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Study On Residual Stress And Warpage Of Chip-on-Glass Package

Posted on:2013-07-03Degree:MasterType:Thesis
Country:ChinaCandidate:J GuoFull Text:PDF
GTID:2248330392457408Subject:Mechanical and electrical engineering
Abstract/Summary:PDF Full Text Request
As the trends of electronic packaging toward lead-free, miniaturization and greaterperformance, the new generation Chip-on-Glass(COG) technique has been widely appliedespecially in high quality liquid crystal display (LCD) panels for several years, because it hadenvironmentally friendly, low bonding temperature, high density, good compatibility and simpleprocess. Residual stress and warpage are two of the common concerns in COG packages. Theseproblems have to be investigated thoroughly for they would induce misregistration anddelamination between the interface of gold bump/anisotropic conductive film (ACF) andACF/glass. The purpose of this study is to investigate the possible parameters to affect the warpageand residual stresses of the COG (Chip-on-Glass) packages with ACF (Anisotropic ConductiveFilm) during curing and cooling. The methodology combines experimental techniques for materialcharacterization, finite element modeling (FEM), and model validation. Experiments wereemployed for measuring the warpage in terms of such parameters. We proposed an optimizationmethod of manufacturing parameters of COG packaging based on these discussions. The mainproblems are discussed as follows:Firstly, the materials of metal particle and polymer particle of Anisotropic Conductive Film(ACF) have been characterized. The curing process of COG packages has been discussed. Theparameters which induce warpage and residual stress during curing process were concluded. Somemain parameters were defined to further research related to warpage and residual stress. Andtheoretical models of COG packages were proposed.Secondly, the simplified models of COG packages with metal particle and polymer particlewere employed using FEM and birth and death element to study the effects of structure of metalparticle and bonding force on COG packages with metal particle. And the effects of the bondingparameters such as bonding force, bonding temperature and temperature difference on the COGmodule with polymer particle were revealed. The levers of effects of bonding parameters abovewere discussed.Finally, we designed experiment process and manufacture some samples with Taguchi method.Warpage measurement instrument with shadow moire method was used for measuring the out-of-plane deformations of the specimens and providing validation of the residual stresses calculatedfrom finite element models, for looking into insight of warpage and residual stresses and correlatedwith finite element results. From the simulation and experiment results, an optimization method ofmanufacturing parameters of COG packaging was proposed because of these discussions.
Keywords/Search Tags:Chip-on-Glass, Warpage, Residual Stress, Finite Element Method, Taguchi, Warpage Measurement Instrument
PDF Full Text Request
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