Presentation on SGS, Crystal Defects & Wafer Preparation

Guided By

MD. Mohiuddin Munna

#Group Members#

Chinmoy Das (2010338012)

Nazmul Hossain (2010338016)

Niloy Bonik (2010338017)

Sohel Rana (2010338033)

#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#

#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 GrowthShapingWafer SlicingWafer lapping & edge grindEtchingPolishingCleaningInspectionPackaging

#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