No Slide TitleMEMS Specific Fabrication
An overview of the primary MEMS fabrication technologies being used
in research & development, followed by product
manufacturing
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Metals - Copper, Nickel, Gold
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Low Temperature - Incomplete Mold Filling
Injection Speed
Slower Speeds
Mold Release Agent (PAT 665) - Does not Adhere to Mold
Low Concentration - Deformation and Breaking
High Concentration - Impurities
Fluorinated Polymers (PVDF)
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Alternative to photolithography for patterning materials
Developed at Harvard’s Whitesides Laboratory by Dr. Younan Xia (now
of University of Washington) and Dr. George M. Whitesides in
1998
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Photolithography limited to photoresists
Can create 3D structures
Adapted for rapid prototyping
Prepared by cast molding
Photolithography
Micromachining
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Advantages
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Polymers in MEMS
Actuators for MEMS – i.e. micro pumps
Bio-compatible
Photopolymer hardens with UV light
Fabricate polymer or metal structures
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MEMS Design & Fab
Methods – IH process
Thin layers of harden polymer are stacked from bottom to top
For metal structures use the a polymer structure as cast and
electroplate with metal
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5 µm
Position accuracy
Min unit size of harden polymer
5 x 5 x 3 µm (X,Y,Z)
Max size of fabrication structure
10 x 10 x 10 mm
Fabrication speed
(a) conventional micro stereo lithography needs base layer
(b) new super IH process needs no base
Sub-Micron Stereo Lithography
New Micro Stereo Lithography for Freely Movable 3D Micro
Structure
-Super IH Process with Submicron Resolution-
Koji Ikuta, Shoji Maruo, and Syunsuke Kojima
Department of Micro System Engineering, school of Engineering,
Nagoya University
Furocho, Chikusa-ku, Nagonya 464-01, Japan
Tel: +81 52 789 5024, Fax: +81 52 789 5027 E-mail:
[email protected]
Schematic diagram of IH Process
Schematic diagram of the super IH process
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Liquid UV polymer solidified only at the focus
Laser beam focused inside polymer
Parallel processing using fine optical fiber arrays
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Viscosity of liquid UV polymer increases
Deformation and destruction can occur
Adhesive force between base and hardened polymer
Use of release technique is necessary
Need very accurate positioning in XYZ directions
Super IH process - solution for “Scale Effect”
Resolution 1 mm in 3D space (IH process: 5mm)
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New Micro Stereo Lithography for Freely Movable 3D Micro
Structure
-Super IH Process with Submicron Resolution-
Koji Ikuta, Shoji Maruo, and Syunsuke Kojima
Department of Micro System Engineering, school of Engineering,
Nagoya University
Furocho, Chikusa-ku, Nagonya 464-01, Japan
Tel: +81 52 789 5024, Fax: +81 52 789 5027 E-mail:
[email protected]
Fig. 10 Micro gear and shaft make of solidified polymer
(b) side view of the gear of four teeth
(d) side view of the gear of eight teeth
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MEMS Design & Fab
SEM image of an object made of three imbricated springs. This
structure consists of 1000 layers of 5mm each, built along the axis
direction.
WEM photograph of a micro-turbine made by
microstereolithography.
Combining Microstereolithography and
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Swiss Federal Institute of Technology (EPFL)
DMT – IMS, CH – 1015 Lausanne, Switzerland
Tel: +41 21 693 6606 Fax: +41 693 6670
E-mail:
[email protected]
Fig. 11 Plastic injected watch gear, total height: 1.4 mm.
Fig. 15 Two level SU-8 structure with an added axle.
Combining Microstereolithography and
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Material ejected by interaction of laser pulses on material
Pulsed gas lasers producing UV radiation in range of 351nm – 193
nm
2 Types of Ablation
Electronic: dissociation of bonds/electron-hole pairs
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Aspect ratio: 2:1
RMS deviation: +/-5%
Throughput efficiency: ~70%
Good resolution, flexibility and selectivity
Clean process, minimal collateral damage
Absence of non-toxic chemicals
Good control over process
Needs manufacture of masks
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