树脂金刚石线锯锯切硅晶体最小极限切片厚度研究

The IC chip thickness is less than 5% of sliced silicon wafer thickness, and the rest is removed during wafer thinning. Besides that, the electronic structure of IC chip uses only 1% of wafer thickness, while the other 99% is used to ensure the mechanical strength and rigidity of wafer during IC chip processing. So the silicon wafer becomes thinner and thinner with the development of semiconductor technology. This project aims at the topic of ultra-thin sliced silicon wafer sawing process. Firstly, the mechanism of formation and propagation for surface layer (surface/subsurface) crack in sliced wafer sawn by resin bonded diamond wire saw will be studied, and the formation mechanism of warp and total thickness variation for sliced silicon wafer will be investigated. Then, to reveal the factors restricting sliced wafer to be thinned. After that, minimum limit thickness for sliced silicon wafer with resin bonded diamond wire saw is determined. Finally, the ultra-thin silicon wafer precise slicing with resin bonded diamond wire saw is realized based on studying resin bonded diamond wire saw slicing technology and processing parameters. The diamond wire saw slicing technology will be improved through this research. Through reducing wire saw sliced silicon wafer thickness, the rate of sliced silicon wafer production can be increased, and the machining amount of wafer thinning and the manufacturing cost for silicon wafer and optoelectronic product can be decreased. The research results of this project can be used to the ultra-thin wafer slicing of super hard crystal, such as SiC and sapphire.

集成电路芯片厚度只占线锯切割硅晶片厚度的5%以下，其余部分均在减薄中去除。且芯片的电子结构只利用了晶圆厚度的1%，其它99%部分只是用于保证芯片加工制造中所需的机械强度和刚度。随着半导体技术的发展，硅晶圆向超薄化方向发展。本项目以硅晶体极限薄片的切片加工为研究主题，开展树脂金刚石线锯切片表层（表面/亚表面）微裂纹形成和扩展机制研究，揭示线锯切片翘曲度和厚度偏差形成机理，阐明制约晶片薄型化的主要因素，确定树脂金刚石线锯切片的最小极限厚度，并通过研究树脂金刚石线锯极薄切片的锯切工艺及参数，实现树脂金刚石线锯对硅晶体的极限薄片精密锯切。通过本项目研究，进一步完善金刚石线锯切片技术。通过减小线锯切片厚度，提高硅晶体出片率，减少晶片的后续加工量，降低硅晶片及光电子产品的制造成本。项目的研究成果可推广应用于SiC、蓝宝石等超硬晶体材料的薄片锯切加工。

单晶硅晶圆衬底的直径增大、厚度减薄和集成电路制程减小是集成电路领域主流发展趋势。为降低光伏电池硅片成本，光伏硅晶体切片加工呈现薄片化。本项目针对树脂金刚石线锯锯切单晶硅的切片厚度问题，开展了树脂金刚石线锯锯切单晶硅的锯切力、硅片表层裂纹损伤机制、硅片断裂强度等研究，提出了切片厚度的确定方法。研究工作对完善金刚石线锯切片技术，提高切片质量，实现切片厚度的薄型化具有重要意义。.通过理论分析和实验研究，建立了多磨粒刻划过程中位裂纹间和亚表面侧向裂纹间耦合作用的力学模型，得到了裂纹尖端应力强度因子随刻划间距的变化规律。揭示了锯切工艺参数对锯切硅片表层裂纹损伤和裂纹损伤对硅片断裂强度的影响规律。.建立了树脂金刚石线锯模型和磨粒切割深度模型，得到了锯切力与工艺参数的定量关系和单晶硅的各向异性对锯切加工晶片面形偏差的影响规律。.通过单晶硅切片表层裂纹损伤实验研究，建立了单晶硅锯切硅片表层裂纹分布模型与硅片断裂强度数值模型，得到了硅片断裂强度的韦布尔分布与裂纹倾角对硅片断裂强度的影响规律，确定了单晶硅锯切硅片断裂强度表征方法。.建立了切片厚度与破片率之间的数学关系，提出了利用锯切过程硅片最大应力和破片率确定切片厚度的方法，确定了不同尺寸和形状的单晶硅切片厚度。.利用正交试验对树脂结合剂金刚石线锯的涂覆层组分进行了优化，研制了树脂结合剂金刚石线锯。以线锯弓角为评价指标，以理论材料去除率和实际材料去除率匹配为准则，建立了确定锯切工艺参数的方法。