Final Exam Notes:
Types of CVD Processes
CVD covers processes such as:
Atmospheric Pressure Chemical Vapour Deposition (APCVD)
Low Pressure Chemical Vapour Deposition (LPCVD)
Metal-Organic Chemical Vapour Deposition (MOCVD)
Plasma Assisted Chemical Vapour
Test # 1 : October 10, 2014
#1: 15 points
Where used in IC
and for what purpose?
High k-Metal Gate
structure; can use thicker
films (providing the same
capacitance as SiO2)
making fabrication easier
Instructors: Professor Srini Raghavan
147 Mines and Metallurgy; [email protected]
Professor Manish Keswani
153 Mines and Metallurgy; [email protected]
Time: MWF 10
Place: Communication 206
Calculate the impingement rate and mean free path for oxygen molecules
(M=32) at 300 K and a pressure of 10-4 Pa. What is this pressure in torr?
Boltzmann constant = 1.38 x 10-23 J/K, Assume diameter of the oxygen molecule
to be 0.36 nm.
Thin Film Deposition Notes:
Test 2 is over Oxidation, Diffusion, and lithography.
Teachers phone number: 520-270-4361
Thin Film Deposition- General Issues:
CDV and PVD processes- know the differences
o PVD- physical vapor deposition
o CVD- Chemical vapor
N x, t
J X o k s N i
B B A
B B A
2 DN 0
Boltzmann constant = 8.617 10-5 eV /K
A W t
RS = Sheet Resistance [Ohms per Square]
Number of Squares of Material
[ - m
(a) How thick should an oxide film be grown in selected areas of a (100) silicon surface to leave
a 250-nm step in silicon after the oxide is removed?
(b) A silicon wafer is subjected to steam oxidation after SC1 and SC2 clean. Calculate the
Weight of Silicon =
Amount of Boron=
k0 of B
Amount of P =
k0 of P
number of atoms of B =
number of atoms of B /cm3 of liquid Si= 5.24224E+015 #/cm3
number of atoms of P=
number of atoms of P/cm3
Collection of Questions # 3
Chemical Mechanical Planarization
1. What experimental parameters affect
the removal rate of films in CMP?
2. What is step height reduction in a
CMP process? What the different
objectives of a CMP process?
1. What are the ingredients in a photoresist formulation? How is the resist applied to a
Acrylic binders with carboxilic acid groups, liquid multifunctional acrylates, a
photosensitizer and a photoinitiator, dyes, additives for improvin
Q3 (30 points).
Answer any two
(1) List the steps (in sequence) involved in a lithographic process that is
capable of producing resist patterns with vertical side walls (no standing
(Start with oxide wafer (SiO2 film on wafer); clean usi
Boron is pre-deposited into silicon containing 1021 m-3 of uniformly distributed phosphorous. If
pre-deposition is carried out at 1000 deg C for 20 minutes, calculate the junction depth and the
amount of boron introduced into silicon. Diffusivity
MSE / ECE 446/546
LIST OF QUESTIONS # 1
1. List the conductors and insulators used in the fabrication of a MOS device.
Create a table of their conductivity values.
2. What are the steps in forming Shallow Trench Isolation (STI) areas?
3. Distinguish betwe
What are the ingredients in a
photoresist formulation? How is the
resist applied to a wafer?
Distinguish between positive and
negative resists in terms of their
reactivity towards light and method of
A <111> silicon wafer with an initial oxide thickness of 25 nm undergoes 1 hour of dry oxidation at
1100 deg C followed by a 5 hour of wet oxidation at 1100 deg C. (a) Calculate the final oxide
thickness after each step. (b) Find the final oxide
= 1/(q n n + q p p)
ni= 3.1x1016 T3/2 exp(-0.603 eV/kT) cm-3
np ni N C NV exp G KT 3 exp G
n ni exp F
n 1 N D N A
EG EC EV
p ni exp i
N A 4ni2