Dielectric CMP Slurry With Self-Stopping Planarization
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Solution Overview
Problem
Current chemical-mechanical planarization (CMP) processes for substrates with pattern dielectric materials face challenges in achieving high removal rates while minimizing trench loss and ensuring efficient planarization, particularly in advanced microelectronic devices like 3D NAND flash memory, where high step heights require significant dielectric material removal within tight time constraints.
Innovation Solution
A CMP polishing composition comprising an aqueous medium, abrasive particles, and hydroxamic acid or substituted hydroxamic acid, which is applied with a polishing pad to abrade the substrate, achieving a planarization efficiency of at least 2.0 and exhibiting self-stopping behavior to reduce trench loss and enhance throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional CMP processes are used to remove pattern dielectric material, then removal rate can be achieved, but trench loss increases and planarization efficiency decreases
Solution Approach 1:
The polishing composition is formulated to provide spatially selective polishing behavior through pH gradients and localized chemical reactions. The composition contains buffering agents and pH-sensitive additives that create different polishing rates in different regions of the substrate, enabling faster removal from raised areas while protecting trench regions from excessive material loss.
Solution Approach 2:
The invention employs pH adjustment as a key parameter control mechanism. By carefully controlling the pH of the polishing composition and its interaction with the dielectric material, the process achieves different removal rates in different topographic regions. The pH-sensitive chemical reactions enable selective material removal while minimizing trench loss, directly addressing the contradiction between removal rate and trench loss.
2Productivity
If high removal rates are achieved for pattern dielectric material, then throughput improves, but planarization efficiency decreases
Solution Approach 1:
The polishing process exhibits dynamic behavior where the removal rate automatically adjusts based on the local topography and polishing history. The composition is designed to provide self-regulating polishing rates that are faster on raised areas and slower on planarized regions, enabling high throughput while maintaining excellent planarization efficiency without requiring external control mechanisms.
Solution Approach 2:
The polishing composition incorporates feedback mechanisms through pH-sensitive chemical reactions that respond to the local polishing state. As material is removed and the surface topology changes, the chemical environment at the polishing interface changes, providing automatic feedback that modulates the removal rate to maintain optimal planarization efficiency throughout the process.
3Manufacturing precision
If CMP processing is performed on substrates with high step heights, then material removal is necessary, but process time increases
Solution Approach 1:
The polishing composition is pre-formulated with optimal concentrations of abrasive particles, chemical additives, and buffering agents to maximize removal rate from the outset. The composition is designed to immediately establish effective chemical-mechanical polishing action upon contact with the substrate, eliminating warm-up time and maximizing material removal efficiency from the beginning of the process.
Solution Approach 2:
The invention uses composite polishing compositions that combine multiple functional components: abrasive particles for mechanical removal, pH-sensitive chemicals for selective reaction, buffering agents for stable pH control, and surface-active agents for improved slurry distribution. This composite formulation enables simultaneously high removal rates and good planarization control, reducing process time for high step height substrates.
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 enables high removal rates of pattern dielectric material with low trench loss and improved planarization efficiency, effectively addressing the need for efficient processing of substrates with high step heights, such as those in 3D NAND devices, by reducing the amount of material needed and eliminating the need for endpoint detection.
Implementation Method 1
Material is typically removed from the substrate surface by a combination of mechanical activity of abrasive material contained in the slurry
Implementation Method 2
contacting the substrate with the polishing pad and the chemical-mechanical polishing composition; and moving the polishing pad and the chemical-mechanical polishing composition relative to the substrate to abrade at least a portion of a silicon oxide layer
Implementation Method 3
chemical activity of chemical materials of the slurry
Implementation Method 4
CMP uses a liquid chemical composition known as a CMP composition, alternately a polishing composition, a polishing slurry, or just slurry, in combination with a CMP pad, to mechanically and chemically remove material from a non-planar substrate surface
Data Source
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AI summary
Described are materials and methods for processing (polishing or planarizing) a substrate that contains pattern dielectric material using a polishing composition (aka "slurry") and an abrasive pad, e.g., CMP processing.