CMP Slurry Composition for Flat Silicon Oxide Polishing
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Solution Overview
Problem
Conventional CMP techniques struggle to achieve a high polishing rate for silicon oxide surfaces with irregularities, leading to inefficiencies in semiconductor production, as the same polishing liquid may not effectively polish substrates with varying irregularities, and often results in poor flatness and decreased productivity.
Innovation Solution
A polishing liquid containing abrasive grains of metal oxide, specifically cerium oxide, and a hydroxy acid compound, which enhances the polishing rate without depending on the surface irregularities, allowing for efficient polishing of both flat and irregular silicon oxide surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional polishing liquid is used for polishing silicon oxide surfaces with irregularities, then the polishing process can be performed, but the polishing rate becomes low and productivity decreases
Solution Approach 1:
The patent changes the chemical composition parameters of the polishing liquid by incorporating specific hydroxy acid compounds (glycolic acid, lactic acid, malic acid, or tartaric acid) with controlled concentrations (0.01-10% by mass) alongside traditional abrasive particles. This parameter modification enables the polishing liquid to maintain effective polishing rates of 12000 Å/min or more on irregular surfaces while achieving 3000 Å/min or more on flat surfaces, resolving the contradiction between productivity and reliability.
Solution Approach 2:
The invention creates a composite polishing liquid system that combines traditional abrasive particles (such as silica or alumina) with hydroxy acid compounds. This composite formulation synergistically enhances both the mechanical abrasion capability and chemical etching effectiveness, allowing consistent high-rate polishing across varying surface irregularities regardless of whether the substrate has convex portions, concave portions, or mixed topography.
2Productivity
If high polishing rate is achieved by removing material rapidly, then productivity improves, but surface flatness deteriorates
Solution Approach 1:
The patent partially replaces the purely mechanical removal mechanism with a chemical mechanism by introducing hydroxy acid compounds into the polishing liquid. These compounds chemically etch the silicon oxide surface, working synergistically with mechanical abrasion to achieve high polishing rates (12000 Å/min or more on irregular surfaces) while maintaining surface flatness through controlled chemical reaction that uniformly removes material from both convex and concave regions.
Solution Approach 2:
The invention modifies the chemical environment parameters of the polishing process by controlling the concentration of hydroxy acid compounds (0.01-10% by mass) and pH conditions. This parameter optimization enables the chemical-mechanical polishing system to achieve high material removal rates while maintaining surface flatness, as the chemical component preferentially attacks protruding regions and fills valleys, producing a more uniform surface topology.
3Ease of manufacture
If conventional polishing liquid is used on substrates with varying irregularities, then the process is simple, but the polishing results are inconsistent across different substrates
Solution Approach 1:
The patent develops a universal polishing liquid formulation containing hydroxy acid compounds that can effectively polish silicon oxide surfaces regardless of their initial irregularity state. The hydroxy acid compounds (glycolic acid, lachic acid, malic acid, or tartaric acid) provide multi-functional action: they chemically etch exposed surfaces, dissolve polishing debris, and maintain slurry fluidity. This single formulation achieves consistent polishing rates of 12000 Å/min or more on irregular surfaces and 3000 Å/min or more on flat surfaces, eliminating the need for substrate-specific polishing liquid variations while maintaining process simplicity.
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 polishing liquid achieves high polishing rates of 12000 Å/min or more for irregular surfaces and 3000 Å/min or more for flat surfaces, maintaining high productivity and surface flatness, even when used in multi-stage CMP processes.
Implementation Method 1
a polishing liquid containing: abrasive grains containing a metal oxide
Implementation Method 2
at least one hydroxy acid compound selected from the group consisting of a hydroxy acid having a structure represented by General Formula (A1) below and a salt thereof
Data Source
AI summary
A polishing liquid containing: abrasive grains containing a metal oxide; at least one hydroxy acid compound selected from the group consisting of a hydroxy acid having a structure represented by General Formula (A1) below and a salt thereof; and water:[In the formula, R11 represents a hydrogen atom or a hydroxy group, R12 represents a hydrogen atom, an alkyl group, or an aryl group, n11 represents an integer of 0 or more, and n12 represents an integer of 0 or more; however, a case where both of R11 and R12 are a hydrogen atom is excluded.]