Challenges and Rewards of Low-Abrasive Copper CMP: Evaluation and Integration for Single-Damascene Cu/Low-k Interconnects for the 90nm Node

2004 ◽  
Vol 816 ◽  
Author(s):  
Christopher L. Borst ◽  
Stanley M. Smith ◽  
Mona Eissa
Keyword(s):  
High Performance ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Low Dielectric ◽  
Process Characterization ◽  
Rate Profile ◽  
Feature Scale ◽  
Cu Cmp ◽  
Low K ◽  
Successful Integration

AbstractLow-abrasive content slurries for copper (Cu) chemical-mechanical planarization (CMP) have been developed to achieve removal rate and removal uniformity comparable to conventional slurries. They can improve post-CMP defectivity, improve topography and allow operation at lower polish pressures that are more compatible with the low-dielectric constant (low-k) materials required for current and future high-performance interconnects. Integration of these slurries into a yielding product with 9-level Cu/low-k metallization requires fundamental learning and process characterization. This paper discusses the some of the challenges encountered during development, integration, and qualification of a low-abrasive Cu CMP process for Texas Instruments (TI) Incorporated's 90 nm technology node with copper/organosilicate interconnect. As abrasive content is reduced, the slurry chemistry must play a larger role in CMP removal. A more aggressive reactive chemical formulation requires an effective inhibitive component to keep Cu static etch rate low. As a result, wafer-scale process and consumable interactions, die-scale planarization efficiency, and feature-scale removal rates each become more sensitive to process changes. Pressure and temperature have larger effects on removal rate/profile than conventional slurries, and complete clearing of Cu puddled over underlying topography becomes more difficult. Successful integration of these slurries, however, can achieve excellent results in dishing and erosion topography, Cu thickness uniformity, and Cu loss in small features such as vias and landing pads. Low-abrasive content solutions are also more stable and easy to handle in slurry distribution vessels and lines, have lower scratch and residue defectivity, and have greatly extended margin for overpolish. As lowabrasive content Cu slurry options continue to evolve to become manufacturable solutions, their benefits far outweigh the costs and challenges encountered in their successful integration.

Finite Element Modeling of Pad Deformation due to Diamond Disc Conditioning in Chemical Mechanical Polishing (CMP)

2012 ◽  
Author(s):  
Emmanuel A. Baisie ◽  
Z. C. Li ◽  
X. H. Zhang
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Material Removal ◽  
High Performance ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Element Analysis ◽  
Fea Model ◽  
Pad Wear ◽  
Diamond Disc

Chemical mechanical planarization (CMP) is widely used to planarize and smooth the surface of semiconductor wafers. In CMP, diamond disc conditioning is traditionally employed to restore pad planarity and surface asperity. Pad deformation which occurs during conditioning affects the material removal mechanism of CMP since pad shape, stress and strain are related to cut rate during conditioning, pad wear rate and wafer material removal rate (MRR) during polishing. Available reports concerning the effect of diamond disc conditioning on pad deformation are based on simplified models of the pad and do not consider its microstructure. In this study, a two-dimensional (2-D) finite element analysis (FEA) model is proposed to analyze the interaction between the diamond disc conditioner and the polishing pad. To enhance modeling fidelity, image processing is utilized to characterize the morphological and mechanical properties of the pad. An FEA model of the characterized pad is developed and utilized to study the effects of process parameters (conditioning pressure and pad stiffness) on pad deformation. The study reveals that understanding the morphological and mechanical properties of CMP pads is important to the design of high performance pads.

New Carbon-bridged Hybrid Polymers for Low-k Materials

2005 ◽  
Vol 863 ◽  
Author(s):  
Bum-Gyu Choi ◽  
Byung Ro Kim ◽  
Myung-Sun Moon ◽  
Jung-Won Kang ◽  
Min-Jin Ko
Keyword(s):  
Mechanical Properties ◽  
Hybrid Materials ◽  
Chemical Mechanical Planarization ◽  
Sol Gel ◽  
Dielectric Constants ◽  
Metal Line ◽  
Inorganic Hybrid ◽  
Low Dielectric ◽  
Continuous Stiffness Measurement ◽  
Low K

AbstractReducing interline capacitance and line resistance is required to minimize RC delays, reduce power consumption and crosstalk below 100nm node technology. For this purpose, various inorganic- and organic polymers have been tested to reduce dielectric constants in parallel with the use of copper as metal line. Lowering the dielectric constants, in particular, causes the detrimental effect on mechanical properties, and then leads to film damage and/or delamination during chemical-mechanical planarization CMP) or repeated thermal cure cycles. To overcome this issue, new carbon-bridged hybrid materials synthesized by organometallic silane precursors and sol-gel reaction are proposed.In this work, we have developed new organic-inorganic hybrid low-k dielectrics with linear or cyclic carbon bridged structures. The differently bridged carbon structures were formed by a controlled reaction. 1H NMR, 29Si NMR analysis and GC/MSD analysis were conducted for the structural characterization of new hybrid low-k dielectric. The mechanical and dielectric properties of these hybrid materials were characterized by using nanoindentation with continuous stiffness measurement and Al dot MIS techniques. The results indicated that these organic-inorganic hybrid materials were very promising polymers for low-k dielectrics that had low dielectric constants with high thermal and mechanical properties. It has been also demonstrated that electrical and mechanical properties of the hybrid films could be tailored by copolymerization with PMSSQ and through the introduction of porogen.

Chemical-Mechanical Planarization of Low-k Polymers for Advanced IC Structures

2002 ◽  
Vol 124 (4) ◽  
pp. 362-366 ◽  
Author(s):  
Christopher L. Borst ◽  
Dipto G. Thakurta ◽  
William N. Gill ◽  
Ronald J. Gutmann
Keyword(s):  
Dielectric Constant ◽  
Surface Chemistry ◽  
Chemical Mechanical Planarization ◽  
Low Dielectric Constant ◽  
Chemical Company ◽  
Low Dielectric ◽  
Scale Models ◽  
Physically Based ◽  
Thickness Measurements ◽  
Low K

Successful integration of copper and low dielectric constant (low-k) materials is dependent on robust chemical-mechanical planarization (CMP) during damascene patterning. This process includes the direct removal of copper and interaction of the copper slurry with the underlying dielectric. Experiments were designed and performed to examine the CMP of two low-k polymers from Dow Chemical Company, bis-benzocyclobutene (BCB*, k=2.65) and “silicon-application low-k material” (SiLK* resin, k=2.65) with both acidic slurries suitable for copper damascene patterning and a KH phthalate-based model slurry developed for SiLK. Blanket polymer films were polished in order to determine the interactions that occur when copper and liner materials are removed by the damascene CMP process. Removal rates were obtained from material thickness measurements, post-CMP surface topography from AFM scans, and post-CMP surface chemistry from XPS measurements. Physically based wafer-scale models are presented which are compatible with the experimental results.

Effect of Complex Agent on Copper Dissolution in Alkaline Slurry for Chemical Mechanical Planarization

2012 ◽  
Vol 455-456 ◽  
pp. 1145-1148
Author(s):  
Yan Gang He ◽  
Jia Xi Wang ◽  
Xiao Wei Gan ◽  
Wei Juan Li ◽  
Yu Ling Liu
Keyword(s):  
Surface Roughness ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Dielectric Materials ◽  
Mechanism Analysis ◽  
Copper Dissolution ◽  
Complex Agent ◽  
High Removal Rate ◽  
Rc Delay ◽  
Low K

With the microelectronic technology node moves down to 45 nm and beyond, and to reduce the RC delay time, low-k dielectric materials have been used to replace regular dielectric materials. Therefore, the down force of chemical mechanical planarization (CMP) needs to decrease based on the characteristics of low-k materials: low mechanical strength. In this study, the effect of new complex agent on copper dissolution in alkaline slurry for CMP was investigated. Based on the reaction mechanism analysis of Cu in alkaline slurry in CMP, the performance of Cu removal rate and surface roughness condition were discussed. It has been confirmed that Cu1 slurry demonstrates a relatively high removal rate with low down force. And also, by utilizing the Cu1 slurry, good result of Cu surface roughness were obtained.

Marangoni Dryer Integrated High Performance Cleaner for Cu/Low k Post Strip Clean for 45nm Technology Node and Beyond

2007 ◽  
Vol 134 ◽  
pp. 337-340 ◽  
Author(s):  
Jian She Tang ◽  
Wei Lu ◽  
Bo Xi ◽  
Eli Martinez ◽  
Fred Li ◽  
...  
Keyword(s):  
High Performance ◽  
Water Film ◽  
Water Evaporation ◽  
Wafer Surface ◽  
Particle Removal ◽  
Technology Node ◽  
Patterned Wafers ◽  
Process Characterization ◽  
Free Environment ◽  
Low K

To address the water mark issue from hydrophobic film drying, and the stringent particle removal requirements for the 45nm technology node and beyond, we developed a cleaner with an innovative single wafer Marangoni dryer. The single wafer Marangoni dryer design features and process characterization data are presented in this paper. The major results can be summarized as: (1) With the immersion type Marangoni dryer, as the wafer is lifted out of a DIW bath, a stable and uniform meniscus can be easily maintained, making the single-wafer Marangoni dryer ideal for drying hydrophilic, hydrophobic or hydrophobic/hydrophilic mixed patterned wafers; (2) The new Marangoni dryer leaves ~14nm [1] water film on the wafer after drying, therefore any dissolved or suspended materials contained inside the water film, and potentially left on the wafer surface after water evaporation, is less than 14nm in diameter. This feature is critical for the 45nm technology node and beyond because 23nm particle could be killer defects at these nodes [2]; (3) Because of the strong Marangoni flow effect, high aspect ratio features can be completely dried without leaving any water droplets inside the trenches; therefore copper corrosion can be prevented; (4) The Marangoni dryer uses N2 as the carrier gas, so when a wafer is lifted out of the degasified DIW bath through the N2/IPA spray zone, it is thoroughly dried in an oxygen-free environment before exposure to the ambient environment; (5) The Marangoni dryer is free of electrostatic charge and centrifugal force because of the slow (2mm/s~20mm/s) wafer linear lifting speed compared to linear speed at wafer edge during SRD.

Chemical-Mechanical Planarization of Copper: The Effect of Inhibitor and Complexing Agent

2003 ◽  
Vol 767 ◽  
Author(s):  
Ying Luo ◽  
Tianbao Du ◽  
Vimal Desai
Keyword(s):  
Hydrogen Peroxide ◽  
Photoelectron Spectroscopy ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Electrochemical Process ◽  
Copper Removal ◽  
Alkaline Condition ◽  
Complexing Agent ◽  
Polarization Studies ◽  
Cu Cmp

AbstractThe present investigation was focused on understanding of the oxidation, dissolution and modification of Cu surface in slurries at various pH using hydrogen peroxide as oxidizer, glycine as complexing agent and 3-amino-triazol (ATA) as inhibitor during Cu-CMP. The electrochemical process involved in the oxidative dissolution of copper was investigated by potentiodynamic polarization studies. Surface modification of copper was investigated using Xray photoelectron spectroscopy to understand the interaction of Cu-H2O2-glycine-ATA during CMP. In the absence of glycine and ATA, the copper removal rate is found to be high in a slurry with 5% H2O2 at pH 2, then it decreases with increasing pH and reaches the minimum at pH 6, it continuously increases at alkaline condition. In the presence of 0.01M glycine, the removal rate of copper decreases in acidic slurries while increases significantly in alkaline slurries. With the further addition of ATA, the copper removal rate was reduced. However, better surface planarity was obtained. The present investigation enhanced understanding of the mechanism of Cu CMP in the presence of oxidizer, complexing agent and inhibitor for formulation of a highly effective CMP-slurry.

A Model of Chemical Mechanical Planarization to Predict Impact of Pad Conditioning on Process Performance

2012 ◽  
Vol 1428 ◽  
Author(s):  
G. Bahar Basim ◽  
Serkan Kincal
Keyword(s):  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Process Performance ◽  
Operating Characteristics ◽  
Profile Model ◽  
Thickness Profile ◽  
Model Based ◽  
Pad Conditioning ◽  
Rate Profile ◽  
Fine Tune

ABSTRACTThis study presents an effort to couple a wafer removal rate profile model based on the locally relevant Preston equation to the change in pad thickness profile which reflects to post polish profile of the wafers after Chemical Mechanical Planarization. The result is a dynamic predictor of how the wafer removal rate profile shifts as the pad ages. These predictions can be used to fine tune the conditioner operating characteristics without having to carry out high cost and time consuming experiments. The accuracy of the predictions is demonstrated by individual confirmation experiments in addition to the evaluation of the defectivity performance with the varied pad conditioning profiles.

Potential-pH Diagrams of Interest to Chemical Mechanical Planarization of Copper Thin Films

2005 ◽  
Vol 867 ◽  
Author(s):  
Serdar Aksu
Keyword(s):  
Performance Metrics ◽  
Ethylenediaminetetraacetic Acid ◽  
Removal Rate ◽  
Chemical Mechanical Planarization ◽  
Copper Removal ◽  
Chemical Components ◽  
Complexing Agents ◽  
Complexing Agent ◽  
Interlayer Dielectric ◽  
Cu Cmp

AbstractChemical mechanical planarization (CMP), which can globally planarize both silicon dioxide (the prevalent interlayer dielectric), and copper films, has become the key process in the damascene method used for producing integrated circuit (IC) devices with multilevel copper interconnects. Cu CMP is typically carried out with slurries containing oxidizing agents, complexing agents, and corrosion inhibitors as the principal chemical components. In such slurries, complexing agents enhance the solubility of copper and increase the dissolution rate of the abraded material in Cu CMP. They also assist achieving high copper removal rates during dynamic polishing conditions. The nature of the complexing agent used, the pH and the redox potential of the slurry system are among the main factors controlling the dissolution and passivation behaviors of copper during CMP. Consequently, these factors are intimately related to the key CMP performance metrics such as removal rate and planarity. In this paper, potentialpH diagrams of copper in aqueous systems containing a number of organic complexing agents including ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA), oxalic acid and malonic acid are presented. The predominance regions of copper complexes under different copper and ligand activities and their implications on copper removal during CMP are discussed.

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