Study of Finishing of Wafers by Magnetic Field-Assisted Finishing

Abstract

The aims of this paper are to propose a new finishing process and show the feasibility of ultra-precision finishing of thin quartz wafers used for high-frequency devices. This particular application requires simultaneous improvement of surface roughness and thickness variation with minimal material removal. Consequently, the process must allow for the control of both super-fine finishing and localized material removal. This paper proposes a method using magnetic field-assisted finishing for the finishing of thin quartz wafers. The magnetic field-assisted finishing process enables localized material removal through control of the magnetic field distribution at the finishing area; and mirror finishing is achieved using magneto-rheological fluid-based slurry. This paper describes the processing principle, the development of the finishing equipment, and the required conditions to realize the principle. The finishing experiments demonstrate the feasibility of the proposed method to perform super-fine finishing of 60 μm thick quartz wafers, in which the control of the magnetic field allows for localization of the material removal to improve or maintain the thickness variation, as desired.