Deflection Measurement and Determination of Young’s Modulus of Micro-cantilever Using Phase-shift Shadow Moiré Method

2009 ◽  
Vol 50 (7) ◽  
pp. 1051-1060 ◽  
Author(s):  
J. H. Lim ◽  
M. M. Ratnam ◽  
I. A. Azid ◽  
D. Mutharasu
2001 ◽  
Author(s):  
Hai Ding ◽  
I. Charles Ume ◽  
Cheng Zhang

Abstract Wafer-level packaging (WLP) is one of the trends of electronic packaging in the 21st century. Since 1994, many companies have released WLP licenses. One of the common concerns among these various approaches is wafer warpage. Warpage of wafer tends to introduces crack or delamination during dicing and low temperature storage process. After wafer dicing, warpage could reduce the quality of each package in the long run. Many documented works indicated that in the design and implementation of WLP, some key parameters have to be carefully considered and closely controlled to ensure higher packaging quality with the minimum warpage. For the case of wafer-level flip chip, the key parameters are Young’s modulus, thickness, and coefficient of thermal expansion (CTE) of underfill. In this research, an experimental design and statistical methods have been used to identify the model structure and parameters that are critical to the warpage of wafers. Regression models were identified based on the data obtained from finite element analysis (FEA) that is verified by shadow Moiré experiments. According to the models, the CTE, the coupling of Young’s modulus and CTE, and the coupling of thickness and CTE of underfill primarily determine wafer warpage. Further FEA and shadow Moiré experiments indicate that the models are capable of predicting of wafer warpage in the process of WLP.


1982 ◽  
Vol 21 (23) ◽  
pp. 4373 ◽  
Author(s):  
Jun-ichiroh Fujimoto

2004 ◽  
Vol 126 (2) ◽  
pp. 265-270 ◽  
Author(s):  
Hai Ding ◽  
I. Charles Ume ◽  
Cheng Zhang

Wafer-level packaging (WLP) is one of the future trends in electronic packaging. Since 1994, many companies have released various WLP licenses. One of the common concerns of WLP is wafer warpage. Warpage of wafers tends to introduce cracking or delamination during dicing and low temperature storage processes. After wafer dicing, warpage could affect the quality of the dies and shorten the life of each packaged product. Many documented works indicated that in the design and implementation of multilayer structured electronic packaging products, some key parameters must be carefully considered and closely controlled to ensure the best packaging quality with the minimum warpage. During the wafer-level flip chip assembly process, the application of underfill on the whole wafer is a critical step. In this step, the key underfill parameters that affect wafer warpage are Young’s modulus, thickness, and coefficient of thermal expansion (CTE). In this paper, an experimental design and statistical methods were used to identify the model structure and parameters that are critical to the warpage of wafers. Bilinear regression models were identified based on the data obtained from finite element analysis (FEA) that was verified by shadow moire´ experiments. In FEA, the underfilled wafer structure is simplified to consisting of two layers of linear elastic materials. According to the models, the CTE, the coupling of Young’s modulus and CTE, and the coupling of thickness and CTE primarily determine wafer warpage. Further FEA and shadow moire´ experiments indicate that the models are capable of predicting wafer warpage in the WLP processes.


2020 ◽  
Vol 12 ◽  
Author(s):  
S.V. Kontomaris ◽  
A. Malamou ◽  
A. Stylianou

Background: The determination of the mechanical properties of biological samples using Atomic Force Microscopy (AFM) at the nanoscale is usually performed using basic models arising from the contact mechanics theory. In particular, the Hertz model is the most frequently used theoretical tool for data processing. However, the Hertz model requires several assumptions such as homogeneous and isotropic samples and indenters with perfectly spherical or conical shapes. As it is widely known, none of these requirements are 100 % fulfilled for the case of indentation experiments at the nanoscale. As a result, significant errors arise in the Young’s modulus calculation. At the same time, an analytical model that could account complexities of soft biomaterials, such as nonlinear behavior, anisotropy, and heterogeneity, may be far-reaching. In addition, this hypothetical model would be ‘too difficult’ to be applied in real clinical activities since it would require very heavy workload and highly specialized personnel. Objective: In this paper a simple solution is provided to the aforementioned dead-end. A new approach is introduced in order to provide a simple and accurate method for the mechanical characterization at the nanoscale. Method: The ratio of the work done by the indenter on the sample of interest to the work done by the indenter on a reference sample is introduced as a new physical quantity that does not require homogeneous, isotropic samples or perfect indenters. Results: The proposed approach, not only provides an accurate solution from a physical perspective but also a simpler solution which does not require activities such as the determination of the cantilever’s spring constant and the dimensions of the AFM tip. Conclusion: The proposed, by this opinion paper, solution aims to provide a significant opportunity to overcome the existing limitations provided by Hertzian mechanics and apply AFM techniques in real clinical activities.


Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 328
Author(s):  
Kamil Anasiewicz ◽  
Józef Kuczmaszewski

This article is an evaluation of the phenomena occurring in adhesive joints during curing and their consequences. Considering changes in the values of Young’s modulus distributed along the joint thickness, and potential changes in adhesive strength in the cured state, the use of a numerical model may make it possible to improve finite element simulation effects and bring their results closer to experimental data. The results of a tensile test of a double overlap adhesive joint sample, performed using an extensometer, are presented. This test allowed for the precise determination of the shear modulus G of the cured adhesive under experimental conditions. Then, on the basis of the research carried out so far, a numerical model was built, taking the differences observed in the properties of the joint material into account. The stress distribution in a three-zone adhesive joint was analyzed in comparison to the standard numerical model in which the adhesive in the joint was treated as isotropic. It is proposed that a joint model with three-zones, differing in the Young’s modulus values, is more accurate for mapping the experimental results.


2018 ◽  
Vol 233 ◽  
pp. 00025
Author(s):  
P.V. Polydoropoulou ◽  
K.I. Tserpes ◽  
Sp.G. Pantelakis ◽  
Ch.V. Katsiropoulos

In this work a multi-scale model simulating the effect of the dispersion, the waviness as well as the agglomerations of MWCNTs on the Young’s modulus of a polymer enhanced with 0.4% MWCNTs (v/v) has been developed. Representative Unit Cells (RUCs) have been employed for the determination of the homogenized elastic properties of the MWCNT/polymer. The elastic properties computed by the RUCs were assigned to the Finite Element (FE) model of a tension specimen which was used to predict the Young’s modulus of the enhanced material. Furthermore, a comparison with experimental results obtained by tensile testing according to ASTM 638 has been made. The results show a remarkable decrease of the Young’s modulus for the polymer enhanced with aligned MWCNTs due to the increase of the CNT agglomerations. On the other hand, slight differences on the Young’s modulus have been observed for the material enhanced with randomly-oriented MWCNTs by the increase of the MWCNTs agglomerations, which might be attributed to the low concentration of the MWCNTs into the polymer. Moreover, the increase of the MWCNTs waviness led to a significant decrease of the Young’s modulus of the polymer enhanced with aligned MWCNTs. The experimental results in terms of the Young’s modulus are predicted well by assuming a random dispersion of MWCNTs into the polymer.


1992 ◽  
Vol 75 (10) ◽  
pp. 2915-2917 ◽  
Author(s):  
Amedeo Maddalena

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