Method for emulation of a photolithographic process and mask inspection microscope for performing the method

A system for emulating a photolithographic process for generating on a wafer an overall structure that is divided into at least two substructures, the two substructures on the wafer being produced based on two corresponding substructures on at least two masks, comprising:

• a mask inspection microscope to capture at least one of aerial images of at least two substructures on at least two masks, the at least two substructures including at least a first substructure on a first one of the at least two masks and at least a second substructure on a second one of the at least two masks, the microscope comprising
• a processing unit that is configured to
• correct errors in the at least one aerial image captured with the mask inspection microscope, the errors including aberrations or distortions introduced into the at least one captured aerial image by the mask inspection microscope, in which correct the errors includes modify the at least one aerial image to reduce the aberrations or distortions, and
• overlay the aerial images of the at least two substructures to form an overall aerial image of the overall structure that includes the first and second substructures, in which prior to the overlay, one of the aerial images has an image of the first substructure but not the second substructure, and another one of the aerial images has an image of the second substructure but not the first substructure, in which the overlaying the aerial images is performed after correcting errors in the at least one aerial image;
• wherein a resist simulation is performed as an adjustment of the aerial images, and before the overlaying of the aerial images of the at least two substructures, the aerial images are adjusted to the ratio of the doses to be used for the masks in a scanner by multiplying all the intensity values of at least one of the aerial images by a factor.

A non-transitory machine-readable storage medium storing instructions that when read by a machine causes a data processor to perform:

• receiving aerial images of at least two substructures on at least two masks, the at least two substructures including at least a first substructure on a first one of the at least two masks and at least a second substructure on a second one of the at least two masks, and at least one of the aerial images being captured with a mask inspection microscope;
• correcting errors in the at least one aerial image captured with the mask inspection microscope, the errors including aberrations or distortions introduced into the at least one captured aerial image by the mask inspection microscope, in which correcting the errors includes modifying the at least one aerial image to reduce the aberrations or distortions;
• and
• overlaying the aerial images of the at least two substructures to form an overall aerial image of the overall structure that includes the first and second substructures, in which prior to the overlaying, one of the aerial images has an image of the first substructure but not the second substructure, and another one of the aerial images has an image of the second substructure but not the first substructure, in which the overlaying the aerial images is performed after correcting errors in the at least one aerial image;
• wherein a resist simulation is performed as an adjustment of the aerial images, and before the overlaying of the aerial images of the at least two substructures, the aerial images are adjusted to the ratio of the doses to be used for the masks in a scanner by multiplying all the intensity values of at least one of the aerial images by a factor.

A method for emulation of a photolithographic process for generating on a wafer an overall structure that is divided into at least two substructures, the two substructures on the wafer being produced based on two corresponding substructures on at least two masks, the method comprising:

• generating aerial images of the at least two substructures on the at least two masks, the at least two substructures including at least a first substructure on a first one of the at least two masks and at least a second substructure on a second one of the at least two masks, and at least one of the aerial images being captured with a mask inspection microscope;
• modifying, by using a processing unit, at least one aerial image captured with the mask inspection microscope to correct errors in the at least one aerial image, the errors including aberrations or distortions introduced into the at least one captured aerial image by the mask inspection microscope, in which modifying the at least one aerial image includes reducing the aberrations or distortions in the at least one aerial image;
• overlaying the aerial images of the at least two substructures to form a double exposure aerial image of the overall structure, in which the overlaying the aerial images is performed after modifying the at least one aerial image to reduce aberrations or distortions;
• and
• simulating a double exposure resist image using the double exposure aerial image of the overall structure and a resist model;
• wherein a resist simulation is performed as an adjustment of the aerial images, and before the overlaying of the aerial images of the at least two substructures, the aerial images are adjusted to the ratio of the doses to be used for the masks in a scanner by multiplying all the intensity values of at least one of the aerial images by a factor.

A method for emulation of a photolithographic process for generating on a wafer an overall structure that is divided into at least two substructures, the two substructures on the wafer being produced based on two corresponding substructures on at least two masks, the method comprising:

• generating aerial images of the at least two substructures on the at least two masks, the at least two substructures including at least a first substructure on a first one of the at least two masks and at least a second substructure on a second one of the at least two masks, and at least one of the aerial images being captured with a mask inspection microscope;
• modifying, by using a processing unit, at least one aerial image captured with the mask inspection microscope to correct errors in the at least one aerial image, the errors including aberrations or distortions introduced into the at least one captured aerial image by the mask inspection microscope, in which modifying the at least one aerial image includes reducing the aberrations or distortions in the at least one aerial image;
• simulating a first resist image based on a first one of the aerial images and a resist model, in which the simulating the first resist image is performed after modifying the at least one aerial image to reduce aberrations or distortions;
• simulating a second resist image based on a second one of the aerial images and the resist model;
• and
• overlaying the first and second resist images to form a double patterning resist image;
• wherein a resist simulation is performed as an adjustment of the aerial images, and before the overlaying of the aerial images of the at least two substructures, the aerial images are adjusted to the ratio of the doses to be used for the masks in a scanner by multiplying all the intensity values of at least one of the aerial images by a factor.

A method for emulation of a photolithographic process for generating on a wafer an overall structure that is divided into at least two substructures, the two substructures on the wafer being produced based on two corresponding substructures on at least two masks, the method comprising:

• generating aerial images of the at least two substructures on the at least two masks, the at least two substructures including at least a first substructure on a first one of the at least two masks and at least a second substructure on a second one of the at least two masks, and at least one of the aerial images being captured with a mask inspection microscope;
• correcting, by using a processing unit, errors in the at least one aerial image captured with the mask inspection microscope, the errors including aberrations or distortions introduced into the at least one captured aerial image by the mask inspection microscope, in which correcting the errors includes modifying the at least one aerial image to reduce the aberrations or distortions;
• and
• adjusting the aerial images to the ratio of the doses to be used for the masks in a scanner by multiplying all the intensity values of at least one of the aerial images by a factor;
• and
• overlaying, using the processing unit, the aerial images of the at least two substructures to form an overall aerial image of the overall structure, in which the intensity values of at least one of the aerial images has been adjusted according to the ratio of the doses to be used for the masks in the scanner, in which the overlaying the aerial images is performed after correcting errors in the at least one aerial image;
• wherein a resist simulation is performed as an adjustment of the aerial images.

A method for emulation of a photolithographic process for generating on a wafer an overall structure that is divided into at least two substructures, the at least two substructures on the wafer being produced based on at least two corresponding substructures on at least two masks, the method comprising:

• capturing a first aerial image of a first substructure on a first mask with a mask inspection microscope;
• generating a second aerial image of a second substructure on a second mask by simulation from mask design data, in which the illumination setting for simulating the second aerial image from mask design data is the same as the illumination setting for capturing the first aerial image with the mask inspection microscope;
• correcting, by using a processing unit, errors in the first aerial image captured with the mask inspection microscope, the errors including aberrations or distortions introduced into the at least one captured aerial image by the mask inspection microscope, in which correcting the errors includes modifying the at least one aerial image to reduce the aberrations or distortions;
• and
• overlaying, using the processing unit, the first and second aerial image of the first and second substructures to form an overall aerial image, in which the overlaying the aerial images is performed after correcting errors in the at least one aerial image;
• wherein a resist simulation is performed as an adjustment of the aerial images, and before the overlaying of the aerial images of the at least two substructures, the aerial images are adjusted to the ratio of the doses to be used for the masks in a scanner by multiplying all the intensity values of at least one of the aerial images by a factor.

A method for emulation of a photolithographic process for generating on a wafer an overall structure that is divided into at least two substructures, the two substructures on the wafer being produced based on two corresponding substructures on at least two masks, the method comprising:

• generating aerial images of the at least two substructures on the at least two masks, the at least two substructures including at least a first substructure on a first one of the at least two masks and at least a second substructure on a second one of the at least two masks, and at least one of the aerial images being captured with a mask inspection microscope;
• correcting, by using a processing unit, errors in the at least one aerial image captured with the mask inspection microscope;
• and
• overlaying the aerial images of the at least two substructures to form an overall aerial image of the overall structure;
• wherein a resist simulation is performed as an adjustment of the aerial images, at least one of the aerial images is generated by simulation from mask design data, and the simulation of the at least one aerial image or reference image is based on the same illumination settings of the mask inspection microscope as the capture of the images.

A system for emulating a photolithographic process for generating on a wafer an overall structure that is divided into at least two substructures, the two substructures on the wafer being produced based on two corresponding substructures on at least two masks, comprising:

• a mask inspection microscope to capture at least one of aerial images of at least two substructures on at least two masks, the at least two substructures including at least a first substructure on a first one of the at least two masks and at least a second substructure on a second one of the at least two masks, the microscope comprising
• a processing unit that is configured to
• correct errors in the at least one aerial image captured with the mask inspection microscope, and
• overlay the aerial images of the at least two substructures to form an overall aerial image of the overall structure;
• wherein a resist simulation is performed as an adjustment of the aerial images, at least one of the aerial images is generated by simulation from mask design data, and the simulation of the at least one aerial image or reference image is based on the same illumination settings of the mask inspection microscope as the capture of the images.

A non-transitory machine-readable storage medium storing instructions that when read by a machine causes a data processor to perform:

• receiving aerial images of at least two substructures on at least two masks, the at least two substructures including at least a first substructure on a first one of the at least two masks and at least a second substructure on a second one of the at least two masks, and at least one of the aerial images being captured with a mask inspection microscope;
• correcting errors in the at least one aerial image captured with the mask inspection microscope;
• and
• overlaying the aerial images of the at least two substructures to form an overall aerial image of the overall structure;
• wherein a resist simulation is performed as an adjustment of the aerial images, at least one of the aerial images is generated by simulation from mask design data, and the simulation of the at least one aerial image or reference image is based on the same illumination settings of the mask inspection microscope as the capture of the images.