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Characterization of Mechanical Properties of Electroplated Nickel Film and Ni3Sn4 Intermetallic Compound
No full text隨著覆晶構裝技術的進步及晶片效率的提升，溫度問題逐漸成為一重要之議題。晶片工作時的高溫會使得具有不同熱膨脹係數(thermal expansion coefficient, CTE)之晶片與基板間造成變形，而變形產生的巨大應力會成為I/O連結處破壞的主因之一。數值方法的模擬常使用在這類構裝體之可靠度分析上，但欲準確預測應力分佈的情形，我們必須對建構起I/O連結處材料的機械性質有正確的掌握。
凸塊底層金屬(under-bump metallization)由多層金屬薄膜組成，而金屬薄膜往往因為成長方式展現出與塊材不同之機械性質；此外，這些金屬薄膜在與銲錫凸塊回銲過程中亦會產生薄且脆之介金屬化合物(Intermetallic Compounds, IMC)。這些材料僅有數微米之厚度因此量測不易，但卻在構裝分析上佔有重要份量。有鑑於此，本文的目的即在發展出一套反算系統以偵測出以鎳為主之金屬薄膜及其介金屬化合物之機械性質。
本文中，將建立起電鍍Ni/Si、Ni3Sn4/Ni/Si、Ni3Sn4/Ni Foil等多層結構試片，透過光學量測技術配合有限元素模型及遺傳演算法可同時得到待求材料之楊式模數(Young’s Modulus)及熱膨脹係數。而透過反算之結果，將從研究文獻、材料理論等多重角度做一佐証及統整。
由於電鍍鎳模及Ni3Sn4因成長方式造成之差異均有可能在構裝中有著決定性的影響，因此透過本文，期望未來在構裝體的應力分析上能夠提供更充足的材料參數。With the improvement of filpchip technique and chip efficiency, temperature problem is becoming an important issue. When chip is working, the high temperature easily causes the packaging to deform because chip and substrate have different thermal expansion coefficients (CTE), and the high stress resulting from the deformation will make I/O connections fracture. Numerical methods have been widely used to analysis the stress distribution and to predict the reliability of packaging, but only if the material properties of these connections are known can we predict the stress distribution very precisely.
Under-bump metallization (UBM) consists of many metal thin films, and these metal films often exhibit different mechanical properties from those of their bulk materials. Furthermore, during reflow process, UBM will react with solder bump to form a hard and brittle material-intermetallic compound (IMC). UBM and IMC are equally important in reliability analysis, but they are so thin that their properties are difficult to be measured. Therefore, the objective of this study is to develop an inverse method to detect the mechanical properties of nickel film and nickel IMC.
In this study, specimens having multi-layer structure, such as Ni/Si, Ni3Sn4/Ni/Si, Ni3Sn4/Ni Foil, were produced. By using optical measurement technique and inverse method, which includes finite element method (FEM) and genetic algorithm (GA), the Young’s modulus and CTE of the unknown material can be obtained simultaneously. The inversely calculated results of Ni and Ni3Sn4 were also verified by relevant literatures and material theories.
Various growing conditions of electroplated nickel or Ni3SN4 will result in different mechanical properties, and that also causes different effects on packaging. Hence, this study was expected to offer more data about Ni and Ni3Sn4 for the stress analysis of packaging.第 1 章 緒論 1
1.1 研究動機 1
1.2 文獻回顧 4
1.3 研究範疇 6
第 2 章 量測技術 7
2.1 引言 7
2.2 相位量測原理介紹 8
2.3 反射疊紋法 13
2.4 實驗系統驗證 17
第 3 章 分析方法之建立、驗證及討論 20
3.1 引言 20
3.2 矽基材機械性質之測定 21
3.3 分析方法 28
3.3.1 數值方法 28
3.3.2 遺傳演算法 31
3.4 反算方法之建立與驗證 35
第 4 章 電鍍鎳膜及Ni3Sn4介金屬化合物之機械性質 43
4.1 引言 43
4.2 電鍍鎳膜及Ni3Sn4之試片製作及實驗方法 44
4.2.1 試片製作 44
4.2.2 實驗方法 47
4.3 電鍍鎳膜之機械性質 51
4.3.1 以銅/鈦(Cu/Ti)為附著層材料性質之決定 51
4.3.2 電鍍鎳膜機械性質之反算結果與討論 55
4.4 Ni3Sn4之機械性質 62
4.4.1 電鍍鎳膜上成長Ni3Sn4機械性質之反算結果 62
4.4.2 在鎳箔上成長Ni3Sn4機械性質之反算結果 64
4.4.3 在電鍍鎳及鎳箔上成長之Ni3Sn4機械性質討論 69
4.5 結語 73
第 5 章 結論及未來展望 74
5.1 結論 74
5.1.1 量測及反算系統 74
5.1.2 薄膜機械性質 76
5.2 未來展望 7
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dynamics and Controls of Fluidic Pressure-Fed Mechanism (FPFM) of Nanopositioning System
Get PDFFlexure or compliant mechanisms are employed in many precisions engineered devices due to their compactness, linearity, resolution, etc. Yet, critical issues remain in motion errors, thermal instability, limited bandwidth, and vibration of dynamic systems. Those issues cannot be negligible to maintain high precision and accuracy for precision engineering applications. In this thesis, a novel fluidic pressure-fed mechanism (FPFM) is proposed and investigated. The proposed method is designing internal fluidic channels inside the spring structure of the flexure mechanism using the additive manufacturing (AM) process to overcome addressed challenges. By applying pneumatic/hydraulic pressure and filling media into fluidic channels, dynamic characteristics of each spring structure of the flexure mechanism can be altered or adjusted to correct motion errors, increase operating speed, and suppress vibration. Additionally, FPFM can enhance thermal stability by flowing fluids without affecting the motion quality of the dynamic system. Lastly, the motion of the nanopositioning system driven by FPFM can provide sub-nanometer resolution motion, and this enables the nanopositioning system to have two linear motion in a monolithic structure. The main objective of this thesis is to propose and validate the feasibility of FPFM that can ultimately be used for a monolithic FPFM dual-mode stage for providing high positioning performance without motion errors while reducing vibration and increasing thermal stability and bandwidth
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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