1. INTRO TO TDM AND BUM TDM – Top Down Manufacturing
BUM – Bottom Up Manufacturing

2. TOP DOWN MANUFACTURING
Materials modified
Cutting, drilling, milling
Machinery used
Many steps needed
Primary method in integrated circuits industry

3. BOTTOM UP MANUFACTURING
Similar to way nature builds objects
Self-assembly
Atomic force microscope
The future of nano-manufacturing?

4. MOORE’S LAW
Integrated circuits (ICs) are electronic circuits on a single piece of silicon
Circuits on ICs are made from many transistors
Since 1965 trend is for the number of transistors per integrated circuit to double every two years
In 1965 there were 30 transistors per chip
Today, more than 1 billion transistors per chip

5. MOORE’S LAW

6. TDM IN SEMICONDUCTOR MANUFACTURING
Transistors are semiconductor devices
Transistors connected together form circuits
Integrated circuits consists of many transistors
Many ICs built simultaneously on silicon wafers
Transistors are built first, then interconnected
ICs are built in a chip fab

7. TDM IN SEMICONDUCTOR MANUFACTURING
ICs are built layer by layer
Process steps include:
Wafer photolithography  ion implant 
Deposition  metallization
Steps repeated many times for each IC

8. PHOTOLITHOGRAPHY Mask is high quality glass
Mask has areas marked to block transmission of light
One mask for every layer of the IC
Photoresist covers IC
Ultraviolet light shines through mask onto photoresist
Photoresist affected by light

9. PHOTOLITHOGRAPHY

10. PHOTOLITHOGRAPHY Photolithography defines transistor size
Part of process is to reduce image on mask
Transistors made of several features
Feature size defines how small transistors are
Smallest feature size currently is 45nm

11. PROBLEM WITH TDM TDM processing reaching physical limits
Difficult to reduce mask images to smaller and smaller levels
Requires shorter wave length light (X-rays)
Requires more sophisticated optical systems to reduce images
This are expensive and technically challenging

12. Bottom Up Manufacturing
Possible way to continue Moore’s Law progress
Build features one atom at a time
Use forces of nature to accomplish this
No machining necessary
Requires proper environmental conditions

13. AFM Atomic force microscope Can image atoms Can move atoms
Forces between atom and ATM tip interact
Measurement of forces used to produce image of atom or to manipulate atoms
IBM logo made from xenon atoms in 1990

14. IBM FROM AFM

15. SELF-ASSEMBLY Self-assembly occurs naturally
Smaller features are created
Smaller features combine to produce larger features
Combinations occur until macro structure is built

16. SELF-ASSEMBLY

17. SELF-ASSEMBLY

18. SELF-ASSEMBLY IN SOAP
Soap bubbles consist od soap molecules and water molecules
Soap molecule ends react differently with water
Hydrophili end links with water easily
Hydrophobic end will not link with water
Monolayers form to create bubble wall
Wall is soap-water-soap

19. SELF-ASSEMBLY IN SOAP

20. PROPERTIES OF NANOSTRUCTURES
Objects at the nano-scale exhibit unique properties
Properties may not exist at larger scales
Color
Light reflection
Order

21. COLOR PROPERTIES OF SOAP