Metal Etching Composition for Uniform 3D NAND Pattern Morphology
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing etching solutions fail to produce a better pattern morphology and often result in uneven etch rates, particularly in high aspect ratio structures like 3D NAND-type flash memory.
Innovation Solution
An etching solution composition containing nitric acid, acetic acid, nitrilotris(methylene phosphonic acid), a halogen compound, and water, which suppresses the etch rate while improving the surface morphology of metals like molybdenum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching solutions are used, then the etching process can be completed, but the surface morphology becomes poor and etch rate becomes uneven
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition parameters of the etching solution. Specifically, it uses nitric acid (0.1-10 M), acetic acid (0.1-10 M), and nitrilotris(methylene phosphonic acid) (0.01-1 M) in specific concentration ranges to achieve both suppressed etch rate and improved surface morphology. The halogen compound concentration is controlled at 0.001-0.1 M to optimize the etching performance without causing excessive etching or poor morphology
Solution Approach 2:
The patent employs composite materials by combining multiple chemical components in the etching solution formulation. The composite system includes nitric acid as the primary etchant, acetic acid as a modifier, nitrilotris(methylene phosphonic acid) as a complexing agent, and halogen compounds as additives. This composite approach allows the solution to simultaneously achieve suppressed etch rate and excellent surface morphology that cannot be obtained with single-component solutions
2Quantity of substance
If the number of layers is increased to increase memory capacity, then the capacity increases, but the aspect ratio increases making etching more difficult
Solution Approach 1:
The patent applies local quality by optimizing the etching solution to provide uniform etching performance throughout the high aspect ratio structure. The combination of nitric acid, acetic acid, and nitrilotris(methylene phosphonic acid) creates a solution that maintains consistent etching characteristics from the top to the bottom of the deep holes, ensuring uniform surface morphology even in structures with extremely high aspect ratios corresponding to increased layer counts
3Length of moving object
If the film thickness is reduced to suppress vertical size increase, then the device size is controlled, but the signal delay increases
Solution Approach 1:
The patent replaces mechanical/physical approaches with chemical substitution by using a specifically formulated chemical etching solution instead of conventional physical or mechanical thinning methods. The chemical composition (nitric acid, acetic acid, nitrilotris(methylene phosphonic acid), and halogen compounds) enables precise control of film thickness at the nanometer scale while maintaining material quality and electrical properties, thereby avoiding signal delay issues that would arise from excessive thinning
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 an excellent etched surface morphology with a suppressed etch rate, enabling even etching across multiple layers in high aspect ratio structures such as 3D NAND-type flash memory.
Implementation Method 1
The etching solution composition contains (A) nitric acid
Implementation Method 2
The etching solution composition contains (B) acetic acid
Implementation Method 3
The etching solution composition contains (C) nitrilotris(methylene phosphonic acid)
Implementation Method 4
The etching solution composition contains (D) a halogen compound
Data Source
AI summary
An object of the invention is to provide an etching solution composition which adds an excellent etched surface morphology to a metal to be etched at a suppressed etch rate. The invention relates to an etching solution composition in which the etching solution composition contains (A) nitric acid, (B) acetic acid, (C) nitrilotris(methylene phosphonic acid), (D) a halogen compound and (E) water.