[54] APPARATUS AND METHOD FOR IN-SITU ADJUSTMENT OF LIGHT TRANSMISSION IN A PHOTOLITHOGRAPHY PROCESS
[75] Inventor: Christopher E. Obszarny,
Poughkeepsie, N.Y.
[73] Assignee: International Business Machines Corporation, Armonk, N.Y.
[21] Appl. No.: 09/116,395 [22] Filed: Jul. 16, 1998
[51] Int. CI.7 G03B 27/42; G03B 27/72;
F21V 9/14
[52] U.S. CI 355/53; 355/71; 362/19
[58] Field of Search 355/53, 18, 71;
430/5, 314, 322, 323, 311; 356/376; 362/19, 277, 282; 396/506
[56] References Cited
U.S. PATENT DOCUMENTS
5,382,483 1/1995 Young .
5,464,713 11/1995 Yoshioka et al. .
5,506,080 4/1996 Adair et al. .
5,521,032 5/1996 Imai et al. .
An adjustable, in-situ photolithography process is taught, where incident exposure light is passed through two polarizers; the first polarizer capable ol altering its polarization direction, during exposure, relative to the polarization direction ol the second polarizer, in order to enhance the contrast ol a patterned image projected on a semiconductor waler. The second polarizer in the optical train is a photo mask transparent substrate impregnated with colloidal crystals that are aligned in a fixed, predetermined direction by magnetic field. The photo mask may also contain a silicon compound lor phase shifting the incident exposure light to lurther enhance the image contrast.
11 Claims, 4 Drawing Sheets
