High order lens aberration monitor

• Published in: Microelectronic engineering 2000-06, Vol.53 (1), p.129-132
• Main Authors: Preuninger, J., Bukofsky, S., Kunkel, G.
• Format: Article
• Language: English
• Subjects: Applied sciences; Circuit properties; Design. Technologies. Operation analysis. Testing; Electric, optical and optoelectronic circuits; Electronics; Exact sciences and technology; Fabrication techniques; lithography, pattern transfer; Integrated circuits; Integrated optics. Optical fibers and wave guides; Lithography, masks and pattern transfer; Microelectronic fabrication (materials and surfaces technology); Microelectronics: LSI, VLSI, ULSI; integrated circuit fabrication technology; Optical and optoelectronic circuits; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/S0167-9317(00)00279-3

A variety of lens aberration effects degrade lithographic performance metrics such as resolution, image fidelity, pattern placement, and best focus. Additionally, these may be different for different pattern orientations. Resolution enhancement techniques, necessary for low k1 imaging, often amplify these undersirable effects, degrading the optimum process window obtainable for an aberration-free lens. The magnitude of the aberration effect depends, among other things, on the illumination condition represented by the numerical aperture and the pupil fill as well as the pattern layout itself. Many lithographic test structures exist to characterize primary aberrations [Piston, tilt, defocus, astigmatism and coma]. However, it is difficult to extract information about higher order lens imperfections. These higher-order effects can seriously degrade imaging when complex reticle patterns [i.e. non-orthogonal layouts] are used. Therefore, we have developed a simple test structure to capture these high order effects.