Prototype Showcase  What is a metamaterial?  How our 2-D sample was created  How our phase mask was created  SEM images of 2-D sample and phase mask

Metamaterials A periodic material that has photonic or phononic properties. *Taken From handout & Physics Worlds 2005 “Sound Ideas”

Deliverables  3-D periodic structure with micro- scale periodicity  Macro-scale representations of the structures

Prototype Design 2-D structure  phase mask  3-D structure 2-D structure: 2 microns thick, 5 microns thick, 15 microns thick Variable spacing 3-D structure: Very thick (~50 microns) Variable spacing

Contact Lithography Coat Exposure Develop plain Si wafer coat with HMDS to make Si wafer hydrophobic coat with SU photoresist using spin coater soft to evaporate solvent and cut into pieces UV exposure for either 15, 20, 25, or 30 seconds flip 90° and expose again post bake at first 65° then 95° to promote crosslink formation submerge in PM acetate to dissolve unexposed photoresist (20 min ） submerge in isopropanol to wash away all remnants—final structure

Phase mask Step 1 Step 2 Step 3 Vacuum sample with open bottle of fluorosilane so that it evaporates onto sample. Layer with PDMS and heat at 65°to 75°for at least three hours. Gently peel off PDMS layer as phase mask.

Fabrication and Processing SU : 15 seconds, 20 seconds, 25 seconds SU : 25 seconds, 30 seconds, 35 seconds, 40 seconds SU : 15 seconds, 20 seconds, 25 seconds, 30 seconds, 35 seconds, 40 seconds, 45 seconds Type of Photoresist

Prototype Functionality Thick Film Photoresist Sin (70) = 58 / t Calculation: Thickness (t) ~ 61 microns Success!

Prototype Functionality 2-D Patterns Top-down view: Hole Spacing ~ 3.38 um Hole Length ~ 1.56 um Hole Height ~ 1.54 um Cross-section view: Width of top ~ 1.81 um Width of bottom ~ 1.00 um Height ~ um

Prototype Functionality Problems in 2-D patterns 1.Over exposure 2.Un-washed monomer 3.Non-uniform columns Width of top ~ 1.81 um Width of bottom ~ 1.00 um

Prototype Functionality Phase mask

? 2-D Pattern Phase Mask3-D Pattern CAD Model 3-D Printing Model Actual Sample

Questions?