原子力显微镜（AFM）Atomic Force Microscopy

技术原理
原子力显微镜（AFM）通过纳米级探针扫描样品表面，基于探针与样品间的范德华力作用产生位移信号：

1. 力传感 - 探针悬臂受原子力作用发生偏转

2. 光路监测 - 激光反射路径变化实时转换为电信号

3. 形貌重建 - 信号处理系统生成表面三维拓扑图

技术演进

• 接触模式（Contact mode）：早期高分辨率扫描，易损伤软性样品

• 轻敲模式（Tapping mode）：主流技术，通过间歇接触避免表面刮伤与静电干扰

多功能扩展
▸ 电学/磁学特性分析需专用探针模块
▸ 集成扫描电容显微镜（SCM）实现半导体载流子浓度分布检测

分析应用

• 纳米形貌表征

  • ≤100μm表面三维形貌测绘

  • 表面粗糙度量化分析（Ra/Rq/Rz）

• 微区计量

  • 微观结构尺寸/台阶高度测量（精度0.1nm）

  • 薄膜涂层缺陷扫描（支持12英寸晶圆全尺寸检测）

• 先进成像

  • 3D拓扑渲染与剖面分析

Technical Principle
Atomic Force Microscopy (AFM) utilizes a nanoscale probe to scan surfaces, converting van der Waals force interactions into topographical data:

1. Force Sensing - Cantilever deflection induced by atomic forces

2. Optical Detection - Laser reflection path shifts translated into electrical signals

3. Topography Reconstruction - Signal processing generates 3D surface maps

Evolution

• Contact Mode: Early high-res scanning with risks of soft sample damage

• Tapping Mode: Dominant technique using intermittent contact to prevent scratching/electrostatic artifacts

Multifunctional Expansion
▸ Electrical/magnetic property analysis requires specialized probes
▸ Integrated Scanning Capacitance Microscopy (SCM) enables semiconductor carrier concentration mapping

Analytical Applications

• Nanoscale Topography

  • 3D surface mapping (≤100μm field)

  • Roughness quantification (Ra/Rq/Rz)

• Micro-Metrology

  • Micro-feature dimensional/step height analysis (0.1nm resolution)

  • Thin-film coating defect scanning (full 12-inch wafer compatible)

• Advanced Imaging

  • 3D rendering & cross-sectional profiling