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#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.
#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.
#Wafer Preparation#
A process of preparing wafer including-
Machining operations
Chemical operations
Surface polishing &
Quality measures.
#Steps’ Introduction#
Crystal GrowthShapingWafer SlicingWafer lapping & edge grindEtchingPolishingCleaningInspectionPackaging
#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.
#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.