Etchant Composition for Tungsten and Titanium Nitride Batch Etching
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Solution Overview
Problem
Conventional etchant compositions fail to accurately form desired pattern shapes for tungsten and titanium nitride films, especially in three-dimensional structures, due to uncontrolled etching rates and significant deviations in the selection ratio between the two materials.
Innovation Solution
An etchant composition comprising nitric acid, water, and optionally sulfuric acid or aliphatic sulfonic acid, such as methanesulfonic acid, with phosphoric acid, is used for batch etching, allowing for controlled etching rates and a selection ratio of approximately 1, enabling precise pattern formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etchant compositions are used for batch etching of tungsten film and titanium nitride film, then etching treatment can be performed, but the etching rate is uncontrolled and the selection ratio deviates significantly from 1, resulting in inaccurate pattern formation
Solution Approach 1:
The patent applies parameter changes by systematically adjusting the concentrations of nitric acid (0.01-10.0 wt%), sulfuric acid (0.1-50.0 wt%), and water (80.0-49.9 wt%) in the etchant composition to achieve both controlled etching rates and selection ratios close to 1, resolving the contradiction between etching control and pattern accuracy
Solution Approach 2:
The patent uses a composite etchant composition combining multiple acids (nitric acid, sulfuric acid, and optionally phosphoric acid and aliphatic sulfonic acid) to simultaneously achieve controlled etching of tungsten film and selective etching of titanium nitride film, enabling both reliability in etching rate control and precision in pattern formation
2Manufacturing precision
If conventional etchant compositions are used, then etching treatment can be performed, but the selection ratio between tungsten film and titanium nitride film is greatly departing from 1, preventing accurate three-dimensional structure formation
Solution Approach 1:
The patent adjusts the compositional parameters of the etchant, specifically optimizing the ratio of nitric acid to sulfuric acid and controlling the concentration ranges, to achieve a selection ratio close to 1 between tungsten and titanium nitride etching rates, enabling precise three-dimensional structure formation
Solution Approach 2:
The patent introduces water as an intermediary component (80.0-49.9 wt%) that moderates the reactivity of the acid components, allowing fine-tuned control over the selection ratio and enabling accurate formation of complex three-dimensional patterns in batch etching processes
3Productivity
If batch etching treatment is performed on tungsten film and titanium nitride film, then processing efficiency is improved, but control over the etching rate of both films becomes difficult
Solution Approach 1:
The patent develops a universal etchant composition that simultaneously etches both tungsten film and titanium nitride film with controllable rates, enabling batch processing of multi-layer structures while maintaining reliable control over the etching behavior of each material through optimized acid concentration ratios
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 etchant composition achieves controlled etching rates and selection ratios, facilitating accurate batch etching of tungsten and titanium nitride films, particularly in forming complex three-dimensional structures with minimal changes over time, suitable for advanced semiconductor memory devices.
Implementation Method 1
an etchant composition comprising nitric acid and water... further comprising at least one selected from the group consisting of sulfuric acid and aliphatic sulfonic acid
Implementation Method 2
etchant composition comprising nitric acid and water... capable of batch etching treatment of tungsten film and titanium nitride film
Data Source
AI summary
An etchant composition that is capable of batch etching treatment of a tungsten film and a titanium nitride film and a method for etching using said etchant composition are provided. The etching composition of the present invention is an etchant composition comprising nitric acid and water for batch etching treatment of a tungsten film and a titanium nitride film.