Polishing Slurry Composition for Selective Oxide Planarization
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Solution Overview
Problem
Inorganic insulation layers in display devices often have uneven surfaces, leading to reduced capacitance and increased risk of disconnection or skew issues due to the formation of capacitor electrodes on these surfaces.
Innovation Solution
A polishing slurry comprising polishing particles, a dispersing agent, an oxide-polishing promoter, and a nitride-polishing inhibitor is used to planarize the insulation layers, specifically formulated to have a high selectivity for silicon oxide over silicon nitride, ensuring a flat surface and minimizing residual distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional polishing slurries are used on insulation layers with stacked silicon oxide and silicon nitride, then the polishing process can proceed, but the selectivity between silicon oxide and silicon nitride is insufficient leading to uneven surface and residual distribution
Solution Approach 1:
The polishing slurry is designed with different chemical components that selectively interact with different materials: oxide-polishing promoters (picolinic acid, nicotinic acid, isonicotinic acid) specifically enhance silicon oxide removal, while nitride-polishing inhibitors (amino acids like glycine, alanine, proline) specifically suppress silicon nitride removal. This local quality approach allows differential polishing rates across different material regions, achieving high selectivity (at least 70:1 for silicon oxide to silicon nitride) and uniform surface planarity without requiring complex multi-step processes.
Solution Approach 2:
The polishing slurry employs a composite formulation combining multiple functional components: polishing particles (ceria, silica, alumina, zirconia, or titania with 6-350 nm diameter), dispersing agents (anionic, cationic, non-ionic, or hydroxyl acid compounds), oxide-polishing promoters (pyridine carboxylic acids), and nitride-polishing inhibitors (amino acids or anionic organic acids). This composite material approach enables simultaneous achievement of high polishing rate for silicon oxide, high selectivity, and uniform surface quality that cannot be obtained with single-component slurries.
2Reliability
If the insulation layer is not planarized, then the manufacturing process is simpler, but the capacitance is reduced and disconnection or skew issues occur
Solution Approach 1:
The polishing slurry achieves high selectivity (at least 70:1) by adjusting critical parameters: pH level (optimized range 3-8), concentrations of oxide-polishing promoters (0.001-1 wt%) and nitride-polishing inhibitors (0.05-0.1 wt%), and polishing particle size (6-350 nm). These parameter optimizations enable the polishing process to selectively remove silicon oxide while preserving silicon nitride, achieving uniform planarization that ensures reliable electrical connections and prevents disconnection or skew issues in the final device.
3Manufacturing precision
If high selectivity polishing is achieved through optimized slurry composition, then surface uniformity improves, but the slurry formulation becomes more complex
Solution Approach 1:
The polishing slurry is designed with different chemical components that selectively interact with different materials: oxide-polishing promoters (picolinic acid, nicotinic acid, isonicotinic acid) specifically enhance silicon oxide removal, while nitride-polishing inhibitors (amino acids like glycine, alanine, proline) specifically suppress silicon nitride removal. This local quality approach allows differential polishing rates across different material regions, achieving high selectivity (at least 70:1 for silicon oxide to silicon nitride) and uniform surface planarity without requiring complex multi-step processes.
Solution Approach 2:
The polishing slurry achieves high selectivity (at least 70:1) by adjusting critical parameters: pH level (optimized range 3-8), concentrations of oxide-polishing promoters (0.001-1 wt%) and nitride-polishing inhibitors (0.05-0.1 wt%), and polishing particle size (6-350 nm). These parameter optimizations enable the polishing process to selectively remove silicon oxide while preserving silicon nitride, achieving uniform planarization that ensures reliable electrical connections and prevents disconnection or skew issues in the final device.
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 achieves a planarized insulation layer with increased profile uniformity and reduced defects, enabling efficient design with narrower line widths and minimizing disconnection issues.
Implementation Method 1
a polishing slurry includes about 0.01 wt % to about 10 wt % of polishing particles
Implementation Method 2
an oxide-polishing promoter including a pyridine compound
Implementation Method 3
about 0.005 wt % to about 0.1 wt % of a dispersing agent
Implementation Method 4
a nitride-polishing inhibitor including an amino acid or an anionic organic acid
Data Source
AI summary
A polishing slurry is disclosed which includes about 0.01 wt % to about 10 wt % of polishing particles, about 0.005 wt % to about 0.1 wt % of a dispersing agent, about 0.001 wt % to about 1 wt % of an oxide-polishing promoter including a pyridine compound, about 0.05 wt % to about 0.1 wt % of a nitride-polishing inhibitor including an amino acid or an anionic organic acid, and water. A method for manufacturing a display device including an active pattern disposed on a base substrate, a gate metal pattern including a gate electrode overlapping the active pattern, a planarized insulation layer disposed on the gate metal pattern, and a source metal pattern disposed on the planarized insulation layer is also disclosed.