![Lithography for fabricating microfluidic devices
• Lithography (from Ancient Greek , lithos meaning 'stone', and , graphein
meaning 'to write')is a method of printing originally based on the immiscibility
of oil and water.
• The printing is from a stone (lithographic limestone) or a metal plate with a
smooth surface.
• It was invented in 1796 by German author and actor Alois Senefelder as a cheap
method of publishing theatrical works.[3][4] Lithography can be used to print
text or artwork onto paper or other suitable material.](https://image.slidesharecdn.com/microfluidics-190505082029/85/nano-material-and-its-applications-7-320.jpg)
nano material and its applications
- 2. What is Microfluidics? • It is the science and technology of systems that process or manipulate small (10–9 to 10–18 litres) amounts of fluids, using channels with dimensions of tens to hundreds of micrometres Microfluidics in nature: Lung alveoli
- 3. • A method of introducing reagents and samples (as fluids) • Methods for moving these fluids around on the chip, and for combining and mixing them A Microfluidic System
- 4. Motivation for miniaturization • Micro scale = laminar flow • Laminar flow allows controlled mixing • Low thermal mass • Efficient mass transport (speedy diffusion) • Good (large) ratio of channel surface area: channel volume • Single cell and molecule manipulations • Protection against contamination and evaporation • Kinetics easy to study
- 5. Benefits of size reduction 1. Decreased reagent consumption 2. Small economic footprint 3. Rapid heat transfer and catalysis 4. Fast diffusive mixing 5. Automation and integration
- 6. Origin of Microfluidics FOUR PARENTS Molecular Analysis BiodefenceMolecular Biology Microelectronics Lithography
- 7. Lithography for fabricating microfluidic devices • Lithography (from Ancient Greek , lithos meaning 'stone', and , graphein meaning 'to write')is a method of printing originally based on the immiscibility of oil and water. • The printing is from a stone (lithographic limestone) or a metal plate with a smooth surface. • It was invented in 1796 by German author and actor Alois Senefelder as a cheap method of publishing theatrical works.[3][4] Lithography can be used to print text or artwork onto paper or other suitable material.
- 8. Importance of Lithography 1. Low Cost Manufacturing 2. Ultra miniatured electronic devices Wafer with IC chips The manufacture of ICs requires several lithographic steps. This lithography is cost about 30 percent of the total cost of manufacturing of that IC. Lithography tends to be the technical limiter for further reduction in feature size reduction and thus transistor speed and silicon area.
- 9. Types of Lithography Photo E-beam or Ion beam X-Ray Interference Scanning Probe Step Growth Nano imprint Shadow Mask Self Assembly Nano Templates Optical UV EUV Voltage Pulse CVD Local Electro- deposition Dip Pen Diblock copolymer Alumina Membrane
- 10. Basic Techniques of Lithography Basic technique of Lithography Substrate Film Pattern the film Etching
- 11. Photolithography • Light is used to transfer the geometric pattern from a photo mask to a light sensitive chemical, which is called the photo resist or just a resist, on the substrate. Substrate Deposited Film Film Deposition Substrate Substrate Deposited Film Deposited Film Substrate Deposited Film Substrate Substrate Photoresist Application Exposure DevelopmentEtchingResist Removal Mask
- 12. Basic Photolithography Processes a) Surface Preparation b) Photoresist Application c) Soft Bake d) Align and Expose e) Develop f) Hard Bake g) Inspection h) Etch i) Resist Strip j) Final Inspection
- 13. Common Factors for Photolithography a) Type of Resists b) Thickness of Resists c) Mask Alignment d) Wafer surface e) Resist Adhesion f) Exposure Energy g) Temperature h) Development Time
- 14. Photoresists Components: • Resin : It is a material that is a binder for obtaining certain property. Certain chemo-mechanical property; certain strains, certain flexibility and certain chemical resistance for pattern transfer. • Sensitizer : A compound or chemical which becomes activated in the presence of light of the wavelength, which you are using. • Solvent : Control the properties for deposition, like the viscosity, the flow properties, etc. • Adhesion Promoter
- 15. Type of Resists Positive Resist Photolithography Negative Resist Photolithography Resulting pattern after the resist is developed. Positive Resist
- 16. Negative Resist
- 17. Optical Lithography Smaller features need smaller wavelengths of light. UV : 365 – 436 nm Deep UV (DUV) : 157 – 250 nm Extreme UV (EUV) : 11 – 14 nm X-Ray : <10 nm
Editor's Notes
- #5: Laminar Flow: the flow of a fluid when each particle of the fluid follows a smooth path, paths which never interfere with one another. One result of laminar flow is that the velocity of the fluid is constant at any point in the fluid. Turbulent Flow: irregular flow that is characterized by tiny whirlpool regions. The velocity of this fluid is definitely not constant at every point. :) Typical examples of both Laminar and Turbulent flows can be observed in the cigarette smoke