Mezzalira Claudia, Conti Fosca, Pedron Danilo, Signorini Raffaella
Department of Chemical Science, University of Padova, Via Marzolo 1, I-35131 Padova, Italy.
Consorzio INSTM, Via G. Giusti 9, I-50121 Firenze, Italy.
Micromachines (Basel). 2024 Jul 31;15(8):990. doi: 10.3390/mi15080990.
The unique electrical properties of silicon nitride have increased the applications in microelectronics, especially in the manufacture of integrated circuits. Silicon nitride is mainly used as a passivation barrier against water and sodium ion diffusion and as an electrical insulator between polysilicon layers in capacitors. The interface with different materials, like semiconductors and metals, through soldering may induce residual strains in the final assembly. Therefore, the dentification and quantification of strain becomes strategically important in optimizing processes to enhance the performance, duration, and reliability of devices. This work analyzes the thermomechanical local strain of semiconductor materials used to realize optoelectronic components. The strain induced in the β-SiN chips by the soldering process performed with AuSn pre-formed on copper substrates is investigated by Raman spectroscopy in a temperature range of -50 to 180 °C. The variation in the position of the E Raman peak allows the calculation of the local stress present in the active layer, from which the strain induced during the assembly process can be determined. The main reason for the strain is attributed to the differences in thermal expansion coefficients among the various materials involved, particularly between the chip, the interconnection material, and the substrate. Micro-Raman spectroscopy allows for the assessment of how different materials and assembly processes impact the strain, enabling more informed decisions to optimize the overall device structure.
氮化硅独特的电学特性增加了其在微电子领域的应用，尤其是在集成电路制造中。氮化硅主要用作防水和钠离子扩散的钝化阻挡层，以及电容器中多晶硅层之间的电绝缘体。通过焊接与不同材料（如半导体和金属）的界面可能会在最终组件中产生残余应变。因此，应变的识别和量化在优化工艺以提高器件的性能、寿命和可靠性方面具有重要的战略意义。这项工作分析了用于实现光电器件的半导体材料的热机械局部应变。通过拉曼光谱在-50至180°C的温度范围内研究了在铜基板上预先形成的AuSn进行焊接过程中在β-SiN芯片中诱导的应变。E拉曼峰位置的变化允许计算有源层中存在的局部应力，由此可以确定组装过程中诱导的应变。应变的主要原因归因于所涉及的各种材料之间热膨胀系数的差异，特别是芯片、互连材料和基板之间的差异。显微拉曼光谱允许评估不同材料和组装工艺如何影响应变，从而能够做出更明智的决策来优化整个器件结构。
