VeritySEM 5i CD-SEM 3D NAND

The newest in the Applied Materials VeritySEM product family, VeritySEM 5i CD-SEM system features first-of-its-kind, in-line, 3D capabilities for high-volume metrology of logic and memory devices at the 1xnm node and beyond. Leveraging market-leading SEMVision® G6 core technology, the new system addresses the unprecedented challenges in measuring physical dimensions posed by leading-edge geometries. Its state-of-the-art, high-resolution SEM column makes possible measurements as small as 6nminnovative image enhancement algorithms aid measurement of fine pattern details. An in-column tilt-beam enables 3D FinFET metrology, while back-scattered electron (BSE) metrology addresses high aspect ratio 3D NAND structures, and BEOL via-in-trench bottom CD and characterization metrology.

FinFETs challenge traditional metrology in such measurements as gate and fin heights, whose uniformity is critical to device performance and yield. Current in-line CD SEM technology can monitor only top-view dimension variations, not those in height and slope. The VeritySEM 5i system’s in-column beam tilt remedies these issues, enabling gate and fin heights to be calculated and controlled.As technology scales down, the aspect ratios of 3D NAND memory structures are increasing to 60:1 and beyond, making accurate measurement of the bottom CD impossible using conventional metrology. High-resolution BSE imaging enhances the signal received from within these structures, allowing the VeritySEM 5i system to “see” deep into vias and trenches for precision measurement. This capability also improves metrology for via-in-trench bottom CD in BEOL processing where the desired connectivity between underlying and overlaying metal layers must be achieved to minimize via resistance.

The VeritySEM 5i system’s exceptional in-line accuracy and process control eliminate more time-consuming and costly off-line wafer cross-sectioning while helping chipmakers to streamline process development, improve device performance and yield, and shorten ramp times to high-volume production.

The VeritySEM 5i system continues to offer hands free recipe creation and full automation. An offline recipe generator (ORG) features recipe editing capabilities via an external server, enabling multiple users to create recipes from computer-aided design offline without the need for wafers. The recipes are automatically stored in the tool database. By eliminating recipe creation time loss, the ORG enables the user to maximize the tool's utilization in production.

The tool's OPC|CheckMax is a proven solution for automating the optical proximity correction (OPC) mask qualification process. As scaling proceeds below 32nm, OPC-enhanced features are commonly incorporated into mask designs for all layers. Hundreds of CD measurements are required to verify that the features printed on the wafer are indeed what the device designers intended to produce. With a suite of proprietary algorithms, OPC|CheckMax receives input from electronic design automation systems, automatically creates CD-SEM measurement recipes, and then directs the VeritySEM 5i system to measure thousands of sites at high throughput without operator assistance.

SEM作为显微镜，可以放大微观物体形态，一般允许误差在放大倍数±5%。在相同工作条件下，放大倍数一般不会漂移，精度可靠。但随着温湿度变化，随着电磁环境变化，可能会有漂移。因为SEM放大和光学显微镜放大完全不同，完全靠扫描线圈和电器元件控制，电器元件的老化，可能会引起放大倍数漂移，因此过两年需要校准放大倍数。另外SEM图像尺寸测量精度问题，这个情况和方舟子质疑韩2身高有些类似，许多人用图像测量得出的结果误差很大。但相同的测量方法精度很高！还有SEM作为材料分析平台，做化学成分分析，晶体结构分析。偏差可以保证2%以内。最后总结：精度靠方法和条件保证！前提是方法一致，条件不要变化！！

对于快速地检测电子束曝光制造出的小纳米结构的尺寸和缺陷并保证其不受到损伤是纳米加工进入10nm尺度面临的另一重大技术问题。同时,在集成电路制造中,多层制造需要对标记进行极高精度的检测"显然,光学的无损伤检测方式己无法应用于10nm尺度范围,因此基于能量束的检测方法是必须采取的方式"。

目前工业界采用CD一SEM对小特征尺寸进行测量。

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