Alignment apparatus including three beams and three gratings

Details Alignment apparatus including three beams and three gratings Alignment apparatus including three beams and three gratings

1990-05-03

1991-06-18

Nelms, David C.

Radiant energy

Photocells; circuits and apparatus

Photocell controls its own optical systems

356401, G01N 2186, G01V 904

Patent

active

050251686

ABSTRACT:
A light source emits light having two components which ave slightly-different frequencies and which have different planes of polarization. The emitted light is separated into first, second, and third parts travelling along different paths respectively. First, second, and third reference gratings diffract the first, second, and third light parts respectively. First, second, and third illumination optical systems selectively transmit the diffracted first, second, and third light parts respectively. First, second, and third mark gratings having predetermined orientations are formed on a mask and are illuminated with the first, second, and third light parts coming from the first, second, and third illumination systems respectively. Similarly, first, second, and third mark gratings are formed on a wafer and are illuminated with the first, second, and third light parts coming from the first, second, and third illumination systems respectively. A first device detects first optical beat signals of the diffracted lights coming from the first mark grating on the mask and the first mark grating on the wafer. Similar detection is made for the diffracted lights coming from the other mark gratings on the mask and the wafer.

REFERENCES:
patent: 3971951 (1976-07-01), Rikukawa et al.
patent: 4311389 (1982-01-01), Fay et al.
patent: 4677301 (1987-06-01), Tanimoto et al.
patent: 4708484 (1987-11-01), Komeyama et al.
"Application of Zone Plates to Alignment in Microlithography", by M. Feldman and et al., 1981 American Vacuum Society, pp. 1224-1228.

Affiliated with

Also associated with

Rating

Alignment apparatus including three beams and three gratings does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Alignment apparatus including three beams and three gratings, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Alignment apparatus including three beams and three gratings will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-147090