铟柱高度快速测量方法研究

在红外探测器铟柱蒸发的工艺试验中,有需要测量大量铟柱高度的情况,因此对铟柱高度测量方法进行了研究.手动逐点测量铟柱高度方式的结果较为准确,但是测量速度比较慢,消耗时间比较多.快速自动测量的方法使用了显微镜的扫描功能,并利用图像识别技术来自动识别铟柱,能够一次获取所有铟柱的高度,所以测量速度很快.详细介绍了这两种方法的操...     

应用于红外焦平面铟柱互连的封装技术

焦平面技术在红外侦察系统和红外成像导弹系统等军事领域都已经进入实际应用阶段,同时还将扩展到诸如工业监控测温、医疗卫生、海上救援、车辆和舰船的驾驶员夜视增强观察仪等广阔的民用领域。红外焦平面阵列是红外成像的核心部件,对于红外焦平面铟柱的连结方式目前主要是通过倒装焊的封装方式,通过涂敷助焊剂并通过红外回流将其重要组成部分的探测器和读出电路互连起来。文章主要介绍了应用于红外焦平面铟柱互连的倒装焊封装技术及其可靠性的影响。     

铟凸点对倒装互连影响的研究

制作了2种形式的铟凸点:即直接蒸发沉积的铟柱和将铟柱回流得到的铟球.分别讨论了铟柱和铟球对倒装互连的影响,着重讨论了铟球和铟柱分别和芯片倒装互连后的剪切强度,结果发现在互连未回流的状态下铟球的剪切强度是铟柱的1.5倍,回流后铟球的剪切强度是铟柱的2.8倍.此外,分析讨论了长时间放置在空气中的铟球对倒装互连的影响,结果发现长时间放置在空气中的铟球和芯片互连后,器件的电学与机械连通性能会受到很大的影响.     

红外探测器倒装互连技术进展

随着红外焦平面技术的发展,红外探测器探测波段已由单波段变为双色及四色波段,半导体元件的封装数量由最初的数十个发展到数百万个,I/O输出密度不断增大,传统微互联技术如引线键合技术、载带自动焊技术等已根本无法满足器件要求。倒装焊技术以其封装尺寸小、互联密度高、生产成本低的特点越来越受到人们的亲睐。倒装互连工艺主要包括:UBM 制备、铟膜沉积、回流成球、倒压焊、填充背底胶。介绍了各工艺步骤的发展状况,并对铟膜沉积、铟柱增高工艺进行详细阐述。     

128×128混合式热释电非致冷焦平面探测器列阵铟膜及铟柱制备工艺研究

着重介绍了我们在\     

百万像素级红外焦平面器件倒装互连工艺研究

介绍了倒装互连技术的工艺原理,阐述了红外焦平面器件倒装互连的工艺特点。通过系列实验和分析,最终优化并确定了百万像素级红外焦平面器件倒装互连的工艺参数,获得了良好的互连效果。     

混合式长波线列TDI红外探测器改进互连工艺研究

根据目前混合式红外焦平面互连工艺以及对长波线列延时积分红外探测器产量增长的需求,结合现有的工艺设备能力,开发出"共片工艺",以最大限度地提高在互连工艺段的生产效率.     

不同像元间距红外探测器的铟柱生长研究

分析了红外探测器铟柱生长工艺中不同像元间距情况下铟柱光刻孔内部的铟沉积情况和微观结构。解释了10■m小像元间距条件下铟柱高度较矮的原因,并给出了像元间距大小与剥离后铟柱高度之间的关系。针对10■m及以下像元间距红外探测器的铟柱生长,给出了解决铟柱高度问题的办法。使用新方法后,铟柱的高度可达到5■m以上。     

10 μm小间距红外探测器的铟柱生长研究

在10 μm小间距的条件下进行红外探测器的铟柱生长工艺,会得到铟柱高度不足的结果;本文针对这种情况,开展了小间距的铟柱生长研究,比较了在不同基片温度和蒸发速率条件下的铟柱高度,并分析了试验结果,得到了最优的生长工艺条件。     

混成式焦平面阵列芯片倒装互连技术研究

介绍了为保证倒装焊接性能,设备所采取的措施.对比了不同形貌铟柱的优缺点,分析了互连可靠性与铟柱高度的关系,介绍了考核互连可靠性的方法.通过互连技术研究,我们实现了较高性能的倒装互连,互连条件选择温度在60℃～140℃范围,压力范围0.1克/铟柱～0.5克/铟柱.互连连通率＞99.9%,互连后的芯片组件在低温(77K)与常温(23℃)间不少于100次的反复冲击的情况下,测试接触性能及InSb二极管性能都无变化,满足了互连器件可靠性要求.     

超长线列双波段红外焦平面探测器杜瓦封装技术研究

针对拼接型短/中波的超长线列焦平面探测器与直线脉管集成耦合的要求,分析了超长线列焦平面杜瓦封装的难点。通过对超长冷平台的温度均匀性、超长冷平台支撑结构、大体积组件杜瓦低热负载、超长线列杜瓦真空寿命等封装技术进行研究,提出了多点S型冷链结合导热层的三维热输出方法,设计了桥式两基板的超长冷平台支撑结构,解决了超长冷平台高温度均匀性、集成探测器后低应力及焦深控制、超长线列探测器杜瓦组件的环境适应性、低热负载和长真空寿命等关键技术,成功研制超长线列双波段焦平面探测器制冷组件,并通过一系列空间环境适应性试验验证,试验前后组件性能未发生明显变化,满足工程化应用的要求。     

Nondestructive methodology for standoff height measurement of flipchip on flex (FCOF) by SAM

Flip chip technology is the emerging interconnect technology for the next generation of high performance electronics. One of the important criteria for reliability is the width of the gap between the die and the substrate, i.e., the standoff height. A nondestructive technique using scanning acoustic microscopy (SAM) for the standoff height measurement of flip chip assemblies is demonstrated. The method, by means of the implementation of a pulse separation technique, time difference of the representative signals of the die bottom and water interface and water and substrate surface interface from the A-scan image can he found. Then, the corresponding standoff height can be calculated. When compared to the traditional destructive measurement method (SEM analysis on sectioned sample), this nondestructive technique yields reliable results     

长线列红外探测器真空密封结构设计

针对长线列碲镉汞红外焦平面探测器封装的特点,文章设计分析相对应的探测器真空密封结构。在用于封装3000元及5000元碲镉汞焦平面红外组件研制中,详细阐明了其真空密封结构的设计和工艺实现。符合航天空间应用的高可靠性真空结构,是长线列探测器组件正常工作并完成地面相关试验验证的关键。     

读出电路铟柱打底层对铟柱成球高度的影响

针对超大规模红外探测器读出电路铟柱成球后高度过低导致倒装互连难度增加这一问题,设计了试验,并分析讨论了读出电路铟柱打底层（UBM）形状对铟柱成球高度的影响。得出了铟球高度与铟柱尺寸和铟柱生长高度成正比,与读出电路铟柱打底层尺寸成反比,并提出了进一步增加铟球高度的思路。     

Optoelectronic and microwave transmission characteristics of indium solder bumps for low-temperature flip-chip applications

This paper describes low-temperature flip-chip bonding for both optical interconnect and microwave applications. Vertical-cavity surface-emitting laser (VCSEL) arrays were flip-chip bonded onto a fused silica substrate to investigate the optoelectronic characteristics. To achieve low-temperature flip-chip bonding, indium solder bumps were used, which had a low melting temperature of 156.7/spl deg/C. The current-voltage (I-V) and light-current (L-I) characteristics of the flip-chip bonded VCSEL arrays were improved by Ag coating on the indium bump. The I-V and L-I curves indicate that optical and electrical performances of Ag-coated indium bumps are superior to those of uncoated indium solder bumps. The microwave characteristics of the solder bumps were investigated by using a flip-chip-bonded coplanar waveguide (CPW) structure and by measuring the scattering parameter with an on-wafer probe station for the frequency range up to 40 GHz. The indium solder bumps, either with or without the Ag coating, provided good microwave characteristics and retained the original characteristic of the CPW signal lines without degradation of the insertion and return losses by the solder bumps.     

双色红外焦平面数字读出电路研究

设计了一款中、长波双色应用的数字化红外焦平面读出电路。由于双色红外焦平面器件在注入电流及动态输出阻抗上存在着数量级的差异,同时双波段均要求高灵敏度,因此读出电路需要在有限像元面积内实现双输入级的结构设计和大动态范围。电路采用基于直接注入型输入级的脉冲频率调制结构,设计电荷复位单元代替传统电压复位结构,可降低可探测的电荷分辨率,并改善由复位遗失电荷带来的非线性影响,同时电路设计了20bit混合结构的计数器,满足电路大电荷容量和低功耗的要求。仿真结果表明,实现的最小电荷分辨率为692e-,对应电荷容量为7.2×10⁸e-,双波段探测线性度均高于99.8%,在中、长波典型应用情况下功耗分别为3.03,6.66μW。     

Study on effect of coupling agents on underfill material in flipchip packaging

Coupling agents are widely used in order to improve the adhesion property of underfill. In this study, three different silane coupling agents, two titanate coupling agents, and one zirconate coupling agent were added into an epoxy underfill material. Their effects on the flow behavior and curing profile of the epoxy underfill were studied with a rheometer and a differential scanning calorimeter, respectively. The thermal stability of the cured underfill material was studied with a thermogravimetric analyzer. A thermal mechanical analyzer and a dynamic mechanical analyzer were used to measure the coefficient of thermal expansion, the glass transition temperature (T_g), and the storage modulus (E'). In addition, the adhesion of the underfill on benzocyclobutene passivated silicon die and polyimide passivated silicon die was measured through die shear test. The effects of aging in an 85°C/85% relative humidity chamber were also studied through moisture absorption test and die shear test     

红外焦平面阵列盲元判据的相关性研究

红外系统中探测器盲元的存在降低了红外图像的质量和红外系统的性能。在红外焦平面阵列最终性能的测试评价中,盲元的判定主要有响应率判据、噪声判据和直流电平判据三种。本文研究了直流电平判据同其他两种盲元判据之间的关系:电平低于正常像元的盲元具有噪声高、响应低的特征;电平高于正常像元的盲元具有噪声低、响应低的特征。实际测试的数据验证了分析的结果,具有较高的判别准确率。电平判据在实现判别盲元的成因与类型的同时,亦可以推断出像元噪声和响应率的状态以及这两种判据的判别结果。在探测器的制造过程中,简单的判别准则有助于早期剔除不合格品;在系统应用中,可快速评估探测器的变化以及新增盲元的原因和特征。     

Effect of multiple reflows on interfacial reaction and shear strength of Sn-Ag electroplated solder bumps for flip chip package

The effect of displacement rate and intermetallic compound (IMC) growth on the shear strength of electroplated Sn-2.5Ag (in wt.%) flip chip solder with Cu under-bump metallization (UBM) were investigated after multiple reflows. Cu₆Sn₅ IMC was formed at the interface after one reflow. After five reflows, two different IMC layers, consisting of a scallop-shaped Cu₆Sn₅ phase and a planar Cu₃Sn phase, and their thicknesses increased with increasing reflow number up to 10. The shear strengths peaked after four reflows, and then decreased with increasing reflow number. Increasing displacement rate increased the shear force. The tendency toward brittle fracture characteristics was intensified with increasing displacement rate and reflow number.