Abstract: A method of fabricating ultra small vias in insulating layers on a semiconductor substrate for an integrated circuit by a first exposure of a photoresist to line pattern with the semiconductor substrate in a first position and the exposure dosage being insufficient to develop the photoresist followed by a second overlapping exposure of the line pattern with the semiconductor substrate being in a position 90° from the first position and again being insufficient in exposure dosage to develop the photoresist, the overlapped line exposures creating via exposures of sufficient dosage to develop the photoresist, thereby creating a smaller via opening than with a single exposure.

Abstract: Isolation regions are formed with greater accuracy and consistency by forming an oxide-silicon nitride stack and then depositing an antireflective layer, of silicon oxime, on the silicon nitride layer before patterning. Embodiments also include depositing the silicon nitride layer and the silicon oxime layer in the same tool.

Abstract: Isolation regions are formed with greater accuracy and consistency by forming an oxide-silicon nitride stack and then depositing an amorphous silicon antireflective layer, on the silicon nitride layer before patterning. Embodiments also include depositing the silicon nitride layer and the amorphous silicon layer in the same tool.

Abstract: Shallow trench isolation among transistors and other devices on a semiconductor substrate is provided by initially forming a layer of highly absorbing silicon rich nitride to serve as a hardmask between a semiconductor substrate and a photoresist. The highly absorbing layer of silicon rich nitride has an extinction coefficient (k)>0.5. As reflected light passes through the layer of silicon rich nitride, a substantially amount of light is absorbed therein thereby blocking such reflected light from negatively interfering with patterning of the photoresist during photolithography. Following patterning of the photoresist, isolation trenches are formed in the semiconductor substrate by etching through the silicon rich nitride in accordance with the pattern formed on the photoresist.