Known Good Die

Advances in reducing size and increasing functionality of electronics have been due primarily to the shrinking geometries and increasing performance of integrated circuit technologies. Recently, development efforts aimed at reducing size and increasingfunctionality have focused on the first level of the electronicpackage. The result has been the development of multichip packaging,technologies in which bare IC chips are mounted on a single high density substrate that serves to package thechips, as well as interconnect them. A number of benefits accruebecause of multichip packaging, namely, increased chip density,space savings, higher performance, and less weight. Therefore, thesetechnologies are attractive for today's light weight, portable, highperformance electronic equipment and devices.In spite of these benefits, multichip packaging has not shown the kind of explosive growth and expansion that was predicted[1]. A major inhibitor for these technologies has been theavailability of fully tested and conditioned bare die, orknown good die. This paper reviews the issues and technologies associated with test and burn-in of bareor minimally packaged IC products.     

可配置的媒体处理器:无线多媒体解决方案

线多媒体依赖于复杂的视频软件/服务器技术，而流视频和音频的生成又依赖复杂的处理技术。有一种产品无疑会从无线多媒体技术中得益，这就是个人数字助理(PDA)。然而，不同的PDA所采用的微处理器性能水平不同，如某些支持低帧速率的视频流和用软件处理低分辨率，而另有一些则不支持任何类型的视频流。一个能支持高质量双向视频通信的PDA的系统需要很强的系统计算能力。提高性能的方法之一是采用常见的小型接口标准，如PCMCIA卡和CF卡，最新的PDA都支持这些接口标准。高级视频和无线处理系统都可以采用PCMCIA和CF电路卡的标准进…     

Texture characterization of Cu interconnects with different Ta-based sidewall diffusion barriers

X-ray diffraction is used to assess the texture of narrow lines and study the impact of different sidewall diffusion barrier materials. All the Ta-based barriers developed a strong 〈1 1 1〉 texture in the scaled geometry, with little effect from sidewall growth. Comparisons were made with blanket wafers, demonstrating the pined grain structure in the narrow lines and contrasting change in texture due to re-crystallization in the unconstrained film. Furthermore, patterned lines showed significant anti-symmetric plane distribution influenced by high strains and twinning along the lines.     

New techniques in SIMS analysis of HgCdTe materials

This paper presents two new approaches used in the secondary ion mass spectrometry (SIMS) for high sensitivity dopant and impurity analysis in HgCdTe materials, namely, the high mass resolution with dynamic transfer and the MCs⁺ technique. It is shown that better detection limits for As and Cu can be obtained at a level of 2–5e14 at/cm³. The MCs⁺ technique has added advantages of better measurement precision, monitoring Cd composition in the same profile, and small device area analysis capability. Advantages and trade-offs of each technique are discussed and compared. An updated detection limit table for all elements measured in HgCdTe materials using SIMS is also presented.     

A comparison of commercially available quasistatic meters and methods

The capacitance-voltage (C-V) technique is one of the most powerful and direct methods to investigate interface traps in metal-insulator-semiconductor (MIS or MOS) related devices. As the C-V technique is of such fundamental importance in detecting and monitoring process related defects the systematic measurement concerns, misinterpretations and limitations associated with the equipment used to implement this technique must be fully understood and characterized. This study reports the results of a detailed comparison of both the (raw) measured C-V curve and the (analyzed) interface trap density versus energy data obtained using commercially available quasistatic meters, specifically the Hewlett-Packard (HP) model 4140B quasistatic/dc picoammeter and the Keithley model 595 quasistatic meter.     

An X-ray Radiography Study of the Effect of Thermal Cycling on Damage Evolution in Large-Area Sn-3.5Ag Solder Joints

There is a need for next-generation, high-performance power electronic packages and systems utilizing wide-band-gap devices to operate at high temperatures in automotive and electricity transmission applications. Sn-3.5Ag solder is a candidate for use in such packages with potential maximum operating temperatures of about 200°C. However, there is a need to understand the thermal cycling reliability of Sn-3.5Ag solders subject to such high-temperature operating conditions. The results of a study on the damage evolution occurring in large-area Sn-3.5Ag solder joints between silicon dies and direct bonded copper substrates with Au/Ni-P metallization subject to thermal cycling between 200°C and 5°C are presented in this paper. Interface structure evolution and damage accumulation were followed using high-resolution X-ray radiography, cross-sectional optical and scanning electron microscopies, and X-ray microanalysis in these joints for up to 3000 thermal cycles. Optical and scanning electron microscopy results showed that the stresses introduced by the thermal cycling result in cracking and delamination at the copper–intermetallic compound interface. X-ray microanalysis showed that stresses due to thermal cycling resulted in physical cracking and breakdown of the Ni-P barrier layer, facilitating Cu-Sn interdiffusion. This interdiffusion resulted in the formation of Cu-Sn intermetallic compounds underneath the Ni-P layer, subsequently leading to delamination between the Ni-rich layer and Cu-Sn intermetallic compounds.     

Host Exciton Confinement for Enhanced Förster‐Transfer‐Blend Gain Media Yielding Highly Efficient Yellow‐Green Lasers

This paper reports state‐of‐the‐art fluorene‐based yellow‐green conjugated polymer blend gain media using Förster resonant‐energy‐transfer from novel blue‐emitting hosts to yield low threshold (≤7 kW cm^?2) lasers operating between 540 and 590 nm. For poly(9,9‐dioctylfluorene‐co‐benzothiadiazole) (F8BT) (15 wt%) blended with the newly synthesized 3,6‐bis(2,7‐di([1,1′‐biphenyl]‐4‐yl)‐9‐phenyl‐9H‐fluoren‐9‐yl)‐9‐octyl‐9H–carbazole (DBPhFCz) a highly desirable more than four times increase (relative to F8BT) in net optical gain to 90 cm^?1 and 34 times reduction in amplified spontaneous emission threshold to 3 µJ cm^?2 is achieved. Detailed transient absorption studies confirm effective exciton confinement with consequent diffusion‐limited polaron‐pair generation for DBPhFCz. This delays formation of host photoinduced absorption long enough to enable build‐up of the spectrally overlapped, guest optical gain, and resolves a longstanding issue for conjugated polymer photonics. The comprehensive study further establishes that limiting host conjugation length is a key factor therein, with 9,9‐dialkylfluorene trimers also suitable hosts for F8BT but not pentamers, heptamers, or polymers. It is additionally demonstrated that the host highest occupied and lowest unoccupied molecular orbitals can be tuned independently from the guest gain properties. This provides the tantalizing prospect of enhanced electron and hole injection and transport without endangering efficient optical gain; a scenario of great interest for electrically pumped amplifiers and lasers.     

Study of metal barrier deposition-induced damage to porous low-k materials

A unique test structure based on a metal-insulator-semiconductor planar capacitor (Pcap) design was used to investigate several aspects of metal barrier-induced low-k damage. A special term called Effective Damage Thickness was introduced to describe the degree of damage. Ta(N) barrier was deposited on various dielectric films with porosity up to 32%. It has been found that the Effective Damage Thickness increases as the porosity increases. The damage is influenced more by the porosity of low-k films than the film density. Furthermore, the damage was modulated by Ta(N) deposition conditions. More damage was observed when higher target and/or substrate bias power was used, suggesting that the ion energy of the barrier material plays an important role in the low-k damage mechanism. A same degree of damage was observed for Ta barrier as for Ta(N), suggesting that Ta(N) deposition-induced low-k damage was primarily caused by Ta ions not nitrogen. Impact of Ru(Ta) and Cu(Mn) self forming barrier on low-k damage was also investigated. Among all the barriers studied in this work, the Ta-based barriers caused the most damage while the Cu(Mn) self forming barrier had the least damage to the low-k. The atomic masses for Ta, Ru, and Cu are 181, 101, and 64, respectively, corresponding with the observed degree of damage in the low-k material.     

A model-based approximation of opportunity cost for dynamic pricing in attended home delivery

OR Spectrum - For online retailers with attended home delivery business models, the decisive factor for promising dynamic time slot pricing decisions is the quality of the opportunity cost...     

Comparison of the Microbiological Quality of Environmentally Friendly and Conventionally Grown Vegetables Sold at Retail Markets in Korea

Fresh produce is usually eaten raw without cooking or heating, which may increase the probability of foodborne infection. The microbiological quality of 11 types of fresh, raw vegetables (romaine lettuce, sesame leaves, crown daisy, garlic chives, iceberg lettuce, cabbage, broccoli, leek, chili pepper, capsicum, and zucchini) purchased at retail markets in Iksan, Korea as affected by cultivation method (environmentally friendly vegetables [organic, pesticide‐free, and low‐pesticide vegetables] and conventionally grown vegetables) and harvest season was determined. Escherichia coli O157:H7 and Salmonella were not detected in all samples of vegetables tested. Aerobic mesophiles (>6 log cfu/g) were detected in environmentally friendly romaine lettuce and crown daisy and environmentally friendly and conventionally grown garlic chives, which also contained coliforms (>3 log cfu/g). Sesame leaf and crown daisy (regardless of cultivation method), as well as conventionally grown romaine lettuce and leek, contained >1 log cfu/g of E. coli. The overall microbiological quality of environmentally friendly and conventionally grown vegetables was not significantly different (P > 0.05). However, there were seasonal effects on populations of coliforms and generic E. coli on vegetables. The greatest numbers of microorganisms were isolated from environmentally friendly or conventionally grown vegetables purchased in winter. The vegetables, regardless of cultivation method or season, should be subjected to appropriate antimicrobial treatment to enhance their microbial safety.