Spin coating is a process that uses centrifugal force to spread a liquid solution evenly and produce a thin film of uniform thickness on a surface. It has various applications in industries like microelectronics. A simple model of spin coating was developed based on assumptions of laminar, axisymmetric flow. This model derived an equation showing film thickness decreases over time according to fluid properties like viscosity and spin speed. Further work aims to model non-Newtonian fluid spin coating and experimentally validate the models.
Thin film deposition using spray pyrolysisMUHAMMAD AADIL
Spray pyrolysis is a simple and low-cost thin film deposition technique that involves spraying a metal salt solution onto a heated substrate. As the droplets impact and spread on the substrate, thermal decomposition occurs, leaving a film of metal oxides. The substrate temperature is the main parameter that determines the film properties, as it influences processes like precursor decomposition and solvent evaporation. Varying the deposition temperature can control the film morphology and optical/electrical characteristics. The precursor solution composition also affects the film structure, as additives can modify the solution chemistry and change the resulting film morphology.
This document discusses physical vapor deposition (PVD) and chemical vapor deposition (CVD) techniques for thin film deposition. It covers common PVD methods like thermal evaporation, sputtering, and molecular beam epitaxy. It also discusses CVD reaction mechanisms, step coverage, and overview. Key aspects include comparing evaporation and sputtering, deriving equations for mean free path and deposition rate, and factors affecting step coverage in CVD like temperature and pressure.
Metal Organic Chemical Vapour Deposition (MOCVD) is a technique used to grow thin semiconductor films on substrates using organometallic compounds as sources. MOCVD is commonly used to fabricate electronic and optoelectronic devices like those in phones, LEDs, and solar cells. The MOCVD process involves heating substrates in a reactor where organometallic source gases decompose and react to form epitaxial semiconductor films precisely controlled in thickness and composition. MOCVD offers high growth quality, flexibility, and throughput making it well-suited for heterostructures like quantum wells used across many applications.
This document provides information on preparing thin films using the Successive Ionic Layer Adsorption and Reaction (SILAR) method. It discusses what thin films are, common thin film deposition techniques like physical vapor deposition and chemical vapor deposition, and the SILAR method specifically. SILAR involves alternating immersion of a substrate in cationic and anionic precursor solutions to deposit materials like cadmium sulfide in a layer-by-layer process. Parameters like concentration, pH, temperature, and deposition time must be optimized to produce adherent thin films. The document also outlines some applications of SILAR-deposited cadmium sulfide thin films and factors that influence thin film characteristics.
Spin coating is a process that uses centrifugal force to spread a liquid solution evenly and create a thin film on a surface, such as a semiconductor wafer. It involves depositing fluid onto a substrate that is then spun to evenly distribute the fluid via centrifugal force. The spinning causes the coating to thin at a rate dependent on viscosity and spinning velocity until the solvent evaporates, leaving a uniform thin film of specific thickness. Spin coating is widely used in microelectronics manufacturing to apply coatings like photoresist and insulating layers. Common defects include bubbles, swirling patterns, and streaks caused by issues with deposition uniformity or process parameters.
The document provides an overview of chemical vapor deposition (CVD) and physical vapor deposition (PVD) processes. CVD involves reacting vapor phase chemicals in a chamber to form a thin solid film on a substrate. It can be used to deposit a variety of materials. PVD involves physically vaporizing a material in a chamber and re-depositing it as a thin film on a substrate. It has various variants like sputtering and evaporative deposition. Both CVD and PVD are used to deposit thin films for applications like semiconductor devices, coatings, optical fibers and composites.
Thin film fabrication using thermal evaporationUdhayasuriyan V
Thermal evaporation is a physical vapor deposition technique where a material is heated in a vacuum until its surface atoms evaporate and are deposited as a thin film on a substrate. The document discusses the principles and working of thermal evaporation, including how the source material is resistively heated to evaporation, how substrates are cleaned, and the advantages of producing films in a high vacuum like reduced impurities. Thermal evaporation can deposit pure elements or compounds and is used to fabricate thin films for applications like semiconductors, solar cells, and optics.
Chemical vapor deposition (CVD) is a process used to produce high-purity solid materials through chemical reactions of vapor phase precursors on a substrate. Key steps include transport of reactants to the substrate surface, adsorption and decomposition reactions, and removal of byproducts. CVD processes are classified based on operating pressure and can be used to deposit a variety of materials through control of temperature, precursor gases, and other parameters.
Pulsed laser deposition is a thin film growth technique where a high-power pulsed laser is focused on a target in a vacuum chamber, vaporizing the target material which then condenses on a substrate. It allows for the growth of a wide variety of oxide, nitride, metal and other films. The composition of the deposited film mimics that of the target. PLD systems are relatively inexpensive and easy to use, leading to its popularity in academic research. Key advantages include nearly stoichiometric transfer, flexibility in depositing different materials, and real-time thickness control. The laser-target interaction process involves rapid heating, vaporization and formation of an energetic plume that interacts strongly with the substrate during deposition.
Epitaxial deposition is a method for growing high quality crystalline films on crystalline substrates. There are two main types: homoepitaxy, where the film and substrate are the same material, and heteroepitaxy, where they differ. Key parameters that affect the epitaxial growth process include temperature, pressure, and reactant flow. Common techniques include vapor phase epitaxy, liquid phase epitaxy, and molecular beam epitaxy, each with their own advantages and disadvantages for producing films for semiconductor and optoelectronic devices.
Thin films are layers of material ranging from 10-500 nanometers thick. Thin film technology is used in many applications like microelectronics, optics, and magnetic coatings. There are various deposition techniques used to fabricate thin films, including physical vapor deposition methods like sputtering and evaporation, and chemical vapor deposition methods like plasma-enhanced CVD and low-pressure CVD. Each deposition technique has advantages and disadvantages depending on the substrate and material properties. Thin films are used to produce microelectronics, sensors, tailored materials, optical coatings, and corrosion/wear resistant coatings.
The document discusses various crystal growth techniques including Czochralski (CZ), float zone, and Bridgman techniques. It describes the limitations of the CZ method including impurities introduced from the quartz crucible. The float zone technique produces very pure silicon crystals but allows for smaller wafer sizes. The Bridgman technique employs a temperature gradient to slowly cool a melt contained in a crucible to produce a single crystal ingot.
Hot wall reactor is a high temperature chamber in which the substrate is placed for coating. In this reactor including the substrate, all other parts (inlet and outlet tubes) inside the chamber get coated.
This to demonstrate the laser ablation of hard materials to form a thin film for optical sensors. The work was done at DIllard University , New Orleans LA by Professor Abdalla Darwish. any comment e-mail adarwish@bellsouth.net.
The document summarizes optical properties of nanomaterials. It discusses topics like optics, optical properties of materials, thin film interference, luminescence, photonic crystals, photoconductivity, solar cells, and optical properties of quantum wells and quantum dots. In particular, it explains how the size-dependent band gap of quantum dots leads to size-tunable fluorescence colors, making quantum dots useful for applications like biological imaging and white LEDs.
The document discusses thin films, which are layers of material ranging from fractions of a nanometer to several micrometers thick. Thin films can be single crystals, epitaxial, polycrystalline, or amorphous. They have properties like a high surface to volume ratio and geometric control from the substrate. Thin films are used in microelectronics, telecommunications, decorative coatings, optical coatings, sensors, and catalysts. Common deposition methods include liquid phase deposition, chemical bath deposition, and chemical vapor deposition.
Chemical vapor deposition (CVD) involves depositing a solid material onto a substrate through chemical reactions of vapor phase precursors. CVD systems include precursor supply, heated reactors to decompose precursors, and effluent gas handling. During CVD, precursors are transported to the substrate surface through diffusion and convection, react on the surface, and deposit the solid material as a thin film as gaseous byproducts desorb. CVD is used to deposit a variety of materials and has applications in semiconductors, coatings, and fiber optics.
A large portion of our polymer optics require thin-film coating. Beware, not all caters are created equally and it takes a unique skill set to coat polymer optics. Some would say coating polymer optics is an art form. So, we leave this to the experts.
Design & Fabrication of a low cost spin coaterSaurabh Pandey
Spin Coating is basically a procedure which is used to deposit uniform thin films to any flat surface of work piece. Usually a small amount of coating material is applied on the centre of the work piece’s surface when the disk is spinning at very low speed. Here in this process we are using the basic principle of centrifugal force. This is applied due to the spinning of Disk.
The document discusses coating process development. It covers several key aspects of the coating process including coating formulation, coating equipment and processes, the material being coated, material handling, and drying/curing ovens. Specifically, it emphasizes the importance of uniform coating formulation, controlling coating equipment and processes, properly preparing the surface of materials to be coated, ensuring uniform material handling, and managing drying/curing oven conditions. The overall goal is to integrate these various elements to produce a consistent, high-quality coating.
Photolithography is a process for transferring geometric patterns onto a substrate using light. It involves coating a photoresist layer on the substrate, exposing it to light through a photomask, and developing it to selectively remove either the exposed or unexposed areas. The key steps are photoresist coating, soft baking, alignment and exposure, development, hard baking, etching, and photoresist removal. Positive photoresist becomes soluble after exposure while negative photoresist becomes insoluble, allowing selective removal of one area versus the other during development.
Vapor Deposition Pattern Transfer discusses various deposition techniques including physical vapor deposition (PVD) methods like thermal evaporation and sputtering, as well as chemical vapor deposition (CVD). It describes the basic processes, parameters, and applications of these techniques for depositing thin films including considerations for step coverage, reaction mechanisms, and mass transport effects.
This document discusses anti-reflection (AR) coating technology for LCD displays. It provides an overview of single-layer and multi-layer AR coating principles and methods, including wet coating, sputtering, and sol-gel coating. Wet coating and sputtering equipment costs are estimated, and sample AR coating reflectivity data is shown for comparison. Issues that can occur during spin coating like bubbles, streaks and defects are also outlined.
This curriculum vitae outlines the educational and professional background of Hien Thu Pham. It includes her education history with degrees in chemistry from Hanoi National University and Chonnam National University. Her research interests involve semiconductor nanocrystals and their application in electrical and energy devices. She has published several journal articles and conference presentations in these areas under the supervision of Professor Hyun-Dam Jeong.
Hind High Vacuum company Pvt ltd is a vacuum science and technology company located in Bangalore, India with two facilities totaling 230,000 square feet. The company specializes in vacuum equipment, deposition systems, instrumentation, components, pumps, thin film coatings, optical windows, and projects for space and defense applications. Hind High Vacuum has manufacturing capabilities for watch crystals, optical glasses, and thin film coatings using various deposition techniques in a class 100k clean room.
The document discusses the Mitsubishi Chemical Center for Advanced Materials (MC-CAM), a research partnership between Mitsubishi Chemical and UCSB focused on new materials. It also discusses the Complex Fluids Design Consortium (CFDC), an academic-industrial partnership aimed at developing computational tools for designing soft materials. The author proposes using field-based simulations rather than particle-based simulations to model polymer fluids at relevant scales, and describes how statistical field theories can be constructed and simulated at either a mean-field or full stochastic level.
Erbium has many varied applications in modern technology, making demand for this rare earth metal continue to grow.
For information about investing in erbium and other rare earth elements, contact London Commodity Markets: http://londoncommoditymarkets.com/contact.php
Dip coating is a process used to prepare porous ceramic membranes by immersing a substrate into a precursor solution, removing it, and allowing the coating to dry. It is an old commercially applied coating technique dating back to a 1939 patent. Key steps to forming defect-free membranes include using a homogeneous support, cleaning the substrate, sufficiently deaerating the solution, avoiding thick coatings, and keeping the environment particle-free. The dip coating process involves three stages: immersion for wetting, deposition and drainage as the substrate is withdrawn, and evaporation of the solvent to form the dried coating layer. Withdrawal speed and other forces determine the thickness of the coated layer.
Erbium-rich thin film materials for optical communications in siliconRoberto Lo Savio
1) The document discusses erbium-containing rare earth compounds such as yttrium-erbium oxide (Y-Eroxide) and yttrium-erbium silicates for applications in silicon optical communications. 2) Thin films of Y-Eroxide were synthesized with varying erbium content using co-sputtering. Higher erbium content led to increased phonon energy and decreased visible and infrared photoluminescence emission. 3) Films with around 3.3% erbium content showed optimal 1.54 μm emission due to reduced erbium-erbium interactions compared to higher concentration films.
The document discusses dip coating and electrodeposition processes. It describes dip coating as a process where a substrate is immersed in a coating material tank, removed, and allowed to dry. The dip coating process has three stages: immersion, dwell time, and withdrawal. Film thickness is controlled by withdrawal speed and viscosity. Electrodeposition coats one metal onto another to modify surface properties like corrosion resistance. It can deposit thin layers with precision and is well-suited for nano- and microtechnologies. Both dip coating and electrodeposition are used for applications like solar panels, electronics, jewelry, and automotive and mechanical parts.
This document provides information on equipment and processes for a research-based integrated circuit fabrication facility. It includes summaries of wafer processing for silicon and compound semiconductors, clean room standards and inventory of wafer processing and clean room equipment. Key steps in photolithography like photoresist application, exposure, and development are also outlined. The document gives cost estimates and specifications for particle counters, air conditioners, and other processing tools needed for the facility.
The document discusses several coating techniques used in ceramic science:
- Dip coating involves withdrawing an object from a liquid coating at a controlled speed, with coating thickness calculated by the Landau-Levich equation. Gelation then occurs through solvent evaporation and sol destabilization.
- Capillary coating combines the advantages of dip coating with utilizing all the coating liquid.
- Spin coating involves spinning a substrate to spread a liquid coating through centrifugal force, with final thickness determined by processing parameters in a semi-empirical formula.
- Compressive stress coatings through densified ceramic or glass coatings below the substrate glass transition temperature can improve glass strength by factors of 4.
Journal of Thin Films, Coating Science Technology and Application vol 3 issue 3STM Journals
Journal of Thin Films, Coating Science Technology and Application (JoTCSTA) Publishes Review /Research articles and attempts to bring out latest cutting –edge technologies in the field of coating technology, Subject areas suitable for publication include ,but are not limited to the following fields
Focus and Scope Covers
Biomaterials, colloid and surface chemistry
Adhesion, contact mechanics and Coatings Technology
Friction and wear, including mechanisms, modeling, characterization, measurement and testing
lubricants and Lubrication technology and applicarion
Coatings and surface treatments and Surface integrity
Tribology of composite materials: metallic, polymeric and ceramic and Tribological applications
Surface modifications, including surface cladding, cutting, polishing and grinding
material science, manufacturing , foundry, welding, joining, composites manufacturing
thermal and plasma spraying, thermo-chemical treatment,
Plating, sol-gel coating, anodization, plasma electrolytic oxidation, etc., but excluding painting.
Corrosion, friction performance and wear resistance
Surfaces, Interfaces, Thin Films, Corrosion and Coatings
Electroless and Friction based coating, Coatings for biological applications and High temperature applications
Craig Hawker of UCSB: Commercial Applications of Polymer as Nanomaterialsucsb.ira
The document discusses using polymers as nanomaterials for biomedical applications. It describes synthesizing multifunctional nanoparticles with a polyethylene glycol shell and reactive internal groups. The nanoparticles can be functionalized with targeting ligands on the surface and therapeutics internally. Radiolabeled nanoparticles showed long blood circulation times and accumulation in tumors, demonstrating their potential for drug delivery and imaging applications.
Bismuth is a crystalline, brittle metal and constitutes the most naturally diamagnetic metal. Bismuth has the property that it expands as it freezes and also has unusually high electrical resistance for a metal. Its thermal conductivity is lower than any metal except mercury. Bismuth is a semimetal with rhombohedral crystal structure and Bi shows a semimetal-semiconductor transition in low-dimensional structures, hence making it a candidate for nano-technical applications. We aim to provide an introduction to these technical applications of bismuth nano-particles by way of this presentation.
The document provides an overview of the basics of semiconductor device fabrication, including crystal growth, wafer preparation, oxidation, photolithography, doping, metallization, and testing. It discusses key processes like thermal oxidation, diffusion, ion implantation, evaporation, sputtering, chemical vapor deposition, wafer probing, and marking/packaging. The summary focuses on the major fabrication stages and techniques covered in the technical document.
The document summarizes key aspects of etching processes used for silicon MEMS fabrication. It defines wet and dry etching methods and discusses their advantages and disadvantages. Wet etching uses liquid etchants and is cheap but not reproducible, while dry etching uses plasma and is more controlled. The document also covers etching figures of merit like rate, uniformity, selectivity between materials, and anisotropy. It provides examples of anisotropic wet etching of silicon and discusses factors that control etch rate and selectivity. Etching can be stopped at boron-doped layers or using electrochemical techniques.
This document provides an overview of the volume of fluid (VOF) method for simulating multiphase flows in STAR-CCM+. It describes the theoretical background of the VOF method, including the high-resolution interface-capturing (HRIC) scheme. It also discusses accounting for surface tension effects, extensions of the VOF method, wave models, and provides examples of applications such as droplet impact, slot coating, and flow around ships. Future developments may include improvements to free surface curvature computation and transitions between multiphase models.
This document discusses various topics related to engineering thermodynamics and heat transfer including Nusselt's theory of condensation, correlations for boiling and condensation, film condensation on vertical plates and radial systems, dropwise condensation, and classifications of pool boiling and flow boiling. It provides explanations, diagrams, and equations for analyzing different heat transfer processes involving phase changes.
This document discusses boundary layer flow over a flat plate. It begins by defining the governing equations and boundary conditions for two-dimensional, incompressible, laminar flow over a flat plate. Dimensionless parameters including the Reynolds number are introduced. Similarity solutions for both the laminar velocity and thermal boundary layers are presented, with the Blasius solution provided for the velocity profile. Methods for evaluating heat transfer via empirical correlations or theoretical solutions are overviewed. Transition to turbulent flow and considerations for mixed laminar-turbulent boundary layers are also covered at a high level.
Rheology is the science of material flow behavior. It uses complex mathematics to describe flow, which can be difficult for non-specialists to understand. The document discusses defining rheology based on physical understanding rather than complex equations. It then covers basic rheology concepts like viscosity and how it varies with temperature and shear rate. Key polymer processing rheology topics are defined, like melt index and moisture content. Common rheological testing equipment is also described.
This document summarizes research on super hydrophobic materials conducted by a group of 4 students. It defines hydrophobicity and super hydrophobicity, and explains the theories of Wenzel and Cassie-Baxter wetting states. The group studied the surface properties, coatings, and self-cleaning effects of super hydrophobic materials. They describe common fabrication methods like templating, nanocasting, and plasma treatment. The applications of super hydrophobic glass powder and coatings in industries like aerospace, automobiles, and buildings are also outlined. In conclusion, the development of long-lasting super hydrophobic surfaces remains an ongoing challenge.
This document discusses modeling viscoelastic flow in porous media. It first describes linear and non-linear viscoelasticity models under small and large deformations. It then discusses continuum and pore-scale approaches to modeling viscoelastic flow, noting advantages and disadvantages of each. Numerical methods like finite element and network modeling are presented as ways to solve the governing equations. Network modeling involves discretizing time and simulating flow using a time-independent network model that accounts for past history through effective local time-dependent viscosity.
This document discusses modeling the flow of non-Newtonian fluids in porous media. It defines Newtonian and non-Newtonian fluids and describes different types of non-Newtonian behavior including time-independent, time-dependent, and viscoelastic. Network modeling techniques are presented for simulating flow using pore-scale images and representative rheological models. Strategies are discussed for modeling time-independent, time-dependent, and viscoelastic fluids using network modeling approaches. Future work is noted to implement time-dependent modeling strategies and investigate viscoelastic effects.
Discusses about photolithography, mask design, wet and dry bulk etching, bonding, thin film deposition and removal, metallization, sacrificial process and other inorganic processes.
Discusses about biomedical microdevices, systems and its various applications such as miniaturized systems including microelectronics, MEMS, microfluidics and nanosystmes measured in microns and nanometers.
Engineering project non newtonian flow back stepJohnaton McAdam
This document describes a numerical simulation of non-Newtonian fluid flow over a backward-facing step using two viscosity models: the power law model and Carreau model. The incompressible Navier-Stokes equations are solved using finite element analysis in MATLAB. Boundary conditions of no-slip walls and zero traction at the outlet are applied. Simulation results at different inlet velocities show shear thinning and thickening behavior for both models. The Carreau model is found to better handle very low or high shear rates compared to the power law model.
Analytical Models of Single Bubbles and FoamsRobert Murtagh
1) The document presents analytical models for describing the shape and interactions of bubbles in foams. It introduces the Z-Cone model which approximates each bubble sector as a circular cone to calculate the excess energy as a function of deformation.
2) The model is then extended to the Kelvin foam structure using a one or two cone approach to match the geometry. Contact losses as liquid fraction increases are also analyzed.
3) Comparisons with Surface Evolver simulations show good agreement for the Z-Cone model at small deformations but deviations at larger deformations where interactions are non-harmonic.
This document discusses condensation and film surface condensation on vertical surfaces. It defines condensation as the phase change from gas to liquid, and describes different types including surface, homogeneous, and direct contact condensation. For film surface condensation, it notes there are three regions - laminar, wavy, and turbulent - depending on the Reynolds number of the liquid film. It reviews the derivation of the laminar film condensation equation first solved by Nusselt, and improvements made by Sparrow and Gregg and Chen to account for inertia effects and vapor drag. Finally, it presents Chen's developed relation for calculating the heat transfer coefficient in the wavy and turbulent film regions.
Rheology is the study of deformation and flow of matter. It involves measuring the viscosity and viscoelastic properties of materials under different conditions like temperature, pressure and shear rates. Various types of instruments called rheometers are used to measure rheological properties including rotational viscometers, capillary rheometers and other moving body viscometers. The document discusses different types of viscometers and rheometers used for measuring rheological properties of polymers and other materials.
ICOMASEF 2013: Influence of the shape on the roughness-induced transitionJean-Christophe Loiseau
- The document discusses how the shape of three-dimensional wall roughness elements can influence transition to turbulence in a boundary layer.
- Direct numerical simulations and stability analyses are used to compare the effects of a cylinder and bump shaped roughness element. The bump induces transition at a higher Reynolds number than the cylinder.
- For both shapes, the most unstable modes are localized over downstream low-speed streaks and extract energy from spanwise shear, resembling localized streak instabilities. However, the bump produces weaker, more localized streaks, resulting in an isolated unstable mode rather than a branch.
This document discusses fluid mechanics and heat transfer concepts related to forced convection. It covers boundary layer development over flat plates, including definitions of boundary layer thickness and wall shear stress. It discusses the governing equations for laminar boundary layer flow and provides the exact solution known as the Blasius solution. It also discusses heat transfer coefficients, turbulent boundary layers, and forced convection over external bodies like cylinders. For internal flows like pipe flow, it covers thermal entrance regions and definitions of mean temperature used in the energy balance.
This document discusses the journey from surfactants to foam. It begins by defining liquid foams and describing their structure. Surfactants are introduced and how they lower the surface tension of water and impart surface elasticity. Thin liquid films stabilized by surfactants are described along with techniques to study them. The processes that govern foam stability and decay are outlined. Methods to characterize foams including their generation, liquid content, bubble size, and stability over time are presented. Key relationships between foam properties, structure, and formulation are highlighted. Examples of foams in art and architecture are shown. References for further reading on the physics and science of foams are listed.
This document provides an overview of important concepts in computational fluid dynamics (CFD) including flow fields, post-processing techniques, and key variables such as pressure, velocity, shear, vorticity, temperature, and turbulence properties. It discusses how to visualize translation, deformation, and rotation of fluid elements using methods like vectors, streamlines, pathlines, and vorticity contours. Examples of CFD simulations of flow over objects like a football and cylinder are presented.
How to Manage Shipping Connectors & Shipping Methods in Odoo 17Celine George
Odoo 17 ERP system enables management and storage of various delivery methods for different customers. Timely, undamaged delivery at fair shipping rates leaves a positive impression on clients.
How to Manage Line Discount in Odoo 17 POSCeline George
This slide will cover the management of line discounts in Odoo 17 POS. Using the Line discount approach, we can apply discount for individual product lines.
View Inheritance in Odoo 17 - Odoo 17 SlidesCeline George
Odoo is a customizable ERP software. In odoo we can do different customizations on functionalities or appearance. There are different view types in odoo like form, tree, kanban and search. It is also possible to change an existing view in odoo; it is called view inheritance. This slide will show how to inherit an existing view in Odoo 17.
Postal Advocate manages the mailing and shipping spends for some of the largest organizations in North America. At this session, we discussed the USPS® July 2024 rate change. Postal Advocate shared all the important information you need to know for this coming rate change that goes into effect on Sunday, July 14, 2024.
We Covered:
-What rates are changing
-How this impacts you
-What you need to do
-Savings tips
This presentation was provided by Shaina Lange of Kidney News, and Dianndra Roberts of the Royal College of Psychiatrists (RCPsych), for the fifth session of NISO's 2024 Training Series "DEIA in the Scholarly Landscape." Session Five: 'DEIA in Peer Review,' was held July 11, 2024.
Benchmarking Sustainability: Neurosciences and AI Tech Research in Macau - Ke...Alvaro Barbosa
In this talk we will review recent research work carried out at the University of Saint Joseph and its partners in Macao. The focus of this research is in application of Artificial Intelligence and neuro sensing technology in the development of new ways to engage with brands and consumers from a business and design perspective. In addition we will review how these technologies impact resilience and how the University benchmarks these results against global standards in Sustainable Development.
Odoo 17 Events - Attendees List ScanningCeline George
Use the attendee list QR codes to register attendees quickly. Each attendee will have a QR code, which we can easily scan to register for an event. You will get the attendee list from the “Attendees” menu under “Reporting” menu.
2. Agenda
Introduction to spin coating
Definition and brief history of spin coating
Uses of spin coating technology
Common spin coating defects
Physics of spin coating
Basic physics behind spin coating
The Spinning Disk Problem
Further work on spin coating in relation to my
honors college thesis
3. What is Spin Coating?
A process in which solution is spread
evenly over a surface using centripetal
force.
Spin coating will result in a relatively
uniform thin film of a specific thickness.
Spin coating is an important way of
creating thin films in the microelectronics
industry.
4. Brief History of Spin Coating
Spin coating was first used to apply coatings
of paint and pitch around seventy years ago.
In 1958 Emslie et. al. developed the first spin
coating model.
This model has been used as a basis for
future more specific or complicated models.
Lawrence and Zhou: “Spin Coating of Non-Newtonian Fluids”
5. Spin Coater Schematic
Lid
Wafer is held to chuck
with vacuum pump.
Lid is placed over
Wafer Basin spinning basin before
spin is initiated.
Vacuum
Chuck
6. Basic Physics of Spin Coating
• Centripetal force is responsible for the spread
of liquid across the wafer.
• At long times the fluid will flow only negligibly,
resulting in a lower limit of the final thickness.
7. Industrial Uses of Spin Coating
Photoresist for patterning wafers in microcircuit
production.
Insulating layers for microcircuit fabrication such as
polymers.
Flat screen display coatings.
Antireflection coatings and
conductive oxide.
DVD and CD ROM
Television tube
antireflection coatings.
8. Common Spin Coating Defects
•Bubbles on the surface of the
coated wafer.
•This occursiswhen fluid is deposited
as the wafer spinning, and may be
caused by a faulty dispense tip.
•A swirling pattern may be
observed.
•Causes: deposited off center
•Fluid
•Acceleration shorthigh
too
•Spin timerate too high
to
•Exhaust http://www.cise.columbia.edu/clean/process/spintheory.pdf
9. Common Spin Coating Defects
•A mark or circle in the center of the
wafer could indicate a chuck mark.
•If a chuck markchanged. type of
chuck should be
occurs the
•Streaks can occurincluding: for a
number of reasons
on the wafer
•Acceleration toooff center
high
•Fluid deposited prior to spin
•Particles on surface
http://www.cise.columbia.edu/clean/process/spintheory.pdf
10. Common Spin Coating Defects
•Uncoated areas is deposited on the
when to little fluid
on wafer occur
wafer.
•Pinholebubbles can be caused by:
defects
•Air in fluid
•Particles on substrate.
•Particles
http://www.cise.columbia.edu/clean/process/spintheory.pdf
11. Agenda
Introduction to spin coating
Definition and brief history of spin coating
Uses of spin coating technology
Common spin coating defects
Physics of spin coating
Basic physics behind spin coating
Derivations of common spin coating models
Further work on spin coating in relation to my
honors college thesis
12. Spin Coating Process
Four main processing steps:
Step 1: Deposit fluid onto
substrate.
Step 2: Accelerate wafer to
final radial velocity.
http://www.mse.arizona.edu/faculty/birnie/Coatings/
13. Spin Coating Process
Four main processing steps:
Step 3: The coating thins at a
rate that depends on the
velocity at which the wafer is
spinning and the viscosity of
the fluid.
Step 4: Solvent is evaporated
from the film, resulting in
further thinning.
http://www.mse.arizona.edu/faculty/birnie/Coatings/
14. The Spinning Disk Problem
Problem:
Consider unsteady behavior of liquid film
thickness under centripetal force.
Goal:
Develop relationship between film thickness and
time.
Middleman, Introduction to Fluid Dynamics
15. The Spinning Disk Problem
Assumptions
∂uθ
Axisymmetric flow of fluid across the wafer =0
Laminar flow of the thinning film
∂θ
Film thickness decreases slowly with time
Angular velocity of fluid is equivalent to the angular
velocity of the disk
Film is thin and has uniform thickness over the wafer
Newtonian and incompressible fluid
Liquid is not volatile
Middleman, Introduction to Fluid Dynamics
16. The Spinning Disk Problem
Continuity Equation:
1 ∂ (ru r ) ∂u z 1 ∂ (ru r )
0= + ≈
r ∂r ∂z r ∂r
Momentum Equation:
∂ur uθ2 ∂p ∂ 2u r
ρu r −ρ =− +µ 2
∂r r ∂r ∂z
ρrω 2
∂ur ∂ 2u r
ρur − ρrω 2 = µ 2
∂r ∂z
Middleman, Introduction to Fluid Dynamics
17. The Spinning Disk Problem
By assuming the nonlinear term in the momentum
equation is small compared to other terms we are able
to solve the resulting equation:
∂ ur 2
− ρrω = µ 2
2
∂z
Boundary Conditions:
dur
= 0 at z = h(r )
dz
ur = 0 at z = 0
Middleman, Introduction to Fluid Dynamics
18. The Spinning Disk Problem
We can now say that the volumetric flow, Q, across the
edge of the spinning disk is equal to the rate change
of the solution volume on disk:
HR dH
Q = 2πr ∫ ur ( z , R )dz = −πR 2
0 dt
d H 2πρω 2 R 2 3
− πR 2 = H R ; Initial Condition H = H R = H 0
dt 3µ
dH 2πρω 2 R 2 3
− πR 2 = H
dt 3µ
Middleman, Introduction to Fluid Dynamics
19. The Spinning Disk Problem
Integrating the previous equation we obtain an expression for film
thickness, H, in terms of time, t :
1 1 4 ρω 2
− 2 = t
H2 H0 3µ
−1
H (t ) 4 ρω H 2 2 2
∴ = 1 +
t
0
H0 3µ
Middleman, Introduction to Fluid Dynamics
20. Model Limitations
−1
This model is limited by the
H (t ) 4 ρω H 2 2 2
assumptions used to derive ∴ = 1 +
t
0
equations so it only applies to: H0 3µ
Newtonian and non-volatile liquids
Uniform substrates
Development of more general models is significantly
more difficult
When developing a model for non-Newtonian flow it must
be considered that the viscosity changes with shear
force.
21. Agenda
Introduction to spin coating
Definition and brief history of spin coating
Uses of spin coating technology
Common spin coating defects
Physics of spin coating
Basic physics behind spin coating
Derivations of common spin coating models
Further work on spin coating in relation to my
honors college thesis
22. Honors College Thesis Topic
Model flow of spin coated Newtonian fluid using
FEMLab, a finite element modeling program.
Extend the FEMLab model to flow of non-Newtonian
and viscoelastic fluids on spin coated wafer.
Verify experimentally that the model is valid by spin
coating fluids with relevant properties on 6 in silicon
wafers and comparing the resultant film thickness
with the predicted film thickness.
23. References
Lawrence, C.J, Zhou, W. “Spin coating of non-Newtonian Fluids”.
Journal of Non-Newtonian Fluid Mechanics, 39 (1991) 137-187
Middleman, S. An Introduction To Fluid Dynamics. John Wiley and
Sons. New York. 1998
http://www.cise.columbia.edu/clean/process/spintheory.pdf
http://www.mse.arizona.edu/faculty/birnie/Coatings
Good afternoon. Introduction More specifically I will introduce you all to spin coating and then discuss the derivation of an equation modeling the retention of liquid on a spinning disk.
I’ll begin with an introduction to spin coating: What is spin coating? Why is it important and where is it used? And because of the importance of uniform and defect free films in industries in which spin coating is used I will discuss some common spin coating defects. Then I will discuss: Physics of spin coating and the “Spinning Disk Problem” Finally I will introduce you all to what I will be working on for my honors college thesis and show how it relates to the presentation I have given today.
Spin coating is a process in which a liquid is spread over a flat uniform surface through centripetal forces. As the surface continues to spin the film gets more and more thin and approaches an asymptotically thin height. The result of spin coating is a uniform thin film on the surface of the wafer. In the case of an oil or lubricant the film will remain liquid. If the deposited material is a polymer in solvent, the solvent will evaporate, leaving a solid film on the substrate.
This is a general schematic of a spin coater. A spin coater has a chuck on which a wafer is held by vacuum. The chuck spins causing the centripetal force which creates the thin film. The excess solution is thrown off the wafer into the basin. A lid is place on top of the spin coater to prevent splashing of solution and as a safety consideration in case the vacuum fails. The lid in the spin coater located in Gleeson has a hole in the center which allows for dynamic addition of the solution to the wafer.
A liquid of an assumed initial thickness H 0 is placed on the wafer. As the wafer begins to spin centripetal forces cause the liquid is spread out and then become thin on the wafer as demonstrated by this animation. If the substrate is spun indefinitely then eventually the rate of thinning will become negligible and a final thin film will be created.
Spin coating is used in a number of industries where it is necessary to create thin films. Spin coating processes are used in the microelectronics industry to coat wafers with photoresist which allow already existing layers on the wafer to be selectively etched. Spin coating is also used to apply thin layers of polymers to wafers for various steps through out the manufacture of processed wafers. Spin coating is also used to apply coatings to DVD and CD ROMs as well as Displays and television tubes.
It is important in the microelectronics industry that each layer be uniform and defect free. So I will discuss some defects that can occur in spin coating and possible causes of those defects. The first defect we will discuss is bubbles observed on the coating surface. Bubbles will disrupt the uniformity over the surface of the wafer. They may be caused by a faulty dispenser during dynamic deposition of coating solution. A swirling pattern may occur if the angular acceleration is too high, if the spin time is not long enough or if the fluid is deposited off center. It can also be caused by too great of a solvent exhaust rate.
When my group did spin coating we had both of these problems when spin coating our unknown.
Moving on to a more in depth explanation of the spin coating process and derivation of a simple model used to relate film thickness to time for spin coating of Newtonian fluids.
The spin coating process can be discussed in three stages. We will consider the process in which the fluid is deposited prior to the wafer spinning. The first step is to apply a known amount of solution to the wafer. The substrate then begins to spin and accelerates until it reaches its final spinning velocity. During spin up, a large amount of excess solution is removed from the wafer.
The third step in the spin coating process is to continue spinning the wafer at constant velocity. During this time centripetal forces will result in gradual thinning of the fluids. At some point the liquid will flow negligible and then the primary film thinning mechanism is evaporation of the solvent from the film. Once the solvent has evaporated a solid thin film will remain.
We will consider the problem of fluid retention on a spinning disk and construct a relationship between time and film thickness under a set of simplifying assumptions.
The continuity equation can be simplified by considering that the flow is radial with negligible flow in the z direction. Where r is radius, and u is velocity. The momentum equation can be simplified using the assumption that the angular velocity of the fluid is equal to the angular velocity of the disk we can say that velocity is equal to radius multiplied by the angular velocity of the disk. Substituting we arrive at this equation further simplified.
If we assume that the nonlinear term in the momentum equation is small compared to the other terms. We arrive at this simplified momentum equation. By applying the following boundary conditions that There is no shear stress on the free surface And there is no radial velocity at the center of the wafer We can write an equation relating the amount of solution on the wafer to the amount of solution leaving the wafer.
We can say now that Q, the volumetric flow over the edge of the substrate, is equal to the change in volume on the substrate. By integrating and applying the assumption that the film height is always uniform across the wafer we are able to solve for film height in terms of time.
For the given assumptions we can say that the ratio of final height to the initial height is related to the density and viscosity of the fluid, the angular velocity of the spinning disk, the initial height of the film and the amount of time the fluid is spun.