Effect of Pad Groove Design on Slurry Injection Scheme during Interlayer Dielectric Chemical Mechanical Planarization

Abstract

In this study, the effect of pad groove design on slurry injection scheme during interlayer dielectric chemical mechanical planarization was investigated. A novel slurry injection system (SIS) with multiple slurry outlets was designed to allow fresh slurry to be injected through one or multiple points. At first, the SIS with one injection point scheme was compared with the standard slurry application method on a concentrically grooved pad and an xy-groove pad. On the concentrically grooved pad, the SIS with one injection point scheme generated significantly higher oxide removal rates (ranging from 22 to 35 percent) compared to the standard slurry application method at different slurry flow rates. On the xy-groove pad, the SIS with one injection point scheme still resulted in higher removal rates (ranging from 3 to 9 percent), however, its removal rate enhancement was not as high as that of the concentrically grooved pad. In order to further improve slurry availability on the xy-groove pad, SIS with multi-injection point scheme was tested. Results showed that the SIS with multi-injection point scheme resulted in significantly higher removal rates (ranging from 17 to 20 percent) compared to the standard slurry application method. This work underscored the importance of optimum slurry injection scheme for accommodating particular pad groove designs.