线路修补

线路修补（CE）是集成电路设计调试阶段一种常用的技术。大多数的线路修补活动都是通过配备有气体注入系统（GIS）的双束电镜系统来完成，利用双束电镜系统，也可以进行定点和精确的材料刻蚀，以及导电接触孔或绝缘体的沉积。

被用作线路修补的典型气体注入系统包括：用于选择性硅基底材质刻蚀的 XeF₂；用于铜刻蚀的水汽；用于提供绝缘体的氧化硅和用于金属连接的钨。然而，线路修补的任务在现代 3D 集成电路器件中变得极具挑战性，因为器件的尺寸越来越小，密度越来越高。为了沿着 Z 方向导航并能够精确触及到感兴趣的膜层，全深度控制和精准的终点检测就显得尤为关键了。

所有TESCAN的双束扫描电镜系统都配备一种用于加强和优化大范围的 FIB 应用（包括线路修补）的气体注入系统。有两种 GIS 配置选项可供选择：五喷头电动 GIS 或多种单通道 GIS 单元。在任一选择中，都可以使用以下的前体：用于金属沉积的铂和钨；用于绝缘体沉积的氧化硅；用于增强刻蚀铜的水汽和用于选择性硅、氧化硅和氮化硅刻蚀的 XeF₂。

TESCAN 的 LYRA 和 GAIA系列双束电镜系统为满足先进的线路修补应用配备了 DrawBeam光刻模块以及为精确刻蚀、沉积和终点检测而设计的专业易用的软件。
精确的终点检测可通过 FIB产生的二次电子信号而获得。例如，在切割断面时发射出的二次电子可被用于鉴别膜层之间的过渡。在集成电路方面，Z 方向检测的精度优于 20 nm。

另外，Synopsys Avalon™ (Camelot™) 软件是一种结合了光电导航模块的完善的 CAD 导航标准，它可以将 CAD 设计数据、光学、红外、X 射线等图像与 SEM 或 FIB 图像进行实时叠加，从而精确导航到集成电路上来完成正面和背面的线路修补。

用光学显微镜对芯片进行彩色叠加的 SEM 图像

Integrated circuit device modification using Camelot

As the complexity of Integrated Circuit (IC) design modifications increase, the time to perform these modifications also increases. As a result, the turn-around-time for bug fixes becomes critical to a product’s success. The Focused Ion Beam (FIB) is powerful tool for circuit edit because it can remove and deposit materials with high precision. These capabilities can be used to cut and connect circuitry within a device, as well as to create probe points for electrical test. To execute circuit edits, the FIB tool is coupled to a CAD navigation system that makes it possible to locate the area of interest.

pdf – 2.2 MB

Live overlay of FIB image with CAD design data for precise navigation over the IC

Multi-scale Electron Beam Lithography using DrawBeam Batch Processing

DrawBeam Advanced is a versatile lithographic software allowing advanced electron- and ion-beam lithography. A CAD-like software interface allows the user to define a multi-layered project along with the processing parameters for each layer independently. It also allows combination of layers with electron- and ion-beam exposure/ milling and possibly also gas‑injection assisted processing. The new feature of Batch Processing allows automation of selected layers as one batch. This allows better optimization of the lithographic process e.g. by combination of high currents for large patterns and high resolution for fine-details.

pdf – 484 kB