Amine-Functionalized CMP Slurry for Boron-Doped Polysilicon
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Solution Overview
Problem
The CMP process for semiconductor devices, particularly for boron-doped polysilicon layers, faces low polishing rates and defects due to the use of amine compounds in the slurry, which cause chemical reactions and variations in polishing rates.
Innovation Solution
A polishing composition incorporating metal oxide particles with a functional group, such as an amine group, bonded to their surface, is used to enhance the polishing rate and selectivity of boron-doped polysilicon layers, while preventing defects and improving surface roughness, with a specific etch rate and selectivity ratio between silicon nitride and boron-doped polysilicon layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If amine compounds are added to the slurry to improve polishing rate, then polishing rate increases, but chemical reactions occur on the wafer causing defects and variations in polishing rate
Solution Approach 1:
The patent uses an amine-functionalized silica particle as an intermediary substance. The amine group is covalently bonded to the silica particle surface, creating a stable compound that acts as a mediator between the polishing mechanical action and the boron-doped polysilicon layer. This intermediary approach allows the amine functionality to enhance polishing rate without the free amine compounds causing harmful chemical reactions on the wafer surface.
Solution Approach 2:
The patent employs a composite material consisting of silica particles functionalized with amine groups. This composite structure combines the mechanical polishing capability of silica particles with the chemical reactivity enhancement of amine groups, creating a material that improves polishing rate while maintaining wafer integrity. The composite nature allows simultaneous achievement of high productivity and reliability.
2Strength
If boron doping level is increased to improve physical strength, then physical strength increases, but polishing rate becomes very low
Solution Approach 1:
The patent changes the chemical parameter of the polishing slurry by introducing amine-functionalized particles. This parameter change specifically targets the interaction between the polishing agent and the boron-doped polysilicon surface, enabling effective removal of heavily doped layers without compromising the physical strength properties achieved through high boron doping levels.
3Ease of manufacture
If conventional slurry is used for polishing, then polishing process is simple, but surface roughness is poor and defects occur
Solution Approach 1:
The patent applies local quality enhancement by functionalizing only the surface of the silica particles with amine groups, while maintaining the bulk silica structure for mechanical polishing. This localized modification allows the polishing process to remain simple and easy to manufacture, while the surface-functionalized particles provide improved surface roughness and defect prevention during the polishing action.
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 solution significantly increases the polishing rate of boron-doped layers, improves polishing selectivity, prevents defects, and enhances surface roughness, achieving a high-quality polished semiconductor substrate.
Implementation Method 1
a chemical reaction occurs partially on a wafer, such that there is a problem that a defect and a variation in the polishing rate occur on the wafer
Implementation Method 2
a surface of a substrate is polished while a slurry is provided to a polishing pad and the substrate is pressed and rotated
Data Source
AI summary
The present disclosure relates to a polishing composition for a semiconductor process that may increase a polishing rate of a boron-doped polysilicon layer, improve polishing selectivity, prevent a defect of a wafer that may occur in a polishing process, and improving surface roughness of the wafer, and a method for polishing a substrate by using the same. In addition, the present disclosure relates to a method for manufacturing a polished substrate by using a polishing composition for a semiconductor process.