Projection exposure apparatus and method involving variation and correction of light intensity distributions, detection and control of imaging characteristics, and control of exposure

A projection exposure apparatus comprising:

• a first illumination optical system for radiating first illumination light on a mask;
• a projection optical system for imaging and projecting an image of a pattern of said mask in a photosensitive substrate;
• a detecting system for receiving second illumination light having a wavelength almost equal to that of the first illumination light passing through said projection optical system and detecting an imaging characteristic of said projection optical system;
• and
• an adjusting system for adjusting an intensity distribution of the second illumination light in said projection optical system so that the intensity distribution of the second illumination light is set substantially equal to an intensity distribution of the first illumination light passing through said mask in said projection optical system.

A projection exposure apparatus comprising:

• an illumination optical system for radiating illumination light having a predetermined wavelength on a mask;
• a projection optical system for imaging and projecting an image of a pattern of said mask on a photosensitive substrate;
• a light amount distribution changing member for changing a light amount distribution on a Fourier transform plane for the pattern of said mask in said illumination optical system or a plane near the Fourier transform plane;
• and
• an exposure control system for interrupting an exposure operation for said photosensitive substrate for a predetermined period of time when said light amount distribution is chanted.

A projection exposure apparatus comprising:

• an illumination optical system for radiating illumination light having a predetermined wavelength on a mask;
• a projection optical system for imaging and projecting an image of a pattern of said mask on a photosensitive substrate;
• a detecting system for detecting information corresponding to a thermal accumulation amount of said projection optical system in correspondence with incidence of the illumination light;
• an exposure control system for controlling start and stop of an exposure operation for said photosensitive substrate based on information from said detection system and a predetermined reference value;
• and
• a setting member for, when an intensity distribution of the illumination light passing through said mask on a Fourier transform plane for the pattern of said mask in said projection optical system is changed, setting the reference value to a value corresponding to the changed intensity distribution.

A projection exposure apparatus comprising;

• an illumination optical system for radiating illumination light having a predetermined wavelength on a mask;
• a projection optical system for imaging and projecting an image of a pattern of said mask on a photosensitive substrate;
• a detecting system for detecting information corresponding to a thermal accumulation amount of said projection optical system in correspondence with incidence of the illumination light;
• an exposure control system for controlling start and stop of an exposure operation for said photosensitive substrate based on information from said detecting system and a predetermined reference value;
• a light amount distribution changing member for changing a light amount distribution on a Fourier transform plane for the pattern of said mask in said illumination optical system or a plane near the Fourier transform plane;
• and
• a setting member for setting the reference value to a value corresponding to the changed light amount distribution when said light amount distribution is changed in accordance with the pattern of said mask.

A projection exposure apparatus comprising:

• a first illumination optical system for radiating first illumination light on a mask;
• a projection optical system for imaging and projecting an image of a pattern of said mask on a photosensitive substrate;
• a focal position detecting system for receiving second illumination light having a wavelength almost equal to that of the first illumination light passing through said projection optical system and detecting a focal position of said projection optical system;
• a measuring system for measuring an intensity distribution of the first illumination light passing through said mask in said projection optical system;
• and
• a correction member for correcting a detection result of said focal position detection system based on the measured intensity distribution of the first illumination light.

A projection exposure apparatus comprising:

• an illumination optical system having an optical integrator, disposed between a light source and a mask to illuminate the mask with light from a secondary light source which the optical integrator forms with light from the light source;
• a projection optical system having a plurality of optical elements disposed between the mask and a substrate along an optical axis to project an image of the illuminated mask on the substrate;
• an optical device disposed within the illumination optical system, that changes an intensity distribution of the secondary light source in accordance with a pattern of the mask;
• and
• an adjusting system having an actuator provided with the projection optical system to move at least two of the plurality of optical elements, that adjusts magnification and an aberration of the projection optical system in accordance with the changed intensity distribution of the secondary light source.

A projection exposure apparatus comprising:

• an illumination optical system having an optical integrator, disposed between a light source and a mask to illuminate the mask with light from a secondary light source which the optical integrator forms with light from the light source;
• a projection optical system having a plurality of optical elements disposed between the mask and a substrate along an optical axis to project an image of the illuminated mask on the substrate;
• an optical device that changes an intensity distribution of light from the illuminated mask on a pupil plane of the projection optical system, the optical device including a first device provided in the illumination optical system to change a shape of the secondary light source and a second device provided in the projection optical system to change a numerical aperture of the projection optical system, wherein the intensity distribution is changed by at least one of the first and second devices;
• and
• an adjusting system having an actuator provided with the projection optical system to move at least two of the plurality of optical elements, that adjusts magnification and an aberration of the projection optical system in accordance with the changed intensity distribution.

A projection exposure apparatus comprising:

• an illumination optical system disposed between a light source and a mask, that forms a secondary light source with light from the light source to illuminate the mask with light from the secondary light source, the illumination optical system including a first optical device that changes a shape of the secondary light source in accordance with a pattern of the mask, and a second optical device disposed between the light source and the first optical device to change an intensity distribution of light incident on the first optical device from the light source in response to the changed shape of the secondary light source;
• a projection optical system having a plurality of optical elements disposed between the mask and a substrate along an optical axis to project an image of the illuminated mask on the substrate;
• and
• an adjusting system having an actuator provided with the projection optical system to move at least one of the plurality of optical elements, that adjust an aberration of the projection optical system in accordance with the changed shape of the secondary light source.

A projection exposure apparatus comprising:

• an illumination optical system disposed between a light source and a mask, said illumination optical system changing a shape of a secondary light source in accordance with a pattern of the mask so that said mask is illuminated with light form the secondary light source of which shape is changed, said illumination optical system including an optical device having a plurality of first stops different from each other in shape for defining said secondary light source, one of said plurality of first stops being selected in accordance with said pattern;
• a projection optical system having a plurality of optical elements disposed between the mask and a substrate along an optical axis to project an image of the illuminated mask on the substrate, said projection optical system including a second stop for changing a numerical aperture thereof;
• and
• a detection system for detecting a changing amount of an image plane of said projection optical system along said optical axis caused by a change in at least one of the shape of said secondary light source, the numerical aperture of said projection optical system and the pattern of said mask.

A projection exposure apparatus comprising:

• a first illumination optical system for radiating first illumination light on a mask;
• a projection optical system for imaging and projecting an image of a pattern of said mask on a photosensitive substrate;
• a stage for holding said photosensitive substrate to be movable along a direction of an optical axis of said projection optical system;
• a reference pattern formed on part of said stage;
• a second illumination optical system for radiating second illumination light having a wavelength almost equal to that of the first illumination light on said reference pattern;
• a photoelectric detector for receiving light generated by said reference pattern and passing through said projection optical system;
• a focal position detection system for detecting a focal position of said projection optical system based on a detection signal from said photoelectric detector;
• and
• a light intensity distribution changing member capable of changing an intensity distribution of the second illumination light generated by said reference pattern in said projection optical system.

A projection exposure apparatus comprising:

• an illumination optical system for radiating illumination light having a predetermined wavelength on a mask;
• a projection optical system for projecting an image of a pattern of said mask on a photosensitive substrate;
• a first correcting member for correcting an imaging characteristic of said projection optical system in accordance with a change amount of the imaging characteristic which is calculated in accordance with a predetermined operation parameter so as to maintain the imaging characteristic of said projection optical system to a predetermined value during exposure of said photosensitive substrate;
• a measuring system for radiating, on a reference mark, light having the same wavelength as that of the illumination light or light having a wavelength range near that of the illumination light, receiving light emerging from said reference mark and passing through said projection optical system, and measuring the imaging characteristic of said projection optical system, said measuring system measuring the imaging characteristic per unit time after the exposure of said photosensitive substrate is started;
• and
• a second correcting member for correcting the operation parameter based on at least one imaging characteristic measured by said measuring system within the predetermined period of time after exposing said photosensitive substrate for a predetermined period of time, and before correcting the operation parameter, correcting a correction operation of the imaging characteristics of said first correcting member in accordance with a measured imaging characteristic every time the imaging characteristic is measured by said measuring system, so as to obtain an almost zero correction error of the imaging characteristic from said first correction member.

A projection exposure apparatus comprising:

• a first illumination optical system for radiating first illumination light on a mask;
• a projection optical system for imaging and projecting an image of a pattern of said mask on a photosensitive substrate;
• a stage for holding said photosensitive substrate to be movable along a direction of an optical axis of said projection optical system;
• a reference pattern formed on part of said stage;
• a second illumination optical system for radiating second illumination light having a wavelength almost equal to that of the first illumination light on said reference pattern;
• a photoelectric detector for receiving light generated by said reference pattern and passing through said projection optical system;
• a focal position detecting system for detecting a focal position of said projection optical system based on a detection signal from said photoelectric detector;
• a light intensity distribution changing member capable of changing an intensity distribution of the second illumination light generated by said reference pattern in said projection optical system;
• a measuring system for measuring an intensity distribution of the first illumination light passing through said mask in said projection optical system;
• and
• a controller for controlling said intensity distribution changing member to match the intensity distribution of the second illumination light generated from said reference pattern in said projection optical system with the measured intensity distribution of the first illumination light.

A method of measuring an imaging characteristic of a projection optical system projecting a pattern image of a mask illuminated with a first illumination light onto a photo-sensitive substrate, comprising:

• measuring a light intensity distribution of the first illumination light passing through said mask, substantially on a pupil plane of said projection optical system;
• illuminating a reference pattern with a second illumination light having a wavelength which is substantially the same as that of the first illumination light, and receiving the light generated from said reference pattern and passing through said projection optical system, thereby to detect the imaging characteristic of said projection optical system;
• and
• correcting the detection result on the basis of the measured light intensity distribution.

A method of exposing a substrate with a pattern of a mask through a projection optical system, comprising the steps of:

• changing a shape of a secondary light source in accordance with the pattern of the mask to illuminate the mask with light from the secondary light source of which the shape is changed;
• moving at least two of a plurality of optical elements of the projection optical system in accordance with the changed shape of the secondary light source to adjust magnification and an aberration of the projection optical system;
• and
• projecting light from the illuminated mask on the substrate through the projection optical system of which magnification and the aberration are adjusted.

A method of exposing a substrate with a pattern of a mask through a projection optical system, comprising the steps of:

• placing one of a plurality of stops different from each other in shape between an optical integrator and said mask to change a shape of a secondary light source in accordance with a pattern of said mask so that said mask is illuminated with light from said secondary light source of which shape is changed;
• moving an image plane of said projection optical system and said substrate relatively along an optical axis to compensate a changing amount of said image plane of said projection optical system along said optical axis caused by a change in shape of said secondary light source;
• and
• exposing said substrate with light generated from the illuminated mask through said projection optical system.

A method of exposing a substrate, through a projection optical system, with illumination light irradiated on a mask by an illumination optical system, comprising:

• changing an intensity distribution of said illumination light on a Fourier transform plane with respect to a pattern surface of said mask in said illumination optical system by change of a stop to define the intensity distribution and movement of an optical element of the illumination optical system to define a distribution of said illumination light on the stop;
• moving at least two optical elements of said projection optical system based on the changed intensity distribution in order to adjust a specific aberration and a magnification of said projection optical system;
• and
• projecting said illumination light onto said substrate through said projection optical system of which said at least two optical elements are moved.