Experimental scanning electron-beam automatic registration system

• Publisher: Elsevier Science
• Year: 1976
• Tongue: English
• Weight: 145 KB
• Volume: 26
• Category: Article
• ISSN: 0042-207X
• DOI: 10.1016/s0042-207x(76)80106-6

✦ Synopsis

35 1674. Deep uv lithography. (USA) Using deep uv light ranging from 2000 to 2600 A, submicrometer patterns in photoresist with height-to-width aspect ratios as high as 15 can be achieved. The well known electron-beam positive resist, polymethyl methacrylate (PMMA), is used as the deep uv photoresist. Its optical absorption coefficient, dissolution rate, and sensitivity are given in the deep uv wavelength region. Its absorption coefficient being a factor of two lower than that of AZ 1350J, makes it suitable for deep penetration of submicrometer-wide beams. The negligible sensitivity at wavelengths longer than 2600 A eliminates the need for an expensive filter. Both Xe-Hg arc lamps and deuterium spectral lamrs have been used to expose the resist. Chrome or aluminum masks on quartz or sapphire substrates were found satisfactory. Chevron patterns of 1.6 tLm width and 0.4 p.m spacing and Y-I bars of 1.6 tJm width and 0.2 t~m gaps were printed in 3 t~m of PMMA 2041, as well as Y-I bars of 0.5/Jm width and 0.25 g.m gaps in 1.78 t~m of PMMA 2041. The exposure time in both cases was below l0 min.