Chapter 4: Positional Deviation Measurement - Sharp IV-S30 User Manual

Chapter 4: Positional Deviation Measurement

The gray scale search function makes it possible to measure positional deviation as
well as the absolute position.
Purpose
- It is possible to detect the work position with high accuracy, at a sub-pixel level.
- A rotation angle of 360° can be detected. (When a one point gray search is
selected).
Positioning of parts and substrates
Application
[Detection of the position of the substrate alignment mark (fiduciary mark)]
(1) 1-point search: Detection of positional deviation in X and Y directions
Reference image: Center coordinates (X1, Y1) Inspection image: Center coordinates (X2, Y2)
(2) 2-point search: Detection of positional deviation in X and Y directions and
angle
Reference image a: Center coordinates (Xa1, Ya1)
Examples
- The angular deviation θ detected in the 2-point search mode will be used to correct
the rotation of the image in order to make measurements 1 to 4.
For details about rotation correction, see section 3-2, item [6] Position correction.
Y2 Y1
Search area
X2 X1
Ya2 Ya1
θ
Xa2 Xa1
Search area (image a)
θ: Angular deviation
[Measurement results]
- Center coordinates of image a: (Xa2, Ya2)
- Image a positional deviation: Xa2 - Xa1, Ya2 - Ya1
- Center coordinates of image b: (Xb2, Yb2)
- Image b positional deviation: Xb2 - Xb1, Yb2 - Yb1
- Angular deviation θ
4-1
Positional Deviation Measurement
[Measurement results]
Center coordinates: (X2, Y2)
Amount of deviation: X2-X1, Y2-Y1
Inspection image a: Center coordinates (Xa2, Ya2)
Reference image b: Center coordinates (Xb1, Yb1)
Inspection image b: Center coordinates
Xb2 Xb1
(Xb2, Yb2)
Yb2 Yb1
Search area (image b)
4