(1) Field of the Invention
In projection exposure apparatus for transferring images of masks, reticles, etc. onto substrates in lithography processes for fabricating semiconductor devices, image pickup devices, liquid crystal display devices, thin-film magnetic heads, etc., the present invention relates to:
an illumination apparatus for illuminating the masks or reticles in the projection exposure apparatus; PA1 a projection exposure apparatus that includes this illumination apparatus; PA1 a method for manufacturing devices using the projection exposure apparatus; and PA1 a method for manufacturing the projection exposure apparatus. PA1 a light source system for supplying a light beam; PA1 an optical integrator for forming a plurality of light sources based on a light beam from said light source; PA1 a condenser optical system for converging beams from said plurality of light sources for illuminating said mask or reticle; PA1 a projection optical system for projecting onto said substrate placed at an image surface, said prescribed pattern on said mask or reticle; and PA1 a filter, placed in a location that is in an optically conjugate relationship to said image surface, or in the proximity of said location, said filter having at least a first area corresponding to a first portion of said plurality of light sources, and a second area corresponding to a portion of said plurality of light sources other than said first portion; PA1 at least one first filter element having a first transmissivity distribution is provided over the entirety of said first area of said filter; and PA1 at least one second filter element having a second transmissivity distribution that is the inverse of said first transmissivity distribution is provided over the entirety of said second area of said filter. PA1 a light source system for supplying a light beam; PA1 an optical integrator for forming a plurality of light sources based on a light beam from said light source; PA1 a condenser optical system for converging beams from said plurality of light sources for illuminating said mask or reticle; PA1 a projection optical system for projecting onto said substrate placed at an image surface, said prescribed pattern on said mask or reticle; and PA1 a filter, placed in a location that is in an optically conjugate relationship to said image surface, or in the proximity of said location, said filter having at least a first area corresponding to a first portion of said plurality of light sources, and a second area corresponding to a portion of said plurality of light sources other than said first portion; PA1 at least one first filter element having a first transmissivity distribution is provided over the entirety of said first area of said filter; and PA1 at least one second filter element having a second transmissivity distribution that is the inverse of said first transmissivity distribution is provided over the entirety of said second area of said filter; PA1 at least one first filter element having a first transmissivity distribution is provided over the entirety of said first area of said filter; PA1 at least one second filter element having a second transmissivity distribution is provided over the entirety of said second area of said filter; and PA1 said first and second filter elements transform to a prescribed light intensity distribution, independently for light converging at prescribed points on said image surface, the light intensity distribution in the Fourier transform planes of microsurfaces constituting said image surface, while maintaining substantially unchanged, the relative illuminance distributed over said image surface. PA1 a light source system for supplying a light beam; PA1 an optical integrator for forming a plurality of light sources based on a light beam from said light source; PA1 a condenser optical system for converging beams from said plurality of light sources for illuminating said mask or reticle; PA1 a projection optical system for projecting onto said substrate placed at an image surface, said prescribed pattern on said mask or reticle; PA1 a first filter, placed in a location that is in an optically conjugate relationship to said image surface, or in the proximity of said location, said filter having transmissivity distribution such as to transform, independently, for light converging at prescribed points on said image surface, the light intensity distribution in the Fourier transform planes of microsurfaces constituting said image surface, to prescribed light intensity distributions; and PA1 a second filter, placed in a location that is in an optically conjugate relationship to said image surface, or in the proximity of said location, said filter having transmissivity distribution for correcting at least nonuniformity of relative illumination distributed over said illuminated surface caused by the transmissivity distribution of said first filter. PA1 a first step of guiding a light beam from a light source through PA1 a second step of measuring the relative illuminance distributed on said image surface, and measuring, in the Fourier transform planes of the microsurfaces that constitute said image surface, the light intensity distributions for light converging at at least two points on said image surface; PA1 a third step of placing in a location that is in an optically conjugate relationship to said image surface, or in the proximity of said location, a filter having at least a first area corresponding to a first portion of said plurality of light sources, and a second area corresponding to a portion of said plurality of light sources other than said first portion; and PA1 a fourth step of providing, over the entirety of said first area of said filter, at least one first filter element having a first transmissivity distribution, while also providing, over the entirety of said second area of said filter, at least one second filter element having a second transmissivity distribution; PA1 wherein, in said fourth step, said first and second transmissivity distributions are set so as to maintain said relative illuminations distributed in said image surface substantially uniform, while transforming said light intensity distributions, independently, to prescribed light intensity distributions. PA1 a first step of simulating the guiding of a light beam from a light source through PA1 a second step of computing the relative illuminations distributed on said image surface, and computing the light intensity distribution in the Fourier transform planes of the microsurfaces that constitute said image surface, for light converging at at least two points on said image surface, based on the results obtained in said simulation of said first step; PA1 a third step of setting in a location that is in an optically conjugate relationship to said image surface, or in the proximity of said location, a filter having at least a first area corresponding to a first portion of said plurality of light sources, and a second area corresponding to a portion of said plurality of light sources other than said first portion; and PA1 a fourth step of setting, over the entirety of said first area of said filter, at least one first filter element having a first transmissivity distribution, while also setting, over the entirety of said second area of said filter, at least one second filter element having a second transmissivity distribution; PA1 wherein, in said fourth step, said first and second transmissivity distributions are set so as to maintain said relative illuminations distributed on said image surface substantially uniform, while transforming said light intensity distributions, independently, into prescribed light intensity distributions.
(2) Background of the Related Art
Conventional illumination apparatus of the type used in projection exposure apparatus is commonly configured to correct illuminance nonuniformities at the illuminated surface in order to obtain uniform illuminance distribution.
With recent improvements in the precision of resolved images, however, problems have surfaced in that line widths that were supposed to be the same as the original dimensions end up being different. These problems primarily involve image height (or if the image height is the same, differences in the meridional and sagittal directions). When pattern line width differs according to location, this can degrade the value of the devices being fabricated. In a logic circuit, for example, it can reduce the amount of data that can be processed in a given amount of time.
USPTO Backgrounds
USPTO Backgrounds