

박병준,Park, Byeong June 한국전기전자재료학회 2017 전기전자재료학회논문지 Vol.30 No.4

Pulverized $FeS_2$ (pyrite) gives different discharge test results with as-received $FeS_2$ electrodes. The as-received $FeS_2$ electrode shows three voltage plateaus during the discharge test. However, the ball-milled $FeS_2$ electrode shows two voltage plateaus. To interpret this result, the effect of $FeS_2$ particle size on electrochemical reactions is investigated by unit cell discharge tests, SEM and XRD. As a result, it is found that the transition reaction product ($Li_2+xFe+xS_2$) of $FeS_2$ explains the difference. The as-received $FeS_2$ reacts according to three reaction steps ($FeS_2{\rightarrow}Li_3Fe_2S_4{\rightarrow}Li_2+xFe_1+xS_2{\rightarrow}LiFe_2S_4$). However, ball-milled $FeS_2$ reacts without the $Li_2+xFe_1+xS_2$ stage. In this study, this result is explained by the difference in electrochemical reaction mechanism. The as-received $FeS_2$ has a larger radius than the ball-milled $FeS_2$. Therefore, the lithium ion has to diffuse into the $FeS_2$ unreacted core, and $Li_2+xFe_1+xS_2$, the transition reaction product of as-received $FeS_2$, is formed during this stage.

Electrochemical Surface Evaluation of Copper by Using a Cyclic Voltammetry Method in a NaNO3 Electrolyte for ECMP Applications

서용진,이영균,이우선 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

Recently, electrochemical-mechanical polishing (ECMP) has been suggested as an alternative to the conventional chemical-mechanical polishing (CMP) process. In the ECMP process, Cu ions are electrochemically dissolved by applying an anodic potential to the Cu surface in an electrolyte. In this work, we demonstrate a voltage-activated electrochemical test, such as cyclic voltammetry (CV) and linear sweep voltammetry (LSV), for studying the correlation between the electrochemical surface state of Cu and various process parameters (operating voltage, concentration of electrolytes, current density, operating time, etc.) in an aqueous NaNO3 electrolyte. We also investigated how this chemical electrolyte affected the process of voltage-induced material removal in the ECMP application of a Cu film. In this way, we monitored the oxidation and the reduction process as of the Cu surface caused by a repetition of the anodic and the cathodic potential in a NaNO3 electrolyte.

구리 ECMP에서 전류밀도가 재료제거에 미치는 영향

박은정(Eunjeong Park),이현섭(Hyunseop Lee),정호빈(Hobin Jeong),정해도(Haedo Jeong) 한국트라이볼로지학회 2015 한국윤활학회지(윤활학회지) Vol.31 No.3

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 lowpressure 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.

Model and Analysis of Piezoelectric Actuator in Practical Three-Stage Mechanism

Dror A. Levy,Amir Shapiro 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.9

Piezoelectric elements (PEMs) are used in a variety of applications. In this paper we developed a full analytical model of a piezoelectric actuator which includes piezo stack elements and a three-stage amplification mechanism. The model was derived separately for each unit of the system. Next, the units were combined, while taking into account their coupling. The hysteresis phenomenon, which is significant in piezoelectric materials, was extensively described. A number of hysteresis calculating algorithms were investigated and a new simple method of examining piezoelectric hysteresis was demonstrated. The theoretical model was verified in a laboratory setup. This setup includes a piezoelectric actuator, measuring devices and an acquisition system. The measured results were compared to the theoretical results, while taking into account the nonlinear phenomena of the piezoelectric materials and the three-stage amplification mechanism, and were found to be very similar. Due to its simplicity, this model can easily be modified in order to be applied to other PEMs or other amplification mechanism methods. The main novelty of this work lies in its system-level approach for piezoelectric actuators. All of the system elements include non-linear phenomena, which mutually influence each other. First, each part of the system will be described separately and then, the combined subsystems and the coupling between their parts will be represented. Finally we treat this system as one whole unit.

Lead-Free All-Inorganic Cesium Tin Iodide Perovskite for Filamentary and Interface-Type Resistive Switching toward Environment-Friendly and Temperature-Tolerant Nonvolatile Memories

Han, Ji Su,Le, Quyet Van,Choi, Jaeho,Kim, Hyojung,Kim, Sun Gil,Hong, Kootak,Moon, Cheon Woo,Kim, Taemin Ludvic,Kim, Soo Young,Jang, Ho Won American Chemical Society 2019 ACS APPLIED MATERIALS & INTERFACES Vol.11 No.8

<P>Recently, organometallic and all-inorganic halide perovskites (HPs) have become promising materials for resistive switching (RS) nonvolatile memory devices with low power consumption because they show current-voltage hysteresis caused by fast ion migration. However, the toxicity and environmental pollution potential of lead, a common constituent of HPs, has limited the commercial applications of HP-based devices. Here, RS memory devices based on lead-free all-inorganic cesium tin iodide (CsSnI<SUB>3</SUB>) perovskites with temperature tolerance are successfully fabricated. The devices exhibit reproducible and reliable bipolar RS characteristics in both Ag and Au top electrodes (TEs) with different switching mechanisms. The Ag TE devices show filamentary RS behavior with ultralow operating voltages (<0.15 V). In contrast, the Au TE devices have interface-type RS behavior with gradual resistance changes. This suggests that the RS characteristics are attributed to either the formation of metal filaments or the ion migration of defects in HPs under applied electric fields. These distinct mechanisms may permit the opportunity to design devices for specific purposes. This work will pave the way for lead-free all-inorganic HP-based nonvolatile memory for commercial application in HP-based devices.</P> [FIG OMISSION]</BR>