GOALI: Assessment of Solder Joint Quality in Microchip Packages Used in Printed Circuit Boards by means of Laser Generated Sound Waves

GOALI：通过激光产生声波评估印刷电路板中使用的微芯片封装的焊点质量

• 批准号: 1536342
• 负责人: I. Charles Ume
• 金额: $ 30万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1536342&HistoricalAwards=false
• 关键词: GOALI; Assessment; Solder; Joint; Quality

The design and manufacture of microchips are a multi-billion dollar business. There is hardly any electronic device that does not contain microchip. These microchips are interconnected to the printed circuit board with solder joints which are hidden between the chip and the board. Often times these solder joints have manufacturing defects which are difficult to inspect because they are hidden from the view. These defects must be detected early before the board is fully assembled. However, traditional inspection tools to detect these defects are very unsatisfactory. This Grant Opportunity for Academic Liaison with Industry (GOALI) award supports fundamental research to provide the knowledge to enable the development of a low cost and efficient inspection tool that is superior to the existing tools. This new tool has the potential to, (1) significantly increase the yields of chips, (2) reduce new product development cycle time, and (3) reduce the costs of devices that use chips. Commercialization of this tool will create employment and wealth, and generate tax revenues for governments.The research objective is to establish the relationship between the strength of the ultrasound generated by the laser array bundle and the number of fibers in the bundle, length of the fibers, and laser energy carried by each fiber. Another objective is to establish the effects of each solder defect (such as crack, open, head-in-pillow, and pad cratering) on the generated ultrasound (in terms of energy of the received time domain signals). In order to accomplish these objectives, a finite element analysis method will be developed and used to predict the strength of the ultrasound (longitudinal, shear, or Lamb waves) generated by the array when the number of fibers, fiber length, and energy density are varied. The model predicted results will be used to guide the experimental set-up of the array sub-system for generating ultrasound in the chip. The measurement system will include an array sub-system, pulse laser which feeds laser energy into the array bundle, and laser interferometer for picking up the vibration signals on the chip surface. The vibration signals picked up by the interferometer at different points on the test chip surface will be correlated to the reference signals which are obtained from a defect-free chip to determine the presence of solder or chip defects.

微芯片的设计和制造是一项数十亿美元的业务。几乎没有任何不包含微芯片的电子设备。这些微芯片与印刷电路板相互连接，并与芯片和木板之间隐藏的焊接接头相互连接。通常，这些焊接接头具有制造缺陷，因为它们是从视图中隐藏的，因此很难检查。这些缺陷必须在董事会完全组装之前提早检测到。但是，检测这些缺陷的传统检查工具非常令人满意。这项与行业联络（Goari）奖的学术联络机会支持基本研究，以提供知识，以开发低成本和有效的检查工具，该工具优于现有工具。该新工具有可能（1）显着提高芯片的产量，（2）减少新产品开发周期和（3）降低使用芯片设备的成本。该工具的商业化将创造就业和财富，并为政府产生税收收入。研究目标是建立激光阵列束产生的超声强度与束，纤维长度，纤维长度和激光能量的超声之间的关系。另一个目的是建立每种焊料缺陷（例如裂纹，开放，头部填充和垫子饰面）对产生的超声（就接收到的时域信号的能量而言）的影响。为了实现这些目标，将开发有限元分析方法，并用于预测当纤维，纤维长度和能量密度的数量变化时，该阵列产生的超声（纵向，剪切或羔羊波）的强度。该模型预测的结果将用于指导阵列子系统的实验设置，以在芯片中生成超声。测量系统将包括一个阵列子系统，脉冲激光器，该脉冲激光器将激光能量输入阵列束和激光干涉仪，用于在芯片表面上拾取振动信号。干涉仪在测试芯片表面的不同点上拾取的振动信号将与从无缺陷芯片获得的参考信号相关，以确定焊料或芯片缺陷的存在。