The mechanics and impact of hygroscopic swelling of polymeric materials in electronic packaging

2002 ◽  
Author(s):  
E.H. Wong ◽  
K.C. Chan ◽  
R. Rajoo ◽  
T.B. Lim
Keyword(s):  
Electronic Packaging ◽  
Polymeric Materials ◽  
Hygroscopic Swelling

The Mechanics and Impact of Hygroscopic Swelling of Polymeric Materials in Electronic Packaging

2002 ◽  
Vol 124 (2) ◽  
pp. 122-126 ◽  
Author(s):  
E. H. Wong ◽  
R. Rajoo ◽  
S. W. Koh ◽  
T. B. Lim
Keyword(s):  
Thermal Stress ◽  
Electronic Packaging ◽  
Flip Chip ◽  
Polymeric Materials ◽  
Packaging Materials ◽  
Excellent Correlation ◽  
Reliable Technique ◽  
Hygroscopic Swelling ◽  
Solder Reflow ◽  
Swelling Characteristics

A reliable technique for characterizing the hygroscopic swelling of materials has been developed and used to characterize a number of packaging materials. Using these data, hygroscopic stress modeling were performed. The hygroscopic stress induced through moisture conditioning was found to be significant compared to the thermal stress during solder reflow. Hygroscopic stress in over-molded wire bond PBGA and molded Flip Chip PBGA was found to be 1.3 times to 1.5 times that of thermal stress. Hygroscopic swelling of the underfill in FCPBGA was found to be the main failure driver during autoclave test. Autoclave performance of FCPBGA package assembled with different underfills and chips were analyzed. Excellent correlation was found between autoclave performance and the hygroscopic swelling characteristics of the underfills.

Characterization of Hygroscopic Swelling and Thermo-Hygro-Mechanical Design on Electronic Package

2009 ◽  
Vol 25 (3) ◽  
pp. 225-232 ◽  
Author(s):  
H.-C. Hsu ◽  
Y.-T. Hsu
Keyword(s):  
Moisture Absorption ◽  
Mechanical Design ◽  
Three Dimensional ◽  
Polymeric Materials ◽  
Moisture Diffusivity ◽  
Moisture Concentration ◽  
Moisture Expansion ◽  
Hygroscopic Swelling ◽  
Three Dimensional Models ◽  
Materials Used

AbstractThis paper discusses a successful experimental procedure to determine the hygroscopic swelling property of polymeric materials used in electronic packaging. Saturated moisture concentration and moisture diffusivity were determined by measuring the weight gain during moisture absorption. Hygromechanical properties, such as the coefficientof moisture expansion (CME), were determined through Thermo-Mechanical Analyzer (TMA) and Thermo-Gravimetric Analyzer (TGA) techniques. Fick's law of transient diffusion is solved by using finite element (FE) analysis to evaluate the overall moisture distributions. Both two-dimensional and three-dimensional models based on the FE software ANSYS were developed to predict the thermal-induced strain, hygroscopic swelling deformation, and residual thermohygro-mechanicalstress distributions. Reliability analysis at three JEDEC preconditioning standards 60°C60%RH, 85°C60%RH and 85°C85%RH was carried out. A series of comprehensive parametric studies were conducted in this research.

The Resolution and Contrast in Biological Sections Determined by Inelastic and Elastic Scattering

1973 ◽  
Vol 31 ◽  
pp. 224-225
Author(s):  
D. L. Misell
Keyword(s):  
Electron Microscopy ◽  
Adverse Effect ◽  
Elastic Scattering ◽  
Inelastic Scattering ◽  
Amorphous Carbon ◽  
Polymeric Materials ◽  
Chromatic Aberration ◽  
Image Resolution ◽  
Quantitative Estimates ◽  
Elastic Ratio

In the electron microscopy of biological sections the adverse effect of chromatic aberration on image resolution is well known. In this paper calculations are presented for the inelastic and elastic image intensities using a wave-optical formulation. Quantitative estimates of the deterioration in image resolution as a result of chromatic aberration are presented as an alternative to geometric calculations. The predominance of inelastic scattering in the unstained biological and polymeric materials is shown by the inelastic to elastic ratio, I/E, within an objective aperture of 0.005 rad for amorphous carbon of a thickness, t=50nm, typical of biological sections; E=200keV, I/E=16.

Application Of Electron Microscopy To Automotive Finish Defect Analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 258-259
Author(s):  
Martin J. Mahon ◽  
Patrick W. Keating ◽  
John T. McLaughlin
Keyword(s):  
Electron Microscopy ◽  
Zero Tolerance ◽  
Polymeric Materials ◽  
Plant Management ◽  
Defect Analysis ◽  
X Ray ◽  
Root Cause ◽  
Cutting Out ◽  
Foreign Materials ◽  
Automotive Finish

Coatings are applied to appliances, instruments and automobiles for a variety of reasons including corrosion protection and enhancement of market value. Automobile finishes are a highly complex blend of polymeric materials which have a definite impact on the eventual ability of a car to sell. Consumers report that the gloss of the finish is one of the major items they look for in an automobile.With the finish being such an important part of the automobile, there is a zero tolerance for paint defects by auto assembly plant management. Owing to the increased complexity of the paint matrix and its inability to be “forgiving” when foreign materials are introduced into a newly applied finish, the analysis of paint defects has taken on unparalleled importance. Scanning electron microscopy with its attendant x-ray analysis capability is the premier method of examining defects and attempting to identify their root cause.Defects are normally examined by cutting out a coupon sized portion of the autobody and viewing in an SEM at various angles.

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