1. Introduction to Wafer fabrication Process
Presented by
Asst.Prof. Dr. Rardchawadee Silapunt

2. Outlines
Clean room 1
Wafer Fab Process 2

3. Outlines
Clean room 1

4. Clean TMEC

5. It took time to install cleanroom
PLAY MOVIE

6. Outlines
Wafer Fab Process 2 6

7. Processing line @ TMEC Down to 0.5μm Technology Furnace
Cleaning Process
Photolithography
Down to 0.5μm Technology
Implanter
Metrology
Plasma CVD
Sputtering
Dry Etching

8. Overview to Lithography process
What is Lithography Process?
The word come from the Greek “Lithos” and “Graphia”
Lithos = Stones , Graphia = to write
It means “ Writing on stones”.
In Semiconductor, stones are Silicon wafers and our patterns are written with a light-sensitive polymer called “Photoresist”

9. Overview to Lithography process
9 Steps of Lithography process.
1. Wafer preparation
5. Post-Exposure Bake (PEB)
6. Development
2. Coat with Photoresist
7. Postbake, Hardbake
3. Prebake, Softbake
8. Etch or Implant
4. Align and Exposure
9. Photoresist strip

10. Photolithography Problem
Without OPC
With OPC
Light Diffraction is occur during photolithography process.
(a)
(b)
(c)
(d)
OPC patterns are used to reduce the error in photolithography process.

11. How to patterning circuit
Processing
- Film Deposition
- Photolithography
- Etching
- Implantation
Wafer
Integrated Circuit (IC)

12. Processing line
Silicon Wafer
p-type wafer
p-type

13. Initial oxidation: O2/H2 (Thickness: 420 nm)
Processing line
Film Deposition
Initial oxidation: O2/H2 (Thickness: 420 nm)
SiO2
p-type

14. Processing line Photolithography Coater Stepper Developer
Photoresist (PR)
p-type

15. Processing line Photoresist Characteristic
PR is made up of a resin R, the photoactive compound M, the solvent S, and component appears during exposure which are exposure products P.
The exposure products generated by the reaction of M with UV light.!!
Applying Beer’s Law, the absorption coefficient  is then,
M0 = initial PAC concentration (non-exposed)
A = bleachable absorption coefficients of
Dill parameters
B = Non-bleachable absorption coefficients of
Other non-bleachable components of the PR such as dye are added to B

16. Processing line Dill Paramaters of Photoresist
Where several assumptions are made in solving this differential equation and I x t is the
optical dose. If D is the resist thickness, the Dill parameters can be measured by:
T(0)
T(∞)
is transmittance at the
air-resist interface
T(0) is the transmittance of the unexposed resist, and
T(∞) is the transmittance of the completely exposed resist
is the initial slope of the transmittance vs dose curve
Two transmittance curves for Kodak 820 resist 365 nm. The curves are for a convection oven post-apply bake of 30 minutes at the temperatures shown

17. Processing line Etching Simulation of Plasma Etching Photoresist (PR)
Dry etch oxide
p-type

18. Directionality of Etcing Process
Processing line
Etching
Directionality of Etcing Process
Isotropic Etch
Directional Etch
Vertical Etch

19. Processing line Etching Wet Etching Dry Etching
Two Kinds of Etching Method
Wet Etching
Dry Etching
by Wet chemical solution
Isotropic etching
by Plasma
Anisotropic etching
Vertical E/R ~ Horizontal E/R Pure Chemical Reaction High Selectivity CD Loss or Gain
Vertical E/R >> Horizontal E/R
Ion assisted Relatively low Selectivity No CD bias

20. n-well implantation : Phosphorus
Processing line
Implantation
n-well implantation : Phosphorus
Photoresist (PR)
p-type

21. Processing line Chemical Mechanical Planarization (CMP)
CMP removes material from uneven topography on a wafer surface until
a flat (planarized) surface is created.
CMP combines the chemical removal effect of an acidic or basic fluid solution with
the "mechanical" effect provided by polishing with an abrasive material.

22. How to patterning a CMOS !!!
Processing line
How to patterning a CMOS !!!

23. Thank You !