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Wastewater from chemical mechanical planarization (CMP) processes in nano-electronics industries must be treated properly in order to fulfil local and international environmental regulations. This study is focused on a performance assessment of membrane distillation (MD) technology for CMP wastewater treatment. A new prototype of air gap membrane distillation (AGMD) module was utilized, with feed water consisting of CMP wastewater collected from imec, Belgium. The module was tested at different operating conditions (temperatures, flow rates and filtration time) and responses in terms of separation efficiency, permeate water quality, transmembrane flux, specific heat demand and exergy efficiency were determined. High quality permeate was produced in all trials, i.e. conductivity ~2.11 µS/cm, pH ~5.4, TOC ~1.13 ppm, IC ~0.24 ppm, TDS ~1.18 ppm and COD ~ 1.9 ppm; for most of the contaminants the separation efficiency was >99%. These findings clearly show that the resulting MD permeate does not exceed environmental regulations for release to recipient, and the permeate can even be considered for reuse. Moreover, the determined specific heat demand at different operating conditions was varying between 1390 and 2170 kWh/m3 whereas; the achievable exergy efficiency was ~19%., QC 20191202

Membrane distillation (MD) is a promising separation technology for the treatment of chemical mechanical planarization (CMP) wastewater releasing from nano-electronics industries. In order to determine the feasibility of the process at industrial scale, the most important factors are large-scale system evaluation and related economics. Since membrane distillation is a thermally driven process, therefore, different integration possibilities between an air gap membrane distillation (AGMD) system and low-grade heat sources are identified and analyzed in this work. Global mass and energy balances are conducted for the AGMD system for CMP wastewater treatment in a typical nano-electronics manufacturing facility. It is determined that around 100 GWh of thermal energy can be readily recovered via internal sources and reused to treat 120,000 m3 CMP wastewater/year with MD feed temperature of 80◦C. Along with the technical feasibility of the system, the detailed economic evaluation has also been performed. Annual capital investment and operating cost showed that the expected CMP wastewater treatment cost can be as low as 3 $/m3 of treated water, which is estimated to be nearly 95% lower than the wastewater treatment cost from electro-chemical systems., QC 20200625

Wastewater from chemical mechanical planarization (CMP) processes in nano-electronics industries must be treated properly in order to fulfil local and international environmental regulations. This study is focused on a performance assessment of membrane distillation (MD) technology for CMP wastewater treatment. A new prototype of air gap membrane distillation (AGMD) module was utilized, with feed water consisting of CMP wastewater collected from imec, Belgium. The module was tested at different operating conditions (temperatures, flow rates and filtration time) and responses in terms of separation efficiency, permeate water quality, transmembrane flux, specific heat demand and exergy efficiency were determined. High quality permeate was produced in all trials, i.e. conductivity ~2.11 µS/cm, pH ~5.4, TOC ~1.13 ppm, IC ~0.24 ppm, TDS ~1.18 ppm and COD ~ 1.9 ppm; for most of the contaminants the separation efficiency was >99%. These findings clearly show that the resulting MD permeate does not exceed environmental regulations for release to recipient, and the permeate can even be considered for reuse. Moreover, the determined specific heat demand at different operating conditions was varying between 1390 and 2170 kWh/m3 whereas; the achievable exergy efficiency was ~19%., QC 20191202

Wastewater from chemical mechanical planarization (CMP) processes in nano-electronics industries must be treated properly in order to fulfil local and international environmental regulations. This study is focused on a performance assessment of membrane distillation (MD) technology for CMP wastewater treatment. A new prototype of air gap membrane distillation (AGMD) module was utilized, with feed water consisting of CMP wastewater collected from imec, Belgium. The module was tested at different operating conditions (temperatures, flow rates and filtration time) and responses in terms of separation efficiency, permeate water quality, transmembrane flux, specific heat demand and exergy efficiency were determined. High quality permeate was produced in all trials, i.e. conductivity ~2.11 µS/cm, pH ~5.4, TOC ~1.13 ppm, IC ~0.24 ppm, TDS ~1.18 ppm and COD ~ 1.9 ppm; for most of the contaminants the separation efficiency was >99%. These findings clearly show that the resulting MD permeate does not exceed environmental regulations for release to recipient, and the permeate can even be considered for reuse. Moreover, the determined specific heat demand at different operating conditions was varying between 1390 and 2170 kWh/m3 whereas; the achievable exergy efficiency was ~19%., QC 20191202

This thesis presents a series of studies related to a new way of analyzing data from previous polishing tests pertaining to tribological, thermal, kinetic and slurry utilization aspects of chemical mechanical planarization (CMP) processes. The purpose of our current studies is to expand upon the correlation of real-time shear force (SF) and coefficient of friction (COF) data with that of real-time platen motor current (PMC) in order to determine if PMC is a viable alternative to SF and COF when studying polishing mechanisms. The first contribution to this thesis is the investigation of the correlations between shear force and platen motor current, as well as those between COF and PMC for various tungsten and interlayer dielectric (ILD) chemical mechanical planarization cases where the processes were intentionally made to be highly non-steady-state. The study initially focuses on non-steady-state conditions because we believe the relationships among shear force, COF, and platen motor current to be clearer as opposed to steady-state conditions. Shear force, normal force and PMC data were collected from twelve different previously obtained Stribeck+ curves at an acquisition frequency of 1,000 Hz and analyzed in order to determine if there were any emerging trends. For the 12 cases, involving 8 pre-polished blanket CVD tungsten and 4 silicon dioxide blanket wafers, it was discovered that PMC closely mirrored shear force as evidenced by a high average correlation coefficient (0.955) and coefficient of determination (0.916) obtained from all runs. For COF vs. PMC, the average correlation coefficient and coefficient of determination for all cases were 0.758 and 0.608, respectively. These average values were dragged down by 5 cases in which the dominant tribological mechanism was found to be “boundary lubrication” where COF changed minimally with the pseudo-Sommerfeld number. The second contribution to this thesis has been the investigation of the relationship between SF an

The experimental analyses in this thesis are presented in two parts (see Chapters 5 and 6). The first study seeks to uncover the relationships that exist between the coefficient of friction (COF) and platen motor current (PMC), as well as shear force (SF) and PMC at highly non-steady-state conditions during chemical mechanical planarization (CMP). The second work expands on the conclusions and realizations made from the first study and focuses on whether in-situ PMC monitoring is reliable at steady state for inferring process conditions or abnormalities. The basis for both studies consists of 12 experimental data sets gathered from Stribeck+ curves (10 for copper, one for cobalt buff, and one for shallow trench isolation). As presented in greater detail in Chapter 5, it is demonstrated that real-time PMC data are strongly correlated with SF data at transient conditions. This becomes evident from high average values of correlation coefficient and coefficient of determination for all 12 cases (0.913 and 0.835, respectively). The average correlation coefficient and coefficient of determination for COF and PMC in Cases A through D were 0.949 and 0.900, respectively. However, for the remaining 8 cases, correlation coefficients ranged from zero to 0.425, with coefficients of determination ranging from zero to 0.180. This was explained based on the predominant contact mechanism which varied between cases. In high-volume manufacturing (HVM) it is desired to run CMP processes at steady-state conditions to reduce variability between polished wafers. Therefore, the follow-up study presented in Chapter 6 investigated whether PMC was a reliable indicator of fundamental tribological phenomena at steady state. From the 12 cases that formed the basis of this thesis, 60 distinct steady-state steps were isolated from their associated Stribeck+ curves and examined. Data averaging, in conjunction with a new trend matching algorithm, signified that PMC was a reasonably good indicator of

The experimental analyses in this thesis are presented in two parts (see Chapters 5 and 6). The first study seeks to uncover the relationships that exist between the coefficient of friction (COF) and platen motor current (PMC), as well as shear force (SF) and PMC at highly non-steady-state conditions during chemical mechanical planarization (CMP). The second work expands on the conclusions and realizations made from the first study and focuses on whether in-situ PMC monitoring is reliable at steady state for inferring process conditions or abnormalities. The basis for both studies consists of 12 experimental data sets gathered from Stribeck+ curves (10 for copper, one for cobalt buff, and one for shallow trench isolation). As presented in greater detail in Chapter 5, it is demonstrated that real-time PMC data are strongly correlated with SF data at transient conditions. This becomes evident from high average values of correlation coefficient and coefficient of determination for all 12 cases (0.913 and 0.835, respectively). The average correlation coefficient and coefficient of determination for COF and PMC in Cases A through D were 0.949 and 0.900, respectively. However, for the remaining 8 cases, correlation coefficients ranged from zero to 0.425, with coefficients of determination ranging from zero to 0.180. This was explained based on the predominant contact mechanism which varied between cases. In high-volume manufacturing (HVM) it is desired to run CMP processes at steady-state conditions to reduce variability between polished wafers. Therefore, the follow-up study presented in Chapter 6 investigated whether PMC was a reliable indicator of fundamental tribological phenomena at steady state. From the 12 cases that formed the basis of this thesis, 60 distinct steady-state steps were isolated from their associated Stribeck+ curves and examined. Data averaging, in conjunction with a new trend matching algorithm, signified that PMC was a reasonably good indicator of

This thesis presents a series of studies related to a new way of analyzing data from previous polishing tests pertaining to tribological, thermal, kinetic and slurry utilization aspects of chemical mechanical planarization (CMP) processes. The purpose of our current studies is to expand upon the correlation of real-time shear force (SF) and coefficient of friction (COF) data with that of real-time platen motor current (PMC) in order to determine if PMC is a viable alternative to SF and COF when studying polishing mechanisms. The first contribution to this thesis is the investigation of the correlations between shear force and platen motor current, as well as those between COF and PMC for various tungsten and interlayer dielectric (ILD) chemical mechanical planarization cases where the processes were intentionally made to be highly non-steady-state. The study initially focuses on non-steady-state conditions because we believe the relationships among shear force, COF, and platen motor current to be clearer as opposed to steady-state conditions. Shear force, normal force and PMC data were collected from twelve different previously obtained Stribeck+ curves at an acquisition frequency of 1,000 Hz and analyzed in order to determine if there were any emerging trends. For the 12 cases, involving 8 pre-polished blanket CVD tungsten and 4 silicon dioxide blanket wafers, it was discovered that PMC closely mirrored shear force as evidenced by a high average correlation coefficient (0.955) and coefficient of determination (0.916) obtained from all runs. For COF vs. PMC, the average correlation coefficient and coefficient of determination for all cases were 0.758 and 0.608, respectively. These average values were dragged down by 5 cases in which the dominant tribological mechanism was found to be “boundary lubrication” where COF changed minimally with the pseudo-Sommerfeld number. The second contribution to this thesis has been the investigation of the relationship between SF an

Wastewater from chemical mechanical planarization (CMP) processes in nano-electronics industries must be treated properly in order to fulfil local and international environmental regulations. This study is focused on a performance assessment of membrane distillation (MD) technology for CMP wastewater treatment. A new prototype of air gap membrane distillation (AGMD) module was utilized, with feed water consisting of CMP wastewater collected from imec, Belgium. The module was tested at different operating conditions (temperatures, flow rates and filtration time) and responses in terms of separation efficiency, permeate water quality, transmembrane flux, specific heat demand and exergy efficiency were determined. High quality permeate was produced in all trials, i.e. conductivity ~2.11 µS/cm, pH ~5.4, TOC ~1.13 ppm, IC ~0.24 ppm, TDS ~1.18 ppm and COD ~ 1.9 ppm; for most of the contaminants the separation efficiency was >99%. These findings clearly show that the resulting MD permeate does not exceed environmental regulations for release to recipient, and the permeate can even be considered for reuse. Moreover, the determined specific heat demand at different operating conditions was varying between 1390 and 2170 kWh/m3 whereas; the achievable exergy efficiency was ~19%., QC 20191202

Wastewater from chemical mechanical planarization (CMP) processes in nano-electronics industries must be treated properly in order to fulfil local and international environmental regulations. This study is focused on a performance assessment of membrane distillation (MD) technology for CMP wastewater treatment. A new prototype of air gap membrane distillation (AGMD) module was utilized, with feed water consisting of CMP wastewater collected from imec, Belgium. The module was tested at different operating conditions (temperatures, flow rates and filtration time) and responses in terms of separation efficiency, permeate water quality, transmembrane flux, specific heat demand and exergy efficiency were determined. High quality permeate was produced in all trials, i.e. conductivity ~2.11 µS/cm, pH ~5.4, TOC ~1.13 ppm, IC ~0.24 ppm, TDS ~1.18 ppm and COD ~ 1.9 ppm; for most of the contaminants the separation efficiency was >99%. These findings clearly show that the resulting MD permeate does not exceed environmental regulations for release to recipient, and the permeate can even be considered for reuse. Moreover, the determined specific heat demand at different operating conditions was varying between 1390 and 2170 kWh/m3 whereas; the achievable exergy efficiency was ~19%., QC 20191202

The first project contained within this script refers to the controllable synthesis and characterization of novel thermally-stable silver-based particles. The experimental approach involves the design of thermally-stable nanostructures by the deposition of a thick interfacial layer of active titania between the primary substrate (SiO2 particles) and the metal nanoparticles (Ag NPs), as well as the doping of Ag nanoparticles with an organic molecule (Congo Red, CR). The nanostructured particles were composed of a 330-nm silica core capped with a granular titania layer (10 to 13 nm in thickness), along with monodisperse (5 to 30 nm) CR-Ag NPs deposited on top. The titania-coated support (SiO2/TiO2 particles) was shown to be chemically and thermally-stable, and promoted the nucleation and anchoring processes of CR-Ag NPs, which prevented the sintering of CR-Ag NPs when the structure was exposed to high temperatures. Different characterization techniques were proposed, and utlized, to examine and determine the thermal stability of the silver composites, among which, electron microscopy (i.e SEM, TEM and EDS) played an important role due to its high resolution capabilities. Based on the information obtained via high resolution imaging and elemental mapping, it was possible to resolve changes on the surface topography, crystalline structure, and chemical composition at different temperatures on the nanometer scale. The second project presented in this dissertation concerns the tribological characterization of retaining rings in Chemical Mechanical Planarization (CMP). This project was divided into several studies, all of which contributed valuable information which made the determination of tribological mechanisms possible. These eventually contributed to minimizing the environmental impact, and reducing cost of ownership (COO) of the CMP module. The first study was conducted to obtain the tribological mechanisms in the ring-slurry interface by analyzing the Stribeck and

The first part of this study investigates the pad surface generated by conditioning with three different CVD-coated diamond discs and the corollary effect on polishing performance in copper CMP. The discs that were used had significantly different micro-structures with varying degrees of aggressiveness. Confocal microscopy was used to study the pad surface after the polishing experiments had been performed, where the contact area, contact density and surface topography were analyzed. The most aggressive disc generated a pad surface with the most contact area, contact density and the tallest asperities. These parameters decreased as the aggressiveness of the disc decreased. Thermal, tribological, and kinetic aspects of copper polishing were also investigated. The pad surface generated by the most aggressive disc produced the highest material removal rates. However, the pad surface generated by the least aggressive disc produced a slightly elevated coefficient of friction and mean pad temperature when compared to the other pad surfaces, most likely due to fluid suction caused by the glazed pad surface. Analysis of the chemical and mechanical rate constants indicated that this process was chemically limited for all P × V investigated. The second part of this study analyzed the thermal, tribological and kinetic aspects of the new and developing area of cobalt “buff step” CMP. A process-specific combination of consumables and polishing settings were used to investigate the removal of silicon dioxide in order to better characterize the second step of cobalt polishing in middle of the line (MOL) applications, where the overburden of deposited cobalt had already been polished away, and residual cobalt, along with the liner, needed to be completely removed. This was realized by polishing some of the surrounding dielectric in the “buff step”. Our study showed that the removal rate of the oxide and the mean pad temperature increased with increasing P × V, while the coefficient

The first part of this study investigates the pad surface generated by conditioning with three different CVD-coated diamond discs and the corollary effect on polishing performance in copper CMP. The discs that were used had significantly different micro-structures with varying degrees of aggressiveness. Confocal microscopy was used to study the pad surface after the polishing experiments had been performed, where the contact area, contact density and surface topography were analyzed. The most aggressive disc generated a pad surface with the most contact area, contact density and the tallest asperities. These parameters decreased as the aggressiveness of the disc decreased. Thermal, tribological, and kinetic aspects of copper polishing were also investigated. The pad surface generated by the most aggressive disc produced the highest material removal rates. However, the pad surface generated by the least aggressive disc produced a slightly elevated coefficient of friction and mean pad temperature when compared to the other pad surfaces, most likely due to fluid suction caused by the glazed pad surface. Analysis of the chemical and mechanical rate constants indicated that this process was chemically limited for all P × V investigated. The second part of this study analyzed the thermal, tribological and kinetic aspects of the new and developing area of cobalt “buff step” CMP. A process-specific combination of consumables and polishing settings were used to investigate the removal of silicon dioxide in order to better characterize the second step of cobalt polishing in middle of the line (MOL) applications, where the overburden of deposited cobalt had already been polished away, and residual cobalt, along with the liner, needed to be completely removed. This was realized by polishing some of the surrounding dielectric in the “buff step”. Our study showed that the removal rate of the oxide and the mean pad temperature increased with increasing P × V, while the coefficient

The first project contained within this script refers to the controllable synthesis and characterization of novel thermally-stable silver-based particles. The experimental approach involves the design of thermally-stable nanostructures by the deposition of a thick interfacial layer of active titania between the primary substrate (SiO2 particles) and the metal nanoparticles (Ag NPs), as well as the doping of Ag nanoparticles with an organic molecule (Congo Red, CR). The nanostructured particles were composed of a 330-nm silica core capped with a granular titania layer (10 to 13 nm in thickness), along with monodisperse (5 to 30 nm) CR-Ag NPs deposited on top. The titania-coated support (SiO2/TiO2 particles) was shown to be chemically and thermally-stable, and promoted the nucleation and anchoring processes of CR-Ag NPs, which prevented the sintering of CR-Ag NPs when the structure was exposed to high temperatures. Different characterization techniques were proposed, and utlized, to examine and determine the thermal stability of the silver composites, among which, electron microscopy (i.e SEM, TEM and EDS) played an important role due to its high resolution capabilities. Based on the information obtained via high resolution imaging and elemental mapping, it was possible to resolve changes on the surface topography, crystalline structure, and chemical composition at different temperatures on the nanometer scale. The second project presented in this dissertation concerns the tribological characterization of retaining rings in Chemical Mechanical Planarization (CMP). This project was divided into several studies, all of which contributed valuable information which made the determination of tribological mechanisms possible. These eventually contributed to minimizing the environmental impact, and reducing cost of ownership (COO) of the CMP module. The first study was conducted to obtain the tribological mechanisms in the ring-slurry interface by analyzing the Stribeck and

Gegenstand dieser Forschungsarbeit war die Entwicklung neuer, ungiftiger, anorganischer Buntpigmente für die Anwendung in Tintenstrahldruckern, die es ermöglichen in großem Maßstab Gläser zu bedrucken. Durch den anspruchsvollen Verarbeitungsprozess kommen nur hochstabile Substanzklassen als potentielle Pigmente in Frage. Entscheidende Anforderungen an die Pigmente stellen, neben der chemischen und thermischen Stabilität, eine intensive Färbung, sowie eine Partikelgröße kleiner zwei als Mikrometer dar. Je eine literaturbekannte Substanzklasse konnte für potentielle grüne beziehungsweise rote Pigmente identifiziert werden. Im Rahmen dieser Dissertation wurde in verschiedenen Studien versucht die kolorimetrischen Eigenschaften dieser Substanzen zu optimieren. Die Pigmentpulver wurden über konventionelle, oder über Flussmittel-unterstützte Festköpersynthesen, mit Hilfe der nasschemischen Pechini Synthese, oder mittels Verbrennungssynthesen hergestellt. Ausgewählte Proben wurden hinsichtlich ihrer kristallographischen, farblichen, und morphologischen Eigenschaften mittels einer Vielzahl von Methoden umfassend charakterisiert. Die erste Substanzklasse, die intensiv untersucht wurde, stellen Cuprate mit der allgemeinen Zusammensetzung M2Cu2O5 (M = Sc, Y, In, Lu-Tb) dar. In einer ersten Studie wurde der Farbraum bestimmt, der mit diesen Verbindungen abgedeckt werden kann, wobei erhöhte Reflektivität im NIR Bereich festgestellt werden konnte. Daher können diese Pigmente als cool pigments bezeichnet werden. In weiterführenden Arbeiten konnte ein intensiv gefärbtes Grünpigment mit der Zusammensetzung Yb1.1In0.9Cu1.4Zn0.6O5 synthetisiert werden. Den zweiten Teil dieser Arbeit bildet die Forschung zu potentiellen Rotpigmenten auf Basis von Verbindungen der Zusammensetzung REFeO3 (RE = Y, La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu). In zahlreichen Versuchen wurde an einer Verbesserung der kolorimetrischen Eigenschaften dieser Pigmente gearbeitet. Darüber hinaus wurde die Eign, Main subject of this doctoral thesis was the development of novel, non-toxic, inorganic colored pigments for application in large-scale inkjet printers, enabling digital printing on glass substrates. The especially harsh processing conditions in glass-printing demand extremely durable substances as potential pigments. Besides thermal and chemical resistance, decisive requirements for these pigments are e.g. intensive colors and particle sizes lower than two micrometers. Two material classes were identified as potential green and red pigments, meeting most criteria for our application. This thesis was aimed at optimizing the colorimetric properties of the according substances. The pigment powders were therefore synthesized through conventional, or through flux-assisted solid state syntheses, via the chemical solution based Pechini route, or through solution combustion syntheses. Selected products were then characterized comprehensively with respect to their crystallographic, colorimetric, and morphological properties using a variety of methods. The first substance class, intensively investigated, were cuprates with the general composition M2Cu2O5 (M = Sc, Y, In, Lu-Tb). A study, initially aiming to verify the color range that could be covered by cuprates of various compositions, led to the discovery of the hitherto unknown high NIR reflectivity of these materials. Therewith, cuprates classify as potential cool pigments. Based on these findings, a deep green pigment with the composition Yb1.1In0.9Cu1.4Zn0.6O5 was developed. Secondly, potential red pigments based on REFeO3 (RE = Y, La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, Yb, Lu) structures were investigated. In various series, it was tried to optimize the colorimetric properties of these compounds. Also, the suitability of CeFeO3 for means of glass polishing, another promising field of application for this substance class, was evaluated. In addition to the pigmentary studies forming the nucleus of this thesis, results, by Lucas Leo Petschnig, Kumulative Dissertation aus sechs Artikeln, Kurzbeschreibung in deutscher Sprache, Die Zahlen sind in den Formeln jeweils tiefgestellt, Universität Innsbruck, Dissertation, 2017, OeBB, (VLID)1943644

This thesis presents a series of studies pertaining to tribological, thermal, kinetic and slurry utilization aspects of chemical mechanical planaraization processes. The purpose of this work is to both develop a better method of characterizing the tribological mechanisms during polishing, as well as propose methods by which slurry utilization efficiency can be increased in order to minimize environmental hazards and operational costs associated with polishing without compromising the desired polish outcomes. The first study was conducted using a modified version of the generic Stribeck curve using real-time shear and down force data collection at 1,000 Hz. This investigation served to provide a better understanding of the tribological and thermal mechanisms associated with polishing copper and tungsten blanket wafers on an industrially relevant soft pad. A multitude of gradual yet continuous changes in sliding velocity and polishing pressure were applied during polishing. Results indicated that polishing on the soft pad produced stable coefficient of friction (COF) values entirely within the "boundary lubrication" regime, while copper polishing on a hard pads produced a tremendous spread of data and resulted in both “boundary lubrication” and "mixed lubrication" regimes. In addition, the average pad surface temperature showed a linear relationship with the product of the COF, sliding velocity, and downward pressure for all copper and tungsten polishes on both soft and hard pads. Another study in this thesis investigated slurry availability and the extent of slurry mixing for three different slurry injection schemes. An ultraviolet enhanced fluorescence technique was employed to qualitatively measure slurry film thicknesses atop the pad surface during polishing. This study investigated standard pad-center point slurry dispensing and a slurry injection system (SIS) that covered only the outer half of the wafer track. Results indicated that the radial position of slurr

This thesis presents a series of studies pertaining to tribological, thermal, kinetic and slurry utilization aspects of chemical mechanical planaraization processes. The purpose of this work is to both develop a better method of characterizing the tribological mechanisms during polishing, as well as propose methods by which slurry utilization efficiency can be increased in order to minimize environmental hazards and operational costs associated with polishing without compromising the desired polish outcomes. The first study was conducted using a modified version of the generic Stribeck curve using real-time shear and down force data collection at 1,000 Hz. This investigation served to provide a better understanding of the tribological and thermal mechanisms associated with polishing copper and tungsten blanket wafers on an industrially relevant soft pad. A multitude of gradual yet continuous changes in sliding velocity and polishing pressure were applied during polishing. Results indicated that polishing on the soft pad produced stable coefficient of friction (COF) values entirely within the "boundary lubrication" regime, while copper polishing on a hard pads produced a tremendous spread of data and resulted in both “boundary lubrication” and "mixed lubrication" regimes. In addition, the average pad surface temperature showed a linear relationship with the product of the COF, sliding velocity, and downward pressure for all copper and tungsten polishes on both soft and hard pads. Another study in this thesis investigated slurry availability and the extent of slurry mixing for three different slurry injection schemes. An ultraviolet enhanced fluorescence technique was employed to qualitatively measure slurry film thicknesses atop the pad surface during polishing. This study investigated standard pad-center point slurry dispensing and a slurry injection system (SIS) that covered only the outer half of the wafer track. Results indicated that the radial position of slurr

The first part of our study introduces a new method for rapidly generating an "improved" Stribeck curve (i.e. Stribeck+ curve) that, compared to traditional Stribeck curves, shows a more complete tribological picture of the chemical mechanical planarization (CMP) process. The method significantly reduces the consumables and time required to obtain the curve compared to traditional means. Results of the Stribeck+ curve are consistent with individual tests using several different consumables combinations. All copper CMP Stribeck+ examples clearly indicate the lubrication mechanism and transitions thereof between different polishing conditions. Variability in COF as well as a much wider range in U/P are also explored. In the second part of our study, the Stribeck+ curve is successfully applied to silicon dioxide CMP processes to characterize the tribology of such processes under different process conditions and consumables. Results show our Stribeck+ curve methodology to be capable of rapidly determining and differentiating the tribological mechanism among all cases studied. The Stribeck+ curve helps indicate process stability as shown by the spread of the COF vertical clusters. The Stribeck+ curve also confirms a previously known effect that the greater the ratio of pad’s up-features to the total pad area, the greater the probability of wafer hydroplaning. As the third part of our study, we investigate the effect of different pad surface micro-textures on the tribological, thermal and kinetic attributes during copper CMP. Different micro-textures are generated by two different chemical vapor deposited (CVD) diamond-coated conditioner discs (i.e. Disc A and Disc B). Results show that while pad temperature and removal rate increase with polishing pressure and sliding velocity on both discs, Disc B generates consistently lower removal rates and COF than Disc A. To fundamentally elucidate the cause(s) of such differences, pad surface contact area and topography are analyz

This dissertation presents a series of studies related to the study and control of slurry flow, process temperature, and aggressive diamonds in Chemical Mechanical Planarization (CMP). The purpose of these studies is to better understand the fundamentals of CMP and to explore solutions to some of CMP’s greatest challenges. Within-wafer removal rate non-uniformity (WIWRRNU) is a critical parameter to determine film thickness planarity on a wafer-scale level and it grossly impacts yield. Resolving this issue continues to be an area of intense focus in the industry. The first study in this dissertation shows the feasibility of adopting a new method to improve WIWRRNU during copper CMP that is solely based on intentional local temperature manipulation of the pad. A pad surface thermal management system is developed to locally change pad surface temperature. This system consists of one or more thermal transfer modules contacting the pad surface. In this study, the system is employed to adjust the "center-fast" copper removal rate profile to illustrate its effect during the process. Results shows that, when two thermal transfer modules are employed, local removal rates in the wafer center region decrease significantly while maintaining the removal rates near the wafer edge thereby significantly improving WIWRRNU. Another contribution of this dissertation is the investigation of the effect of pad groove design on slurry injection scheme during interlayer dielectric CMP. A novel slurry injector with multiple slurry outlets is designed, which provides optional slurry injection schemes (i.e. one injection point scheme and multi-injection point scheme). These schemes are compared with the standard slurry application method on a concentrically grooved pad and an xy-groove pad, respectively. On the concentrically grooved pad, the one injection point scheme generates significantly higher oxide removal rates (ranging from 22 to 35 percent) compared to the standard slurry applicati

With stringent requirements of copper chemical mechanical planarization (CMP), such as minimized step heights, enhanced uniformity and minimal defects, the CMP process needs to be improved based on a fundamental understanding of the material removal mechanisms. Also, with the stringent requirements, the problems in copper CMP process cannot be resolved solely improving the process itself; rather, systemic understanding of the entire manufacturing processes is necessary, demanding a robust copper CMP model to be implemented to design for manufacturing (DfM) tools. Previous models heavily relied on Preston's equation ( ), which needs to be calibrated for every new set of processing parameters, slowing down the process development. Previous models focused on limited interactions of the consumables and the workpiece during copper CMP, being insufficient at capturing the synergies between chemical and mechanical aspects of copper CMP. Therefore, a quantitative and physicochemical model of copper CMP that predicts material removal rate (MRR) was proposed while focusing on the interplay of consumables and copper and the synergies between chemical and mechanical aspects of the process. While considering the synergies, two mechanisms of the material removal during copper CMP were suggested: chemically dominant and mechanically dominant mechanisms. The total MRR during copper CMP was determined by summing those two contributions.The chemically dominant mechanism attributed the material removal during copper CMP to the removal of the protective material formed on the surface of copper and to the chemical dissolution of copper from the surface both at regions occupied and not occupied by the protective material with different rates. The kinetics of the formation of the protective material at the millisecond scale were studied through electrochemical experiments and theoretical analysis where a governing equation for the adsorption of benzotriazole (BTA) was constructed and solv

With stringent requirements of copper chemical mechanical planarization (CMP), such as minimized step heights, enhanced uniformity and minimal defects, the CMP process needs to be improved based on a fundamental understanding of the material removal mechanisms. Also, with the stringent requirements, the problems in copper CMP process cannot be resolved solely improving the process itself; rather, systemic understanding of the entire manufacturing processes is necessary, demanding a robust copper CMP model to be implemented to design for manufacturing (DfM) tools. Previous models heavily relied on Preston's equation ( ), which needs to be calibrated for every new set of processing parameters, slowing down the process development. Previous models focused on limited interactions of the consumables and the workpiece during copper CMP, being insufficient at capturing the synergies between chemical and mechanical aspects of copper CMP. Therefore, a quantitative and physicochemical model of copper CMP that predicts material removal rate (MRR) was proposed while focusing on the interplay of consumables and copper and the synergies between chemical and mechanical aspects of the process. While considering the synergies, two mechanisms of the material removal during copper CMP were suggested: chemically dominant and mechanically dominant mechanisms. The total MRR during copper CMP was determined by summing those two contributions.The chemically dominant mechanism attributed the material removal during copper CMP to the removal of the protective material formed on the surface of copper and to the chemical dissolution of copper from the surface both at regions occupied and not occupied by the protective material with different rates. The kinetics of the formation of the protective material at the millisecond scale were studied through electrochemical experiments and theoretical analysis where a governing equation for the adsorption of benzotriazole (BTA) was constructed and solv

This dissertation presents a series of studies with regards to wear and contact phenomena in existing and future large-scale chemical mechanical planarization (CMP). They are also evaluated with the purposes of reducing cost of ownership (COO) and minimizing environmental impacts. The first study is performed to investigate the effect of retaining ring slot design, material and temperature on pad wear during interlayer dielectric CMP. During polishing, friction is generated at the retaining ring-pad interface resulting in pad wear. Three retaining rings are used in this study and the results show that the retaining ring material and temperature have significant impacts on the pad wear rate. In the next study, a custom-made sample holder is designed to heat pad sample. Pad surface contact area and density are measured at three different temperatures using laser confocal microscopy to illustrate the effect of temperature on the mechanical contact during CMP. In the third study, the tribological, thermal and kinetic attributes of 300 mm copper CMP process are investigated. The current state-of-the-art IC manufacturing factories have migrated from 200 mm wafer processes to 300 mm to reduce manufacturing COO and increase throughput. In this study, a two-step modified Langmuir-Hinshelwood model is used to simulate copper removal rate as well as chemical and mechanical dominance during CMP. The fourth study evaluates the relationship between planarization and pad surface contact area and micro-topography using laser confocal microscopy. Results of confocal microscopic analysis are correlated with polishing performance in terms of coefficient of friction, removal rate, time to clear, dishing and erosion. As Ti has recently regained attention in copper barrier applications, the effect of temperature during Ti CMP is investigated in another study to provide fundamental understanding of Ti removal mechanism. The last contribution of this dissertation involves a study on 450 mm

This dissertation presents a series of studies relating to optimization of kinematics and consumables during chemical mechanical planarization processes. These are also evaluated with the purpose of minimizing environmental and cost of ownership impacts.In order to study diamond micro-wear and substrate wear during planarization processes, a series of static etch tests and wear tests were performed using different types of diamond discs and subjected to various treatments. Scanning Electron Microscopy (SEM) and Inductively Coupled Plasma Membrane Spectroscopy (ICPMS) were used to estimate the extent of diamond micro-wear and substrate wear.Next, the impact of various factors (type of slurry abrasive, pH, abrasive content and abrasive concentration) on pad wear rate during planarization process was studied. Another study in this dissertation focuses on the development of a novel technique of using coefficient of friction (COF) data to distinguish between good and bad diamond discs. This study made use of the innovative tool diamond disc dragging device (DDD-100) designed and developed for the purpose of this study.It is known that the performance of chemical mechanical planarization depends significantly on the polishing pad grooving type and the kinematics involved in the process. Variations in pad grooving type as well as pressure and sliding velocity can affect polishing performance. One study in this dissertation investigates the effect of pressure and sliding velocity on the polishing performance. The study is conducted on multiple pressure and sliding velocity variations to understand the characteristic of each condition. A subsequent study focuses on the impact of pad grooving type on polishing performance.The greatest contribution of this dissertation involves development of the novel slurry injector to optimize the utilization of slurry during planarization processes. Slurry is a critical component in chemical mechanical planarization processes and accounts

This dissertation presents a series of studies relating to kinetics and kinematics of inter-layer dielectric and metal chemical mechanical planarization processes. These are also evaluated with the purposes of minimizing environmental and cost of ownership impact.The first study is performed to obtain the real-time substrate temperature during the polishing process and is specifically intended to understand the temperature distribution across the polishing wafer during the chemical mechanical planarization process. Later, this technique is implemented to study the effect of slurry injection position for optimum slurry usage. It is known that the performance of chemical mechanical planarization depends significantly on the polishing pad and the kinematics involved in the process. Variations in pad material and pad grooving type as well as pressure and sliding velocity can affect polishing performance. One study in this dissertation investigates thermoset and thermoplastic pad materials with different grooving methods and patterns. The study is conducted on multiple pressure and sliding velocity variations to understand the characteristic of each pad. The analysis method elaborated in this study can be applied generically.A subsequent study focuses in a slurry characterization technique. Slurry, a critical component in chemical mechanical planarization, is typically a water-based dispersion of fine abrasive particles with various additives to control material removal rate and microscratches. Simultaneous turbidity and low angle light scattering methods under well-defined mixing conditions are shown to quantify the stability of abrasive particle from aggregations. Further contribution of this dissertation involves studies related to the spectral analysis of raw shear force and down force data obtained during chemical mechanical planarization. These studies implemented Fast Fourier Transforms to convert force data from time to frequency domain. A study is performed to d

Micron-sized subwavelength structured photonic sensors could allow critical thermo-mechanical phenomena in manufacturing processes to be monitored, while offering tremendous advantages. To implement these novel sensors into real manufacturing processes, the microring sensors can be embedded at critical locations in metallic structures, which are heavily used in hostile manufacturing environments. This paper presents our research progress on fabrication, embedding, and application of integrated mciroring sensors. For fundamental study, microring resonators have been microfabricated on-chip with silicon-on-insulator wafer substrates. The fabricated optical resonators offer Qs on the order of 20,000, enabling significantly improved temporal sensing and detection of high-frequency strain variation. A new approach to fabricate metal embedded photonic structures was developed. Various thin film photonic materials were studied for embedded microphotonic sensors. Effect of process parameters on refractive index of silicon nitride/silicon oxynitride films was studied. Issues on design and implementation of micro sensors for Chemical Mechanical Planarization (CMP) were studied and a grafting process was designed to embed micro sensors into polishing pads. A preliminary design for the sensor and its installation into a continuous casting mold was also developed.

Micron-sized subwavelength structured photonic sensors could allow critical thermo-mechanical phenomena in manufacturing processes to be monitored, while offering tremendous advantages. To implement these novel sensors into real manufacturing processes, the microring sensors can be embedded at critical locations in metallic structures, which are heavily used in hostile manufacturing environments. This paper presents our research progress on fabrication, embedding, and application of integrated mciroring sensors. For fundamental study, microring resonators have been microfabricated on-chip with silicon-on-insulator wafer substrates. The fabricated optical resonators offer Qs on the order of 20,000, enabling significantly improved temporal sensing and detection of high-frequency strain variation. A new approach to fabricate metal embedded photonic structures was developed. Various thin film photonic materials were studied for embedded microphotonic sensors. Effect of process parameters on refractive index of silicon nitride/silicon oxynitride films was studied. Issues on design and implementation of micro sensors for Chemical Mechanical Planarization (CMP) were studied and a grafting process was designed to embed micro sensors into polishing pads. A preliminary design for the sensor and its installation into a continuous casting mold was also developed.

Chemical mechanical polishing (CMP) has been used for a long time in the manufacturing of prime silicon wafers for the IC industry. Lately, other substrates, such as silicon-on-insulator has become in use which requires a greater control of the silicon CMP process. CMP is used to planarize oxide interlevel dielectric and to remove excessive tungsten after plug filling in the Al interconnection technology. In Cu interconnection technology, the plugs and wiring are filled in one step and excessive Cu is removed by CMP. In front end processing, CMP is used to realize shallow trench isolation (STI), to planarize trench capacitors in dynamic random access memories (DRAM) and in novel gate concepts. This thesis is focused on CMP for front end processing, which is the processing on the device level and the starting material. The effects of dopants, crystal orientation and process parameters on silicon removal rate are investigated. CMP and silicon wafer bonding is investigated. Also, plasma assisted wafer bonding to form InP MOS structures is investigated. A complexity of using STI in bipolar and BiCMOS processes is the integration of STI with deep trench isolation (DTI). A process module to realize STI/DTI, which introduces a poly CMP step to planarize the deep trench filling, is presented. Another investigated front end application is to remove the overgrowth in selectively epitaxially grown collector for a SiGe heterojunction bipolar transistor. CMP is also investigated for rounding, which could be beneficial for stress reduction or to create microoptical devices, using a pad softer than pads used for planarization. An issue in CMP for planarization is glazing of the pad, which results in a decrease in removal rate. To retain a stable removal rate, the pad needs to be conditioned. This thesis introduces a geometrically defined abrasive surface for pad conditioning.

Chemical mechanical polishing (CMP) has been used for a long time in the manufacturing of prime silicon wafers for the IC industry. Lately, other substrates, such as silicon-on-insulator has become in use which requires a greater control of the silicon CMP process. CMP is used to planarize oxide interlevel dielectric and to remove excessive tungsten after plug filling in the Al interconnection technology. In Cu interconnection technology, the plugs and wiring are filled in one step and excessive Cu is removed by CMP. In front end processing, CMP is used to realize shallow trench isolation (STI), to planarize trench capacitors in dynamic random access memories (DRAM) and in novel gate concepts. This thesis is focused on CMP for front end processing, which is the processing on the device level and the starting material. The effects of dopants, crystal orientation and process parameters on silicon removal rate are investigated. CMP and silicon wafer bonding is investigated. Also, plasma assisted wafer bonding to form InP MOS structures is investigated. A complexity of using STI in bipolar and BiCMOS processes is the integration of STI with deep trench isolation (DTI). A process module to realize STI/DTI, which introduces a poly CMP step to planarize the deep trench filling, is presented. Another investigated front end application is to remove the overgrowth in selectively epitaxially grown collector for a SiGe heterojunction bipolar transistor. CMP is also investigated for rounding, which could be beneficial for stress reduction or to create microoptical devices, using a pad softer than pads used for planarization. An issue in CMP for planarization is glazing of the pad, which results in a decrease in removal rate. To retain a stable removal rate, the pad needs to be conditioned. This thesis introduces a geometrically defined abrasive surface for pad conditioning.

Chemical mechanical polishing (CMP) has been used for a long time in the manufacturing of prime silicon wafers for the IC industry. Lately, other substrates, such as silicon-on-insulator has become in use which requires a greater control of the silicon CMP process. CMP is used to planarize oxide interlevel dielectric and to remove excessive tungsten after plug filling in the Al interconnection technology. In Cu interconnection technology, the plugs and wiring are filled in one step and excessive Cu is removed by CMP. In front end processing, CMP is used to realize shallow trench isolation (STI), to planarize trench capacitors in dynamic random access memories (DRAM) and in novel gate concepts. This thesis is focused on CMP for front end processing, which is the processing on the device level and the starting material. The effects of dopants, crystal orientation and process parameters on silicon removal rate are investigated. CMP and silicon wafer bonding is investigated. Also, plasma assisted wafer bonding to form InP MOS structures is investigated. A complexity of using STI in bipolar and BiCMOS processes is the integration of STI with deep trench isolation (DTI). A process module to realize STI/DTI, which introduces a poly CMP step to planarize the deep trench filling, is presented. Another investigated front end application is to remove the overgrowth in selectively epitaxially grown collector for a SiGe heterojunction bipolar transistor. CMP is also investigated for rounding, which could be beneficial for stress reduction or to create microoptical devices, using a pad softer than pads used for planarization. An issue in CMP for planarization is glazing of the pad, which results in a decrease in removal rate. To retain a stable removal rate, the pad needs to be conditioned. This thesis introduces a geometrically defined abrasive surface for pad conditioning.

Chemical mechanical polishing (CMP) has been used for a long time in the manufacturing of prime silicon wafers for the IC industry. Lately, other substrates, such as silicon-on-insulator has become in use which requires a greater control of the silicon CMP process. CMP is used to planarize oxide interlevel dielectric and to remove excessive tungsten after plug filling in the Al interconnection technology. In Cu interconnection technology, the plugs and wiring are filled in one step and excessive Cu is removed by CMP. In front end processing, CMP is used to realize shallow trench isolation (STI), to planarize trench capacitors in dynamic random access memories (DRAM) and in novel gate concepts. This thesis is focused on CMP for front end processing, which is the processing on the device level and the starting material. The effects of dopants, crystal orientation and process parameters on silicon removal rate are investigated. CMP and silicon wafer bonding is investigated. Also, plasma assisted wafer bonding to form InP MOS structures is investigated. A complexity of using STI in bipolar and BiCMOS processes is the integration of STI with deep trench isolation (DTI). A process module to realize STI/DTI, which introduces a poly CMP step to planarize the deep trench filling, is presented. Another investigated front end application is to remove the overgrowth in selectively epitaxially grown collector for a SiGe heterojunction bipolar transistor. CMP is also investigated for rounding, which could be beneficial for stress reduction or to create microoptical devices, using a pad softer than pads used for planarization. An issue in CMP for planarization is glazing of the pad, which results in a decrease in removal rate. To retain a stable removal rate, the pad needs to be conditioned. This thesis introduces a geometrically defined abrasive surface for pad conditioning.

This animation is provided by Maricopa Advanced Technology Education Center (MATEC) and shows the dual damascene process. There are many different ways in which the dual damascene process is used. The animation shows an overview of one process:In the dual damascene process, a low-k dielectric is added. ​CMP is used to remove dielectric down to depth of the vias.Silicon nitride is deposited and the resist is added and exposed.The surface is etched and a second layer of low-k dielectric is added.CMP is used to remove the dielectric down to the final thickness of the metal lines.Resist is added for vias and metal lines.The surface is exposed and removed.The dielectric is etched and the resist is removed.The metal barrier and metal are added.Depending on the process, this could be copper.The metal and metal barrier are removed through CMP.The animation also includes brief text descriptions. An .mp4 is also available and runs 01:16 minutes in length.&nbsp

This resource, provided by the Maricopa Advanced Technology Education Center (MATEC), is an animation of the workflow of a planarization workstation. An .mp4 file is available for viewing and is 02:23 minutes in length.&nbsp

This simulation, provided by Maricopa Advanced Technology Education Center (MATEC), uses controls (drop down menus) to adjust down force and platen speed parameters to determine an optimum CMP process recipe for focal semiconductor manufacturing. Users may assume that focal is using a rotational tool with on-the-pad slurry delivery, and wafer/polish pressure is through the carrier. Users will keep track of "test runs" in separate tables, one for down force and one for platen speed, and then observe the effect of the parameters on wafer thickness and uniformity. Next, users can try to make predictions about the necessary settings for achieving a prescribed WIWNU goal. The objectives of this simulation include:solving for removal rate in a simulated CMP processadjusting planarization equipment process parameters to determine the optimal values needed to achieve the processing objectives in a simulated CMP processestimating control parameter settings in a CMP recipe simulation for optimal WIWNU and removal rate. An .mp4 recording is included that provides an example of the simulation. The recording runs 01:51 minutes in length.&nbsp

This resource, provided by Maricopa Advanced Technology Education Center (MATEC), is an animation that illustrates the chemical action of slurry in the chemical-mechanical planarization process. The objective of the animation is to explain the mechanical and chemical steps in the CMP process. An .mp4 is also available for viewing and runs 01:16 minutes in length.&nbsp