Presentation on SGS, Crystal Defects & Wafer Preparation Guided By MD. Mohiuddin Munna

#Group Members# Chinmoy Das ( ) Nazmul Hossain ( ) Niloy Bonik ( ) Sohel Rana ( )

#Semiconductor Grade Silicon (SGS)# The highly refined silicon used for wafer fabrication. Also known as Electronic Grade Silicon. Has ultra high purity.

#Steps to obtaining SGS#

Obtaining MGS

#Steps to obtaining SGS# Pure Silicon Producing System

#Crystal Defects in Silicon# Interruption in the repetitive nature of the unit cell crystal structure. Aiso known as micro defect.

#Types of Defects# Point Defects: Localized crystal defect at the atomic level. Dislocations: Displaced unit cells. Gross Defects: Defects in crystal structure.

#Point Defects# Vacancy Defect Interstitial Defect Frenkel Defect

#Vacancy Defect#

#Interstitial Defect#

#Frenkel Defect#

#Dislocations#

#Gross Defects#

#Wafer Preparation# A process of preparing wafer including- Machining operations Chemical operations Surface polishing & Quality measures.

#Basic Process Flow#

#Steps’ Introduction# Crystal Growth Shaping Wafer Slicing Wafer lapping & edge grind Etching Polishing Cleaning Inspection Packaging

#Shaping Operations# End Removal Diameter Grinding

#Wafer Slicing#

#Wafer Lapping# Two-sided lapping operation to remove damage left by slicing. Performed under rotational pressure with pads & mixture of alumina or silicon carbide & glycerin.

#Edge Contour#

#Etching#

#Polishing#

#Cleaning# Wafers must be cleaned to achieve an ultraclean state. Wafers should be free of particles & contamination.

#Wafer Evaluation# Wafers need to be inspected carefully before packaging. Standard quality should be measured.

#Packaging# Finally wafers should be packaged carefully.

Here is the END of our presentation Thanks everyone for being with us