Abstract: Energy levels (dose) are manipulated to modify the resultant photomask representation in a controlled manner such that the final image in the semiconductor device fabrication is close to an ideal image. Feature sizes and shapes are modified by assigning relative mask writer doses rather than physically manipulating feature sizes in layout designs. This approach, based on coding of relative dose information onto the design data, allows continuous scale line width variation for all features without impact to data volume. Two embodiments are described. In the first embodiment, distortion knowledge in the form of a lookup table or convolution function is applied to CAD data which is fractured into numerous designs having specific dose assignments. In the alternative embodiment, distortion knowledge in the form of a lookup table or convolution function is applied to CAD data which generates an attribute file containing hierarchical dose information that is mapped onto the mask data.

Abstract: An apparatus for separating impurities from coal, includes a device for removing a predetermined amount of ash-forming substances from the coal and a device for removing a predetermined amount of high specific gravity (e.g., pyrite) from the coal having been processed by the ash-forming substance removing device. The ash-forming substance removing device and the high specific gravity material removing device each possess characteristics that allow them to more efficiently reject different types of mineral impurities from coal.