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Ara Philipossian - One of the best experts on this subject based on the ideXlab platform.
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effect of temperature in titanium Chemical Mechanical Planarization
Japanese Journal of Applied Physics, 2015Co-Authors: Yan Mu, Yasa Sampurno, Yun Zhuang, Yubo Jiao, Siannie Theng, Ara PhilipossianAbstract:The effect of temperature on the tribological and kinetic attributes of Ti Chemical Mechanical Planarization (CMP) was investigated. Results indicated that processes at platen temperatures of 25 and 50 °C behaved similarly in terms of their tribological mechanism. At both temperatures, average coefficient of friction (COF) ranged from 0.19 to 0.41, indicating that boundary lubrication was the dominant tribological mechanism. Results also showed that average COF decreased with increasing platen temperature likely due to softening of pad asperities and lower slurry viscosity at the higher temperature. Due to exponentially accelerated Chemical effects, Ti removal rate was higher when platen temperature was set at 50 °C. A two-step modified Langmuir–Hinshelwood model was used to simulate Ti removal rate and the Chemical and Mechanical rate constants under different polishing conditions. Simulated values of removal rate agreed well with experimental data. Simulated Chemical rate to Mechanical rate constant ratios suggested that the removal mechanism shifted from a more Chemically-controlled to a more Mechanically-controlled process as platen temperature was raised.
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Effect of temperature on pad surface contact area in Chemical Mechanical Planarization
ECS Solid State Letters, 2012Co-Authors: Yubo Jiao, Yun Zhuang, Leonard Borucki, Xiaoyan Liao, Ananth Naman, Ara PhilipossianAbstract:In this study, pad surface contact area measurement was performed using laser confocal microscopy at elevated temperatures under dry and static condition to illustrate the effect of temperature on the Mechanical contacts in Chemical Mechanical Planarization. Pad surface contact area and contact density were measured for a Cabot Microelectronics Corporation D100 pad sample at 27.6 kPa with a custom-made sample holder that was designed to heat the pad sample during the measurement. When the pad surface temperature increased from 25 to 45 ◦ C, pad asperities became much softer and resulted in a significant increase (from 0.029% to 0.092%) in the
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Pad Wear Analysis during Interlayer Dielectric Chemical Mechanical Planarization
ECS Journal of Solid State Science and Technology, 2012Co-Authors: Yubo Jiao, Mansour Moinpour, Yasa Sampurno, Yun Zhuang, Anand Meled, Siannie Theng, Jiang Cheng, Don Hooper, Ara PhilipossianAbstract:In this study, pad wear during interlayer dielectric (ILD) Chemical Mechanical Planarization (CMP) was investigated using retaining rings with different materials and slot designs as well as pads with different materials at different platen temperatures. Results showed that the retaining ring slot design did not significantly affect the pad wear rate. On the other hand, the polyether ether ketone (PEEK) retaining ring exhibited a significantly lower pad wear rate (by 31%) than the polyphenylene sulfide (PPS) retaining ring. At both platen temperatures (25 and 50◦C), the thermoplastic D100 pad exhibited lower pad wear rates than the thermoset IC1000 pad. © 2012 The ElectroChemical Society. [DOI: 10.1149/2.022205jss] All rights reserved
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analysis of a novel slurry injection system in Chemical Mechanical Planarization
Japanese Journal of Applied Physics, 2011Co-Authors: Anand Meled, Yasa Sampurno, Yun Zhuang, Yubo Jiao, Siannie Theng, Leonard Borucki, Ara PhilipossianAbstract:Slurry mean residence time (MRT), removal rate, and polishing defects were analyzed for a novel slurry injection system used in Chemical Mechanical Planarization. The novel slurry injection system was placed adjacent to the wafer on the pad surface and slurry was injected towards the wafer through multiple holes in the trailing edge of the injector bottom. Results showed the novel slurry injection system provided more efficient slurry delivery to the pad–wafer interface and generated lower slurry MRT, higher removal rate, and lower polishing defects than the standard pad center area slurry application method currently used in the IC manufacturing industry.
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End-point detection of Ta/TaN Chemical Mechanical Planarization via forces analysis
Japanese Journal of Applied Physics, 2010Co-Authors: Yasa Sampurno, Ara Philipossian, Xun Gu, Takenao Nemoto, Yun Zhuang, Akinobu Teramoto, Tadahiro OhmiAbstract:This study explores the transition of shear force spectral fingerprints during tantalum (Ta) and/or tantalum nitride (TaN) Chemical Mechanical Planarization on patterned wafers using a polisher and tribometer that has the unique ability to measure shear force and down force in real-time. Fast Fourier Transformation is performed to convert the raw force data from time domain to frequency domain and to illustrate the amplitude distribution of shear force and down force. Results show that coefficient of friction, variance of shear force and variance of down force increase during polishing when the Ta/TaN layer is removed thus exposing the inter-layer dielectric layer. Unique and consistent spectral fingerprints are generated from shear force data showing significant changes in several fundamental peaks before, during and after Ta/TaN clearing. Results show that a combination of unique spectral fingerprinting, coefficient of friction and analysis of force variance can be used to monitor in real-time the polishing progress during Ta/TaN Chemical Mechanical Planarization for optimal polishing time.
Haedo Jeong - One of the best experts on this subject based on the ideXlab platform.
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Mechanical effect of colloidal silica in copper Chemical Mechanical Planarization
Journal of Materials Processing Technology, 2009Co-Authors: Haedo JeongAbstract:The Mechanical effect of colloidal silica concentration in copper Chemical Mechanical Planarization (CMP) is considered in this paper by using friction force monitoring system. The copper peak was detected in the result of the energy-dispersive X-ray (EDX) spectra of the polishing residues. The addition of colloidal silica into copper CMP slurry increased both the material removal rate and the friction force. During CMP, as the concentration of the colloidal silica was increased, the temperature generated by the friction force also increased. To understand effect of abrasive concentration on the material removal and friction force, we considered the material removal and the friction energy for a single abrasive. The surface of the polished copper film was measured by X-ray photoelectron spectroscopy (XPS). All the material removal rates as a function of friction energy after polishing with various concentrations of colloidal silica had a non-linear characteristic.
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Effect of polishing pad with holes in electro-Chemical Mechanical Planarization
Microelectronic Engineering, 2008Co-Authors: Sukhoon Jeong, Haedo JeongAbstract:Electro-Chemical Mechanical Planarization (ECMP) process dissolves copper ions electroChemically by applying an anodic potential on the copper surface in an aqueous electrolyte, and then removes a copper (Cu) complex layer by the Mechanical abrasion of a polishing pad or abrasives in the electrolyte. The ECMP process is a low pressure polishing method for metals such as copper, aluminium (Al) and tungsten (W) on dielectric materials such as silicon dioxide, low-k (LK) and ultra low-k (ULK) dielectrics, comparing to the amount of defects by the traditional Cu Chemical Mechanical Planarization (CMP). The polishing pad used in the ECMP process is a conventional closed cell type pad (IC 1400K-groove pad) with holes. It supplies the aqueous electrolyte to the copper surface and removes the copper complex layer. The material removal rate (MRR) and MRR profile were simulated and tested according to the changes of the wafer overhang distance (WOD) from the platen and the electric contact area (ECA). In order to derive the design rule of the system, the experimental results are compared with the simulation results. After the ECMP process, it was verified that the within wafer non-uniformity (WIWNU) was lower than 2% using the relatively uniform ECA pad (C-type) under the smallest WOD condition. The experimental results well matched the simulated results.
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influence of slurry components on uniformity in copper Chemical Mechanical Planarization
Microelectronic Engineering, 2008Co-Authors: Boumyoung Park, Haedo JeongAbstract:Many researchers studying copper Chemical Mechanical Planarization (CMP) have been focused on mechanisms of copper removal using various Chemicals. On the basis of these previous works, we studied the effect of slurry components on uniformity. Chemical Mechanical Planarization of copper was performed using citric acid (C"6H"8O"7), hydrogen peroxide (H"2O"2), colloidal silica, and benzotriazole (BTA, C"6H"4N"3H) as a complexing agent, an oxidizer, an abrasive, and a corrosion inhibitor, respectively. As citric acid was added to copper CMP slurry (pH4) containing 3vol% hydrogen peroxide and 3wt% colloidal silica, the material removal (MRR) at the wafer center was higher than its edge. Hydrogen peroxide could not induce a remarkable change in the profile of MRR. Colloidal silica, used as an abrasive in copper CMP slurry containing 0.01M of citric acid and 3vol% of hydrogen peroxide, controlled the profile of MRR by abrading the wafer edge. BTA as a corrosion inhibitor decreased the MRR and seems to control the material removal around the wafer center. All the results of in this study showed that the MRR profile of copper CMP could be controlled by the contents of slurry components.
Yun Zhuang - One of the best experts on this subject based on the ideXlab platform.
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effect of temperature in titanium Chemical Mechanical Planarization
Japanese Journal of Applied Physics, 2015Co-Authors: Yan Mu, Yasa Sampurno, Yun Zhuang, Yubo Jiao, Siannie Theng, Ara PhilipossianAbstract:The effect of temperature on the tribological and kinetic attributes of Ti Chemical Mechanical Planarization (CMP) was investigated. Results indicated that processes at platen temperatures of 25 and 50 °C behaved similarly in terms of their tribological mechanism. At both temperatures, average coefficient of friction (COF) ranged from 0.19 to 0.41, indicating that boundary lubrication was the dominant tribological mechanism. Results also showed that average COF decreased with increasing platen temperature likely due to softening of pad asperities and lower slurry viscosity at the higher temperature. Due to exponentially accelerated Chemical effects, Ti removal rate was higher when platen temperature was set at 50 °C. A two-step modified Langmuir–Hinshelwood model was used to simulate Ti removal rate and the Chemical and Mechanical rate constants under different polishing conditions. Simulated values of removal rate agreed well with experimental data. Simulated Chemical rate to Mechanical rate constant ratios suggested that the removal mechanism shifted from a more Chemically-controlled to a more Mechanically-controlled process as platen temperature was raised.
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Effect of temperature on pad surface contact area in Chemical Mechanical Planarization
ECS Solid State Letters, 2012Co-Authors: Yubo Jiao, Yun Zhuang, Leonard Borucki, Xiaoyan Liao, Ananth Naman, Ara PhilipossianAbstract:In this study, pad surface contact area measurement was performed using laser confocal microscopy at elevated temperatures under dry and static condition to illustrate the effect of temperature on the Mechanical contacts in Chemical Mechanical Planarization. Pad surface contact area and contact density were measured for a Cabot Microelectronics Corporation D100 pad sample at 27.6 kPa with a custom-made sample holder that was designed to heat the pad sample during the measurement. When the pad surface temperature increased from 25 to 45 ◦ C, pad asperities became much softer and resulted in a significant increase (from 0.029% to 0.092%) in the
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Pad Wear Analysis during Interlayer Dielectric Chemical Mechanical Planarization
ECS Journal of Solid State Science and Technology, 2012Co-Authors: Yubo Jiao, Mansour Moinpour, Yasa Sampurno, Yun Zhuang, Anand Meled, Siannie Theng, Jiang Cheng, Don Hooper, Ara PhilipossianAbstract:In this study, pad wear during interlayer dielectric (ILD) Chemical Mechanical Planarization (CMP) was investigated using retaining rings with different materials and slot designs as well as pads with different materials at different platen temperatures. Results showed that the retaining ring slot design did not significantly affect the pad wear rate. On the other hand, the polyether ether ketone (PEEK) retaining ring exhibited a significantly lower pad wear rate (by 31%) than the polyphenylene sulfide (PPS) retaining ring. At both platen temperatures (25 and 50◦C), the thermoplastic D100 pad exhibited lower pad wear rates than the thermoset IC1000 pad. © 2012 The ElectroChemical Society. [DOI: 10.1149/2.022205jss] All rights reserved
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analysis of a novel slurry injection system in Chemical Mechanical Planarization
Japanese Journal of Applied Physics, 2011Co-Authors: Anand Meled, Yasa Sampurno, Yun Zhuang, Yubo Jiao, Siannie Theng, Leonard Borucki, Ara PhilipossianAbstract:Slurry mean residence time (MRT), removal rate, and polishing defects were analyzed for a novel slurry injection system used in Chemical Mechanical Planarization. The novel slurry injection system was placed adjacent to the wafer on the pad surface and slurry was injected towards the wafer through multiple holes in the trailing edge of the injector bottom. Results showed the novel slurry injection system provided more efficient slurry delivery to the pad–wafer interface and generated lower slurry MRT, higher removal rate, and lower polishing defects than the standard pad center area slurry application method currently used in the IC manufacturing industry.
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End-point detection of Ta/TaN Chemical Mechanical Planarization via forces analysis
Japanese Journal of Applied Physics, 2010Co-Authors: Yasa Sampurno, Ara Philipossian, Xun Gu, Takenao Nemoto, Yun Zhuang, Akinobu Teramoto, Tadahiro OhmiAbstract:This study explores the transition of shear force spectral fingerprints during tantalum (Ta) and/or tantalum nitride (TaN) Chemical Mechanical Planarization on patterned wafers using a polisher and tribometer that has the unique ability to measure shear force and down force in real-time. Fast Fourier Transformation is performed to convert the raw force data from time domain to frequency domain and to illustrate the amplitude distribution of shear force and down force. Results show that coefficient of friction, variance of shear force and variance of down force increase during polishing when the Ta/TaN layer is removed thus exposing the inter-layer dielectric layer. Unique and consistent spectral fingerprints are generated from shear force data showing significant changes in several fundamental peaks before, during and after Ta/TaN clearing. Results show that a combination of unique spectral fingerprinting, coefficient of friction and analysis of force variance can be used to monitor in real-time the polishing progress during Ta/TaN Chemical Mechanical Planarization for optimal polishing time.
Abhijit Chandra - One of the best experts on this subject based on the ideXlab platform.
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Modeling and Control of Surface Quality in Chemical Mechanical Planarization (CMP)
Volume 2: Mechatronics; Estimation and Identification; Uncertain Systems and Robustness; Path Planning and Motion Control; Tracking Control Systems; M, 2017Co-Authors: Pavan A. Poosarla, Abhijit Chandra, Hamid Emadi, Sourabh BhattacharyaAbstract:Obtaining uniform surface finish across large length scales is extremely important in Chemical Mechanical Planarization (CMP). Existing control strategies use results from model simulations to propose open-loop control strategies to reduce the step height on surfaces being polished. In the present work, we propose a strategy to control the surface profile of substrate during CMP process. The evolution of the surface profile is predicted using the state space model of the polishing process. The resulting state space equation is solved and a closed form solution of the surface profile is obtained as a function of time. Based on the solution, we provide a fundamental limitation for the machining process in terms of the extent of Planarization that can be achieved for a given material budget.
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Diffusion-Limited Agglomeration and Defect Generation during Chemical Mechanical Planarization
Journal of The Electrochemical Society, 2008Co-Authors: R. Biswas, Pavan Karra, Peter J Sherman, Abhijit ChandraAbstract:Chemical Mechanical Planarization (CMP) of copper involves removal of surface asperities with abrasive particles and polishing processes. This leads to copper-containing nanoparticles extruded into the solution. We model the diffusion-limited agglomeration (DLA) of such nanoparticles which can rapidly grow to large sizes. These large particles are detrimental because they can participate in polishing, causing scratches and surface defects during CMP. The agglomeration is much slower in the reaction-limited agglomeration process. Under realistic conditions the defect generation probability can increase significantly over time scales of {approx}10 to 20 min from DLA, unless prevented by slurry rejuvenation or process modification measures.
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prediction of scratch generation in Chemical Mechanical Planarization
Cirp Annals-manufacturing Technology, 2008Co-Authors: Abhijit Chandra, R. Biswas, Ashraf Bastawros, Silvia Armini, Pavan Karra, Peter J Sherman, D A LuccaAbstract:A multi-scale model encompassing pad response and slurry behavior is developed to predict scratch propensity in a Chemical Mechanical Planarization (CMP) process. The pad response delineates the interplay between the local particle level deformation and the cell level bending of the pad. The slurry agglomerates in the diffusion limited agglomeration (DLA) or reaction limited agglomeration (RLA) regime. Various nano-scale slurry properties significantly influence the spatial and temporal modulation of the material removal rate (MRR) and scratch generation characteristics. The model predictions are first validated against experimental observations. A parametric study is then undertaken. Such physically based models can be utilized to optimize slurry and pad designs to control the depth of generated scratches and their frequency of occurrence per unit area.
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Surface Evolution during the Chemical Mechanical Planarization of Copper
CIRP Annals, 2006Co-Authors: Ashraf Bastawros, Abhijit Chandra, P.m. LonardoAbstract:Stressed surfaces are configurationally unstable under Chemical etching wherein they may evolve to reduce their total energy. This paper investigates how such an effect may influence the Planarization rate in a Chemical Mechanical Planarization (CMP) process. Nano-wear experiments on electro-plated copper surfaces have been conducted with systematic exposures to Chemically active slurry. The nano-wear experiments have been first performed to generate local variation of the residual stress levels, followed by Chemical etching to investigate the variation of the wear depth and the evolution of surface topography. It is found that the residual stress caused by the Mechanical wear enhances the Chemical etching rate.
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Atomistic Mechanisms Underlying Chemical Mechanical Planarization of Copper
MRS Proceedings, 2003Co-Authors: Y. Ye, R. Biswas, Ashraf Bastawros, Abhijit ChandraAbstract:AbstractWith an aim to understanding the fundamental mechanisms underlying Chemical Mechanical Planarization (CMP) of copper, we simulate the nanoscale polishing of a copper surface with molecular dynamics utilizing the embedded atom method. Mechanical abrasion produces rough planarized surfaces with a large chip in front of the abrasive particle, and dislocations in the bulk of the crystal. The addition of Chemical dissolution leads to very smooth planarized copper surfaces and considerably smaller frictional forces that prevent the formation of bulk dislocations. This is a first step towards understanding the interplay between mechanistic material abrasion and Chemical dissolution in Chemical Mechanical Planarization of copper interconnects.
Ashraf Bastawros - One of the best experts on this subject based on the ideXlab platform.
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prediction of scratch generation in Chemical Mechanical Planarization
Cirp Annals-manufacturing Technology, 2008Co-Authors: Abhijit Chandra, R. Biswas, Ashraf Bastawros, Silvia Armini, Pavan Karra, Peter J Sherman, D A LuccaAbstract:A multi-scale model encompassing pad response and slurry behavior is developed to predict scratch propensity in a Chemical Mechanical Planarization (CMP) process. The pad response delineates the interplay between the local particle level deformation and the cell level bending of the pad. The slurry agglomerates in the diffusion limited agglomeration (DLA) or reaction limited agglomeration (RLA) regime. Various nano-scale slurry properties significantly influence the spatial and temporal modulation of the material removal rate (MRR) and scratch generation characteristics. The model predictions are first validated against experimental observations. A parametric study is then undertaken. Such physically based models can be utilized to optimize slurry and pad designs to control the depth of generated scratches and their frequency of occurrence per unit area.
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Surface Evolution during the Chemical Mechanical Planarization of Copper
CIRP Annals, 2006Co-Authors: Ashraf Bastawros, Abhijit Chandra, P.m. LonardoAbstract:Stressed surfaces are configurationally unstable under Chemical etching wherein they may evolve to reduce their total energy. This paper investigates how such an effect may influence the Planarization rate in a Chemical Mechanical Planarization (CMP) process. Nano-wear experiments on electro-plated copper surfaces have been conducted with systematic exposures to Chemically active slurry. The nano-wear experiments have been first performed to generate local variation of the residual stress levels, followed by Chemical etching to investigate the variation of the wear depth and the evolution of surface topography. It is found that the residual stress caused by the Mechanical wear enhances the Chemical etching rate.
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Atomistic Mechanisms Underlying Chemical Mechanical Planarization of Copper
MRS Proceedings, 2003Co-Authors: Y. Ye, R. Biswas, Ashraf Bastawros, Abhijit ChandraAbstract:AbstractWith an aim to understanding the fundamental mechanisms underlying Chemical Mechanical Planarization (CMP) of copper, we simulate the nanoscale polishing of a copper surface with molecular dynamics utilizing the embedded atom method. Mechanical abrasion produces rough planarized surfaces with a large chip in front of the abrasive particle, and dislocations in the bulk of the crystal. The addition of Chemical dissolution leads to very smooth planarized copper surfaces and considerably smaller frictional forces that prevent the formation of bulk dislocations. This is a first step towards understanding the interplay between mechanistic material abrasion and Chemical dissolution in Chemical Mechanical Planarization of copper interconnects.
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pad effects on material removal rate in Chemical Mechanical Planarization
Journal of Electronic Materials, 2002Co-Authors: Ashraf Bastawros, Abhijit ChandraAbstract:The role of a porous pad in controlling material-removal rate (MRR) during the Chemical-Mechanical Planarization (CMP) process has been studied numerically. The numerical results are used to develop a phenomenological model that correlates the forces on each individual abrasive particle to the applied nominal pressure. The model provides a physical explanation for the experimentally observed domains of pressure-dependent MRR, where the pad deformation controls the load sharing between active-abrasive particles and direct pad-wafer contact. The predicted correlations between MRR and slurry characteristics, i.e., particle size and concentration, are in agreement with experimentally measured trends reported by Ouma1 and Izumitani2.
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Simulation of Chemical Mechanical Planarization of copper with molecular dynamics
Applied Physics Letters, 2002Co-Authors: Y. Ye, R. Biswas, Ashraf Bastawros, Abhijit ChandraAbstract:With an aim to understanding the fundamental mechanisms underlying Chemical Mechanical Planarization (CMP) of copper, we simulate the nanoscale polishing of a copper surface with molecular dynamics utilizing the embedded atom method. Mechanical abrasion produces rough planarized surfaces with a large chip in front of the abrasive particle, and dislocations in the bulk of the crystal. The addition of Chemical dissolution leads to very smooth planarized copper surfaces and considerably smaller frictional forces that prevent the formation of bulk dislocations. This is a first step towards understanding the interplay between mechanistic material abrasion and Chemical dissolution in Chemical Mechanical Planarization of copper interconnects.