70 likes | 236 Views
Engr 1182 Nano Pre-Lab . Chip Lid Molding. Micro-fabrication. How can we produce devices on a very small scale ? E.g Device dimensions 10 nm – 400 µm Answer: Two ways Top – Down conventional manufacturing approaches at a reduced scale, such as CNC milling and photolithography
E N D
Engr1182 Nano Pre-Lab Chip Lid Molding Presentation Short Title
Micro-fabrication • How can we produce devices on a very small scale ? • E.g Device dimensions 10 nm – 400 µm • Answer: Two ways • Top – Down conventional manufacturing approaches at a reduced scale, such as CNC milling and photolithography • Bottom – Up controlling molecular-level interactions to create substances with the required properties Reference: Nick Ferrell P. 2 Presentation Short Title
Evolution of Top – DownMicro-fabrication • Originally developed by microelectronics silicon industry • Refined for nanoscale fabrication • Extended to polymer micro/nanofabrication • polymers are flexible and bio-compatible Presentation Short Title
Photolithography • Photolithography is a common micro-fabrication technique used to transfer an image from a photomask to the surface of a substrate by using ultraviolet light. • The components needed for Photolithography are light source, photomask, lens and wafer. Presentation Short Title
LOC fabrication • For this LOC project chips will be produced in a three step process. • First, each team creates a CAD file of their LOC design. • Second, acrylic wafers are milled with a CNC machine from the CAD design. • Third, we will mold plain lids (no pattern) to enclose the channels and wells of the acrylic wafer. Presentation Short Title
Molding • LOC wells and channels will be sealed with a flexible lid. • In order to mold our LOC lids, we mix PDMS (silicone rubber) resin with its hardener(catalyst) in a disposable cup by stirring rigorously. • This mixing creates a lot of bubbles and we need to get rid of those bubbles since we do not want any optical defects in our molds. Presentation Short Title
Degassing Liquids • We get rid of those bubbles by pulling a vacuum on solution. • Lower pressure expands bubbles by increasing the volume of the gas • Lower pressure reduces the solubility of air in the liquid thus causing bubbles to surface. • Cycling vacuum and atmospheric pressure creates a driving force to remove bubbles from the liquid phase and have a defect free mold. Presentation Short Title