Polycrystalline Silicon CMP Slurry for Low-Roughness Polishing
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Solution Overview
Problem
Low-temperature polycrystalline silicon films produced using laser crystallization methods often exhibit poor surface roughness due to protrusions, which can lead to defects in subsequent processing steps, such as reduced breakdown voltage, increased leakage current, and nonuniformity in etching and exposing processes.
Innovation Solution
A chemical mechanical polishing (CMP) slurry composition is developed, comprising abrasive particles, a surface roughness modifier (such as a water-soluble polymer), a polishing regulator (organic acid), and a pH regulator, designed to minimize damage to silicon crystals while improving the surface roughness of polycrystalline silicon films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser crystallization method is used to crystallize amorphous silicon film, then crystallization efficiency is improved and polycrystalline silicon with excellent properties is formed, but surface protrusions are generated leading to poor surface roughness
Solution Approach 1:
The invention changes the chemical parameters of the polishing slurry by incorporating specific organic acids (polishing regulators) with controlled molecular weights and functional groups, along with pH regulators, to optimize the chemical interaction with polycrystalline silicon surface. This chemical parameter optimization enables selective removal of protrusions while preserving the underlying crystal structure, thus improving surface roughness without compromising crystallization efficiency
Solution Approach 2:
The invention introduces an intermediary chemical system (CMP slurry with organic acids and pH regulators) that mediates between the laser crystallization process output and the desired surface quality. The slurry components act as intermediaries that selectively interact with protrusion regions, enabling controlled material removal and surface smoothing while maintaining the benefits of laser crystallization
2Manufacturing precision
If wet air oxidation and HF treatment are repeatedly performed to remove surface protrusions, then surface roughness is improved, but polycrystalline silicon film other than protrusions is also lost reducing process reliability
Solution Approach 1:
The invention applies local quality by designing a polishing slurry that selectively interacts with protrusion regions rather than uniformly treating the entire surface. The organic acids and pH regulators create localized chemical environments that preferentially react with protrusion material, enabling selective removal while preserving the bulk polycrystalline silicon film integrity, thus improving both surface roughness and process reliability
Solution Approach 2:
The invention uses partial action by controlling the polishing process to remove only the excessive protrusion material rather than uniformly removing material across the entire surface. The slurry composition and polishing parameters are optimized to achieve just enough removal to eliminate protrusions while minimizing loss of the underlying functional polycrystalline silicon film, thereby maintaining process reliability
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 CMP slurry composition effectively reduces the maximum peak-to-valley (Rpv) surface roughness to 4 nm or less and the arithmetic average roughness (Ra) to 0.4 nm or less, enhancing the reliability of thin film transistors and reducing hillock formation on polycrystalline silicon films.
Implementation Method 1
chemical mechanical polishing (CMP) slurry composition for polishing polycrystalline silicon
Implementation Method 2
abrasive particles
Implementation Method 3
a polishing regulator including an organic acid
Data Source
AI summary
The present disclosure relates to a CMP slurry composition for polishing polycrystalline silicon and a polishing method using the same. A CMP slurry composition for polishing polycrystalline silicon according to an embodiment of the present disclosure includes: abrasive particles; a surface roughness reducing agent; a polishing regulator containing an organic acid; and a pH regulator.