Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/48621
標題: Using New Measurement Methods for the Study of Novel Plastic Deformation Recovery, Inhomogeneous and Viscoelastic Mechanical Properties of Thin Film(III)
以新式實驗方法探討新興微奈米薄膜塑性回復非均質與黏彈性等新穎機械行為(III)
作者: 林明澤
關鍵字: 商品化
機械工程類
摘要: The microsystems technology has grown rapidly in recent years. Continued growth ofcomputing power requires still further miniaturization, with a corresponding need tounderstand how mechanical behavior of all the components. As the technologies of deviceprocesses advanced, many new thin film materials structures had been developed. Manynovel mechanical properties of micrometer to nanometer scale thin films yet beendiscovered.Recently, two articles in “Science” report (1) An experimental investigation ofstress-driven grain boundary migration exhibited as grain growth in nanocrystallinealuminum thin films. This report outlines very differently in nanocrystalline aluminum thinfilms. By contrast, it is traditionally known grain boundaries are fundamentally to bemechanically static structures. Mechanics and materials scientists traditionally acknowledgethe geometric structure of grain boundaries as mechanically static, immovable structures.However, recent studies involving nanocrystalline materials have introduced convincingevidence to suggest that grain boundaries are not static. (2) The deformation recovery ispossible for nanocrystalline metal and suggests that the strain recovery was the results fromthe combined effect of a small mean grain size and inhomogeneities in the microstructure.Although the inhomogeneities phenomena of metal thin films were found in the articles, theproperties of plastic deformational recovery were first to be suggested due to the cause of itand yet many unknown mechanical behavior remain.In addition, temperature and time dependence in the modulus of the novel scale-relatedthin film are another mechanical properties that are motivated by the need to characterizeand understand the magnitude and origin of this thin film properties for MEMS andMicrosystems applications.In order to gain a better understanding of mechanical function mechanisms in thenanoscale regime, it is desirable to develop a better characterization method that wouldallow us to extend study on the mechanical behavior of films. Here, the principleinvestigator follow previous projects to extend further research that has the merit to study thestress driving grain boundary migration, the plastic deformational recovery, inhomogeneitiesmechanical behavior of thin films, and capable to study time and temperature dependence inthe modulus of thin film properties. The technique including two aspects of measurementmethods; the first method utilized “paddle” cantilever beam coated with a thin film withdimensions as few hundred nanometers to less than 10 nanometers. Load the sample bydriving its static bending or resonance by electrostatic actuation with an underlyingpull-down electrode, capacitance measurement based on the top can measure its mechanicalbehavior with respected to load, time and temperature. The inhomogeneities can be observedfrom the resonant frequency and drive amplitude in each tested temperature cycle. Fornon-metal thin films, the capacitance measurement based is replaced by the optical toolsusing laser deflection to precisely measure changing distance of “paddle” cantilever beamspecimen. If the film with thickness in the range of above 200 nm, the second method can beused to study its stress or strain driving grain boundary migration, plastic deformationalrecovery and inhomogeneities behavior using unaxial tensile method.Success completion of this project will provide important information of mechanicalproperties of nanocrystalline thin films in terms of deformation mechanisms, dislocationtheories, temperature dependent stress relaxation behavior, inhomogeneities and reliabilityconcerns. This information will be used to accurate predict stress models and provide a newsight in mechanics of scientific study for the mechanical behavior of thin films for modernmicroelectronics, MEMS and nanotechnologies.
目前半導體積體電路、光電元件、顯示器、奈米科技與微機電系統等高科技產業已迅速的成長;為研究及發展更新更快之元件,學者專家們不斷的增加微小結構之複雜性及高密度性,以使更多的功能可被安置在一微處理器中;然在持續增加其計算能力的要求下,需要更進一步的微形化,也因此隨著微小化的過程而衍生各種新興材料微結構與機械性質的問題;同時隨著各種先進設備與製程技術的提升,很多新穎之薄膜材料被設計與研發,但由於材料結構在微奈米尺度之各項性質和其巨觀塊狀結構有著極大的不同,在控制化學製程及晶粒大小的過程中產生了許多新穎材料特性改變,此現象對製造生產某些特性需求而調配的機能材料提供一個極大的可行性,對高科技產業的發展與提昇是相當重要的一環。最近在2009年及2007年科學"Science"期刊中,各刊出了一篇發現對於奈米結晶晶粒nanocrystalline組成之金屬薄膜表現出與傳統對基礎材料力學認知上相反之新穎機械行為,分別為(1)晶粒晶界非固定且會產生遷移的機械行為;此行為推翻了傳統上界定晶界為一靜止結構且其作用在塑性變形中差排滑移之阻障行為的認知;文中報告此新穎之行為在應力作用(尤其剪應力)下極為明顯,因此造成晶粒長大而同時降低材料之降伏強度(2)塑性變形回復的機械行為;文中建議此新穎塑性變形回復是來自在微結構裡小而平均的奈米晶粒和薄膜非均質現象inhomogeneities所影響的結果。然而有關此金屬薄膜材料晶界遷移與非均質影響其機械行為的現象與理論,目前仍存在許多未知,尤其上述發現之行為推翻了基礎材料科學與應用力學上對於材料的認知:(1)金屬材料之晶粒晶界為一靜止結構且其作用在塑性變形中差排滑移之阻障(2)金屬材料受外力產生之塑性變形為永久變形並不可回復;因此更深入的對於奈微米材料結構及其機械性質之量測及瞭解在基礎科學的研究上有著迫切的需要。目前為止,有許多相關的實驗和理論都是依據材料在大尺度規模時巨觀的性質來推演;相較之下,以材料在微奈米尺度的機械行為依據的實驗與研究探討卻往往因其試件製程與量測機制的種種限制而無法有完整而合理的結果。因此設計研究新而適合量測材料在微小尺度的高準度實驗,進而衍生一完整而有價值的次微米到奈米薄膜材料之新穎機械行為的分析有著重要且亟為迫切的需求。本研究計畫接續之前之研究計劃提出以兩種實驗方法設計(1)以靜電力驅動試件並同步以電容或單點雷射光學量測(2)微拉伸方法量測次微米、奈米薄膜在均質平面應力懸臂樑結構之彎曲曲率改變量與拉伸試件自然共振反應來探討其所呈現出的機械性質,此研究是計畫主持人依據近幾年來設計執行之研究計畫,並參考國內外各種先進之量測技術而提出之最新且直接的實驗,用以量測運用無塵室標準製程產生之薄膜試件奈米級材料機械性質之量測試驗技術,受量測之試件薄膜厚度可由數百奈米厚到十奈米薄之等級。此計畫可準確的量測試件可能之晶界遷移、塑性回復、薄膜非均質行為、彈塑性及黏彈性行為、溫度對應力與應力釋放之影響、薄膜厚度對薄膜機械性質的影響等。其中試件製程完全依照實際製程上的反應與環境的狀況,使得研究測試之數據,更能清楚對照微製程使用的材料於應用過程中產生之材料機械行為與製程條件之相關性,同時以此簡單的試件製程步驟更可提升其良率與實驗效率;更由於因其以簡單的感測方法推算出應力應變的關係,實驗設計的準確性可大大的提升。成功的完成這項研究計畫,不僅可以建構出結合以靜電力驅動懸臂樑結構曲率與自然共振分析次微米-奈米尺度金屬薄膜試件之量測設備,其所產生完整的數據亦可用以分析其材料機械性質,提供微系統設計製造時選用材料之參考,也對產品元件之製程設計與可靠度分析提供一極有價值之研究,更可為研發下一代奈米等級元件設計提供一最新式、嚴謹而可靠之機械性質研究方法。
URI: http://hdl.handle.net/11455/48621
其他識別: NSC99-2628-E005-002
文章連結: http://grbsearch.stpi.narl.org.tw/GRB/result.jsp?id=2100655&plan_no=NSC99-2628-E005-002&plan_year=99&projkey=PB9907-0729&target=plan&highStr=*&check=0&pnchDesc=%E4%BB%A5%E6%96%B0%E5%BC%8F%E5%AF%A6%E9%A9%97%E6%96%B9%E6%B3%95%E6%8E%A2%E8%A8%8E%E6%96%B0%E8%88%88%E5%BE%AE%E5%A5%88%E7%B1%B3%E8%96%84%E8%86%9C%E5%A1%91%E6%80%A7%E5%9B%9E%E5%BE%A9%E9%9D%9E%E5%9D%87%E8%B3%AA%E8%88%87%E9%BB%8F%E5%BD%88%E6%80%A7%E7%AD%89%E6%96%B0%E7%A9%8E%E6%A9%9F%E6%A2%B0%E8%A1%8C%E7%82%BA%28III%29
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