Method of making semiconductor integrated circuit, pattern detecting method, and system for semiconductor alignment and reduced stepping exposure for use in same

Claim 1

A projection exposure system wherein a pattern on a main surface of a reticle or a mask is imaged for reduced projection exposure onto a thin photosensitive film in a step-and-repeat manner, said thin photosensitive film being formed on a first main surface of a semiconductor wafer, an integrated circuit wafer, or a plate material which is used for the production of a semiconductor device of an integrated circuit device, said projection exposure system comprising: (a) exposure light source means for directing a monochromatic exposure light beam of a short wave length to the main surface side of said reticle or mask; (b) reticle or mask holding means for holding said reticle or mask so that the main surface thereof is located opposedly in parallel with the first main surface of said wafer or plate material; (c) a projection lens group substantially telecentric on the image side and comprising a plurality of lenses free of various aberrations for said exposure light, for imaging the pattern on the main surface of said reticle or mask onto said photosensitive film on the first main surface of said wafer or plate material on a reduced scale using said exposure light through said projection lens group; (d) wafer or plate material holding means for holding said wafer or plate material so that the first main surface thereof is opposed to the main surface of said reticle or mask in a substantially parallel relation thereto, said wafer or plate material holding means allowing said wafer or plate material to move relatively in a plane perpendicular to a single linear optical axis of said projection lens group to effect step-and-repeat exposure in a substantially aligned condition of said optical axis of the projection lens group, the center of a portion to be exposed of said wafer or plate material, and the center of a portion to be projected of said reticle or mask; (e) an off-axis through-the-lens alignment optical system for observation, said alignment optical system performing a horizontal alignment of said wafer or plate material by using reflecting means, disposed off the optical axis of said projection lens group, to direct a reference light comprising one of a polychromatic light and a continuous spectrum light having a predetermined spectral width, having a wave length longer than that of said exposure light, to the first main surface of said wafer or plate material through said projection lens group from a position off the optical axis of said projection lens group, and to direct reference light reflected from the first main surface of said wafer or plate material to the position off the optical axis along substantially the same path along which the reference light is directed to the first main surface of said wafer or plate material, and by observing a predetermined alignment pattern formed on the first main surface of the wafer or plate material; and (f) a correction lens group disposed off the optical axis of said projection lens group and in an optical path of said alignment optical system for correcting longitudinal and lateral chromatic aberrations, in the sense of an achromat, with respect to the reference light, of said projection lens group for the reference light reflected from the first main surface of said wafer or plate material and directed to the position off the optical axis by said reflecting means; wherein said correction lens group comprises a pair of substantially the same chromatic aberration correcting lens group disposed substantially symmetrically with respect to a first imaging point in said alignment optical system.

Claim 20

A method of making a semiconductor device, characterized in that in laminating a plurality of characteristic layers successively on the surface of a semiconductor wafer using a mask, there is formed a stepped pattern of an asymmetric section having first and second edges at both ends thereof with a vertical axis through the wafer as the center, and a first illumination light which is radiated inclinedly from the second edge side is used in detecting the position of the first edge, while a second illumination light which is radiated inclinedly from the first edge side is used in detecting the position of the second edge, then central coordinates of both edges are calculated using coordinates of the first edge position obtained by the radiation of the first illumination light and coordinates of the second edge position obtained by the radiation of the second illumiantion light, and the characteristic layer formed thereon is positioned with respect to the mask on the basis of said central coordinates calculated.

Claim 21

A method of making a semiconductor device, characterized in that in laminating a plurality of characteristic layers successively on the surface of a semiconductor wafer using a mask, there is formed a stepped pattern of an asymmetric section having first and second edges at both ends thereof with a vertical axis through the wafer as the center, and a first illumination light which is radiated inclinedly from the second edge side is used in detecting the position of the first edge, while a second illumination light which is radiated inclinedly from the first edge side is used in detecting the position of the second edge, then central coordinates of both edges are calculated using coordinates of the first edge position obtained by the radiation of the first illumination light and coordinates of the second edge position obtained by the radiation of the second illumiantion light, and the characteristic layer formed thereon is positioned with respect to the mask on the basis of said central coordinates calculated.