Abstract
A new structure for a character projection (CP) mask has been developed for the electron-beam (EB) lithography system, EX-8D. The mask comprises an electroplated Au membrane on which apertures are formed and a (110) oriented Si substrate. The Au membrane is 4 µm thick, which is thick enough to stop 50 keV electrons. The aspect ratio of the Au aperture is much less than that of the conventional Si aperture, so that the size of the apertures can be well controlled. By a repair process using a focused ion beam (FIB), the edge roughness and the curvature radius at the corner of the aperture are reduced to less than 0.2 µm. Since the demagnification ratio of EX-8D is 1/36, these errors are 0.006 µm on the wafer and sufficiently small for 0.15 µm lithography. On the CP mask, we arranged a 7×7 array of apertures in a 1650×1650 µm2 area with a small amount of dead space. This arrangement can be realized by the use of a Si (110) substrate on which back-etched holes with ve rtical sidewalls were formed. In addition, this CP mask has sufficient mechanical rigidity and heat conductivity, because the aperture membrane is supported by Si struts.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
