Purpose

Wafer bonding is a key process for 3 D advanced packaging of integrated circuits. It requires very high accuracy for the wafer alignment. To solve the problems of large movement stroke, position calibration error and low production efficiency in optical alignment, this paper aims to propose a new wafer magnetic alignment technology (MAT) which is based on tunnel magneto resistance effect. MAT can realize micro distance alignment and reduces the design and manufacturing difficulty of wafer bonding equipment.

Design/methodology/approach

The current methods and existing problems of wafer optical alignment are introduced, and the mechanism and realization process of wafer magnetic alignment are proposed. Micro magnetic column (MMC) marks are designed on the wafer by the semiconductor manufacturing process. The mathematical model of the space magnetic field of the MMC is established, and the magnetic field distribution of the MMC alignment is numerically simulated and visualized. The relationship between the alignment accuracy and the MMC diameter, MMC remanence, MMC thickness and sensor measurement height was studied.

Findings

The simulation analysis shows that the overlapping double MMCs can align the wafer with accuracy within 1 µm and can control the bonding distance within the micrometer range to improve the alignment efficiency.

Originality/value

Magnetic alignment technology provides a new idea for wafer bonding alignment, which is expected to improve the accuracy and efficiency of wafer bonding.

中文翻译：

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用于晶圆键合的磁对准技术

目的

晶圆键合是集成电路3D先进封装的关键工艺。它需要非常高的晶圆对准精度。针对光学对准运动行程大、位置校准误差大、生产效率低的问题，提出一种基于隧道磁阻效应的晶圆磁对准技术（MAT）。MAT可以实现微距对准，降低晶圆键合设备的设计和制造难度。

设计/方法论/途径

介绍了目前晶圆光对准的方法和存在的问题，提出了晶圆磁对准的机理和实现过程。微磁柱（MMC）标记是通过半导体制造工艺在晶圆上设计的。建立了MMC空间磁场的数学模型，并对MMC对准的磁场分布进行了数值模拟和可视化。研究了对准精度与MMC直径、MMC剩磁、MMC厚度和传感器测量高度之间的关系。

发现

仿真分析表明，重叠式双MMC可以实现晶圆对位精度在1μm以内，并且可以将键合距离控制在微米范围内，提高对位效率。

原创性/价值

磁对准技术为晶圆键合对准提供了新的思路，有望提高晶圆键合的精度和效率。