摘要:
A method of forming a semiconductor device includes forming of layers of polysilicon and dielectric layers in manufacturing a semiconductor device and patterning the layers into devices using phototlithography and etching process steps. End point mode detection is used in the etching process in a way in which the area exposed during etching is increased to enhance the end point detection capacity, by adding a surplus pad area before pad formation. Specifically an EPROM device is formed with a first level of polysilicon above a gate oxide layer patterned into a floating gate electrode of an EPROM device. Then form an ONO layer above the floating gate electrode. Define array protection, grow a second gate oxide layer, deposit a second level of polysilicon, define peripheral gates from the second level of polysilicon, and define an EPROM transistor gate electrode from the second level of polysilicon.
摘要:
A variable transmission focal mask to compensate lens heating is disclosed. A semiconductor fabrication alignment and exposure equipment includes an exposure and alignment unit, a variable transmission mask, and a stage. The unit has a light source and a lens. The mask is under the lens, and at least indirectly measures focus. The mask further can adjust the focus in real time in response to determining that the focus is out of specification. A wafer is placed on the stage for exposure to the light source through a mask or a reticle. The variable transmission mask normally has a substantially high transmission of light rating that can be adjusted downward to adjust the focus. For example, the mask can be a liquid crystal display (LCD) that can be darkened to so reduce its transmission of light rating.