Principle

Focus Variation with White Light Interferometer

- Light is divided into 2 optical paths at Half Mirror.

 One is Reference path and another is

 Reflection path from a surface.

- Reflection path is delayed based on sample

 surface unevenness.

-     There is no phase shifting between

      Reflection and Reference at Red Point.

-     Phase is always shifted ½ of

      wave length at Blue Point.

Specification Overview

Base unit              

OST3100 Base ( 1 LP)

Functions

- Conventional Microscope Observation & Image Capturing

- Precision height and roughness measurement

- Creating wafer map, recipe and automatic measurement including Auto Focusing and

 Enhanced Global Alignment.

Applications 

- 200/300mm micro bump, redistribution lines and cu pillar.

- TSV and MEMS

Wafer size

200mm and 300mm

Wafer thickness

400um ~ 1,500um

Wafer warped volume

Less than 800um (Need to evaluate)