MARK DETECTION METHOD AND MARK POSITION SENSOR

Title:

MARK DETECTION METHOD AND MARK POSITION SENSOR

Document Type and Number:

WIPO Patent Application WO/1999/027567

Kind Code:

A1

Abstract:

A method for sensing the position of a mark formed on the back of a film (for instance, a polysilicon layer) which does not transmit visible light. A planarized alignment mark (26) is formed on a wafer (4) onto which the pattern of a reticle (R) is transferred, and a polysilicon film (27) is formed on it. Light beams (LA, LB) which are generated by a laser source (10) and a frequency shifter (12) and whose frequencies are within a range of 800 nm - 1500 nm and slightly different from each other are applied to the alignment mark (26) through the polysilicon film (27) by a projection optical system (PL), etc. Diffracted light (LD) from the alignment mark (26) is received by a photodetector (16) through the projection optical system (PL), etc. and, in accordance with the detection signal, the position of the alignment mark (26) is measured.

Inventors:

SHIRAISHI NAOMASA (JP)

Application Number:

PCT/JP1998/005226

Publication Date:

June 03, 1999

Filing Date:

November 19, 1998

Export Citation:

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Assignee:

NIKON CORP (JP)
SHIRAISHI NAOMASA (JP)

International Classes:

G03F9/00; (IPC1-7): H01L21/027; G03F7/20

Foreign References:

JPH08250391A

1996-09-27

Other References: