晶圆减薄过程TTV调整技术研究

晶圆背面减薄是集成电路后封装关键工艺,通过金刚石磨轮的磨削作用,对芯片背面的基体材料-硅材料去除一定的厚度,从而降低芯片厚度,改善芯片的散热效果,有利于后期的封装工艺。主要介绍了在晶圆减薄过程中的关键指标TTV 的影响因素,通过设备自动控制,进行工艺角度调整,能够减小晶圆TTV 值,从而提高晶圆磨削质量。     

量子阱红外探测器衬底完全去除技术研究

背面减薄技术对于提高量子阱红外焦平面探测器的性能有着重要的意义,通过衬底减薄能够缓解探测器芯片与读出电路的热膨胀失配,提高互连混成芯片可靠性,同时能够有效降低串扰。本文结合机械研磨、化学机械抛光和选择性湿法腐蚀技术,实现了量子阱探测器互连混成芯片的衬底完全去除。     

大尺寸硅片超薄技术

随着器件小型化技术的发展,硅芯片厚度成为了发展超薄封装的关键问题。为了实现大尺寸硅片减薄到100μm的批量生产,研究了减薄工艺原理和大尺寸(以直径为200 mm为例)Si片超薄工艺的控制点。通过对不同减薄工艺的对比,分析了减薄工艺不同参数对减薄质量的影响,验证了不同砂轮目数、化学腐蚀工艺对硅片减薄质量、碎片率和背面金属质量的影响。根据实验数据给出了提高减薄质量、降低碎片率、提升生产效率的工艺实现方法,实现了大尺寸硅片超薄厚度的批量生产。     

单点金刚石切削InSb单晶的研究

InSb红外焦平面探测器一直在中波波段占据重要地位。随着科技的发展,迫切需要针对InSb单晶的精密加工方法。采用单点金刚石切削(Single Point Diamond Turning,SPDT)精密机床对InSb晶体进行减薄工艺开发。在机床加工工艺中,可变参数有主轴转速、单次去除量和进给速度等。通过正交试验,确定了单点金刚石切削InSb晶体的最佳工艺参数。对于切削后的InSb晶体,结合双晶衍射测试,其切削损伤低于3 μm。InSb红外器件流片证实单点金刚石切削InSb晶体工艺能满足用户的使用要求,获得较好的结果。     

大尺寸硅片背面磨削技术的应用与发展

集成电路芯片不断向高密度、高性能和轻薄短小方向发展，为满足IC封装要求，图形硅片的背面减薄成为半导体后半制程中的重要工序。随着大直径硅片的应用，硅片的厚度相应增大，而先进的封装技术则要求更薄的芯片，超精密磨削作为硅片背面减薄主要工艺得到广泛应用。本文分析了几种常用的硅片背面减薄技术，论述了的基于自旋转磨削法的硅片背面磨削的加工原理、工艺特点和关键技术，介绍了硅片背面磨削技术面临的挑战和取得的新进展。     

锑化铟焦平面器件背面减薄后的表面处理方法研究

经传统的背面减薄工艺处理后,锑化铟焦平面器件的表面上经常会有细微划道;采用传统的表面清洗方式时也容易对器件表面造成划道,导致工艺重复性差。因此,当器件经过背面减薄后,利用腐蚀液去除划道,并采用基于石油醚和无水乙醇的非接触式清洗方法,有效降低了器件表面产生划道的几率,同时避免了由于表面腐蚀速率不均匀导致测试时部分区域电平较高、在测试图像上出现亮斑等情况;另外还提高了工艺的重复性,使锑化铟器件的红外成像均匀且没有划道,从而提高了该器件的成品率。     

快速退火在提高芯片背金质量中的应用

论述了芯片背面蒸金在管式合金炉合金后存在的质量问题,通过分析影响焊接质量的原因,提出用快速退火炉合金代替传统的管式合金炉合金,并优化合金温度和时间,最终找出合适的工艺条件,彻底解决了背金质量问题.该工艺生产的芯片饱和压降、热阻降低10%左右,且一致性好,同时使用快速退火炉合金后金层的厚度可大幅度减薄,大大降低了芯片成本.     

使用凹槽磨块减薄GaAs功率MESFET芯片

在GaAs功率MESFET的研制和生产过程中,为了减小器件热阻,必须减薄芯片之后再进行管芯装架。目前我们要求芯片减薄到大约100μm。 为了改进芯片减薄工艺,我们加工了如图1所示的不锈钢凹槽磨块。其槽深是关键尺寸,它应该等于减薄之后的芯片厚度与粘料厚度之和。     

单点金刚石车削技术的研究

介绍了单点金刚石车削原理,分析了单点金刚石车削技术中影响光学零件面形精度和粗糙度的重要技术因素,同时提出了相应的解决方案,并展望了单点金刚石车削技术在光学制造领域的应用前景.     

锑化铟红外焦平面阵列探测器的热应力结构优化

在液氮冲击实验中,锑化铟红外焦平面阵列探测器中各层材料之间线膨胀系数的不同将导致热失配产生,过大的热失配应力将引起锑化铟芯片断裂失效。为了降低热失配对锑化铟芯片的影响,基于弹性多层体系热应力计算理论,借鉴平衡复合物结构设计方法,优化平衡复合物结构上表面的热应变,使得平衡复合物结构中硅读出电路上表面的热应变尽可能接近锑化铟芯片下表面的热应变,从而大幅降低锑化铟芯片中的热应力。考虑器件加工工艺成熟度,经一系列计算表明:当硅读出电路的厚度取25 μm时,平衡复合物结构中硅读出电路上表面的热应变与InSb芯片下表面的热应变最为接近,此时锑化铟芯片中的拉应力最小。锑化铟芯片中拉应力的大幅降低,将为消减液氮冲击中锑化铟芯片的碎裂几率提供可以信赖的结构设计方案和实现途径。     

Preparation and Characterization of TaN ALD Precursors

High purity organic-tantalum precursors for thin film ALD TaN were synthesized and characterized.Vapor pressure and thermal stability of these precursors were studied.From the vapor pressure analysis,it was found that TBTEMT has a higher vapor pressure than any other published liquid TaN precursor,including TBTDET,TAITMATA,and IPTDET.Thermal stability of the alkyl groups on the precursors was investigated using a 1H NMR technique.The results indicated that the tertbutylimino group is the most stable group on TBTDET and TBTEMT as compared to the dialkylamido groups.Thermal stability of TaN precursors decreased in the following order:TBTDET ＞ PDMAT ＞ TBTEMT.In conclusion,precursor vapor pressure and thermal stability were tuned by making slight variations in the ligand sphere around the metal center.     

Curved crystal spectrometer for the measurement of X-ray lines from laser-produced plasmas

In order to diagnose the laser-produced plasmas, a focusing curved crystal spectrometer has been developed for measuring the X-ray lines radiated from a laser-produced plasmas. The design is based on the fact that the ray emitted from a source located at one focus of an ellipse will converge on the other focus by the reflection of the elliptical surface. The focal length and the eccentricity of the ellipse are 1350 mm and 0.9586, respectively. The spectrometer can be used to measure the X- ray lines in the wavelength range of 0.2-0.37 nm, and a LiF crystal （200） （2d = 0.4027 nm） is used as dispersive element covering Bragg angle from 30° to 67.5°. The spectrometer was tested on Shengnang- Ⅱ which can deliver laser energy of 60-80 J/pulse and the laser wavelength is 0.35 μm. Photographs of spectra including the 1 s2p ^1P1-1s^2 ^1S0 resonance line（w）, the 1s2p ^3P2-1s^2 1S0 magnetic quadrupole line（x）, the 1s2p ^3P1-1 s^2 ^1S0 intercombination lines（y）, the 1 s2p ^3S~1-1 s^2 ^1S0 forbidden line（z） in helium-like Ti Ⅹ Ⅺ and the 1 s2s2p ^2P3/2-1 s622s ^2S1/2 line（q） in lithium-like Ti Ⅹ Ⅹhave been recorded with a X-ray CCD camera. The experimental result shows that the wavelength resolution（λ/△ 2） is above 1000 and the elliptical crystal spectrometer is suitable for X-ray spectroscopy.     

Electronic Structure of Semiconductor Nanocrystals

This paper reviews our recent development of the use of the large-scale pseudopotential method to calculate the electronic structure of semiconductor nanocrystals, such as quantum dots and wires, which often contain tens of thousands of atoms. The calculated size-dependent exciton energies and absorption spectra of quantum dots and wires are in good agreement with experiments. We show that the electronic structure of a nanocrystal can be tuned not only by its size,but also by its shape. Finally,we show that defect properties in quantum dots can be significantly different from those in bulk semiconductors.     

Critical Stage Rule-Based Real Time Dispatch（RTD）System in Highly-Mixed-Products （HMP） FAB

An improving utilization and efficiency of critical equipments in semiconductor wafer fabrication facilities are concerned. Semiconductor manufacturing FAB is one of the most complicated and cost sensitive environments. A good dispatching tool will make big difference in equipment utilization and FAB output as a whole. The equipment in this paper is In-Line DUV Scanner. There are many factors impacting utilization and output on this equipment group. In HMP environment one of the issues is changing of reticule in this area and idle counts due to load unbalance between equipments. Here we'll introduce a rule-based RTD system which aiming at decreasing the number of recipe change and idle counts among a group of scanner equipment in a high-mixed-products FAB.     

GaAsSb/InAlAs PA DHBTs Grown by Production MBE

The epi material growth of GaAsSb based DHBTs with InAlAs emitters are investigated using a 4 × 100mm multi-wafer production Riber 49 MBE reactor fully equipped with real-time in-situ sensors including an absorption band edge spectroscope and an optical-based flux monitor. The state-of-the-art hole mobilities are obtained from 100nm thick carbon-doped GaAsSb. A Sb composition variation of less than ± 0.1 atomic percent across a 4 × 100mm platen configuration has been achieved. The large area InAlAs/GaAsSb/InP DHBT device demonstrates excellent DC characteristics,such as BVCEO＞6V and a DC current gain of 45 at 1kA/cm2 for an emitter size of 50μm × 50μm. The devices have a 40nm thick GaAsSb base with p-doping of 4. 5 × 1019cm-3 . Devices with an emitter size of 4μm × 30μm have a current gain variation less than 2% across the fully processed 100mm wafer. ft and fmax are over 50GHz,with a power efficiency of 50% ,which are comparable to standard power GaAs HBT results. These results demonstrate the potential application of GaAsSb/InP DHBT for power amplifiers and the feasibility of multi-wafer MBE for mass production of GaAsSb-based HBTs.     

Technology innovation and process integrations for sub-100nm gate patterning

This paper presents a brief overview of the Applied Centura(R)DPS(R)system,configured with silicon etch DPS Ⅱ chamber, with emphasis on discussing tuning capability for CD uniformity control. It also presents the studies of etch process chemistry and film integration impact for an overall successful gate patterning development. Discussions will focus on resolutions to key issues, such as CD uniformity, line-edge roughness, and multilayer film etching integration.     

White organic light-emitting devices based on fac tris（2- phenylpyridine） iridium sensitized 5,6,11,12-tetraphenylnap -hthacene

We have fabricated the white organic light-emitting devices （WOLEDs） based on 4,4＇ -bis（2,2 -diphenyl vinyl）-1,1＇ - biphenyl （DPVBi） and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene （rubrene）. The device structure is ITO/2T-NATA （20 nm）/NPBX （20 nm）/CBP： x%Ir（ppy）3：0.5% rubrene （8 nm）/NPBX （5 nm）/DPVBi （30 nm）/Alq（30 nm）/LiF（0.5 nm）/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris （2-phenylpyridine） iridium [Ir（ppy）3], acts as a yellow light-emitting layer, and N,N＇ -bis- （1-naphthyl）- N,N＇ -diphenyl -1, 1＇ -biphenyl-4,4＇ -diamine （NPBX） acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir （PPY）3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.     

Complete approach to automatic identification and subpixel center location for ellipse feature

To meet the need of automatic image features extraction with high precision in visual inspection, a complete approach to automatic identification and sub-pixel center location for similar-ellipse feature is proposed. In the method, the feature area is identified automatically based on the edge attribute, and the sub-pixel center location is accomplished with the leastsquare algorithm. It shows that the method is valid, practical, and has high precision by experiment. Meanwhile this method can meet the need of instrumentation of visual inspection because of easy realization and without man-machine interaction.     

小角度扩展相关性近似算法分析

本论文提出一种在多天线MIMO信道相关性建模中小角度扩展近似理论算法,并应用于分析MIMO系统性能。分析中分别对三种不同角能量分布情况下的空间相关性研发快速近似计算法,并同时提出双模(Bi-Modal)角能量分布情况下的近似运算。通过分析这些新方法的近似效率,可以得到计算简单、复杂度低、而且符合实际的MIMO相关信道矩阵,对系统级的快速高效计算法的研究和系统级的评估以及误差分析具有重要的意义。     

Noise character analysis and the restraint of self-pulsation laser diodes

We calculate the Langevin noise sources of self-pulsation laser diodes, analyze the effects of active region noise and saturable-absorption region noise on the power fluctuation as well as period fluctuation, and propose a novel method to restrain the noise effects. A visible SIMULINK model is established to simulate the system, The results indicate that the effects of noise in absorption region can be ignored; that with the increase of DC injecting current, the noise effects enhance power jitter, and nevertheless, the period jitter is decreased; and that with external sinusoidal current modulating the self-pulsation laser diode, the noise-induced power jitter and period jitter can be suppressed greatly. This work is valuable for clock recovery in all-optical network.