CMP Slurry with Alkyl Aryl Polyether Sulfonate for Selective Polishing
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Solution Overview
Problem
Current chemical mechanical polishing compositions fail to provide a balanced removal rate and selectivity that favors the removal of silicon nitride and silicon oxide over polysilicon, which is necessary for advanced semiconductor device designs.
Innovation Solution
A chemical mechanical polishing composition comprising water, an abrasive, and an alkyl aryl polyether sulfonate compound with a hydrophobic portion and a nonionic acyclic hydrophilic portion, which suppresses the removal rate of polysilicon while maintaining or increasing the removal rates of silicon oxide and silicon nitride, is used in conjunction with a polishing pad to abrade the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing compositions are used, then polysilicon is removed at a high rate, but silicon oxide and silicon nitride cannot be selectively removed over polysilicon
Solution Approach 1:
The invention changes the chemical parameters of the polishing composition by introducing alkyl aryl polyether sulfonate compounds with specific hydrophobic and hydrophilic portions. This chemical parameter change creates selective interaction with silicon oxide and silicon nitride surfaces while minimizing interaction with polysilicon, achieving both selectivity and maintained productivity
Solution Approach 2:
The polishing composition uses a composite surfactant structure combining hydrophobic alkyl groups and hydrophilic polyether chains. This composite material design allows the molecule to interact with both the hydrophobic polysilicon surface and hydrophilic silicon oxide/nitride surfaces differently, enabling selective removal while maintaining overall polishing efficiency
2Manufacturing precision
If polishing composition favors removal of silicon oxide and silicon nitride over polysilicon, then selectivity is improved, but overall polishing efficiency decreases
Solution Approach 1:
By adjusting the chemical parameters of the polishing composition through specific alkyl aryl polyether sulfonate compounds, the invention achieves selective removal of silicon oxide and nitride without significantly reducing the overall polishing rate, thus minimizing loss of time while improving selectivity
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 a substantial reduction in polysilicon removal rate (>50%) while maintaining or increasing the removal rates of silicon oxide and silicon nitride, providing a selective polishing process that supports advanced semiconductor manufacturing requirements.
Implementation Method 1
abrading at least a portion of the substrate to polish the substrate
Implementation Method 2
an alkyl aryl polyether sulfonate compound which has a hydrophobic portion having an alkyl group bound to an aryl ring and a nonionic acyclic hydrophilic portion
Data Source
AI summary
A method for chemical mechanical polishing of a substrate is provided, comprising: providing a substrate, wherein the substrate comprises polysilicon and at least one of silicon oxide and silicon nitride; providing a chemical mechanical polishing composition, comprising, as initial components: water; an abrasive; and an alkyl aryl polyether sulfonate compound, wherein the alkyl aryl polyether sulfonate compound has a hydrophobic portion having an alkyl group bound to an aryl ring and a nonionic acyclic hydrophilic portion having 4 to 100 carbon atoms; providing a chemical mechanical polishing pad with a polishing surface; moving the polishing surface relative to the substrate; dispensing the chemical mechanical polishing composition onto the polishing surface; and, abrading at least a portion of the substrate to polish the substrate; wherein at least some of the polysilicon is removed from the substrate; and, wherein at least some of the at least one of silicon oxide and silicon nitride is removed from the substrate.