Method of forming optical images, apparatus for carrying out said method and process for manufacturing a device using said method

Abstract

An optical image is formed in a radiation-sensitive layer ( 5 ), by a number of sub-illuminations, in each of which an array of light valves ( 21 - 25 ) and a corresponding array of converging elements ( 91 - 95 ) are used to form a pattern of spots ( 111 - 115 ) in the resist layer in accordance with a sub-image pattern. Between the sub-illuminations, the resist layer is displaced relative to the arrays. Bright and well-defined spots are obtained by using refractive lenses ( 43 ) as converging elements. The radiation-sensitive layer may be a resist layer on top of a substrate wherein a device is to be configured by means of lithography or an electrostatic charged layer used in a printer.

1 - 18 . (canceled)  
     
     
         19 . A method of forming an optical image in a radiation-sensitive layer, the method comprising the steps of: 
 providing a radiation source;    providing a radiation-sensitive layer;    positioning a two-dimensional array of individually controlled light valves between the radiation source and the radiation-sensitive layer;    positioning a two-dimensional array of radiation-converging elements between the array of light valves and the radiation-sensitive layer, wherein each of plurality of the radiation-converging elements corresponds to a different one of the light valves and serves to converge radiation from the corresponding light valve in a spot area in the radiation-sensitive layer;    simultaneously writing image portions in areas of the radiation-sensitive layer by scanning said layer areas, and the associated light valves/converging element pairs, relative to each other and switching each light valve between an “on” and an “off” state in dependence upon the image portion to be written by the light valve;    wherein at least a portion of the converging elements are refractive lenses, and the array of radiation-converging elements and the array of light valves are used for forming a matrix array of spots, said matrix having a pitch which is substantially larger than the spot size; and    wherein the intensity of a spot at the border of an image feature is adapted to the distance between the feature border and a neighboring feature.    
     
     
         20 . The method of  claim 19  comprising part of a lithographic process for producing a device in a substrate, wherein 
 the radiation-sensitive layer is a resist layer provided on the substrate, and the image pattern corresponds to a pattern of features of the device to be produced; and    the optical image is divided into sub-images each belonging to a different level of the device to be produced, and during formation of the different sub-images, the resist layer surface is set at different distances from the array of refractive lenses.    
     
     
         21 . An apparatus comprising: 
 a radiation source;    positioning means for positioning a radiation-sensitive layer relative to a radiation beam from the source;    a two-dimensional array of individually controllable light valves arranged between the source and the location for the radiation-sensitive layer; and    an imaging element comprising an array of radiation-converging elements arranged between the array of light valves and the location of the radiation-sensitive layer, each converging element corresponding to a different one of the light valves and serving to converge radiation from the corresponding light valve in a spot area in the resist layer,    wherein the converging elements are refractive lenses, and    wherein a projection lens is arranged between the array of light valves and the array of refractive lenses.