Title:
Analysis of handling stresses and breakage of thin crystalline silicon wafers

dc.contributor.advisor Melkote, Shreyes N.
dc.contributor.author Brun, Xavier F. en_US
dc.contributor.committeeMember Danyluk, Steven
dc.contributor.committeeMember Griffin, Paul
dc.contributor.committeeMember Johnson, Steven
dc.contributor.committeeMember Kalejs, Juris
dc.contributor.committeeMember Sitaraman, Suresh
dc.contributor.department Mechanical Engineering en_US
dc.date.accessioned 2009-01-22T15:44:03Z
dc.date.available 2009-01-22T15:44:03Z
dc.date.issued 2008-09-08 en_US
dc.description.abstract Photovoltaic manufacturing is material intensive with the cost of crystalline silicon wafer, used as the substrate, representing 40% to 60% of the solar cell cost. Consequently, there is a growing trend to reduce the silicon wafer thickness leading to new technical challenges related to manufacturing. Specifically, wafer breakage during handling and/or transfer is a significant issue. Therefore improved methods for breakage-free handling are needed to address this problem. An important pre-requisite for realizing such methods is the need for fundamental understanding of the effect of handling device variables on the deformation, stresses, and fracture of crystalline silicon wafers. This knowledge is lacking for wafer handling devices including the Bernoulli gripper, which is an air flow nozzle based device. A computational fluid dynamics model of the air flow generated by a Bernoulli gripper has been developed. This model predicts the air flow, pressure distribution and lifting force generated by the gripper. For thin silicon wafers, the fluid model is combined with a finite element model to analyze the effects of wafer flexibility on the equilibrium pressure distribution, lifting force and handling stresses. The effect of wafer flexibility on the air pressure distribution is found to be increasingly significant at higher air flow rates. The model yields considerable insight into the relative effects of air flow induced vacuum and the direct impingement of air on the wafer on the air pressure distribution, lifting force, and handling stress. The latter effect is found to be especially significant when the wafer deformation is large. In addition to silicon wafers, the model can also be used to determine the lifting force and handling stress produced in other flexible materials. Finally, a systematic approach for the analysis of the total stress state (handling plus residual stresses) produced in crystalline silicon wafers and its impact on wafer breakage during handling is presented. Results confirm the capability of the approach to predict wafer breakage during handling given the crack size, location and fracture toughness. This methodology is general and can be applied to other thin wafer handling devices besides the Bernoulli gripper. en_US
dc.description.degree Ph.D. en_US
dc.identifier.uri http://hdl.handle.net/1853/26538
dc.publisher Georgia Institute of Technology en_US
dc.subject Wafer breakage en_US
dc.subject Bernoulli gripper en_US
dc.subject Wafer handling en_US
dc.subject Finite element modeling en_US
dc.subject Computational fluid dynamics en_US
dc.subject.lcsh Silicon solar cells
dc.subject.lcsh Semiconductor wafers Mechanical properties
dc.subject.lcsh Computational fluid dynamics
dc.title Analysis of handling stresses and breakage of thin crystalline silicon wafers en_US
dc.type Text
dc.type.genre Dissertation
dspace.entity.type Publication
local.contributor.advisor Melkote, Shreyes N.
local.contributor.corporatename George W. Woodruff School of Mechanical Engineering
local.contributor.corporatename College of Engineering
relation.isAdvisorOfPublication e78c9d4f-2d4a-4337-9739-f9179a9fd7fb
relation.isOrgUnitOfPublication c01ff908-c25f-439b-bf10-a074ed886bb7
relation.isOrgUnitOfPublication 7c022d60-21d5-497c-b552-95e489a06569
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