Slidw vật liệu nano và màng mỏng nontraditional microfabrication techniques

.c om cu u du o ng th an co ng Nontraditional Microfabrication Techniques CuuDuongThanCong.com https://fb.com/tailieudientucntt th an co ng • Electric discharge machining • Precision mechanical machining • Thermomigration • Photosensitive glass • Focused ion beam • SCREAM cu u du o ng • Template replication • Sealed cavity formation • Surface modification • Printing • Stereolithography (3-D) • Sharp tip formation • Chemical-mechanical polishing c om Other Micromachining Techniques CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om Sealed Cavity Formation ng • Form structure using sacrificial material and cu u du o ng th an co small access holes • Cover holes using one of three methods – Simple application of glues, plastics, photoresist, etc – Thin-film application such as sputtered, evaporated, and CVD films – Reactive sealing, i.e thermal oxidation, etc • Gettering- collect gases in cavity CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om Surface Modification cu u du o ng th an co ng • Used to change surface properties, especially in biomedical applications • HMDS used to “methylate” surface and remove hydroxyl groups • Self-assembled monolayers (SAMs) formed using RSiCl3 (R is alkyl group) • Often used to reduce wear and adhesion forces • Apply dendrimers (hyper-branched polymers) for molecule recognition CuuDuongThanCong.com https://fb.com/tailieudientucntt Printing cu u du o ng th an co ng c om • Useful for non-planar substrates • Very low-cost • Screen printing – Resolution limit of about 100 mm – Alignment more difficult – Great for patterning polymer layers in biosensors – One step process – Requires liquid form • Transfer printing – Raised bumps used to transfer ink, etc • Powder loaded polymers – Material properties dependent on material in plastic liquid that can be rolled on and patterned • Ink jet CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om Micromechanical Machining An Option to Lithography cu u du o ng th an co ng • Can produce extremely smooth, precise, highresolution structures • Expensive, non-parallel, but handles much larger substrates • Precision cutting on lathes produces miniature screws, etc with 12 mm accuracy • Chip Processes – diamond machining, tools ~100 mm thermal surfaces, fluid microchannels – microdrilling, tools > 25 mm manifolds, fiber optics, molds – micromilling, tools ~22 mm, features < mm molds, masks, thermal surfaces CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om Micromechanical Machining An Option to Lithography cu u du o ng th an co ng • Energy Processes – microEDM, tools > 10 :m microturbines, toolselectrodes, stators – focused ion beam (FIB), atomic-scale machining, micromilling tools, probes, etc – laser, micron-scale spot ablate hard materials, polymerization CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om Micromechanical Machining Characteristics cu u du o ng th an co ng • Relative tolerances are more typically 1/10 to 1/1000 of feature or part dimensions • Absolute tolerances are typically similar to those for conventional precision machining (micrometer to submicrometer) • Feature is often inaccessible by conventional metrology techniques (high aspect ratio boolean negative features) • Like conventional machining, in-process, on-line metrology is preferred over post-process or off-line metrology CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om General Micromachining Metrology cu u du o ng th an co ng • Tool location – Endmills mm x mm – 22 mm x mm – Drills 25 mm x mm – Diamond 100 mm x mm • Part/fixture location for multiple processes in multiple machines • Post processing of lithographic molds • Post processing of electroplated structures CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om Complementary Processes (Direct Removal Processes) cu u du o ng th an co ng • Chip making (force processes) – Diamond machining – Microdrilling – Micromilling – Grinding and polishing – Microsawing • Energy beam (forceless processes) – Focused ion beam – Micro electrical discharge – Laser ablative and photo polymerization CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om Examples of UV-LIGA processed SU-8 Tilted SU-8 exposure ng 20 m UV light cu u du o ng th an co 110 m CuuDuongThanCong.com 31.6o https://fb.com/tailieudientucntt Molding • Molding co ng c om – Low cost massive production of precise plastic parts using LIGA or UV-LIGAprocessed metallic mold inserts th cu u du o ng – Molten plastic is injected onto a metallic mold insert – Heated above glass transition temperature (Tg) of the plastic – Polymers an • Injection molding • PE, PP, PC, PMMA, COC, or biodegradable polymers (e.g RESOMER®) CuuDuongThanCong.com https://fb.com/tailieudientucntt Injection molding system LSU du o ng th an co ng c om Source: www.osha.gov cu u Injection molded plastic toys www.toysrgus.com CuuDuongThanCong.com https://fb.com/tailieudientucntt PDMS molding process – Microelectronics compatible silicone elastomer, durable, optically transparent, and inexpensive 10:1 pre-polymer and curing agent Metallic mold insert Substrate ng • Process c om • PDMS (polydimethyl siloxane) co – A mixture of PDMS pre-polymer and a curing agent cast or spin-coated onto master molds – Cured at 100 C for ~1 hour (65 C for hours) – Replicated PDMS peeled off from master molds • Advantages du o ng th an Desiccator cu u – No need of expensive equipment such as injection molding and hot embossing machines for polymer replication – Low temperature processing for curing PDMS (65 C) Removal of air bubbles Vacuum Pump CuuDuongThanCong.com Replicated PDMS HARMs after curing https://fb.com/tailieudientucntt ng PDMS Casting Attachment of PDMS to Si co Ni or SU-8 Mold Replicated PDMS Mold c om PDMS replication and pattern transfer process Electroplated Ni & PDMS removal th an Application : massive replication of precision PDMS microstructures, pattern transfer of MEMS components on circuit 20 m m 300 m 300 m cu u du o 300 m ng 20 m 300 m 20 m Ni mold 20 m 300 m Replicated PDMS CuuDuongThanCong.com https://fb.com/tailieudientucntt Hot embossing • Hot embossing cu u du o ng th an co ng c om – Plastic is heated above Tg and a mold insert is pressed into the plastic CuuDuongThanCong.com https://fb.com/tailieudientucntt th cu u du o ng Stamping picture an co ng c om Micro contact printing (μCP) Source: http://www.zurich.ibm.com/st/microcontact/highres/mucp.html CuuDuongThanCong.com https://fb.com/tailieudientucntt Stereolithography (SL) • Stereolithography c om – Repeatedly print layers that become part of a final microstructures – Freeform 3D structures made of polymers • Optical energy is focused and locally hardens a photopolymer cu u du o ng th an co ng – Rapid prototyping – Low cost – No integration w/ electronics CuuDuongThanCong.com https://fb.com/tailieudientucntt cu u du o ng th an co ng c om Micro SL examples CuuDuongThanCong.com Source: http://dmtwww.epfl.ch/ims/micsys/ https://fb.com/tailieudientucntt Miscellaneous micromachining techniques c om • EDM (Electro-discharge machining) – Also called spark machining co an du o ng th – Used for unusual designs in hard, brittle metals ng • Metal is locally removed by high frequency electrical sparks Source: http://www.eng.nus.edu.sg/ EResnews/0601/sf/sf_4.html u • LCVD (Laser-assisted chemical vapor deposition) cu – Energy needed for deposition is provided by photons – Complex 3D structures rice • Adjusting the focal point of the laser continuously CuuDuongThanCong.com A 7-mm car fabricated by precision machining https://fb.com/tailieudientucntt .c om cu u du o ng th an co ng Packaging Technology CuuDuongThanCong.com https://fb.com/tailieudientucntt ng cu u du o ng th an co • Wafer bonding • Plasma bonding • Anodic bonding • Adhesive bonding c om Bonding techniques CuuDuongThanCong.com https://fb.com/tailieudientucntt Wafer bonding co ng A technique to create cavities or channels Joint wafers together to provide hermetic sealing Bond similar or dissimilar substrates permanently Various bonding techniques are used u du o ng th an • Anodic bonding, fusion bonding, eutectic bonding, glass frit bonding, … cu – – – – c om • Wafer bonding technique CuuDuongThanCong.com https://fb.com/tailieudientucntt IC vs MEMS packaging ng co du o ng – MEMS devices are mostly freestanding and moveable – Non-standardized process an • MEMS packaging th – ICs are 2D planar devices and immoveable – Standardized process – Well established mass production technology – 1/3 ~2/3 of the total manufacturing cost c om • IC packaging cu u • Packaging requirement different from one MEMS device to another – Easily takes up 2/3 or more of the manufacturing cost for initial commercialization CuuDuongThanCong.com https://fb.com/tailieudientucntt cu u du o ng th an co ng c om TI DLP packaging process CuuDuongThanCong.com https://fb.com/tailieudientucntt ... https://fb.com/tailieudientucntt .c om ng cu u du o ng th an co Microfabrication Using Polymers CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om Polymers for Microfabrication cu u du o ng th an co ng •... machining (micrometer to submicrometer) • Feature is often inaccessible by conventional metrology techniques (high aspect ratio boolean negative features) • Like conventional machining, in-process,... Stereolithography (3-D) • Sharp tip formation • Chemical-mechanical polishing c om Other Micromachining Techniques CuuDuongThanCong.com https://fb.com/tailieudientucntt .c om Sealed Cavity Formation ng