| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an exposure method for setting illumination conditions to improve resolution performance in three-luminous-flux image formation and to secure a focus depth. <P>SOLUTION: The exposure method is used for a zigzag-latticed contact hole pattern in which each periodic pattern of one row deviates by a half pitch from each other in a line where the periodic patterns are adjacent to each other. An effective optical source of illumination light is composed so that a distance (a) from the center of a pupil of a projection optical system is equal, an angle (α) from a row direction is located in directions of 0, 2α, π-2α, π, π+2α, and 2π-2α. If a pitch in the row direction between the contact holes of the periodic pattern is set as Px, a pitch in the line direction as Py, the number of openings of the projection optical system as NA, and a wavelength of the illumination light as λ; formulas: Pxo/2=(Px/2)NA/λ, Pyo/2=(Py/2)NA/λ, α=tan<SP>-1</SP>(Pxo/(2Pyo)), and a=1/(4(Pyo/2))/sin(2α) are established. The three luminous fluxes in diffracted light from the contact hole pattern are interfered and image-formed in the pupil of the projection optical system. <P>COPYRIGHT: (C)2007,JPO&INPIT |
