Failure Probability Estimation of Anisotropic Conductive Film Packages With Asymmetric Upper-to-Lower Pad Size and Misalignment Offsets
Anisotropic conductive films (ACFs) are widely used in the packaging of flat panel displays and liquid crystal displays and for attaching bare chips to both flexible and rigid substrates. This paper utilizes the V-shaped curve method to analyze the failure probability of ACF packages with an asymmetric upper/lower pad size and misalignment offsets. In the proposed method, the probability of opening failures is modeled using a Poisson function, modified to take into account the effects of the pad-width difference and misalignment offset on the effective conductive area between opposing pads. Meanwhile, the probability of bridging failures is evaluated using an enhanced bridging model based on the distance between the neighboring pad pairs in the array. The failure probability of the pad array is evaluated as a function of both the difference in width of the upper and lower pads and the degree of misalignment between the opposing pads in the array. The results show that the V-shaped curve method provides the means to predict the ACF volume fraction which minimizes the failure probability of the ACF assembly given a knowledge of the pad-width difference and the misalignment offset. In addition, it is shown that when the misalignment offset is greater than the pad-width difference, the minimum failure probability reduces as the pad-width difference increases due to the corresponding increase in the effective conductive area between opposing pads. Conversely, when the misalignment offset is less than the pad-width difference, the minimum failure probability increases with an increasing pad-width difference due to the corresponding reduction in the effective conductive area between the pads.
Advanced Packaging of Optoelectronic Devices
In recent years, the packaging technologies of advanced optoelectronics devices and systems have evolved rapidly to meet the fast-growing industry of optoelectronics. However, packaging expense still accounts for a major portion of the overall cost of optoelectronics devices and systems. With the driving trend of higher power, smaller size, and higher reliability, many advanced packaging technologies are emerging. In this article, we present a comprehensive introduction of packaging design rules, advanced packaging materials, and packaging processes. Specific examples with state-of-art packaging methodologies are given for some typical devices, including high-power, light-emitting diodes; high-power semiconductor lasers; liquid crystal displays; and fiber-related optical devices. Insights on the technological development trend and philosophy are also discussed for advanced packaging of optoelectronic devices. 
 
 
Keywords: 
 
optoelectronic packaging; 
light-emitting diodes; 
semiconductor lasers; 
liquid crystal displays; 
fiber-optic modules
Fortune and Responsibility in Calderón's La gran Cenobia
La gran Cenobia deals with the war between Queen Zenobia of Palmyra and the Emperor Aurelian. Calderón de la Barca draws most of his information from historical sources; the dramatist, however, changes history and adapts it to his own dramatic purpose. The theme of Fortune gives unity to the play. Aureliano is portrayed as a tyrant who, to prove his independence from Fortune, behaves tyrannically, causing his eventual downfall. Cenobia believes that Fortune controls her life, but does not acknowledge that her own actions contribute to her misfortune. The analysis concludes that Fortune, as depicted in this play, is not an omnipotent and blind force, but what one has forged with his or her own actions coupled with the actions of others and circumstance.