inline monitoring

**Inline Monitoring** is the **systematic measurement of wafers at key process steps during production** — using non-destructive metrology tools to track film thickness, CD, overlay, defects, and electrical parameters throughout the fabrication flow. **Key Inline Measurements** - **Film Thickness**: Ellipsometry or reflectometry at CVD, oxidation, and deposition steps. - **Critical Dimension**: OCD or CD-SEM after lithography and etch steps. - **Overlay**: Overlay metrology after lithography alignment. - **Defects**: Laser scanning and SEM review after critical process steps. - **Sheet Resistance**: Four-point probe or eddy current after implant and anneal. **Why It Matters** - **Yield Assurance**: Early detection of out-of-spec conditions prevents yield loss downstream. - **SPC**: Statistical Process Control charts track inline measurements for trend detection. - **Disposition**: Inline data determines whether lots proceed, are reworked, or are scrapped. **Inline Monitoring** is **the manufacturing health check** — measuring wafers at every critical step to catch problems before they become yield killers.