| 1. | Flip chip underfill technology
的芯片倒装技术 |
| 2. | The height and angle of no - flow underfill fillet little effects on the die cracking
在特定的焊点排布下，芯片断裂的可能性会达到最小。 |
| 3. | However , the die cracking was dependent on the young ' s modulus and cte of underfill materials . due to the higher cte and lower
山于薄型芯片在高密度封装使用中越来越广泛，本文的结果对高密度封装设计有重要意义。 |
| 4. | The stress intensity factor ( sif ) and the strain energy release rate were simulated with different pre - crack length for the cases with no - flow underfill and with capillary - flow underfill
本文第六章用断裂力学方涪和有限元模拟分析了填充不流动胶芯片断裂问题，计算了芯片的应力强度因于k和能量释放率g 。 |
| 5. | 2 . the die cracking with no - flow underfill was analyzed during cooling process from the curing temperature of underfill to the room temperature or to the lowest temperature ( - 55 ) in thermal cycle test
近年来，不流动胶倒装焊工艺己开始得到应用，但由于不流动胶的固化温度比常规底充胶高，芯片在冷却过程中将承受更大的热应力。 |
| 6. | The cracking with these two types of underfill might become unstable and lead to catastrophic failure at the end . the critical length was about 12m for the assembly with no - flow underfill and 20m for the package with capillary - flow underfill at 20 ?
模拟表明，山固化温度冷却到室温时，所研究的倒装焊封装在填充不流动胶时芯片断裂临界裂纹长度为12pm ，而填充传统底充胶时为20hm 。 |
| 7. | Delamination occurred when the liquid and gas phases of water coexist in micro - holes at chip / underfill interface . the adhesive strength between underfill and chip would be reduced due to the absorbed water molecules , resulting in extension and linkage of these micro - holes to form the delamination
认为在一定的水汽浓度下，器件内部塑封材中国科学院上海微系统与信启、技术研究所博十学位论文料在界面处的微孔洞可能出现气液两相共存。 |
| 8. | In the second part , the reliability research on electronic packaging was concentrated with finite element method ( fem ) on moisture diffusion in plastic materials , die cracking of flip - chip with no - flow underfill and thermal performance of high power electronic components . in the last chapter , the design tool for advanced electronic package was studied . the main conclusions in the second part are as follows
论文第二部分电子封装可靠性研究包含对塑封材料中水汽扩散研究、填充不流动胶的倒装焊芯片可靠性研究以及大功率器件散热问题研究三方面内容，最后为实现封装设计标准化和自动化，研究了若干最主要的电子封装构型的参数化有限元建模、加载和相应的求解方法。 |
| 9. | According to the m1l - std - 883c standard of thermal cycle loading , the delamination propagation rates at the interface between chip and underfill were studied experimentally by using c - mode scanning acoustic microscope ( c - sam ) for two types of flip chip packages with different states of solder joint
采用mil - std - 883c标准，通过温度循环实验，使用高频超声显微镜( c - sam )无损检测技术，测量了在不同焊点状态下， b型和d型两种实际倒装焊封装芯片与底充胶界面分层裂缝传播速率。 |
| 10. | Zhang liji ( material physics and chemistry ) directed by professor xie xiaoming this paper is intended to solve problems for those who are designing , using pbgas . failure mechanism , as well as cycles to failure of two groups of pbga samples ( with / without underfill ) for thermal cycling conditions in the range of - 40 ~ 125 , were presented . the experiment shows that solder ball in the samples without underfill cracked after 500 times cycle , no crack was found in the underfilled samples even after 2700 cycles
通过一系列的实验，得到以下实验结果： ?在本论文设定的温度循环条件下，未充胶pbga样品的热疲劳品寿命在500周左右，充胶样品的焊点寿命高于2700周； ?对于未充胶器件，中心距( dnp )是决定焊点应力、应变大小的最主要因素，裂纹总是从中心距较大处萌生并向中心处扩展； ?温度循环的过程中焊盘附近焊料组织明显粗化。 |
