极端远紫外光刻技术

半导体器件与集成电路的不断小型化要求特征尺寸越来越小 ,极端远紫外光刻是 5种下一代光刻技术候选者之一 ,它的目标是瞄准 70纳米及 70纳米以下的特征尺寸光刻。本文从极端远紫外光源、极端远紫外光学系统、反射掩模、光刻胶、光刻机等方面对极端远紫外光刻技术进行了分析论述 ,并且对它的应用前景进行了简要分析     

Stress relaxation behavior of composite and eutectic Sn-Ag solder joints

Stress relaxation experiments were carried out at 25 C and 150 C on 96.5Sn-3.5Ag eutectic solder and Sn-Ag composite solder joints (Sn-Ag eutectic solder with 20 vol.% Cu₆Sn₅ reinforcements incorporated by in-situ methods). The magnitude of the stress drop during relaxation depends primarily upon the plastic shear strain imposed prior to the stress relaxation process. For sequential stress relaxation experiments that include unloading, the stress drop is nearly independent of the accumulated plastic shear strain. However, for sequential stress relaxation that does not include unloading, the stress relaxation is more dependent upon the cumulative plastic shear strain history. The stress in single shear lap joints does not relax to zero stress, as is observed in stress relaxation of bulk tension specimens, even at 150 C. Creep strain rates extracted from the relaxation data were much lower with smaller pre-strains in both eutectic Sn-Ag and composite solder joints. The stress exponent values (n) calculated from the stress relaxation test data ranged from 7 to 15 for both eutectic and composite solder joints, which were consistent with conventional creep data. These stress-relaxation behaviors can be explained on the basis of dislocation recovery processes that occur during relaxation and when specimens are unloaded.     

双极模拟集成电路版图识别的模式识别算法

双极模拟ＩＣ在广泛应用于个人移动通信ＲＦＩＣ中占有重要地位。双极模拟ＩＣ版图识别与验证是其ＣＡＤ研究的重要内容之一。基于模式识别和专家系统的思想,提出了一种双极模拟ＩＣ版图识别的模式识别算法。该方法定义了五种基本版图图形关系,在此基础上构造了版画图技术向量,建立了算法系统及识别系统。该识别算法的优点在于与具体工艺过程无关,从而使识别过程完全系统化。实验表明,该识别系统有效、准确、可靠。     

相移掩模的制作

本文阐述相移掩模技术研究中，常用的几种主要相移掩模制作方法，重点介绍了无络ＰＳＭ、Ｌｅｖｅｎｓｏｎ交替型ＰＳＭ、边级ＰＳＭ、亚分辨辅助ＰＳＭ以及激光直写制作ＰＳＭ的方法。     

光刻技术的现状和发展

着重从涂胶、曝光(包括光源和曝光方式等)、光刻胶和深度光刻等方面介绍了光刻技术的现状和未来的发展趋势.     

Damage accumulation under repeated reverse stressing of Sn-Ag solder joints

To better understand the effect of repeated reverse stress in solder joints, a new testing method was developed. Tin-silver solder joints were fabricated, constrained between Cu blocks, and then subjected to repeated shear loading in a tensile tester. Constant strain amplitudes were applied to simulate service conditions. However, large loads were used to accelerate the damage accumulation. Microstructural features of the damage were very similar to those found with studies on thermomechanical fatigue (TMF) of small, single shear lap samples. Concentrated-shear banding or striations were observed to form along Sn dendrites. The load behavior of the solder with each cycle and during hold times at the extreme strain amplitude was consistent with damage accumulating with each successive cycle. Effects of strain amplitude, hold times at the stress extremes, number of cycles, and solder-joint thickness were found to play significant roles on the stress-strain behavior and surface damage.     

Solder balling of lead-free solder pastes

Solder balling in Sn/Ag/Cu solder pastes was studied in this work. Three different solder pastes, several different reflow profiles and conditions, and two stencil thicknesses were used in the investigation. During the first phase, called the verification phase, the solder pastes were checked to ensure they met the minimum requirements. In the process-screening phase, the reflow profile was varied. Results show that besides flux chemistry, reflow atmosphere plays the major role in solder balling. The average number of solder balls with the best paste was one fifth of that with the worst paste. Furthermore, with all the pastes, the number of solder balls dropped close to zero when nitrogen atmosphere was used. Another finding during the reflow process screening was the influence of the stencil thickness on the solder-balling result. With a thinner stencil, two of the pastes exhibited significant solder balling. This is assumed to be caused by the different ability of fluxes to withstand oxidation during the preheating in the reflow process. In the last phase, the effect of the solder-paste particle size on solder balling was studied more closely. The flux chemistry was kept unchanged, and the solder particle size was varied between type 3 and type 4. The results show that, with type 4 paste, significantly more solder balls are formed compared to type 3 paste. It was also confirmed that, regarding the reflow profile, the ramp-up rate from 150°C to 217°C and the reflow atmosphere were the most significant factors that determine the solder-ball formation for both types of paste.     

深亚微米光学光刻工艺技术

光学光刻的生命力仍然在不断延续 ,即使在 0 13 μm及 0 13 μm以下集成电路制造水平上 ,光学光刻仍然是一个非常重要的候选者。深亚微米光学光刻工艺技术目前面临着越来越严重的挑战。对深亚微米光学光刻中的一些关键工艺技术如移相光刻、光学邻近效应校正、远紫外光刻胶、套刻对准误差等进行了论述。     

Flux development for lead-free solders containing zinc

New lead-free solders containing zinc are promising candidates to replace near-eutectic tin-lead solders because the solders melt at lower temperatures than Sn-Ag-base solders. They also possess good mechanical and fatigue properties and are less expensive. However, the contact angle on copper for Sn-Zn solders is high when fluxes used for Sn-Pb solders are utilized. A novel approach for flux development to improve wetting of copper surfaces by tin-zinc eutectic solder was developed: tin containing organic compounds, which decomposes at soldering temperatures and produces metallic tin on surfaces to be soldered was added to several specially formulated fluxes. This process improves wetting of copper surfaces by molten tin-zinc eutectic solder. Fluxes were developed that give a contact angle as low as 20°.     

Ce对Sn-Ag-Cu系焊料合金的组织与性能影响

通过添加稀土Ce研究了Sn-3.0Ag-2.8Cu系焊料合金的显微组织和性能。用光学显微镜、SEM、EDX对其显微组织进行分析,并且对其导电性,润湿性,硬度等重要性能进行测试。结果表明,添加稀土w(Ce)为1%焊料合金的导电性明显提高;而润湿角明显减小,润湿性增强;同时焊料合金的硬度也有所增加。