US 7,468,239 B2
Mask for photolithography, method of forming thin film, liquid crystal display device, and method of producing the liquid crystal display device
Masato Imai, Kanagawa (Japan); Akira Maehara, Kanagawa (Japan); and Yoko Fukunaga, Kanagawa (Japan)
Assigned to Sony Corporation, Tokyo (Japan)
Filed on Sep. 29, 2004, as Appl. No. 10/953,301.
Application 10/953301 is a division of application No. 10/314528, filed on Dec. 09, 2002, granted, now 7,153,614.
Claims priority of application No. 2001-380338 (JP), filed on Dec. 13, 2001.
Prior Publication US 2005/0042528 A1, Feb. 24, 2005
Int. Cl. G03F 7/20 (2006.01)
U.S. Cl. 430—321  [430/322; 430/396; 355/18; 355/53] 17 Claims
 
6. A method of forming a thin film comprising:
performing photolithography by exposing a mask to light, wherein the mask comprises a light-shielding area and a plurality of transmission areas, and
wherein characteristics of adjacent transmission areas are varied such that there is a phase difference for light that has passed through adjacent transmission areas so that a thin-film pattern in which the number of steps thereof is greater than the number of transmission areas is formed, and wherein a lowest level of the resultant thin film pattern for adjacent portions resulting from different adjacent transmission areas is no less than a lowest level of the two adjacent levels; and
wherein exposing the mask is comprised of exposing the mask to the light.