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The phrase depth of focus is sometimes erroneously used to refer to depth of field (DOF), which is the distance from the lens in acceptable focus, whereas the true meaning of depth of focus refers to the zone behind the lens wherein the film plane or sensor is placed to produce an in-focus image. Depth of field depends on the focus distance ...
Photolithography (also known as optical lithography) is a process used in the manufacturing of integrated circuits. It involves using light to transfer a pattern onto a substrate, typically a silicon wafer .
However, [clarification needed] the depth of focus, or tolerance in wafer topography flatness, is improved compared to the corresponding "dry" tool at the same resolution. [ 4 ] The idea for immersion lithography was patented in 1984 by Takanashi et al. [ 5 ] It was also proposed by Taiwanese engineer Burn J. Lin and realized in the 1980s. [ 6 ]
The range of distances that are nearly in focus is called the depth of field. Depth of field generally increases with decreasing aperture diameter (increasing f-number). The unfocused blur outside the depth of field is sometimes used for artistic effect in photography. The subjective appearance of this blur is known as bokeh.
Acceptably sharp focus" is defined using a property called the "circle of confusion". The depth of field can be determined by focal length, distance to subject (object to be imaged), the acceptable circle of confusion size, and aperture. [2] Limitations of depth of field can sometimes be overcome with various techniques and equipment.
The first type is distortion corrections, namely pre-compensating for distortions inherent in the manufacturing process, be it from a processing step, such as: photolithography, etching, planarization, and deposition. These distortions are measured and a suitable model fitted, compensation is carried out usually using a rule or model based ...
With no modification to the microscope, i.e. with a simple wide field light microscope, the quality of optical sectioning is governed by the same physics as the depth of field effect in photography. For a high numerical aperture lens, equivalent to a wide aperture, the depth of field is small (shallow focus) and gives
Focus stacking – also called focal plane merging, z-stacking, [1] or focus blending – is a digital image processing technique which combines multiple images taken at different focus distances to give a resulting image with a greater depth of field (DOF) than any of the individual source images.