The four companies have all thought of using electric fields in the EUV lithography exposure process because the EUV sets off electrons in the resist which can then migrate randomly, causing roughness and resolution loss. An electric field would be an obvious way to keep them moving predominantly vertically to preserve the image best.
First to propose this was Intel (US7374867, 2003) which involved a conductive layer on the resist and an RF coil. Then ASML proposed directly apply the potential to the metallic layer on the resist (US7463336, 2004). Samsung (US9482953, 2014) proposed using an auxiliary microwave unit in addition to the electric field. Finally, TSMC proposed (US10520833, 2018) a powered electrode above the substrate, actually located above at least one of the projection optics elements.
It would be amusing, to say the least, as ASML would carry the main burden as the key practitioner, whereas ASML's customer merely applies a conductive layer (even then as an option).
First to propose this was Intel (US7374867, 2003) which involved a conductive layer on the resist and an RF coil. Then ASML proposed directly apply the potential to the metallic layer on the resist (US7463336, 2004). Samsung (US9482953, 2014) proposed using an auxiliary microwave unit in addition to the electric field. Finally, TSMC proposed (US10520833, 2018) a powered electrode above the substrate, actually located above at least one of the projection optics elements.
It would be amusing, to say the least, as ASML would carry the main burden as the key practitioner, whereas ASML's customer merely applies a conductive layer (even then as an option).
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