首页> 外文会议>CPES Annual Power Electronics Conference >Thermo-Mechanical Reliability of Nano-Silver Sintered Joints versus Lead-Free Solder Joints for Attaching Large-Area Silicon Devices
【24h】

Thermo-Mechanical Reliability of Nano-Silver Sintered Joints versus Lead-Free Solder Joints for Attaching Large-Area Silicon Devices

机译:纳米银烧结接头的热机械可靠性与无铅焊点连接,用于连接大面积硅装置

获取原文

摘要

Nano-silver sintered bonding was carried out at 275°C and under 3 mPa pressures, and soldering in a vacuum reflowing oven to reduce voiding. Both joints are subject to large shear stresses due to the mismatch in coefficients of thermal expansion (CTE) between the chip and the substrate. In this study, residual stresses in the chip-on-substrate assemblies were determined by measuring the bending curvatures of the bonded structures. An in-house optical setup measured the bending curvatures using a thin-film stress measurement technique. From the measured bending curvatures and the mechanical properties of the constituent materials, residual stresses were calculated. The thermo-mechanical reliabilities of both joining techniques were tested by thermal cycling. The chip assemblies were cycled between -40°C and 125°C (100 minutes of cycle time, 10 minutes of dwell time) and the changes in their bending curvatures were measured. Residual stresses were found to decrease with temperature cycling, which may be due to stress relaxation from creep or crack formation in the die-attach materials. Failure analysis of sintered nano-silver joints, eutectic Sn-3.5Ag solder (SAC305) joints and eutectic SnCu0.7Ni solder (SN100C) joints was performed by means of cross-sectioning and scanning electron microscopy (SEM) after 800 thermal cycles. For both solder materials with copper substrate, fatigue fracture started at the edge of the solder, and crack propagation across the solder joint was observed. No cracks were found at the joints between silicon and sintered nano-silver. The stress-relaxation behavior of all die-attach layers are hypothesized.
机译:纳米银烧结键合在275℃并在3MPa压下下进行,并焊接在炉中的真空中以减少空隙。由于芯片和基板之间的热膨胀系数(CTE)的系数不匹配,两个接头受到大的剪切应力。在该研究中,通过测量粘合结构的弯曲曲率来确定芯片上衬底组件中的残余应力。内部光学设置使用薄膜应力测量技术测量弯曲曲率。从测得的弯曲曲率和组成材料的机械性能,计算残余应力。通过热循环测试两个连接技术的热机械可靠性。芯片组件在-40℃和125℃之间循环(循环时间100分钟,停留时间10分钟),并测量其弯曲曲率的变化。发现残留应力随温度循环而降低,这可能是由于芯片附着材料中的蠕变或裂缝形成的应力松弛。通过横截面和扫描电子显微镜(SEM)在800个热循环后,通过横截面和扫描电子显微镜(SEM)进行烧结纳米银接头的失效分析,共晶Sn-3.5Ag焊料(SAC305)接头和共晶SNCU0.7NI焊接(SN100C)接头。对于具有铜基材的焊料材料,在焊料边缘开始疲劳裂缝,并且观察到焊接接头上的裂纹传播。在硅和烧结纳米银之间的关节中没有发现裂缝。所有模具附着层的应力松弛行为都是假设的。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号