Surface-Modified Silica Particles for Selective CMP
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Solution Overview
Problem
Current chemical mechanical polishing (CMP) processes face challenges in achieving selective removal rates between conductive and dielectric materials, particularly in efficiently removing tungsten without damaging underlying silicon dioxide layers.
Innovation Solution
Surface-modified silica particles with an alkoxy organosilane are used in an acidic composition for CMP, where the silica particles are treated with an alkoxy organosilane and optionally doped with aluminate, enhancing selectivity by adjusting the pH and reaction conditions to optimize the polishing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional silica particles are used in CMP slurry, then general polishing capability is maintained, but selectivity between conductive and dielectric materials is insufficient
Solution Approach 1:
The silica particles are surface-modified with alkoxy organosilane compounds, changing the chemical parameters of the particle surface. This modification alters the interaction between silica particles and different materials (conductive vs. dielectric), enabling selective removal. The alkoxy groups provide specific chemical affinity that differentiates between material types, achieving the desired selectivity without sacrificing overall polishing effectiveness.
Solution Approach 2:
The invention creates a composite structure by combining silica particles with alkoxy organosilane surface modifiers. This composite approach integrates the mechanical polishing capability of silica with the selective chemical interaction properties of the organosilane coating, resulting in particles that simultaneously provide abrasion and material-specific chemical recognition for enhanced selectivity.
2Productivity
If high removal rate for tungsten is achieved, then conductive layer polishing efficiency is improved, but dielectric layer damage increases
Solution Approach 1:
The alkoxy organosilane modification creates local chemical quality differences on the silica particle surface, enabling selective interaction with specific materials. The modified surface exhibits enhanced affinity for conductive materials (tungsten) while maintaining reduced interaction with dielectric materials (silicon dioxide), allowing high tungsten removal rates without proportional dielectric damage.
Solution Approach 2:
By modifying the surface chemistry parameters of silica particles through alkoxy organosilane treatment, the slurry achieves differential removal rates. The chemical parameter changes enable the particles to preferentially react with and remove tungsten while minimizing silicon dioxide removal, thus improving the selectivity ratio between conductive and dielectric material removal.
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 surface-modified silica particles demonstrate improved selectivity with high tungsten removal rates and significantly reduced silicon oxide removal rates, maintaining high tungsten removal efficiency while minimizing dielectric material loss, thus enhancing CMP process efficiency.
Implementation Method 1
surface-modified silica particles comprising an alkoxy organosilane
Implementation Method 2
the silica particles and the alkoxy organosilane into contact with each other, thereby obtaining the modified silica particles
Implementation Method 3
the polishing preferably is done by a combination of mechanical polishing and chemical corrosion
Implementation Method 4
Pad and substrate or surface, e.g. a wafer, are pressed together and generally rotated non-concentrically, i.e. with different rotational axes, thereby abrading and removing material from the surface or substrate
Implementation Method 5
Pad and substrate or surface, e.g. a wafer, are pressed together and generally rotated non-concentrically
Data Source
AI summary
The present invention relates to surface-modified silica particles comprising an alkoxy organosilane and to compositions comprising such particles as well as to uses of such surface-modified silica particles and compositions comprising such particles.