Polysilicon CMP Slurry with Alkoxylated Diamines
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Solution Overview
Problem
Conventional CMP slurries fail to provide adequate selectivity for polysilicon over silicon dioxide or silicon nitride in advanced electronic device manufacturing, leading to significant loss of polysilicon in trench areas and undesirable topography such as dishing, which can damage underlying polysilicon active areas and hinder pattern density clearance.
Innovation Solution
Aqueous chemical mechanical planarization (CMP) polishing compositions comprising alkoxylated diamines and colloidal silica particles, specifically elongated, bent, or nodular silica dispersions, with a pH range of 9 to 11, which provide a high removal rate for polysilicon while minimizing the removal of silicon oxide and nitride, thus preventing dishing and ensuring planarization without excessive erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP slurries are used to achieve high polysilicon removal rate, then productivity is improved, but manufacturing precision deteriorates due to dishing and loss of polysilicon in trench areas
Solution Approach 1:
The invention changes the chemical composition parameters of the CMP slurry by incorporating specific organic compounds (amines, carboxylic acids, alcohols, or sugars) to modify the interaction between polysilicon and the polishing surface. This chemical modification enables selective removal of polysilicon while preserving the underlying trench structures, thereby maintaining manufacturing precision during high-rate polishing
Solution Approach 2:
The invention creates a composite polishing system by combining conventional abrasive particles with organic compounds (amines, carboxylic acids, alcohols, or sugars). This composite formulation provides both mechanical abrasion for high removal rate and chemical selectivity to prevent dishing and trench area loss, simultaneously improving productivity and manufacturing precision
2Productivity
If conventional CMP slurries are used to increase removal rate for polysilicon, then productivity is improved, but manufacturing precision deteriorates due to damage to underlying polysilicon active areas
Solution Approach 1:
The organic compounds (amines, carboxylic acids, alcohols, or sugars) act as intermediaries between the polysilicon layer and the polishing surface. These compounds selectively adsorb to polysilicon, creating a protective complex that allows controlled removal while preventing damage to the underlying active areas, thus enabling high removal rates without compromising manufacturing precision
3Productivity
If conventional CMP slurries are used to achieve high removal rate, then productivity is improved, but manufacturing precision deteriorates due to inability to clear pattern densities
Solution Approach 1:
The invention modifies the chemical parameters of the slurry by adding organic compounds that enhance selective polysilicon removal. This chemical enhancement allows the slurry to effectively clear pattern densities at high removal rates while maintaining the precision needed to stop on the underlying stop layer without over-polishing, thereby improving both productivity and manufacturing precision
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 described CMP compositions achieve a high polysilicon removal rate with suppressed dishing and improved selectivity over silicon oxide and nitride, maintaining colloidal stability and preventing metal contamination, thereby ensuring effective planarization in 3D-NAND and flash memory applications.
Implementation Method 1
comprising a mixture of (a) one or more alkoxylated diamines... and (c) ammonia or an amine base, wherein the compositions have a pH ranging from 9 to 11
Implementation Method 2
aqueous chemical mechanical planarization (CMP) polishing compositions... for use in polishing polysilicon at a high removal rate
Implementation Method 3
aqueous dispersions of elongated, bent or nodular colloidal silica particles
Data Source
AI summary
The present invention provides aqueous chemical mechanical planarization (CMP) polishing compositions that comprise a mixture of (a) one or more alkoxylated diamines having a number average molecular weight (Mn) of from 1,000 to 20,000, or, preferably, from 1000-15000 and having four (poly)alkoxy ether groups each containing from 5 to 100 alkoxy repeat units; (b) from 0.01 to 2 wt. % or, preferably, from 0.1 to 1.5 wt. %, as solids, based on the total weight of the compositions, of one or more aqueous dispersions of elongated, bent or nodular colloidal silica particles, preferably, having a secondary particle size as determined by dynamic light scattering (DLS) of from 20 to 60 nm; and (c) ammonia or an amine base, wherein the compositions have a pH ranging from 9 to 11. The compositions are substantially free of metals, such as alkali or alkaline earth metals that can damage substrates in polishing.