高压玻璃钝化管芯新型工艺

针对玻璃钝化二极管管芯制造过程中的晶片弯曲及切割速度慢等问题,设计开发了一种新型的制造工艺,为大批量生产创造了条件.     

高压晶体管正斜角造型工艺过程的改进

本文提出一种改进高压晶体管正斜角造型工艺过程的方案.设计了一套模具.兼作对版和喷胶掩蔽管芯的基准.将园片载体和钢网格规范化,以便与模具配合使用.     

通过TRL校准提取管芯S参数的技术

介绍了一种基于TRL法的提取管芯S参数的方法.该方法从TRL校准出发,实际测量得到封装器件的S参数;管芯以外的参量(管壳及键和线)用等效电路表示,最后用微波仿真软件模拟得到管芯S参数.此方法在没有精确的测试夹具条件下,仍可以得到较理想的器件和管芯S参数.实验证明该方法简便、实用性强,可推广应用于不宜直接测量管芯S参数的器件.     

适合批量生产的GaAs数字IC背面金属化工艺

当前,IC逐步向高集成度、高密度、多功能方向发展,管芯尺寸也在增大;剪切力是器件考核的基本项目,随管芯面积的增大而增大,这就对背面金属化可靠性提出了较高的要求.本文通过分析、实验、分析改进的方法,提出了适合批量生产又兼顾成本因素的数字背面金属化工艺,使背面金属化性能满足了器件可靠性要求.     

提高小功率塑封管中测合格率的几项措施

由于目前塑料封装晶体三极管大批量生产,提高中测合格率后,能节约大批人力、物力,从而对降低产品成本,加强产品对市场的竟争力有着重大意义和贡献,必须引起足够的重视。 我们认为一般小功率塑封管中测合格率(η=合格品数/成品管芯总数×100％;合格品指成品管经过晶体管图示仪检测有V-I特性曲线的)高低,除了与管芯有一定联系外,主要与中后道工序中的烧结、热键压、内涂等几道工序有着较密切的关系。采用合理的工艺改进方法;与提高中测合格率是休戚相关的。 1.管芯装架     

热敏电阻在发光二极管热阻测量中的应用

文章介绍了用热敏电阻测量发光二极管热阻的实验装置和原理.把微小尺寸热敏电阻封装在发光二极管管芯支架上,用一次指数衰减函数拟合封装在发光二极管管芯支架上的热敏电阻R-T阻温曲线.通过测量微小尺寸热敏电阻电阻,计算发光二极管管芯温度以及发光二极管的热阻.该实验方法原理简单、明了,数据处理方便,结果可信.     

808 nm半导体激光器烧结工艺的研究

研究了808 nm半导体激光器烧结过程中容易出现的"爬"铟现象,根据实验室的实验条件,采用了侧壁氧化结构来解决这个问题.制作了普通结构和侧壁氧化结构的激光器,烧结测试后发现:侧壁氧化结构的管芯烧结成品率可以达到95%以上,比普通结构的烧结成品率提高了20%.再将这两批管芯在500mA下老化测试,发现:侧壁氧化的管芯寿命明显长于普通结构的管芯.     

13.7～14.5GHz内匹配型GaAs大功率器件

经过对器件结构、钝化等工艺的改进,成功研制出总栅宽为19.2mm的GaAs功率HFET.两管芯合成的内匹配器件,当Vds=9V,输入功率Pin=35dBm时,在f=13.7～14.5 GHz频段内,输出功率Po＞42dBm(15.8W),功率增益Gp＞7dB,功率附加效率PAE＞35%,两管芯合成效率大于90%,其中在14.3GHz频率点,输出功率达到42.54dBm(17.9W),增益7.54dB.     

13.7～14.5GHz内匹配型GaAs大功率器件

经过对器件结构、钝化等工艺的改进,成功研制出总栅宽为19.2mm的GaAs功率HFET.两管芯合成的内匹配器件,当Vds=9V,输入功率Pin=35dBm时,在f=13.7～14.5 GHz频段内,输出功率Po＞42dBm(15.8W),功率增益Gp＞7dB,功率附加效率PAE＞35%,两管芯合成效率大于90%,其中在14.3GHz频率点,输出功率达到42.54dBm(17.9W),增益7.54dB.     

C波段连续波200 W GaN内匹配功率管设计与实现

研制了一款C波段连续波大功率GaN内匹配功率管.设计采用4个12 mm栅宽GaN高电子迁移率(HEMT)管芯合成输出,功率管总栅宽4mmx12mm.利用负载牵引(Load-pull)和大信号建模技术提取GaN管芯阻抗,根据管芯阻抗进行匹配电路设计.电路设计充分考虑合成损耗等因素的影响,研制的连续波GaN内匹配功率管在4...     

量子骰子

量子博弈是量子信息的一个重要分支.以Meyer所研究的单硬币博弈游戏为基础,主要讨论了具有六个态的骰子游戏.对于经典的二人骰子游戏而言,游戏者双方P和Q获胜的几率相同,都是1/2.而在量子骰子游戏中,用骰子的态密度矩阵来表示该态,若其中一个游戏者Q用量子策略来代替经典游戏中随机的翻转过程,而另一个游戏者P仍然采用经典策略,则Q完全可以控制游戏的胜负.从而对于量子骰子游戏而言,可以得出:量子策略比经典策略更具优越性.     

Sea of Leads Compliant I/O Interconnect Process Integration for the Ultimate Enabling of Chips With Low-$hbox k$Interlayer Dielectrics

Sea of leads (SoL) process integration for the series of steps required to transform a fully intact die at the wafer level to a die that is assembled onto a board is described. The primary goal is to address the issues involved in reconciling the fabrication and assembly requirements of compliant leads, such as SoL, with those of standard semiconductor processes and chip assembly techniques. The effort is motivated in-part by the potential failure of the low-$hbox k$interlayer dielectric in microprocessors as a result of high mechanical stresses due to the coefficient of thermal expansion (CTE) mismatch between the chip and the board. SoL, and other compliant interconnections, mitigate this problem by mechanically decoupling the chip and the board. While compliant leads offer advantages over C4 technology, there is much to consider during the series of steps needed to transform the fully intact dice at the wafer level to dice that are assembled onto the board. The use of an encapsulation film over the leads during wafer sawing is shown to be necessary for slippery leads and other free-standing compliant leads. The use of a suitable flux when the leads are finished with a nickel–oxide nonwettable layer is essential for a successful wafer-level solder reflow. Successful die assembly using thermocompression bonding is demonstrated using two different SoL dice with correspondingly different substrates. The resistance of a chain of 30 cascaded leads is 2.7$Omega$.     

Void-free Au-Sn eutectic bonding of GaAs dice and its characterization using scanning acoustic microscopy

A new technique to produce perfect bonding between GaAs dice and alumina substrates is reported. Utilizing this technique, void-free bondings have been achieved consistently. The quality of the bonded devices is confirmed by a Scanning Acoustic Microscope (SAM) having a spatial resolution of 25 μm. Thermal cycling between -25° C and 125° C, and thermal shock between -196° C and 135° C, have been used to assess the reliability of the specimens. The SAM was used to study the variation of the bonds in the tests. After the tests, the bonds show no sign of degradation and the GaAs dice did not crack. Shear test has also been performed. All the well bonded specimens passed the shear test. The shear strength correlated very well with the SAM images of the specimens taken before the test.     

Multifocus Holographic 3-D Image Fusion Using Independent Component Analysis

We present multifocus holographic 3-D image fusion based on independent component analysis (ICA). In this paper, the ICA technique is used to fuse multiple reconstructed holographic images at different distances from the image sensor. A hologram of two dice located at distances of 315 and 345 mm, respectively, from the sensor is recorded using phase-shifting digital holography and used in our experiments. The resulting reconstructed fused holographic image shows both dice objects clearly in focus. This is compared with a single reconstructed holographic image in which only one of the die objects is in focus at a particular reconstruction distance.     

Fluxless process of fabricating In-Au joints on copper substrates

Based on the oxidation-free fluxless bonding technology, we have developed a bonding process to manufacture In-Au joints on copper substrates. 4 mm×4 mm Si blank dice and 6 mm×6 mm copper substrates are used. The dice are deposited with indium-rich Au/In/Cr multilayer structure in a single high vacuum cycle to prevent oxidation. Right after deposition, the outer Au layer interacts with the In layer to form AuIn₂ intermetallic compound. This compound is quite stable and thus can protect the In layer against oxygen penetration when it is exposed to ambient. On the other hand, it can easily be dissolved by the molten In during the bonding process. The substrate is deposited with Cr and Au. The dice are bonded to the substrates at 180°C in inert environment. Nearly void-free joints have been obtained as examined by a 75 MHz Scanning Acoustic Microscope (SAM). Cross sections of several samples are studied using SEM and EDX to identify the microstructure and composition of the joints. Shear test has been performed according to MIL-STD-883C. All the well-bonded devices meet the shear test force requirement. Despite the large mismatch on the thermal expansion coefficient between silicon and copper, no die cracking is observed on the 30 samples produced. To assess further endurance, two samples underwent thermal cycling test between -50 and 120°C for 20 cycles, SAM examination indicates that the joints incur little degradation after the test. This bonding method requires neither flux nor scrubbing action. It is thus particularly attractive for bonding devices that cannot be exposed to flux     

Die repackaging for failure analysis

This paper presents different methods of preparation to repack dice with a non destructive access to the backside. With new processes, and where backside milling is not possible, this work is mandatory for any fault localisation technique. Various mountings, to be chosen depending on the original package (mainly BGA) and on the requirements of the emission techniques, will be described. We will see also how these techniques could be used for a new product family: the System In Package (multiple dice inside a package). In this case the challenge is to extract the failed die without destroying the module.     

如何有效地提高功率型LED封装工艺

从芯片选择、改善热处理工艺以及如何选择硅胶等几个方面入手，本文讨论了如何有效地提高功率型LED封装工艺。     

LED全彩显示屏配光解决方案

介绍了LED全彩显示屏基于最主要部件-LED的全套配光方案，包括投产晶片的K-factor管理、封装工艺的控制、白平衡的调节以及LED光学透镜的设计，代表着业界先进的配光解决理念。     

Comment on "Dice, entropy, and likelihood"

We suggest an alternative interpretation of Frieden's results which better explains the relationship between Maximum Entropy, Maximum A Posteriori, and Minimum Mean-Square Error estimation in his dice problem.     

Analysis of room-temperature luminescence spectra of VPE-grown nitrogen-doped gallium phosphide

The effect of nitrogen doping on the 300°K quantum efficiency and luminescence spectra of VPE-grown gallium phosphide has been investigated. The range of nitrogen concentrations studied was 2 × 10¹⁸ –1.5 × 10¹⁹ cm{⁻³ on the corrected Lightowlers scale. Over this range, the external quantum efficiency of contactless dice at 40 amp/cm² in air varied from 0.04% to 0.13%, increasing monotonically with increasing nitrogen concentration. The photoluminescence spectra from as-grown epi layers and the electroluminescence spectra of contacted dice in reflecting cups were compared, and were characterized by the parameters lumens/watt, radiometric center of gravity, and photometric center of gravity. The relationship of these parameters to each other and their variation with nitrogen concentration in GaP has been determined. The problem of filtering the spectra to obtain greener devices with acceptable brightness has been investi-gated using the transmission spectra of two specific filters.