1) Micromachining involves fabrication of micro-components sized 1-500 micrometers. Common processes include etching, LIGA, EDM, and various types of lithography. 2) Etching can be isotropic or anisotropic, wet or dry. Bulk micromachining uses anisotropic etching of silicon while surface micromachining layers materials like polysilicon. 3) LIGA uses X-ray lithography combined with electroforming or molding to create high aspect ratio microstructures. EDM can machine any conductive material including complex 3D shapes.

1. VISVESVARAYA NATIONAL INSTITUTE OF TECHNOLOGY
NAGPUR
DEPARTMENT OF MECHANICAL ENGINEERING
SEMINAR ON
“ ”
GUIDED BY:
PROF. Y. M. PURI
CAD/CAD ENGG.
PREPARED BY:
BHUPESH D. SARODE
CAD/CAM ENGG.
FIRST SEM
2012-13

2. Scope Of Presentation
What is Micromachining
Types of Machines in Micromachining
Various Micro Machines
Etching Process,
Bulk Micromachining,
Surface Micromachining,
LIGA Process
EDM
Application

3. MICRO-MACHINING
• Micromachining is the basic technology
for fabrication of micro-components of
size in the range of 1 to 500 micrometers

4. TYPES OF MACHINE IN MICROMACHINING
Tool based
Solid Tool Image ToolIsotropic
Process
Micromachining
Mask based
Anisotropic
Process
 Wet etching
 Ion beam
machining
 LIGA
 Laser beam
machining
 Laser beam
 Electron beam
 Ion beam
 Excimer laser
 Wet etching
 Plasma etching
 Electroforming
 Cutting
 Grinding
 Milling
 EDM
 ECM
 Punching
 Pressing
 Injection

5. Micro-Machining Processes
5
Micro-Machining
ETCHING
Bulk
Micro-
Machining
Surface
Micro-
Machining
LIGA EDM

6. ETCHING PROCESS
Etching process consists of three steps:
 Mass transport of reactants (through a boundary layer)
to the surface to be etched
 Reaction between reactants and the film(s) to be
etched at the surface
 Mass transport of reaction products from the surface
through the boundary layer

7. ETCHING PROCESS
• Isotropic vs. Anisotropic
• Isotropic– etch rate is same in all directions
• Anisotropic– etch rate is orientation dependent
• Dry vs. Wet
• Dry– uses gas-phase process
• Wet– uses liquid-phase process

8. WET ETCHING PROCESS
DESCRIPTION
The wet etching process involves :
 Performed in an immersion tank
 Wafers in wafer carrier are lowered into etchant solution
 Wafers remain in solution for specified amount of time
.referred to as etch duration
 Wafer carrier is removed from solution
 Wafers are rinsed in deionized water
 Wafers are dried

9. BULK MICROMACHINING
• Process for producing 3D MEMS
structures –older process
• Uses anisotropic etching of single crystal
silicon
Example: silicon cantilever beam for
atomic force microscope

10. Dopant Diffusion
Masking
Anisotropic Etching
BULK MICROMACHINING

11. • Newer process for producing MEMS structures
• Uses etching techniques to pattern micro-
scale structures from polycrystalline (poly)
silicon, or metal alloys
• Examples: accelerometers, pressure sensors,
micro gears and transmissions,micro mirrors
etc.
SURFACE MICROMACHINING

12. SURFACE MICROMACHINING
(a) DEPOSITION OF
POLYSILICON;
(b)ETCHING OF
POLYSILICON;
(c) SELECTIVE WET
ETCHING OF PSG,
LEAVING THE
SILICON
SUBSTRATE AND
DEPOSITED
POLYSILICON
UNAFFECTED

13. GERMANACRONYM
LITHOGRAPHIE -----------------LITHOGRAPHY
GALVANOFORMUNG -------------- ELECTROFORMING
ABFORMNG -----------------------------MOLDING
LIGA

14. LIGA
X-ray Irradiation
Resist Development
Electroforming
Resist Removal

15. VIDEO ON LIGA

16. workpiece +anode
-cathode
(a) Tool and workpiece immersed in
dielectric liquid.
(b) A spark is generated between tool and
workpiece.
(c) The high temperature causes the melting
and vaporization of electrodes.
(d) At the end of the pulse, the molten
material is ejected from surface, leaving a
shallow crater.
electrode
Material Removal Mechanism of EDM

17. Micro EDM Equipment

18. VIDEO ON EDM

19. 1. Machine any conductive materials.
2. Single or medium size production.
3. Slots and Arbitrary 3D micro molds.
Capabilities of Micro EDM

20. MICRO-LATHE

22. MICRO-FACTORY

23. APPLICATIONS
 IC Packages with Micro Devices like computer
processors
 Fuel Injection Nozzle for Automobiles
 Biotechnology for micro-needles, drug delivery
systems
 Medical Applications for tablet camera
 Multifunctional Compact Devices like mobile, data
storage device,
 Micro sensors, actuators, etc

24. THANK YOU