Experimental investigation of process parameters for roll-type linear chemical mechanical polishing (Roll-CMP) system

The fabrication processes for electronic components are now demanding a higher degree of planarity for integration and multistacking, with chemical mechanical polishing (CMP) processes replacing conventional etching or mechanical polishing owing to their ability to attain global planarization. As CMP has been applied to more and more fields, new types of CMP machines have been developed. This study introduces a novel roll-type linear CMP (Roll-CMP) process that uses a line-contact material removal mechanism to for the polish flexible substrates, and examines the effect of the process parameters on the material removal rate (MRR) and its nonuniformity (NU). The parameters affecting the Roll-CMP process include down force, roll speed, table feed rate, slurry flow rate, slurry temperature, and the table oscillation length. Increasing the down force, roll speed, slurry flow rate, and slurry temperature resulted in a high average MRR (MRR_avg). Further, the MRR_avg was found to decrease with an increase in the oscillation length because of the effect of the polishing area. A large down force, high roll speed, high table feed rate, and high slurry flow rate were effective for reducing the NU. These results will be helpful for understanding the newly developed Roll-CMP process.     

利用FPGA实现红外焦平面器件的非均匀性校正

与红外单元器件系统相比,焦平面面阵测器的一个最大的缺点是其固有的非均匀性,尽管现在面阵探测器的非均匀性有了很大改进,但是非均匀性仍然限制凝视红色系统的探测性能。实用化、、实时的非均匀性校正是红外焦平面器件应用的一个关键技术,尽管现在已经有很多种基于场景的非均匀性校正方法,但是两点校正算法仍然是基础的校正方法,有不可替代的价值。两点校正算法的流程简单固定,非常适合用ＦＰＧＡ实现。文章介绍了利用ＦＰＧ     

Influence of a Retaining Ring on Strain and Stress in the Chemical Mechanical Polishing Process

In this article, a two-dimensional axisymmetric quasi-static finite element wafer scale model for chemical mechanical polishing (CMP) process involved in the wafer carrier, the carrier film, the wafer, the pad, and the retaining ring was developed to investigate the effect of a retaining ring surrounding the wafer carrier to the strain, stress, and nonuniformity of the wafer surface for the purpose of improving edge exclusion of wafer and preventing the wafer sliding from the carrier while grinding. Considering the same revolutions of the wafer and the pad and the axisymmetric distributed force forms of the wafer carrier and the retaining ring, and applying the principle of minimum potential energy, a two-dimensional axisymmetric quasi-static finite element model for CMP process was established. Following the developed model, the effects of the retaining ring on the strain components, the stress components, the von Mises stress, and the wafer's nonuniformity were investigated. The findings indicated that a retaining ring installed in the conventional CMP mechanism could reduce the variation of the von Mises stress distribution to reach the lower wafer's nonuniformity effectively, improve the over-grinding phenomenon and prevent the wafer sliding from the carrier while grinding.     

The Role of Nonuniformity in Convective Heat and Mass Transfer through Porous Media,Part 1

Through-air drying is commonly used in the drying of high-quality tissue and towel products. A representative elementary volume method was used to model the fluid flow and heat and mass transfer during through drying in heterogeneous porous biobased materials such as tissue and towel products. Results of flow both upstream and downstream of a modeled porous sheet allowed visualization of the effects of mixing at the top and bottom of the porous medium. The effect of initial nonuniformity on fluid flow and convective heat and mass transfer in heterogeneous porous media was studied. The effect of material nonhomogeneity and associated transport properties on moisture content of the porous material as a function of drying time was studied. Modeling results indicate that for the first time it is possible to simulate the effect of nonuniformity on fluid flow and convective heat and mass transfer in porous media during through-air drying of paper. Moisture and structural nonuniformity contributing to nonuniformity in air flow might contribute significantly to drying nonuniformity. Depending on the moisture regimes and degree of saturation of the convective medium, heat and mass transfer coefficients may have varying effects on the overall drying.     

The Role of Nonuniformity in Convective Heat and Mass Transfer through Porous Media,Part 2

Nonuniformities in porous materials can play a significant role in the convective and diffusive transport of fluid, heat, and mass. This study provides experimental results and corresponding numerical simulation results. The experiments report continuous data in transient test runs with measurements of temperature and velocity at distributed locations in the domain immediately downstream of the porous materials. An increasing degree of nonuniformity was found to produce a lower drying rate as well as an earlier onset of falling rate drying. The numerical model provides results of the effects of different nonhomogeneities such as distributed holes or distributed regions of varying permeability and moisture content. Comparisons between numerical and experimental test results indicate general agreement with differences with regard to details of the drying curve features. This provides a tool for studying the role of nonuniformity in fluid flow and heat and mass transfer in porous media.     

高温合金GH150氩弧焊接头的组织和力学性能

用金相分析和微型剪切试验等方法研究了高温合金ＧＨ１５０焊接接头各区域的微观组织和力学性能分布特性。该焊接接头中的熔合区组织和力学不均匀性最为严重，是该焊接接头最薄弱的部位。     

钢锭锭型对高速钢碳化物不均匀度的影响

根据Ｗ１８Ｃｒ４Ｖ高速钢的生产数据，采用统计分析方法推导导出评价锭型对钢材碳化物不均匀度，级别的影响，可用来选用合理锭型和改善产品材的碳化物不均匀性。     

防砂管外堆积砂渗透率实验研究

国内外对于松散颗粒床渗透率、窄分砂(均匀砂)渗透率的研究很多,但对于地层砂渗透率的研究很少,也没有将这种方法引入到石油工程领域;筛管完井后的产能变化主要取决于筛管外堆积砂渗透率的变化和筛管的堵塞程度,为此本文针对地层砂渗透率与地层砂粒度中值,非均匀系数和小于44μm颗粒含量的关系展开了实验研究,通过实验拟合出地层砂渗透率与上述几种影响因素的关系图版。由此对于任意给定的地层砂,可以通过测试其粒度分布结合该图版得出渗透率的大致变化范围,为产能预测中渗透率的变化提供理论依据,从而可以更加准确地预测防砂井在不同防砂精度下产能的变化规律,对指导工程实践具有一定意义。     

基于USB接口的高速高精度实时红外视频采集系统设计

提出了一种高速高精度实时红外视频处理及采集系统设计,采用高速DSP芯片对红外视频图像进行非均匀校正,配以传输速度高达480Mb／s的USB2．0接口芯片实现与主机接口,视频图像的显示及后续处理由计算机完成。实验验证了该系统具有高速、高精度、实时性强等特点,适用于高精度的红外视频采集和辐射特性测量。     

一种新型的非制冷红外机芯组件图像校正算法研究

非制冷红外探测器由于其结构简单、响应快等优势,在诸多领域得到广泛应用。然而由于结构和制作工艺等的限制,传统的非制冷红外焦平面阵列非均匀性校正方法并不能很好完成非均匀性校正任务,在挡片打开后画面会出现一层蒙纱感,严重影响图像质量,限制探测器的应用范围。从试验数据出发,对蒙纱感可能的来源进行分析,并针对其来源提出一种针对非理想因素的新型非均匀性校正方法,较好地对蒙纱感进行处理和补偿,极大提高成像质量。该方法操作简单,容易实现,在红外成像相关的应用上有重大意义。