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A photomask (also simply called a mask) is an opaque plate with transparent areas that allow light to shine through in a defined pattern. Photomasks are commonly used in photolithography for the production of integrated circuits (ICs or "chips") to produce a pattern on a thin wafer of material (usually silicon ).
Contrast is the difference from exposed portion to unexposed portion. The higher the contrast is, the more obvious the difference between exposed and unexposed portions would be. Sensitivity Sensitivity is the minimum energy that is required to generate a well-defined feature in the photoresist on the substrate, measured in mJ/cm 2. The ...
The difference between steppers and scanners is that, during exposure, a scanner moves the photomask and the wafer simultaneously, while a stepper only moves the wafer. Contact, proximity and projection Mask aligners preceded steppers [39] [40] and do not move the photomask nor the wafer during exposure and use masks that cover the entire wafer.
When the thickness is suitably chosen, the interference of the phase-shifted light with the light coming from unmodified regions of the mask has the effect of improving the contrast on some parts of the wafer, which may ultimately increase the resolution on the wafer. The ideal case is a phase shift of 180 degrees, which results in all the ...
A variety of reticles, each appropriate for one stage in the process, are contained in a rack in the reticle loader, usually located at the upper front of the stepper. Before the wafer is exposed a reticle is loaded onto the reticle stage by a robot, where it is also very precisely aligned. Since the same reticle can be used to expose many ...
An illustration of OPC (Optical Proximity Correction). The blue Γ-like shape is what chip designers would like printed on a wafer, in green is the pattern on a mask after applying optical proximity correction, and the red contour is how the shape actually prints on the wafer (quite close to the desired blue target).
Bottom line: Knowing the differences between an eye cream, gel and mask can help you choose the one that will best enhance your routine. The 15 Best Retinol Eye Creams, From Drugstore MVPs to ...
Using an LED as a reticle is an innovation that greatly improves the reliability and general usefulness of the sight: there is no need for other optical elements to focus light behind a reticle; the mirror can use a dichroic coating to reflect just the red spectrum, passing through most other light; and the LED itself is solid state and ...