manufacturing processes for engineering materials (5th edition in...
TRANSCRIPT
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Manufacturing Processes
Micro Fabrication
Associate Professor Su-Jin Kim
School of Mechanical Engineering
Gyeongsang National University
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
OCW
• CPU manufacturing: https://youtu.be/UvluuAIiA50
• MEMS: https://youtu.be/iPGpoUN29zk
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Index
• Micro fabrication of IC(Integrated Circuits) 반도체제조1. Weiper(웨이퍼)
2. Lithography(노광)
3. Etching(식각)
4. Doping(확산)
5. Deposition(증착)
6. Packaging(포장)
• MEMS(Microelectromechanical system) 미소기전
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Micro-manufacturing
• Manufacturing on a microscopic scale
• IC: Integrated circuit
• MEMS: micro electro mechanical system
• Products
1. Sensors
2. Inkjet printing heads
3. Micro-actuators
4. Hard-drive heads
5. Computer processors
6. Memory chips
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Transistor to IC
• Transistors(1947) IC (integrated circuits), MOS (metal-oxide-semiconductor) VLSI (very large-scale integration)
• Moore’s Law : The number of transistors per chip doubles every 18 months.
Transistor IC
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Clean Rooms
• Essential for the production of IC (integrated circuits).
• Cleanliness are defined by class of the clean rooms.
• Air is passed through a high-performance particulate air (HEPA) filter.
• Largest source of contaminants is people.
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
P
-
-
--
-
B
-
--
Si
-
-
--
Silicon (Semiconductors)
• Natural silicon dioxide SiO2 is an excellent insulator.
• Single crystal silicon Si is semiconductor.
• Get n-type by doping P or p-type doping B.
SiO2
Insulator Single crystal silicon n-type p-type
+phosphorus +boron
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Integrated Circuits; IC Process
Wafers
DepositionFilm deposition
Oxidation
LithographyCoat photoresist
Photolithography
Remove exposed photoresist
Etching
Doping
Wet etching
Dry etching
Diffusion
Ion implantation
DeviceWire bonding
Packaging
Ingot
Wafer
https://youtu.be/qm67wbB5GmI CPU Fab (10 min)
https://youtu.be/_8HwIHyVD1E Hynix Kr (5min)
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Ingot & Wafer
1. natural SiO2 purification electric-grade silicon Si
2. Single-crystal silicon ingot is grown from the purified silicon melt.
3. The Ingot is cut into silicon wafers. The wafers are polished until they have mirror-smooth surfaces.
Wafer: http://www.youtube.com/watch?v=LWfCqpJzJYM&feature=related
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Lithography 노광
1. Drop down photoresist on spinning wafer.
2. Photolithography : UV light passes through mask to wafer surface.
3. Exposed photoresist is dissolved by a solvent.
Photolithography: http://www.youtube.com/watch?v=9x3Lh1ZfggM&feature=related
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Etching 식각
1. The photoresist protects material not be etched away in an acid solution.
2. After the etching the photoresist is removed and the desired shape becomes visible.
scale: transistor level (~50-200nm)
IC Process: Photoresist, Lithography, Etching, Doping, Deposition
http://www.youtube.com/watch?v=26fkuAY8jKs&feature=related(4min)
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Doping 확산
1. The photoresist (blue) will protect material that should not get ions implanted.
2. In Ion implantation, ions accelerate through a high-voltage beam and impact on the exposed areas (green) of the silicon wafer.
3. After the ion implantation the photo resist is removed
4. Operation of microelectronic devices depends on different doping types and concentrations.
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Deposition 증착
1. Three holes have been etched into the insulation layer (magenta color) above the transistor.
2. The wafers are put into a copper sulphate solution. The copper ions are deposited onto the transistor thru a process called electroplating.
3. On the wafer surface the copper ions settle as a thin layer of copper.
4. The excess material is polished off. Three holes are filled with copper which will make up the connections to other transistors.
PVD: http://www.youtube.com/watch?v=dpwIswozTdw&feature=related (30s)
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Metallization & Testing
1. Metallization: Devices are interconnected by multiple metal layers (Al, Cu).
2. Testing: Test each of the individual circuits with probe
3. The wafer is cut into pieces called dies.
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Wire Bonding and Packaging 포장
1. Working dice is attached to a rugged foundation with epoxy or eutectic bond.
2. Chip is electrically connected to the package lead by thermo-sonic wire bonding.
3. Package: The green substrate, the die and the silver heat-spreader are put together to form a completed processor.
Packaging m. p.: http://www.youtube.com/watch?v=Cg-mvrG-K-E&feature=related
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Printed Circuit Boards; PCB
• Packaged integrated circuits are combined with other ICs as building blocks for a larger system.
• Printed circuit board (PCB) is the substrate for the final interconnections.
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
MEMS Devices
• The MEMS(Microelectromechanical systems) devices can be made through the IC Process:
• Bulk micromachining: Pressure sensor
• Surface micromachining: Accelerometer
http://www.youtube.com/watch?v=ZuE4oVrtEQY
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Bulk micromachining
• Mask pattern by SiO2 or Si3N4
• Etching silicon substrate
• Pressure sensor
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Surface micromachining
Micro-cantilever
1. Silicon substrate, Si
2. Deposit silicon nitride, Si3N4
3. Grow silicon oxide, SiO2
4. Pattern by Lithography
5. Deposit polysilicon
6. Remove SiO2 by Etching
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Accelerometer for airbags
• Acceleration Displacement of beam Capacitive change Turn on the airbag
© Pearson & GNU Su-Jin Kim
MEMS
Manufacturing Processes
Comb Drive / Capacitive
• Parallel Plate Capacitor
C = ε A/d
• Electrostatic Force
Fe = ½ ε (A/d2)V2