Photolithography focus improvement by reduction of autofocus radiation transmission into substrate
View Patent ↗An anti-reflective coating material, a microelectronic structure that includes an anti-reflective coating layer formed from the anti-reflective coating material and a related method for exposing a resist layer located over a substrate while using the anti-reflective coating layer provide for attenuation of secondary reflected vertical alignment beam radiation when aligning the substrate including the resist layer located thereover. Such enhanced vertical alignment provides for improved dimensional integrity of a patterned resist layer formed from the resist layer, as well as additional target layers that may be fabricated while using the resist layer as a mask.
1. A method for exposing a resist layer comprising:
forming layered over a substrate a target layer, an anti-reflective layer located over the target layer and a resist layer also located over the target layer to form a layered substrate, the anti-reflective coating layer including a composition of matter that exhibits a first absorption peak corresponding with an exposure apparatus vertical alignment beam wavelength;
vertically aligning the layered substrate within an exposure apparatus while using an exposure apparatus vertical alignment beam and horizontally aligning the layered substrate within the exposure apparatus while using an exposure apparatus horizontal alignment beam to yield an aligned layered substrate; and
exposing the resist layer within the aligned layered substrate within the exposure apparatus while using an exposure beam.
2. The method of claim 1 further comprising: developing the resist layer to form a patterned resist layer; and treating the target layer while using the patterned resist layer as a mask.
3. The method of claim 1 wherein the first absorption peak is in a range greater than about 800 nanometers.
4. The method of claim 3 wherein: the composition of matter exhibits a second absorption peak corresponding with an exposure wavelength; and the exposure wavelength is less than about 300 nanometers.
5. The method of claim 4 wherein the composition of matter does not exhibit a third absorption peak interposed between the first absorption peak and the second absorption peak.
6. The method of claim 1 wherein the anti-reflective coating layer is interposed between the resist layer and the target layer.
7. The method of claim 1 wherein the resist layer is interposed between the anti-reflective coating layer and the target layer.
8. A method for exposing a resist layer comprising:
positioning within an exposure apparatus a microelectronic structure that includes a reflective layer located over a substrate and a resist layer located over the reflective layer;
vertically aligning the microelectronic structure within the exposure apparatus while attenuating a reflection of a vertical alignment beam from the reflective layer, to provide an aligned substrate; and
exposing the aligned substrate within the exposure apparatus.
9. The method of claim 8 wherein the resist layer comprises an infrared absorptive dye.