Effect of Ceria Size and Concentration in Shallow Trench Isolation (STI) Chemical Mechanical Polishing (CMP)

Conference: ICPT 2007 - International Conference on Planarization / CMP Technology
10/25/2007 - 10/27/2007 at Dresden, Germany

Proceedings: ICPT 2007

Pages: 6Language: englishTyp: PDF

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Pandija, S.; Babu, S. V. (Center for Advanced Materials Processing, Clarkson University, Potsdam, New York 13699-5665, USA)
Crinière, G.; Ceintrey, C. (Rhodia Electronics and Catalysis, France)

The effect of size and concentration of ceria abrasive particles (untreated and treated with a poly-acrylic acid (PAA) additive used as a dispersant) on oxide and nitride polish rates for STI CMP was investigated. It was observed that a significantly high oxide polish rate (~ 350-370 nm min-1 at 4 ψ down pressure) was obtained for both 60 nm and 45 nm ceria particles at a low concentration of 0.25 to 0.375% by wt. The corresponding nitride polish rates were also relatively high (~80-100 nm min-1). In contrast, for 25 nm ceria particles, both the oxide and nitride polish rates were low (<15 nm min-1) at all the studied concentrations. In case of ceria treated with PAA, the highest oxide polish rate (~250 nm min-1) was obtained for 1% ceria concentration. The addition of proline to this dispersion suppressed nitride polish rates, leading to a (oxide:nitride) selectivity that is as high as ~150:1.