Defect inspection apparatus of rotary type

Details Defect inspection apparatus of rotary type Defect inspection apparatus of rotary type

1994-08-24

1995-11-28

Westin, Edward P.

Radiant energy

Photocells; circuits and apparatus

With circuit for evaluating a web, strand, strip, or sheet

356237, G01N 2188

Patent

active

054710669

ABSTRACT:
A simple signal processing system is utilized to detect defects on the surface of a substrate formed with a circuit pattern at high speed. Light flux from a light source illuminates an inspection point P on the wafer. The light flux from the inspection point P passes a Fourier transform lens and forms a Fourier transform spectrum of the circuit pattern on the inspection point P in the rear focal plane. From the Fourier transform spectrum, a Fourier transform spectrum including no defect information is eliminated by a spatial filter and thereafter the light flux is received by a photoelectric converting device. While the wafer is rotated by a turn table and shifted in a y direction, the spatial filter is rotated in synchronism with rotation of the wafer.

REFERENCES:
patent: 4330775 (1982-05-01), Iwamoto et al.
patent: 5172000 (1992-12-01), Scheff et al.
patent: 5264912 (1993-11-01), Vaught et al.
patent: 5274434 (1993-12-01), Morioka et al.
patent: 5276498 (1994-01-01), Galbraith et al.
patent: 5377002 (1994-12-01), Malin et al.
patent: 5389794 (1995-02-01), Allen et al.

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