Copper CMP for Dual Damascene Technology: Some Considerations on the Mechanism of Cu Removal

2001 ◽  
Vol 671 ◽  
Author(s):  
David Wei ◽  
Yehiel Gotkis ◽  
Hugh Li ◽  
Stephen Jew ◽  
Joseph Li ◽  
...  
Keyword(s):  
Oxygen Atom ◽  
Removal Rate ◽  
Wafer Surface ◽  
H2o2 Concentration ◽  
Passivation Film ◽  
Mechanical Removal ◽  
Slurry System ◽  
High Removal Rate ◽  
Cu Cmp ◽  
Passivating Oxide

ABSTRACTIt was found in a Cu-CMP process using EP-C 5001 slurry and IC 1000 pad that Cu removal rate, being extremely low without H2O2 in the slurry, increases up to a maximum with the addition of H2O2, and then decreases again. Analysis of polarization curves and Eh-pH diagrams shows that without H2O2 Cu has the lowest electric potential, as a result, the highest thermodynamic stability in the Cu/slurry system. Addition of H2O2 shifts the potential up and induces the formation of Cu2O, resulting in a high removal rate. At high H2O2 concentration, a CuO passivation film is formed. In this case, only mechanical removal of the passivating oxide film allows the process to proceed. It is speculated that the moving pad surface adheres the oxidized species via the formation of hydrogen bonds with oxygen atoms of copper oxide molecules, thus detaching them from the wafer surface. Each oxygen atom is capable of pulling out two Cu atoms if Cu2O is formed on the surface and only one Cu atom if CuO is formed. This would explain why the removal rate is high at low H2O2 concentration and low at high H2O2 concentration.

Effect of Corrosion Inhibitor (BTA) in Citric Acid based Slurry on Cu CMP

2005 ◽  
Vol 867 ◽  
Author(s):  
In-Kwon Kim ◽  
Young-Jae Kang ◽  
Yi-Koan Hong ◽  
Jin-Goo Park
Keyword(s):  
Etch Rate ◽  
Removal Rate ◽  
Passivation Layer ◽  
Chemical Dissolution ◽  
H2o2 Concentration ◽  
Removal Rates ◽  
Abrasive Particles ◽  
Mechanical Abrasion ◽  
Abrasion Rate ◽  
Cu Cmp

AbstractIn this study, the effect of BTA on polishing behavior was investigated as functions of H2O2, slurry pH and abrasive particles. The addition of BTA effectively prevented Cu from etching by forming the passivation layer of Cu-BTA regardless of pH and H2O2 concentration in slurry. A thinner passivation layer was grown on Cu in BTA added slurry solutions with a higher contact angle of 60°. The dynamic etch rate, the removal rate with abrasive free slurry, also decreased when BTA was added in slurry at pH 2, 4 and 6. The removal rate of Cu was strongly dependent on types of abrasive particles in slurry. The larger hardness of slurry abrasive particles, the higher removal rates of Cu. The reduction of removal rates in BTA added slurry was determined by the competition between chemical dissolution rate and mechanical abrasion rate.

Beveling of Silicon Carbide Wafer by Plasma Chemical Vaporization Machining

2008 ◽  
Vol 600-603 ◽  
pp. 843-846 ◽  
Author(s):  
Takehiro Kato ◽  
Yasuhisa Sano ◽  
Hideyuki Hara ◽  
Hidekazu Mimura ◽  
Kazuya Yamamura ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Atmospheric Pressure ◽  
Removal Rate ◽  
Atmospheric Pressure Plasma ◽  
High Hardness ◽  
Wafer Surface ◽  
Plasma Chemical ◽  
Pressure Plasma ◽  
Surface Polishing ◽  
High Removal Rate

Beveling is essential for preventing the chipping of the edge of a wafer during surface polishing and other processes. Plasma chemical vaporization machining (PCVM) is an atmospheric-pressure plasma etching process. It has a high removal rate equivalent to those of conventional machining methods such as grinding and lapping, which are used for high-hardness materials such as silicon carbide, due to the generation of high-density radicals in atmospheric-pressure plasma. Furthermore, PCVM does not damage the wafer surface because it is a purely chemical process; therefore, it is considered that PCVM can be used as an effective method of beveling the edge of SiC wafers. In this paper, we report the investigation of the beveling of SiC wafers by PCVM.

Surfactants in Controlling Removal Rates and Selectivity in Barrier Slurry for Cu CMP

2007 ◽  
Vol 991 ◽  
Author(s):  
Jinru Bian
Keyword(s):  
Integrated Circuits ◽  
Dielectric Material ◽  
Removal Rate ◽  
Leading Edge ◽  
Dielectric Surface ◽  
Wafer Surface ◽  
Capping Layer ◽  
Charge Interaction ◽  
High Removal Rate ◽  
Low K

ABSTRACTLeading edge integrated circuits (ICs) are complicated structures designed to have up to 3 capping layers above a low k dielectric material. The upper capping layer may use TEOS and/or silicon nitride (SiN), while the lower one may use silicon carbon nitride (SiCN), silicon carbide (SiC), or carbon doped oxide (CDO) immediately above the low k dielectric. Therefore, a barrier slurry for copper CMP, in addition to exhibiting a high removal rate of the barrier, must be able to remove the upper capping layer and stop at the underlying dielectric surface.We have developed a slurry family that can effectively remove TaN, TEOS, SiN, CDO, and/or SiCN, or any combination of these films, or can stop at any one or two film surfaces of TEOS, SiN, CDO, SiCN, and SiC, depending on the specific slurry design. Removal rate control is achieved by one or two additives. One of the additives is an anionic surfactant. When selecting a surfactant, the surfactant hydrophobicity and charge interaction between the surfactant and the wafer surface are two important factors to be considered. This report discusses these two factors in selecting a proper surfactant for a specific slurry application.

A Model of Cu-CMP

2004 ◽  
Vol 816 ◽  
Author(s):  
Ed Paul ◽  
Vlasta Brusic ◽  
Fred Sun ◽  
Jian Zhang ◽  
Robert Vacassy ◽  
...  
Keyword(s):  
Tungsten Oxide ◽  
Removal Rate ◽  
Formation Rate ◽  
Quantitative Model ◽  
Wafer Surface ◽  
Surface Kinetics ◽  
Oxide Formation ◽  
Mechanical Removal ◽  
High Concentrations ◽  
Oxidizer Concentration

AbstractCMP has been described qualitatively in terms of alternating cycles of chemical formation and mechanical removal of a thin layer on the wafer surface. A quantitative model of CMP has been developed2-7 which is based on mechanisms for surface kinetics, treating mechanical removal as one step in the mechanism. This model has been used successfully to explain removal rates for tungsten and thermal oxide CMP. In particular, for tungsten CMP the removal rate increases steeply with increasing oxidizer concentration at low concentrations, and then approaches an asymptotic maximum removal rate at high concentrations. The model explains this by starting with the assumption that mechanical abrasion removes only tungsten oxide but not tungsten metal. It then focuses on the fraction of wafer surface covered by a tungsten oxide layer. At low oxidizer concentrations, the oxide formation rate is small compared the removal rate, so only a small fraction of the surface is oxidized and the removal rate is small. At high oxidizer concentrations, the oxide formation rate is large compared to the removal rate, so most of the surface is oxidized and the removal rate is large. Increasing the oxidizer concentration in the high oxidizer concentration region does not significantly increase the surface fraction of tungsten oxide, and the removal rate approaches a constant value.

Interaction between abrasive particles and film surfaces in low down force Cu CMP

2004 ◽  
Vol 816 ◽  
Author(s):  
Yuchun Wang ◽  
Isaac Zomora ◽  
Joe Hawkins ◽  
Renjie Zhou ◽  
Fred Sun ◽  
...  
Keyword(s):  
Surface Finish ◽  
Removal Rate ◽  
Film Formation ◽  
Abrasive Particles ◽  
High Removal Rate ◽  
Performance Results ◽  
Cu Cmp ◽  
Copper Passivation

A robust copper slurry should have high removal rate, efficient planarization, optimal over polishing window and fast clearing without corrosion. These requirements were addressed in the choice of abrasive particles, film formation for copper passivation, selectivity of copper to barrier, and interactions between particles and film surfaces. The performance results of low dishing erosion and surface finish are discussed with the proposed mechanism.

Newly Developed Abrasive-free Copper CMP Slurry Based on Electrochemical Analysis

2007 ◽  
Vol 991 ◽  
Author(s):  
Jin Amanokura ◽  
Katsumi Mabuchi ◽  
Takafumi Sakurada ◽  
Yutaka Nomura ◽  
Masanobu Habiro ◽  
...  
Keyword(s):  
Removal Rate ◽  
Electrochemical Analysis ◽  
Disk Electrode ◽  
Copper Cmp ◽  
High Removal Rate ◽  
Cu Cmp

ABSTRACTIn order to reduce microscratches and obtain minimized dishing and erosion, we have developed new abrasive-free Cu CMP slurries. During the development of these slurries, some electrochemical examination was performed. The most effective knowledge was obtained through the analysis using rotary Cu disk electrode under pressure. On the basis of these studies, new abrasive-free Cu CMP slurries with a high removal rate and excellent planarity were designed and developed. The mechanism of reducing dishing and erosion was also discussed.

High Removal Rate CMP Process on TSV Thick Cu Overburden

2010 ◽  
Vol 1249 ◽  
Author(s):  
Raymond Caramto ◽  
Jamal Qureshi ◽  
Jerry Mase
Keyword(s):  
Cross Sections ◽  
Removal Rate ◽  
Aspect Ratios ◽  
Overburden Thickness ◽  
Cu Electroplating ◽  
Constant Resistance ◽  
3D Packaging ◽  
High Removal Rate ◽  
Silicon Vias ◽  
Cu Cmp

AbstractIn 3D packaging, Through Silicon Vias (TSVs) with high aspect ratios and depths measuring tens of microns are filled by advanced Cu electroplating processes. Today's 300mm TSV plating platforms are intended to produce bottom-up via fill, no seam voids, and minimal, controlled overburden. To achieve this, the preceding Cu-seed coverage must be continuous at a constant resistance, and the plating chemistries optimized. However, other factors such as hardware configurations and simple depletion of the plating formulations during the extended TSV process can lead to high Cu overburden thickness requiring a high removal rate (HRR) chemical-mechanical polish (CMP) process to remove the thick Cu layer.Presented here are CMP results of a thick Cu overburden (~6um) resulting from the fill of 5 x 25um TSVs on 300mm wafers. The goal is to uniformly polish the overburden and utilize the tool's endpoint system at Cu clear before the next step of conventional barrier CMP. Slurries were screened for removal rate, uniformity, planarization ability, and defectivity. This study focuses on achieving a removal rate of >2.5um/min through evaluation of several commercial slurries in a multi-step polish application. Cross-sections post-plating show the Cu overburden, barrier and liner layer. Cross-sections post-CMP quantify Cu recess, dielectric loss, and presence/absence of seam defects. The process selected is demonstrated to achieve good planarization results with low occurrence of polish defects, at a rate and selectivity suitable for emerging 3D TSV Cu CMP applications.

The Important Role of Oxidant in Copper Interconnection Chemical Mechanical Polishing for GLSI

2010 ◽  
Vol 663-665 ◽  
pp. 1111-1114 ◽  
Author(s):  
Xiao Yan Liu ◽  
Yu Ling Liu ◽  
Xin Huan Niu ◽  
Zhi Wen Zhao ◽  
Yi Hu
Keyword(s):  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Copper Surface ◽  
Surface Topology ◽  
Passivation Film ◽  
Low Area ◽  
Mechanical Removal ◽  
Copper Interconnection ◽  
High Area

Chemical mechanical planarization (CMP) of copper interconnection in hydrogen peroxide (H2O2) as oxidizer based alkaline slurry was investigated. The new model is put forward, which is based on the characteristic of H2O2, chemical kinetics and mechanical removal. This properties of H2O2 can be effectively compensated the defect of surface topology during the process of polishing. Researcher previous study has shown that the surface is largely copper metal with Cu2O at low H2O2 concentrations and largely CuO at high H2O2 concentrations. Cu2O is more easily removed by both chemical and mechanical processes than CuO. During the CMP process, as the oxidizer concentration increases, the removal rate goes up initially followed by a gradual decay. This characteristic of oxidizer is used to achieve copper surface global planarity. The surface planarity was achieved by removing high area on the surface more quickly relative to the low area, because the concentration of Cu2O in the low area as the passivation film is more than the high area. Meanwhile the passivation film of the low area is thicker than the high area. In order to achieve polishing process optimization, the influence of pH adjustment and pressure, are also taken into consideration. Combining both RR and PE, the optimal H2O2 concentration and pressures are in range 1.0 ~1.5 vol% and 0.04 ~0.07 mpa, respectively. The roughness of surface which is measured by AFM is 0.49 after CMP.

Issues and Challenges of Chemical Mechanical Polishing for Nano-scale Memory Manufacturing

2009 ◽  
Vol 1157 ◽  
Author(s):  
Choon Kun Ryu ◽  
Jonghan Shin ◽  
Hyungsoon Park ◽  
Nohjung Kwak ◽  
Kwon Hong ◽  
...  
Keyword(s):  
Vertical Integration ◽  
Removal Rate ◽  
Memory Device ◽  
Design Rule ◽  
Integration Scheme ◽  
New Materials ◽  
Degree Of Control ◽  
High Removal Rate ◽  
Cu Cmp ◽  
Nano Size

AbstractAs the design rule of memory devices is scaled down to nanoscale, the number of the CMP process has increased considerably due to the complexity of integration scheme. The CMP for isolation has increased significantly because the isolation process of metal contact plugs and damascene metallization at nanoscale has been successfully enabled by the CMP. The CMP selectivity, which depends strongly on the chemistry of the slurry, must be tuned for the various new materials. Recently, in order to get over the limitation in lateral shrinkage of the memory device, several emerging applications have been investigated extensively. A vertical integration needs the new CMP process such as high removal rate Cu CMP. Next generation memories need the CMP process for new materials such as GeSbTe, conductive oxide, and magnetic materials. Since any nano-size scratch will be a killer defect at the nanoscale memory, both the CMP equipment and the consumables must be maintained with tighter degree of control specifications.

Derivation of Optimum Study Factors for Samples Contaminated with Cd Using Electric/Magnetic Field and ORP

2013 ◽  
Vol 813 ◽  
pp. 519-524
Author(s):  
Sang An Ha ◽  
Jei Pil Wang
Keyword(s):  
Magnetic Field ◽  
Heavy Metals ◽  
Removal Rate ◽  
Underground Water ◽  
Liquid Electrode ◽  
Oxidation Reduction ◽  
Oxidation Reduction Potential ◽  
Removal Of Heavy Metals ◽  
High Removal Rate ◽  
Membrane Treatment

A purpose of the present study is to derive optimum study factors for removal of heavy metals using combined alternating current electric/magnetic field and electric membranes for the area contaminated with heavy metals in soil or underground water. ORP (Oxidation Reduction Potential) analysis was conducted to determine an intensity of tendency for oxidation or reduction of the samples contaminated with heavy metals, and electrical membrane treatment was used with adjustment of concentrations and voltages of liquid electrode (Na2SO4) to derive a high removal rate. Removal constants were analyzed to be 0.0417, 0.119, 0.1594 when the voltages were 5V, 10V, 15V, respectively, and treatment efficiency was shown to increase as the liquid electrode concentration was increased. Keywords: heavy metals, electric/magnetic field, ORP, electrical membrane

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