8:30 – 9:00Research and Educational Objectives / Spanos 9:00 – 9:45 CMP / Doyle, Dornfeld, Talbot, Spanos 9:45 – 10:30 Plasma & Diffusion / Graves, Lieberman, Cheung, Haller 10:30 – 10:45 break 10:45 – 12:00 Poster Session / Education, CMP, Plasma, Diffusion 12:00 – 1:00 lunch 1:00 – 1:45 Lithography / Spanos, Neureuther, Bokor 1:45 – 2:30 Sensors & Controls / Aydil, Poolla, Smith, Dunn, Cheung, Spanos 2:30 – 2:45 Break 2:40 – 4:30 Poster Session / all subjects 3:30 – 4:30 Steering Committee Meeting in room 373 Soda 4:30 – 5:30 Feedback Session 3rd Annual SFR Workshop & Review, May 24, 2001

5/24/ Chemical Mechanical Planarization SFR Workshop & Review May 24, 2001 David Dornfeld, Fiona Doyle, Costas Spanos, Jan Talbot Berkeley, CA

5/24/ CMP Milestones September 30 th, 2001 –Build integrated CMP model for basic mechanical and chemical elements. Develop periodic grating metrology (Dornfeld, Doyle, Spanos,Talbot). Model Outline Progressing- initial Chemical and Mechanical Modules in Development September 30 th, 2002 –Integrate initial chemical models into basic CMP model. Validate predicted pattern development. (Dornfeld, Doyle, Spanos,Talbot). September 30 th, 2003 –Develop comprehensive chemical and mechanical model. Perform experimental and metrological validation. (Dornfeld, Doyle, Spanos, Talbot)

5/24/ Abstract 2002 Milestone: Integrate initial chemical models into basic CMP model. Validate predicted pattern development. Key areas involved in this are: Chemical Aspects of CMP (Talbot and Gopal) Glycine effects on CMP & chemical effect on abrasion (Doyle and Asku) Material Removal in CM P: Effects of Abrasive Size Distribution and Wafer-Pad Contact Area (Dornfeld and Luo) Fluid/Slurry Flow Analysis for CMP Model (Dornfeld and Mao) Fixed Abrasive Design for C MP (Dornfeld and Hwang) CMP Process Monitoring using Acoustic Emission (Dornfeld and Chang) Establishing full-profile metrology for CMP modeling (Spanos and Chang) Recent activities in yellow will be reviewed here

5/24/ Overview Model Structure & Development Basic Process Mechanism Model Validation Metrology, Process Control, & Optimization ChemMech Chemical Aspects XXX Mechanical Aspects XXX Fluid Aspects XXX Pad Surface Effects X Process Monitoring XX Grating Metrology X Process control X X X

5/24/ Model development scenario Identify key influences of chemical and mechanical activity Experimental analysis of influences in parallel with model formulation for “module” development Identification of “coupling” elements of mechanical and chemical activity Build “coupling” elements into integrated model Full scale model verification by simulation and test Strategies for model-based process optimization

5/24/ Focus of this presentation Review of progress in understanding the role of chemistry in CMP Update on process monitoring activity Full-profile metrology for CMP modeling Details of these and other key areas in posters

5/24/ Contact Pressure Model Model of Active Abrasive Number N Model of Material Removal VOL by a Single Abrasive Physical Mechanism; MRR: N´VOL Slurry Concentration, Abrasive Shape, Density, Size and Distribution Slurry Chemicals Chemical Reaction Model (RR 0 ) chem Pad Roughness Pad Hardness Wafer, Pattern,Pad and Polishing Head Geometry and Material Pressure and Velocity Distribution Model (FEA and Dynamics) Down Pressure Relative Velocity Wafer Hardness Dishing & Erosion Preston’s Coefficient K e (RR 0 ) mech WIWNU Surface Damage WIDNU WIWNU MRR Fluid Model Review - Overview of Integrated Model

5/24/ Chemical Aspects of CMP Role of Chemistry Chemical and electrochemical reactions between material (metal, glass) and constituents of the slurry (oxidizers, complexing agents, pH) –Dissolution and passivation Solubility Adsorption of dissolved species on the abrasive particles Colloidal effects Change of mechanical properties by diffusion & reaction of surface

5/24/ Modeling of Chemical Effects Electrochemical/chemical dissolution and passivation of surface constituents Colloidal effects (adsorption of dissolved surface to particles or re-adsorption) Solubility changes Change of mechanical properties (hardness, stress)

Copper Interconnection using Chemical Mechanical Planarization (CMP) Fiona Doyle and Serdar Asku How Glycine Changes Electrochemistry of Copper?  Comparison of Cu Behavior in Aqueous Solutions with and without Glycine in terms of  Potential-pH Diagrams  Polarization Experiments How Electrochemical Behavior Changes under Abrasion  In-situ Electrochemical Experiments during Polishing using Slurries/ Solutions with or without Glycine  In-situ Polarization Experiments  In-situ Monitoring of Open Circuit Potential (E OC ) Conclusions Experimental Results and Their Comparison with the Theoretical Diagrams

5/24/ Copper Interconnection with CMP

5/24/ Objective and Methods In Copper CMP, Electrochemical and Mechanical Mechanisms are not Well Understood  Slurries are formulated empirically at present  Develop a Fundamental Basis for the Behavior of Slurries with Complexing Agents  Tertiary Potential-pH Diagrams  Polarization Experiments using Cu Rotating Disk Electrode  In-situ Electrochemical Experiments during Polishing

5/24/ Experimental Techniques Magnetic stirrer Rotating Disk Electrode In-situ Electrochemical Experiments Pt Counter Electrodes Luggin Probe & Reference Electrode Polish pad Copper Working Electrode Slurry pool P Rotator Frame  Fritted glass gas bubbler Rotating Cu Disk electrode

5/24/ Cu T =10 -5 Cu-H 2 O System RDE 200 rpm Scan Rate 2 mV/sec 2.17x , No Buffer 3.23x , With Carbonate Buffer M Na 2 SO x , With Acetate Buffer M Na 2 SO 4 i OC (A/cm 2 )E OC (mV vs. SHE) pH and pH Buffer System

5/24/ Cu T =10 -5 ; L T =10 -2 Cu-H 2 O-Glycine System RDE 200 rpm Scan Rate 2 mV/sec M Glycine 1.21x , No Buffer 1.04x , No Buffer M Na 2 SO x , With Acetate Buffer M Na 2 SO 4 i OC (A/cm 2 ) E OC (mV vs. SHE) pH and pH Buffer System

5/24/ Cu-H 2 O-Glycine System (De-aerated) Cu T =10 -5 ; L T =10 -2 Cu T =10 -4 ; L T =10 -1 pH=9 pH=11 pH=12 pH=10 pH=9 pH=11 pH=12 pH=10

5/24/ In-Situ Polarization at pH=4 RDE/ IN-SITU 200 rpm 27.6 kPa Scan Rate 2 mV/s 1.16x Polishing w/ pad + 5wt % Al 2 O x Polishing w/ pad only 6.41x No abrasion Acetate Buffer M Na 2 SO M glycine 6.18x Polishing w/ pad + 5wt % Al 2 O x Polishing w/ pad only 4.43x No abrasion (RDE) Acetate Buffer M Na 2 SO 4 No Glycine i OC (A/cm 2 ) E OC (mV vs. SHE) Abrasion Type Chemical Composition No Glycine M Glycine

5/24/ In-Situ Polarization at pH=9 RDE/ IN-SITU 200 rpm 27.6 kPa Scan Rate 2 mV/s 2.87x Polishing w/ pad + 5wt % Al 2 O x Polishing w/ pad only 1.04x No abrasion No Buffer Na 2 SO M glycine 4.09x Polishing w/ pad + 5wt % Al 2 O x Polishing w/ pad only 3.23x No abrasion (RDE) Carbonate Buffer M Na 2 SO 4 No Glycine i OC (A/cm 2 ) E OC (mV vs. SHE) Abrasion Type Chemical Composition No Glycine M Glycine

5/24/ In-Situ Polarization at pH=12 RDE/ IN-SITU 200 rpm 27.6 kPa Scan Rate 2 mV/s 8.62x Polishing w/ pad + 5wt % Al 2 O x Polishing w/ pad only 1.21x No abrasion No Buffer No Na 2 SO M glycine 9.72x Polishing w/ pad + 5wt % Al 2 O x Polishing w/ pad only 2.17x No abrasion (RDE) No Buffer/Na 2 SO 4 DD Water with No Glycine i OC (A/cm 2 ) E OC (mV vs. SHE) Abrasion Type Chemical Composition No Glycine M Glycine

5/24/ In-Situ OC Potential Measurements Without Glycine With M Glycine

5/24/ Conclusions Polarization results well correlated with potential-pH diagrams No significant changes in in-situ polarization for active behavior Mechanical components significantly affected in-situ polarization for active-passive behavior Kaufman’s tungsten CMP model is also valid for Cu CMP Glycine (complexing agents) may enhance the polishing efficiency.

5/24/ Future Work-I Determination of Chemical (Electrochemical) and Mechanical Contributions  Maintain a Constant Level Of In-Situ Polarization, Measure Current  CHEMICAL CONTRIBUTION from Time-Averaged Current  POLISH RATE from Weight Loss  MECHANICAL CONTRIBUTION from the Difference Generation of Chemical,Mechanical and Total Removal Rate versus Polarization Plots at Different pH’s.

5/24/ Future Work-II In-Situ Electrochemical Experiments using “Patterned” Cu Electrodes  In-Situ Polarization Experiments  Polishing at a Constant Level of Polarization  Surface Examination of Passive Films XPS, Auger Spectroscopy Verification of Kaufman’s Model using “Patterned” Cu Electrodes

5/24/ Process Monitoring of CMP using Acoustic Emission Andrew Chang UCB Motivation Endpoint Detection -The characteristics of the acoustic emission signal from various materials can be easily discernable during the polishing process. -Outside noise sources, once characterized, can be minimized and filtered from disturbing the process signal. Scratch Detection -Scratches and/or other mechanically induced flaws (large agglomeration of particles, contaminants on the pad, etc.) can be detected and used as feedback for purposes of real-time process control. Abrasive Slurry Design -Energy of the AE signal can be correlated to the active number of abrasive particles during polishing for slurry concentration optimization

5/24/ Acoustic Emission Propagation in the Wafer Schematic view of abrasive particles during polishing (exaggerated view) Oil film couplant Sensor Carrier ring Wafer carrier Wafer Pad Polishing plate Abrasives in slurry Individual burst emission waves generated by abrasive particles contacting wafer produce a continuous acoustic emission source. Wafer

5/24/ Experimental Setup Pressure = ~ 1 psi Table Speed = 50 RPM Wafer Carrier Speed = Stationary Slurry flowrate = 150 ml/min Polishing Conditions IC 1000/Suba IV stacked padPad type ILD 1300, abrasive size (~100 nm) Alumina slurry, abrasive size (~100 nm) Slurry type Bare silicon & copper blanket wafersTest Wafers Toyoda Float Polishing MachineCMP Tool PC Data Acquisition Raw Sampling Rate = 2 MHz Raw AE Signal Conditioning ( dB) Pre-amplification & Primary amplification

5/24/ Raw Acoustic Emission from CMP Process Low frequency noise due vibrations from table motor, pad pattern effects, etc. Filtered raw signal containing high frequency AE content

5/24/ Establishing full-profile metrology for CMP modeling Costas Spanos & Tiger Chang UCB Substrate Oxide Use scatterometry to monitor the profile evolution The results can be used for better CMP modeling

5/24/ Mask Designed to explore Profile as a function of pattern density The size of the metrology cell is 250  m by 250  m Periodic pattern has 2  m pitch with 50% pattern density

5/24/ Sensitivity of Scatterometry (GTK simulation) We simulated 1  m feature size, 2  m pitch and 500nm initial step height, as it polishes. The simulation shows that the response difference was fairly strong and detectable.

5/24/ Characterization Experiments Completed Three one-minute polishing steps were done using the DOE parameters Initial profiles Sopra/AFM CMP Nanospec Thickness measurement Sopra Spectroscopic ellipsometer AFM (AMD/SDC) Wafer cleaning Slurry Flow (ml/min) Table Speed (rpm) Down Force (psi) Wafer #

5/24/ Library-based Full-profile CMP Metrology Reference: X. Niu, N. Jakatdar, J. Bao, C. Spanos, S. Yedur, “Specular spectroscopic scatterometry in DUV lithography”, Proceedings of the SPIE, vol.3677, pt.1-2, March Five variables were used in to generate the response library: bottom oxide height (A), bottom width (B), slope 1 (C), slope 2 (D) and top oxide height (E). Substrate A B C D E oxide

5/24/ AFM Full Profile CMP Results, so far Extracted profiles match SEM pictures within 10nm Scatterometry is non-destructive, faster and more descriptive than competing methods. Next challenge: explore application in wet samples. SEM Scatterometry

5/24/ Conclusions Chemical effects model and synergy with mechanical effects being developed and validated Mechanical effects model validated for abrasive size and activity and wafer-pad contract area Fabrication technique for micro-scale abrasive design experiments Sensing system for process monitoring and basic process studies being validated Scatterometry metrology sensitivity study indicates suitability for observing profile evolution

5/24/ & 2003 Goals Develop comprehensive chemical and mechanical model. Perform experimental and metrological validation, by 9/30/2003. Simulation of Integrated CMP model Experimental verification of integrated CMP model (role of chemistry elements, mechanical elements in mechanical material removal)