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BIBEBUVABSc in Micro- and MedicaltechnologyPiezoelectric ceramics deposition on quartzMechatronik / Thesis advisor: Prof. Dr. Bertrand DutoitExpert: Dr. Bernhard SchnyderThe Swiss quartz crystal manufacturer Micro Crystal AG is perpetually reducing the size of its products. Ofcourse, this results in big challenges on adapting critical production processes, particularly in the photolithographicsection. New methods and concepts are in demand. One of them involves the coating of apiezoelectric ceramic thin film on quartz substrates. As this has never been done before, the feasibility mustbe proven.Lukas Schneiderschnl6@gmail.comBackgroundSince years, the miniaturisation ofcomponents is a well-known trendin the micro electronics sector.This progress led to the impressingpotential of present-day electronicgadgets, such as tabletPC’s or smart-phones. At MicroCrystal, one can understand theextent of this trend by looking atthe development of a standardcrystal resonator’s package size:In the past 25 years, its volume gotdecreased by 97%. Nowadays,the required accuracy on photolithographicprocess steps is veryhigh, making them highly criticaland expensive due to narrow processlatitudes. To dodge some ofthese critical processes, MicroCrystal’s development departmenthas designed a new resonatorconcept. It involves the coatingof a piezoelectric ceramic thin filmon the quartz substrates.ResultsAs a first step, the required theoreticalfoundations related to theproject were investigated. Detailedinformation on quartz crystalproperties and their manufacturingprocesses was collected. Possiblepiezoelectric ceramic thinfilm deposition methods werecompared. As it is offering crucialadvantages like homogeneity andhigh production throughput,pulsed laser deposition becamethe method of choice.In order to define the requiredthickness of the piezoelectric thinfilm, elaborate FEM simulationswere performed. They providedpromising results by approving theresonator concept to be functional.Thereby the knowledge wassufficient to perform practicaldeposition tests. For that purpose,contacts with a company specialisedon pulsed laser depositionwere made.A face to face meeting was held atthe Micro Crystal headquarters.The most important specificationswere exchanged and a detailedexperiments set-up was writtendown. Substrates were preparedat Micro Crystal and shipped. Afterthe first deposition runs, anexternal partner offered a detailedanalysis of the quality, homogeneityand performance of the thinfilms. The first coatings were successful,as there were no majordifficulties such as insufficient adhesionor high residual strain andstress in-between substrate andthin film.Piezo ceramics thin film on quartz substrate268 ti.bfh.ch