Ceria CMP Slurry With Organic Diacid for Oxide Selectivity
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Solution Overview
Problem
Existing CMP compositions for polishing silicon-containing substrates, particularly those using ceria abrasives, face challenges in achieving improved removal rates, planarization efficiency, and material selectivity, especially between silicon oxide and polysilicon, with a need for compositions that provide enhanced removal rate selectivity and reduced erosion and dishing.
Innovation Solution
A chemical mechanical polishing composition comprising cubiform ceria abrasive particles dispersed in a liquid carrier, along with an organic diacid, which enhances the polishing process by improving removal rates and selectivity between silicon oxide and polysilicon, while reducing erosion and dishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional ceria abrasive compositions are used for polishing silicon oxide, then polishing can be performed, but removal rates are insufficient and selectivity between silicon oxide and polysilicon is poor
Solution Approach 1:
The patent modifies the chemical composition parameters of the polishing slurry by incorporating specific organic acids (sulfonic acid, carboxylic acid, or phenolic compound) and controlling pH levels (2-6), which changes the chemical reactivity parameters to achieve both high removal rates and selective polishing between silicon oxide and polysilicon
Solution Approach 2:
The patent uses composite abrasive particles consisting of ceria combined with other metal oxides (such as zirconia, titania, or alumina) in specific ratios, creating a composite material that provides both high polishing power for silicon oxide and controlled selectivity against polysilicon
2Productivity
If higher removal rates are achieved with ceria abrasives, then throughput increases, but erosion and dishing increase reducing planarization quality
Solution Approach 1:
The patent optimizes physical parameters including particle size distribution (D10-D90 ranges), particle concentration (0.1-5 wt%), and slurry viscosity by adjusting solvent composition, achieving a balance where sufficient removal rate is maintained while minimizing erosion and dishing through controlled mechanical action
Solution Approach 2:
The patent creates local quality variations in the abrasive system by using multi-modal particle size distributions where finer particles fill valleys and coarser particles provide peak removal, ensuring uniform planarization across the wafer surface while maintaining high overall removal rates
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition achieves significantly improved silicon oxide removal rates, reduced polysilicon removal rates, and enhanced selectivity, as well as improved planarization over a wide range of pattern features and densities, particularly effective for carbon doped silicon oxide materials.
Implementation Method 1
cubiform ceria abrasive particles dispersed in the liquid carrier
Implementation Method 2
chemical additives for increasing the rate of material removal
Implementation Method 3
an organic diacid... enhancing the polishing process by improving removal rates
Implementation Method 4
cubiform ceria abrasive particles dispersed in the liquid carrier
Data Source
AI summary
A chemical mechanical polishing composition for polishing a substrate having a silicon oxygen material includes a liquid carrier, cubiform ceria abrasive particles dispersed in the liquid carrier, and an organic diacid.