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Integrated circuits (ICs) and discrete solid state devices are manufactured on semiconductor wafers. The following focuses on the general principles and methods with regard to wafer formation.

Introduction

Integrated circuits (ICs) and discrete solid state devices are manufactured on semiconductor wafers. Silicon based devices are made on silicon wafers, while III-V (13-15) semiconductor devices are generally fabricated on GaAs wafers, however, for certain optoelectronic applications InP wafers are also used. The electrical and chemical properties of the wafer surface must be well controlled and therefore the preparation of starting wafers is a crucial portion of IC and device manufacturing. In order to obtain high fabrication yields and good device performance, it is very important that the starting wafers be of reproducibly high quality. For example, the front surface must be smooth and flat on both a macro- and microscale, because high-resolution patterns (lithography) are optically formed on the wafer. In principle, cutting a crystal into thin slices and polishing one side until all saw marks are removed and the surface appears smooth and glossy could produce a suitable wafer. However, due in part to the brittleness of Si and GaAs crystals, as well as the increasing requirements of wafer cleanliness and surface defect reduction with ever decreasing device geometries, a very complex series of processing steps are required to produce analytically clean, flat and damage-free wafer surfaces.

The following focuses on the general principles and methods with regard to wafer formation. Detailed formulas, recipes, and specific process parameters are not given as they vary considerably among different wafer producers. However, in general, techniques for fabrication of Si wafers have generally become standardized within the semiconductor industry. In contrast, GaAs wafer technology is less standardized, possibly due to either (a) the similarity to silicon practices or (b) the lower production volume of GaAs wafers. There are two general classes of processes in the methodology of making wafers: mechanical and chemical. As both Si and GaAs are brittle materials, the mechanical processes for their wafer fabrication are similar. However, the different chemistry of Si and GaAs require that the chemical processes be dealt with separately.

Wafer formation procedures

Each of the processing steps in the conversion of a semiconductor ingot (formed by Czochralski or Bridgeman growth) into a polished wafer ready for device fabrication, results in the removal of material from the original ingot; between 1 / 3 and 1 / 2 of the original ingot is sacrificed during processing. Methods for the removal of material from a crystal ingot are classified depending on the size of the particles being removed during the process. If the removed particles are much larger than atomic or molecular dimensions the process is described as being macro-scale. Conversely, if the material is removed atom-by-atom or molecule-by-molecule then the process is termed micro-scale. A further distinction between various types of processes is whether the removal occurs as a result of mechanical or chemical processes. The formation of a finished wafer from a semiconductor ingot normally requires six machining (mechanical) operations, two chemical operations, and at least one polishing (chemical-mechanical) operation. Additionally, multiple inspection and evaluation steps are included in the overall process. A summary of the individual steps, and their functions, involved in wafer production is shown in [link] .

Questions & Answers

are nano particles real
Missy Reply
yeah
Joseph
Hello, if I study Physics teacher in bachelor, can I study Nanotechnology in master?
Lale Reply
no can't
Lohitha
where we get a research paper on Nano chemistry....?
Maira Reply
nanopartical of organic/inorganic / physical chemistry , pdf / thesis / review
Ali
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
hey
Giriraj
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
has a lot of application modern world
Kamaluddeen
yes
narayan
what is variations in raman spectra for nanomaterials
Jyoti Reply
ya I also want to know the raman spectra
Bhagvanji
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
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Source:  OpenStax, Chemistry of electronic materials. OpenStax CNX. Aug 09, 2011 Download for free at http://cnx.org/content/col10719/1.9
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