1. #4 (Oct. 22) Photolithgraphy -What is photolithgraphy? -Thin-film patterning using phtolithgraphy -Applications of photolithgraphy -Trends in minimum pattern sizes

2. What Is Photolithgraphy? Photo + Lithograph Technologies to replicate patterns on a photomask to substrates or thin films on the substrates by using photo-chemical reaction photoresist Photomask Thin film on a substrate

3. What Is Photoresit A material that changes its solubility to developer by irradiation of light (ultraviolet or X ray) and electron beam Changes: (1) Non-soluble to solvable (positive-type photoresist) (2) Soluble to non-soluble (negative-type photoresist)

4. Composition of Photoresist Sensitizer

5. Change of Sensitizer by UV Irradiation Non-soluble Soluble

6. Purposes and Features of Photolithography Purposes -Fabrication of electron devices such as LSIs -Fabrication of micromachines -Packaging of LSIs and micromachines Features -Minimum size of 1  m or less is achievable -Batch process -Pattern repetition

7. a Photoresist （ 1  m ） Chromium thin film （ 50 nm) Fused-quartz substrate (1 mm) bab Photomask Fabrication (1) Chromium thin film deposition and photoresist deposition

8. Electron beam abab Photomask Fabrication (2)

9. abab Photomask Fabrication (3) Development

10. abab Photomask Fabrication (4) Etching of chromium thin film

11. abab Photomask Fabrication (5) Photoresisit removal

12. Silicon substrate abab Phtolithography of Al Thin Film (1)

13. SiO 2 thin film(1  m) abab Phtolithography of Al Thin Film (2)

14. Al thin film （ 1  m) abab Phtolithography of Al Thin Film (3)

15. Photoresist abab Phtolithography of Al Thin Film (4) Followed by pre-baking at 120 ℃

16. Mercury lamp Photomask abab Phtolithography of Al Thin Film (5)

17. Wavelength (nm) Intensity (relative) Emission Spectrum of Mercury Lamp

18. abab Phtolithography of Al Thin Film (6) Development Followed by post-baking at 120~180 ℃

19. abab Phtolithography of Al Thin Film (7) Al thin film etching

20. abab Phtolithography of Al Thin Film (8) Photoresist removal

21. aba Photoresist Lift-Off of Al Thin Film (1) b

22. (2) Mercury lamp Photomask abab Lift-Off of Al Thin Film (2)

23. abab Lift-Off of Al Thin Film (3) Development

24. abab Lift-Off of Al Thin Film (4)

25. (5) abab Lift-Off of Al Thin Film (5)

26. abab Lift-Off of Al Thin Film (6)

27. Wiring Using Al Thin Films Contact holes

28. Cross-Section of CMOS LSI

29. Electron beam scanner Reticle Photomask Stepper Pattern generator Stepper Pattern Size Reduction by Stepper Wafer Design data Contact aligner Projection aligner

30. Stepper http://www.tochigi-nikon.co.jp/business/stepper/

31. Trends in Minimum Pattern Size http://public.itrs.net/

32. Inside Clean Room (MIT)

33. by Richard P. Feynman http://www.zyvex.com/nanotech/feynman.html There's Plenty of Room at the Bottom An Invitation to Enter a New Field of Physics Homework: Read This Article by 11/4