1 Chemical Engineering Tools for Semiconductor Fabrication David Cohen, PhD AIChE Norcal Symposium April 12, 2005

2 Novellus Confidential DGC-4/05 Integrated Circuit Courtesy of Integrated Circuit Engineering (ICE)

3 Novellus Confidential DGC-4/05 Moore’s Law Courtesy of Intel Number of Transistors per Integrated Circuit

4 Novellus Confidential DGC-4/05 Feature Size Evolution

5 Novellus Confidential DGC-4/05 Chemical Unit Operations SABRE xT ALTUS INTERCONNECT VIA CONTACT INOVA xT METALS STI SPEED ILD/PMD PASSIVATION IMD BARRIER/ARL VECTOR DIELECTRICS SEQUEL FEATURE SIZE

6 Novellus Confidential DGC-4/05 Example of Chemical Process - Electroplating Electrofill Cu Anode Cathode (Wafer) Cu 0 (solid) = Cu +2 (aq) + 2e - Cu +2 (aq) + 2e - = Cu 0 (solid) CuSO 4 Electrolyte Novellus Sabre

7 Novellus Confidential DGC-4/05 Example of Chemical Process - CVD Heater Block Shower Head SiN RF Plasma SiH 4, NH 3 and N 2 Optional RF Bias RF Power PECVD Novellus Vector

8 Novellus Confidential DGC-4/05 Plasmas Today PECVD Plasmas have played vital role in:  Physical Vapor Deposition  Plasma Enhanced Chemical Vapor Deposition (right)  Etching  Cleaning  Passivation  Plasma sources of UV radiation for lithography Plasmas have played vital role in:  Physical Vapor Deposition  Plasma Enhanced Chemical Vapor Deposition (right)  Etching  Cleaning  Passivation  Plasma sources of UV radiation for lithography

9 Novellus Confidential DGC-4/05 Future Limitations of Plasmas  Extreme selectivity required for advanced applications. Need to produce desired plasma chemical reactions and prevent undesirable ones. The ability to tailor the energy distributions of plasma particles is key to this selectivity.  As feature sizes get smaller, plasma energy requirements get larger.  Need to enhance models to fully couple reactor scale to feature scale.  Extreme selectivity required for advanced applications. Need to produce desired plasma chemical reactions and prevent undesirable ones. The ability to tailor the energy distributions of plasma particles is key to this selectivity.  As feature sizes get smaller, plasma energy requirements get larger.  Need to enhance models to fully couple reactor scale to feature scale.

10 Novellus Confidential DGC-4/05 Atomic Layer Deposition  Surface controlled, layer by layer deposition method ALD Group, Univ of Colorado

11 Novellus Confidential DGC-4/05 Quantum Chemistry Modeling  Predict surface reactions to understand ALD  Challenge coupling reactor scale flow behavior with surface chemistry  Ability to model is limited by computational power because of extreme complexity of film growth chemistry  Predict surface reactions to understand ALD  Challenge coupling reactor scale flow behavior with surface chemistry  Ability to model is limited by computational power because of extreme complexity of film growth chemistry Collin Mui, Novellus Systems

12 Novellus Confidential DGC-4/05 Moving to Low-k  As features become smaller, reduced capacitance is necessary to increase IC clock speed  Reduction in dielectric constant (k)  SiO 2 is primary insulator – k=4.0  Need to get down to k<2.0  As features become smaller, reduced capacitance is necessary to increase IC clock speed  Reduction in dielectric constant (k)  SiO 2 is primary insulator – k=4.0  Need to get down to k<2.0

13 Novellus Confidential DGC-4/05 Challenges of Low-k Porosity increases with decreasing dielectric constant (k) ä Thermal Conductivity ä Mechanical Strength (CMP, bonding, packaging) ä Pore Size killer pore (< 10% CD) need for CVD barrier CVD barrier increases effective k Porosity increases with decreasing dielectric constant (k) ä Thermal Conductivity ä Mechanical Strength (CMP, bonding, packaging) ä Pore Size killer pore (< 10% CD) need for CVD barrier CVD barrier increases effective k

14 Novellus Confidential DGC-4/05 Chemical Mechanical Planarization  Removes surface textures and allows multiple interconnect layers to be used  Removes excess material  Removes surface textures and allows multiple interconnect layers to be used  Removes excess material Novellus Xceda Courtesy of Alpsitec

15 Novellus Confidential DGC-4/05 CMP Challenges  Pressure of CMP Pad results in dishing of soft materials or damage of low-k films  Need to provide better polishing control Chemistry of CMP slurries will drive more uniform polish Chemical polish can replace mechanical force  Uniformity prediction relies on development of model that takes into account pad motion, fluid- structure interaction, and removal rate  Need to provide better polishing control Chemistry of CMP slurries will drive more uniform polish Chemical polish can replace mechanical force  Uniformity prediction relies on development of model that takes into account pad motion, fluid- structure interaction, and removal rate

16 Novellus Confidential DGC-4/05 Electroplating Modeling ä Need to include: turbulent/rotating flow mass transfer electrical current flow terminal effect (electrical current flow in the seed layer) Chemistry – not well understood ä Need to include: turbulent/rotating flow mass transfer electrical current flow terminal effect (electrical current flow in the seed layer) Chemistry – not well understood

17 Novellus Confidential DGC-4/05 Use of Electroplating Models  Model can be used to test various additive chemistries for Cu electroplating Larry Gochberg, Novellus Systems

18 Novellus Confidential DGC-4/05 Effluent Management  On-site abatement necessary to minimize environmental impact of IC manufacturing  Gas phase emissions Hazardous Air Pollutants (HAPs) Volatile Organic Compounds (VOCs) Ozone Depleting Substances (ODSs) Perfluorinated Compounds (PFCs)  Liquid phase emissions Suspended solids Phosphates, Nitrates Organics Transition Metals pH, Temperature, etc.  On-site abatement necessary to minimize environmental impact of IC manufacturing  Gas phase emissions Hazardous Air Pollutants (HAPs) Volatile Organic Compounds (VOCs) Ozone Depleting Substances (ODSs) Perfluorinated Compounds (PFCs)  Liquid phase emissions Suspended solids Phosphates, Nitrates Organics Transition Metals pH, Temperature, etc.

19 Novellus Confidential DGC-4/05 Summary  There are a number of chemical unit operations involved in IC manufacture.  Feature size has evolved to below 100 nm.  New technologies will be required to keep reducing IC feature size.  Modeling enhancements are needed to better understand plasma, electroplating, CMP, ALD.  Advances in semiconductor manufacture need to include emission control and energy reduction.  There are a number of chemical unit operations involved in IC manufacture.  Feature size has evolved to below 100 nm.  New technologies will be required to keep reducing IC feature size.  Modeling enhancements are needed to better understand plasma, electroplating, CMP, ALD.  Advances in semiconductor manufacture need to include emission control and energy reduction.