Kwang-Bok Kim

Control of Microscratches in Chemical-Mechanical Polishing Process for Shallow Trench Isolation

A method of controlling microscratches on silicon oxide surfaces induced by chemical-mechanical polishing (CMP) process for the planarization of shallow trench isolation is discussed. The frequency of microscratches during polishing shows its high dependency on the characteristics of CMP consumables such as slurry and pad. A diluted slurry solution, pH-controlled with a potassium hydroxide (KOH) solution of pH 13, produces best results in reducing microscratches on silicon oxide surfaces during polishing. In conclusion, careful preparation of the CMP consumables is required to reduce microscratches on silicon oxide during polishing.

A Study of the Planarity by Sti Cmp Erosion Modeling

In this work, we propose a new equation that predicts the planarity as a function of active pattern density, initial step height, selectivity between gapfilled oxide and silicon nitride and over CMP amounts. In order to achieve highly planarized STI surface, uniform active density, reduced initial step height, minimization of over CMP amounts and high selective slurry were required. Our new equation was applied to the 0.18um graded CPU devices’ STI CMP to enhance planarity and these parameters were evaluated quantitatively. It is concluded that the model suggested is useful in predicting CMP planarity

A Study on STI and Damascene CMP using Chip Level Simulation

Simulation of chemical-mechanical polishing is important because the chip-level planarity are difficult to control. The simulator has been developed for predicting and optimizing the thickness distribution after the STI and damascene CMP as well as ILD CMP using chip-level pattern density, elastic spring model and erosion model. In this study, the results of CMP simulation is shown to agree well with the measured data. The simulator can be used to optimize CMP process conditions and to generate design rules for filling dummy patterns which are used to improve the planarity and uniformity.