Polysilicon CMP Slurry Composition for Selective High-Rate Polishing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing CMP polishing methods struggle to achieve a high polishing rate for polysilicon, leading to inefficiencies in semiconductor production, particularly in the formation of element isolation regions and 3D-NAND manufacturing.
Innovation Solution
A CMP polishing liquid containing abrasive grains and a specific cationic polymer, comprising polymers with nitrogen and carbon atoms and hydroxyl groups, is used to enhance the polishing rate for polysilicon, while suppressing the polishing rate for silicon oxide and silicon nitride.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP polishing liquid is used to polish polysilicon, then the polishing process can be performed, but the polishing rate for polysilicon is insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the CMP polishing liquid by introducing a specific cationic polymer with nitrogen-containing groups and hydroxyl groups. This chemical parameter change enables the polishing liquid to achieve a polishing rate for polysilicon of 1200 Å/min or more, resolving the insufficient polishing rate issue while maintaining process reliability
Solution Approach 2:
The patent creates a composite polishing liquid system by combining abrasive grains with a specifically designed cationic polymer. The composite structure of the polishing liquid, containing both mechanical abrasion components and chemical reaction components (the cationic polymer with nitrogen and hydroxyl groups), achieves high polishing rates for polysilicon while maintaining consistent performance
2Productivity
If high polishing rate for polysilicon is achieved, then productivity is improved, but it becomes difficult to selectively polish only polysilicon without affecting silicon oxide and silicon nitride
Solution Approach 1:
The cationic polymer in the polishing liquid exhibits local quality by selectively reacting with polysilicon through its nitrogen-containing groups and hydroxyl groups. This selective chemical interaction provides high polishing rate for polysilicon (1200 Å/min or more) while maintaining low polishing rates for silicon oxide and silicon nitride, achieving both productivity improvement and manufacturing precision
Solution Approach 2:
The patent changes the chemical parameters of the polishing liquid by incorporating a cationic polymer with specific functional groups (nitrogen-containing groups and hydroxyl groups). This parameter change creates selective chemical reactivity that enhances polysilicon removal rate while preserving selectivity against silicon oxide and silicon nitride
3Manufacturing precision
If multiple polishing steps are used to achieve desired surface flatness, then polishing quality is improved, but production time increases
Solution Approach 1:
The patent merges multiple polishing functions into a single polishing step by using the composite CMP polishing liquid containing abrasive grains and cationic polymer. This single-step process simultaneously achieves high material removal rate (1200 Å/min or more for polysilicon) and desired surface flatness, eliminating the need for multiple sequential polishing steps and reducing production time
Solution Approach 2:
The polishing liquid maintains continuous effective action throughout the polishing process by combining mechanical abrasion from abrasive grains with continuous chemical reaction from the cationic polymer. This continuous dual-action mechanism enables high polishing rates and good surface flatness to be achieved in a single continuous polishing step, reducing total process time
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 method achieves a high polishing rate for polysilicon of 1200 Å/min, with a ratio of polysilicon to silicon oxide polishing rates of 1 or more, and improves productivity by allowing one-stage polishing of polysilicon and silicon nitride.
Implementation Method 1
CMP (chemical mechanical polishing) technique
Implementation Method 2
the cationic polymer includes at least one selected from the group consisting of a polymer A having a main chain containing a nitrogen atom and a carbon atom and a hydroxyl group bonded to the carbon atom
Implementation Method 3
abrasive grains
Data Source
AI summary
An aspect of the present disclosure provides a CMP polishing liquid for polishing polysilicon, the CMP polishing liquid containing: abrasive grains; and a cationic polymer, in which the cationic polymer includes at least one selected from the group consisting of a polymer A having a main chain containing a nitrogen atom and a carbon atom and a hydroxyl group bonded to the carbon atom and an allylamine polymer B. Another aspect of the present disclosure provides a polishing method including a step of polishing a material to be polished by using this CMP polishing liquid.