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991.
Deok-Hoon Kim Peter Elenius Michael Johnson Scott Barrett 《Microelectronics Reliability》2002,42(12):536-1848
Wafer level packages (WLPs) have demonstrated a very clear cost-advantage vs traditional wire-bond technologies, especially for small components that have a high number of dice and I/O per wafer. Ultra CSP® is a WLP developed by the Kulicke & Soffa Flip Chip Division (formally Flip Chip Technologies). Typical products utilizing the Ultra chip scale package (CSP) have 5×5 or less area arrays at 0.5 mm pitch. This relatively small array has been limited by the inherent solder joint reliability of WLPs. A much larger subset of higher I/O IC’s could benefit from WLPs provided that standard reliability requirements are achieved without the use of underfill.A new polymer reinforcement technology, “Polymer Collar WLP™”, has been developed by K&S Flip Chip Division. Polymer Collar WLP utilizes a polymer reinforcement structure surrounding the solder joint and it has demonstrated more than 50% increase in solder joint life in thermal cycling tests. The most attractive feature of the Polymer Collar WLP process is its simplicity. A simple replacement of the standard solder flux with Polymer Collar material during the solder attach process is all that is required. This simplicity makes Polymer Collar the most cost-effective solution for adding a polymer reinforcement structure to the solder joint. Other methods in use today require additional complex and costly manufacturing steps.This Polymer Collar WLP is expected to widen the WLP market to include larger arrays where the Ultra CSP did not have suitable solder joint reliability. 相似文献
992.
Csaba Szeles Scott E. Cameron Stephen A. Soldner Jean-Olivier Ndap Michael D. Reed 《Journal of Electronic Materials》2004,33(6):742-751
The high-pressure electro-dynamic gradient (HP-EDG) crystal-growth technology has been recently developed and introduced at
eV PRODUCTS to grow large-volume, semi-insulating (SI) CdZnTe single crystals for room-temperature x-ray and gamma-ray detector
applications. The new HP growth technology significantly improves the downstream CdZnTe device-fabrication yield compared
to earlier versions of the HP crystal-growth technology because of the improved structural and charge-transport properties
of the CdZnTe ingots. The new state-of-the-art, HP-EDG crystal-growth systems offer exceptional flexibility and thermal and
mechanical stability and allow the growth of high-purity CdZnTe ingots. The flexibility of the multi-zone heater system allows
the dynamic control of heat flow to optimize the growth-interface shape during crystallization. This flexibility combined
with an advanced control system, improved system diagnostics, and realistic heat-transport modeling provides an excellent
platform for continuing process development. Initial results on large-diameter (140 mm), SI Cd1−xZnxTe (x=0.1) ingots grown in low temperature gradients with the HP-EDG technique show reduced defect density and complete elimination
of ingot cracking. The increased single-crystal yield combined with the improved charge transport allows the fabrication of
large-volume, high-sensitivity, high energy-resolution detector devices at increased yield. The CdZnTe ingots grown to date
produced large-volume crystals (≥1cm3) with electron mobility-lifetime product (μτe) in the (3–7) × 10−3 cm2/V range. The lower-than-desired charge-transport uniformity of the HP-EDG CdZnTe ingots is associated with the high density
of Te inclusions formed in the ingots during crystallization. The latest process-development efforts show a reduction in the
Te-inclusion density, an increase of the charge-transport uniformity, and improved energy resolution of the large-volume detectors
fabricated from these crystals. 相似文献
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995.
A novel type of binary geothermal installation is analyzed. It would increase the work obtained by more than 20%. This installation utilizes partial evaporation of the secondary fluid and flashing of the remaining liquid. Freon, ammonia and isobutane are examined as secondary fluids for the new installation. They all yield superior thermodynamic performance with respect to a conventional binary unit because the binary-flashing installation optimizes two parameters rather than one only. It also appears that the new installation is economically advantageous over existing installations. 相似文献
996.
Reactor systems based on tapered fluidized beds are being developed for aqueous bioprocesses in which adhering microorganisms or immobilized active biological fractions are used. The use of a fluidized bed prevents biomass buildup, accommodates particulates in the feed stream, is compatible with gas sparging, and allows easy removal or addition of the active materials. The tapered reactor tends to stabilize the fluidized bed, thus allowing a much wider range of operating conditions. Preliminary experimental results and an empirical mathematical model of the tapered bed indicate that bed stability is associated with a decreasing velocity and void-fraction profile up the bed and the pressure drop across the bed decreases with increasing flow rates. The tapered fluidized bed bioreactor is being evaluated for use in the enzymatic production of hydrogen, microbiological denitrification, and microbiological degradation of coal conversion aqueous waste streams. The enzyme catalyzed conversion of lactose to glucose and galactose was used in the evaluation of the reactor concept. 相似文献
997.
Reviews studies concerned with symptomatic behavior, clinical characteristics, genetic factors, and pharmacological response in relation to the unipolar–bipolar distinction in depressive disorders. The findings suggest that differences among some forms of the larger polar disorders do exist in the above areas. However, heterogeneity of results remains evident, indicating that finer subdivisions within the larger polar groups are necessary. Accordingly, research within the guidelines of a genetic taxonomy of polar groups is assessed and recommended as the most productive framework for future investigation of the depressive disorders. (4 p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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999.
A review of the experience with 134 consecutive patients with germinal cell testicular neoplasia indicates that definitively accurate staging of the malignancy at presentation is the single most important prognostic factor. Nearly two-thirds of the patients with all types of germinal malignancies survived or died of other causes and the highest survival rates were seen among patients with earlier stages of seminoma. In recent years patients with all types of germinal malignancies of the testis have been treated by radical retroperitoneal lymphadenectomy with enhancement of survivals. Patients with seminoma and non-seminomatous tumors exhibited increased survival rates with node dissection. In 66 consecutive lymphadenectomies the complication rate was less than 14 per cent, with only 1 death related to the operation. Retroperitoneal lymphadenectomy not only affords therapeutic advantage but also provides an opportunity for accurate surgical staging of disease and allows for rational decision relative to additional treatment, radiation therapy or chemotherapy. 相似文献
1000.
Although a great deal of attention has been given to the study of learning and memory, relatively little has been paid to the problem of preparing tests for assessing memory functioning in clinical settings. Available memory batteries (e.g., the Wechsler Memory Scale) and tests for verbal and nonverbal learning and memory are reviewed. It is noted that, with the exception of the Wechsler Memory Scale, there are no widely known clinical tests of memory functioning, and the Wechsler Memory Scale does little more than establish norms for a set of tasks ordinarily included in a mental status exam. Critical issues are summarized, and implications for memory testing in clinical settings and for preparing future test batteries are listed. (3? p ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献