基于晶圆栅格标准样片的特征尺寸扫描电子显微镜放大倍数在线校准

金红霞; 饶张飞; 秦凯亮

doi:10.12338/j.issn.2096-9015.2022.0294

基于晶圆栅格标准样片的特征尺寸扫描电子显微镜放大倍数在线校准

doi: 10.12338/j.issn.2096-9015.2022.0294

西安微电子技术研究所，西安 710065

基金项目: 国家重点研发计划项目（2018YFF0212303）。

详细信息

作者简介:
金红霞（1992-），西安微电子技术研究所工程师，研究方向：微纳参数计量、标准样片研制，邮箱：jin929496@foxmail.com

通讯作者:
饶张飞（1980-），西安微电子技术研究所研究员，研究方向：微纳几何参数计量，邮箱：13519129593@163.com

中图分类号: TB921
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出版历程
- 收稿日期: 2022-12-01
- 录用日期: 2023-01-28
- 修回日期: 2023-01-17
- 网络出版日期: 2023-03-02

Online Calibration of CD-SEM Magnification Based on Nanolattice Pitch Wafer Standard

Xi’an Microelectronic Technology Institute, Xi’an 710065, China

摘要

摘要: 半导体制程中特征尺寸扫描电子显微镜（CD-SEM）是用于芯片特征尺寸在线测量的高精度设备，其测量结果会直接影响器件电性能参数评估和电路产品可靠性判断。对CD-SEM的计量特性评价，国内目前仍缺乏专用计量标准器具和校准规范，在实际工作中，大多参照JJF 1916-2021《扫描电子显微镜校准规范》进行测长示值误差的在线计量。基于100 nm晶圆栅格标准样片对CD-SEM放大倍数在线校准方法进行了重点讨论，并结合实例阐述了特定放大倍数下不确定度分析过程和结果符合性判定方法，同时进一步对校准过程中的3类问题和相应解决措施进行了总结，对今后集成电路纳米级参数测量设备在线校准研究具有借鉴意义。
- 计量学 /
- 晶圆栅格标准样片 /
- 特征尺寸 /
- CD-SEM /
- 放大倍数校准 /
- 不确定度分析
Abstract: In semiconductor manufacturing, the critical dimension scanning electron microscope (CD-SEM) is a high-precision device used for the online measurement of chip feature size. The measurement results directly affect the evaluation of device electrical performance parameters and the judgment of circuit product reliability. However, there is still a lack of special measuring standards and calibration specifications for evaluating the measurement characteristics of CD-SEM. As a result, most calibrators refer to the JJF 1916-2021 Calibration Specification for Scanning Electron Microscopes (SEM) for online measurement of length indication errors in practice. The essence of using the nanolattice pitch standard to calibrate the CD-SEM magnification is to observe the measured image and obtain the pitch result by setting various instrument parameters and multiple pitches under different magnification conditions. Subsequently, the measured pitch result is compared to the certificate value of the standard to determine whether the instrument status is normal and whether the measurement accuracy meets process requirements. In this paper, we discuss an online calibration method of CD-SEM magnification based on the 100 nm nanolattice pitch wafer standard and introduce the measurement principle. We then describe the uncertainty analysis and conformity decision method of results under specific magnification with specific examples. Additionally, we briefly introduce three problems of the calibration process, such as the deterioration of the wafer standard, the noise of the measuring instrument, and contamination caused by an improper operational program. Finally, we summarize corresponding solutions, which have some reference value for future research on the online calibration of integrated circuit nano-parameters measurement equipment.
- metrology /
- nanolattice pitch wafer standard /
- critical dimension /
- CD-SEM /
- magnification calibration /
- uncertainty analysis

HTML全文

图 1 迟滞电子光学模块

Figure 1. Hysteresis electron-optical module

下载: 全尺寸图片幻灯片

图 2 像散修正模块

Figure 2. Astigmatism correction module

下载: 全尺寸图片幻灯片

图 3 100 nm晶圆栅格标准样片

Figure 3. 100 nm nanolattice pitch wafer standard

下载: 全尺寸图片幻灯片

图 4 线边缘粗糙度计算

Figure 4. The calculation of line edge roughness

下载: 全尺寸图片幻灯片

图 5 CD-SEM放大倍数在线校准流程

Figure 5. Online calibration process of CD-SEM magnification

下载: 全尺寸图片幻灯片

图 6 角度测量偏差

Figure 6. Angular measurement deviation

下载: 全尺寸图片幻灯片

图 7 扫描非线性计算

Figure 7. Calculation of sweep nonlinearity

下载: 全尺寸图片幻灯片

图 8 CD-SEM校准的3类问题

Figure 8. 3 types of problems of CD-SEM calibration

下载: 全尺寸图片幻灯片

表 1 放大倍数与栅格周期对应关系

Table 1. Correspondence between magnification and nanolattice pitch

栅格周期值/nm 100 200 400 800 1000

放大倍数/k 250 100 50 20 10

下载: 导出CSV

表 2 250 k放大倍数在线校准结果

Table 2. Online calibrating results of the 250 k magnification /nm

标准值 9个位置的测量结果

99.7 97.7 99.1 98.5 99.4 100.0
98.1 99.8 99.1 98.4 /

下载: 导出CSV

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