US 6,806,456 B1 · System and method for lithography process monitoring and control

Abstract

In one aspect, the present invention is a technique of, and a system and sensor for measuring, inspecting, characterizing and/or evaluating optical lithographic equipment, methods, and/or materials used therewith, for example, photomasks. In one embodiment, the system, sensor and technique measures, collects and/or detects an aerial image produced or generated by the interaction between the photomask and lithographic equipment. An image sensor unit may measure, collect, sense and/or detect the aerial image in situ—that is, the aerial image at the wafer plane produced, in part, by a product-type photomask (i.e., a wafer having integrated circuits formed during the integrated circuit fabrication process) and/or by associated lithographic equipment used, or to be used, to manufacture of integrated circuits. In this way, the aerial image used, generated or produced to measure, inspect, characterize and/or evaluate the photomask is the same aerial image used, generated or produced during wafer exposure in integrated circuit manufacturing. In another embodiment, the system, sensor and technique characterizes and/or evaluates the performance of the optical lithographic equipment, for example, the optical sub-system of such equipment. In this regard, in one embodiment, an image sensor unit measures, collects, senses and/or detects the aerial image produced or generated by the interaction between lithographic equipment and a photomask having a known, predetermined or fixed pattern (i.e., test mask). In this way, the system, sensor and technique collects, senses and/or detects the aerial image produced or generated by the test mask—lithographic equipment in order to inspect, evaluate and/or characterize the performance of the lithographic equipment.

Claims32

Dependent claims

A system to collect image data which is representative of an aerial image of a mask used in the manufacture of integrated circuits, wherein the mask includes features having a line width, the system comprising:

an optical system to produce the image of the mask on a wafer plane;
a platform moveable between a plurality of discrete locations in a first direction and a plurality of discrete locations in a second direction;
an image sensor unit disposed on the moveable platform, the image sensor unit includes a sensor array located in the wafer plane, wherein the sensor array includes a plurality of sensor cells wherein each sensor cell includes an active area to sample light of a predetermined wavelength that is incident thereon, wherein the active area is smaller than the line width, and wherein at each discrete location of the platform the sensor cells samples the intensity of light;
a processing unit, coupled to the image sensor unit, to generate image data which is representative of the aerial image, wherein the processing unit generates the aerial image of the mask by interleaving the image data sampled by each sensor at each discrete location of the platform.

1 more element

A system to collect image data which is representative of an aerial image of a mask used in the manufacture of integrated circuits, the system comprising:

an optical system to produce the image of the mask on a wafer plane;
a platform moveable between a plurality of discrete locations along a plurality of axes;
an image sensor unit disposed on the moveable platform, the image sensor unit includes a sensor array located in the wafer plane, wherein the sensor array includes a plurality of sensor cells wherein each sensor cell includes an active area to sample light of a predetermined wavelength that is incident thereon and wherein at each discrete location of the platform the sensor cells samples the intensity of light;
and
a processing unit, coupled to the image sensor unit, to generate image data which is representative of only a portion of the aerial image of the mask wherein the portion of the aerial image includes a plurality of non-contiguous sub-images and wherein the processing unit generates each sub-image of the plurality of non-contiguous sub-images using the intensity of light sampled by a corresponding sensor cell when the platform is positioned at a plurality of discrete locations relative to the aerial image.

2 more elements

an optical system to produce the image of the mask on a wafer plane;
a platform moveable between a plurality of discrete locations;
an image sensor unit disposed within the moveable platform, the image sensor unit includes a sensor array, wherein the sensor array includes a plurality of sensor cells wherein each sensor cell includes an active area to sample light of a predetermined wavelength that is incident thereon, wherein the active area is smaller than the line width, and wherein at each discrete location of the platform the sensor cells samples the intensity of light;
a processing unit, coupled to the image sensor unit, to generate image data which is representative of the aerial image of the mask, wherein the processing unit generates the aerial image of the mask by interleaving the image data sampled by each sensor at each discrete locations of the platform.

1 more element

Dependencies are inferred from the claim text.

System and method for lithography process monitoring and control

Life of this patent

System and method for lithography process monitoring and control

Life of this patent

Abstract

Claims32