Date of Award

Summer 8-2015

Author's School

School of Engineering & Applied Science

Author's Department

Mechanical Engineering & Materials Science

Degree Name

Master of Science (MS)

Degree Type

Thesis

Abstract

Diamond embedded abrasive wire (henceforth called diamond wire) sawing process of Si is a highly efficient technique for rapid wafering of solar Si ingots. However, the root causes for cutting efficiency losses are unknown. One approach to understanding this complex process is to study 1) diamond particles on diamond coated wire (DCW) and 2) Si swarf collected during cutting process. In this thesis, we use confocal, micro Raman spectroscopy to unravel loss mechanisms of wafer sawing efficiency.

In the first part, we analyze the diamond microparticles which perform the sawing. By analyzing the phase transformation and stress distribution on single diamond particle, graphitization (i.e. softening of diamond) and residual stresses are observed.

By studying the individual Si particles (swarf), correlations between particle shape and phase is established. Fibrillar Si particles are found to be amorphous – indicative of a ductile cut; while spherical Si articles are crystalline – indicative of a brittle cut. This important find helps to quantify the rates of cutting efficiency by simply measuring the entire Si swarf cluster; its phase distribution and stress change, as a function of Si swarf extraction time during the cutting process.

Language

English (en)

Chair

Parag Banerjee

Committee Members

Katharine Flores, Parag Banerjee, Omid Rezvanian

Comments

Permanent URL: https://doi.org/10.7936/K7XG9PBM

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