CMP Slurry Composition for Preventing Polishing Pad Groove Clogging
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Solution Overview
Problem
Chemical mechanical polishing slurries with elongated colloidal silica particles often cause clogging of polishing pad grooves, leading to non-uniform polishing and planarization performance due to local blockage of slurry transportation.
Innovation Solution
A chemical mechanical polishing composition comprising water, bimodal distributed colloidal silica particles with elongated and spherical particles, polyvinyl alcohol 80% to 90% hydrolyzed, an electrolyte, and a pH greater than 7, which inhibits groove clogging by maintaining dynamic contact and slurry flow during polishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If elongated colloidal silica particles are used in polishing slurry, then polishing efficiency is improved, but polishing pad groove clogging occurs leading to non-uniform polishing performance
Solution Approach 1:
The patent changes the shape parameter of colloidal silica particles from spherical to elongated, and optimizes the size distribution parameters (bimodal distribution with specific diameter ranges). This resolves the contradiction by selecting particle morphology and size parameters that enhance polishing efficiency while preventing groove clogging through appropriate dimensional characteristics
Solution Approach 2:
The patent creates a composite abrasive system by combining elongated colloidal silica particles with spherical colloidal silica particles in a bimodal distribution. This composite approach allows the elongated particles to provide high polishing efficiency while the spherical particles help prevent groove clogging, thus resolving the contradiction between productivity and manufacturing precision
2Loss of substance
If polishing is performed for extended periods, then more material is removed, but groove clogging increases causing gradual shifting in polishing uniformity
Solution Approach 1:
The patent performs preliminary action by optimizing the slurry composition with bimodal particle distribution before polishing begins. The carefully selected combination of particle shapes and sizes prevents groove clogging from occurring during extended polishing periods, allowing continuous material removal while maintaining uniformity throughout the polishing process
Solution Approach 2:
The patent enables continuity of useful action by formulating a slurry that maintains its effectiveness throughout extended polishing periods. The bimodal particle distribution ensures that abrasive action continues uniformly without interruption from groove clogging, allowing sustained material removal while preserving polishing uniformity
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 effectively prevents groove clogging, ensuring consistent polishing uniformity and improved planarization performance by maintaining slurry flow and preventing gradual shifting in polishing uniformity on semiconductor wafer surfaces.
Implementation Method 1
the wafer surface is polished and made planar by the chemical and mechanical action of the pad surface and slurry
Implementation Method 2
Chemical mechanical polishing (CMP), is a common technique used to planarize substrates
Data Source
AI summary
An aqueous based chemical mechanical polishing composition for polishing a semiconductor substrate includes an abrasive having bimodal distributed colloidal silica particles which include elongated colloidal silica particles, polyvinyl alcohol 80% hydrolyzed to less than or equal to 90% hydrolyzed, an electrolyte and a pH greater than 7, and a method of polishing the semiconductor substrate to planarize the substrate. The aqueous based chemical mechanical polishing composition and method inhibits polishing pad groove clogging during chemical mechanical polishing of the semiconductor substrates.