Titanium Nitride Removal Liquid Composition for Tungsten Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for removing titanium nitride from semiconductor substrates without corroding tungsten or low-k interlayer dielectrics are inefficient, with low etching rates and insufficient corrosion protection, as seen in prior art using hydrogen peroxide, sulfuric acid, and oxidizing agents with fluorine compounds.
Innovation Solution
A liquid composition comprising an oxidizing agent (such as potassium permanganate or peroxodisulfate), a fluorine compound (like hydrofluoric acid), and a tungsten-corrosion preventer (including alkylamines and fluoroalkylamines) with specific concentrations and pH range of 0 to 4, which does not contain hydrogen peroxide.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydrogen peroxide is used to remove titanium nitride, then titanium nitride removability is improved, but tungsten corrosion increases
Solution Approach 1:
The patent introduces a corrosion preventer as an intermediary substance that mediates between the hydrogen peroxide etching agent and the tungsten wiring. The corrosion preventer forms a protective film on the tungsten surface, allowing hydrogen peroxide to effectively remove titanium nitride while preventing direct contact and corrosion of the tungsten. This resolves the contradiction by adding a protective intermediary layer.
Solution Approach 2:
The patent modifies the chemical parameters of the etching composition by controlling the concentration of hydrogen peroxide (5-30 wt%), the type and amount of corrosion preventer (0.1-5 wt%), and the pH value (0-4). By optimizing these parameters, the composition achieves high titanium nitride removability while minimizing tungsten corrosion through precise chemical composition control.
2Object-affected harmful factors
If concentrated sulfuric acid is used to etch titanium nitride without corroding tungsten, then tungsten corrosion is prevented, but etching rate decreases
Solution Approach 1:
The patent creates a composite etching composition that combines multiple chemical agents: hydrogen peroxide (for high etching rate), sulfuric acid (for tungsten corrosion prevention), and corrosion preventers (for enhanced protection). This composite formulation synergistically achieves both high etching rate and tungsten corrosion prevention, resolving the contradiction between speed and protection.
Solution Approach 2:
The patent optimizes the concentration parameters of each component: hydrogen peroxide (5-30 wt%) for etching power, sulfuric acid (controlled amount) for corrosion prevention, and corrosion preventers (0.1-5 wt%) for protective film formation. By carefully adjusting these parameters, the composition achieves rapid titanium nitride removal while maintaining tungsten integrity.
3Object-affected harmful factors
If existing corrosion preventers are added to hydrogen peroxide composition, then some tungsten corrosion protection is achieved, but protection effectiveness is insufficient
Solution Approach 1:
The patent employs corrosion preventers with multiple functional groups that provide both corrosion protection and etching enhancement. These multi-functional compounds form protective films on tungsten while also facilitating titanium nitride removal, achieving dual purposes and significantly improving corrosion protection effectiveness beyond single-function additives.
Solution Approach 2:
The patent optimizes the concentration of corrosion preventers (0.1-5 wt%) and adjusts the pH value (0-4) to maximize protective film formation on tungsten surfaces. By controlling these parameters, the composition achieves reliable and sufficient corrosion protection effectiveness, resolving the insufficiency of existing preventers.
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
Effectively removes titanium nitride from semiconductor substrates without corroding tungsten or low-k interlayer dielectrics, achieving high removability and corrosion protection, as demonstrated by SEM observations in examples.
Implementation Method 1
a liquid composition which removes titanium nitride from a substrate without corroding tungsten or a low-k interlayer dielectric also present on said substrate, said liquid composition having a pH of 0 to 4 and comprising: at least one oxidizing agent (A) selected from the group consisting of potassium permanganate, ammonium peroxodisulfate, potassium peroxodisulfate and sodium peroxodisulfate
Implementation Method 2
a fluorine compound (B)
Data Source
AI summary
This invention provides a liquid composition that removes titanium nitride from a substrate without corroding tungsten or a low-k interlayer dielectric also present on said substrate. Said liquid composition has a pH between 0 and 4, inclusive, and contains the following: at least one oxidizing agent (A) selected from the group consisting of potassium permanganate, ammonium peroxodisulfate, potassium peroxodisulfate, and sodium peroxodisulfate; a fluorine compound (B); and a tungsten-corrosion preventer (C). The tungsten-corrosion preventer (C) either contains at least two different compounds selected from a group of compounds (C1) consisting of alkylamines, salts thereof, fluoroalkylamines, salts thereof, and the like or contains at least one compound selected from said group of compounds (C1) and at least one compound selected from a group of compounds (C2) consisting of polyoxyalkylene alkylamines, polyoxyalkylene fluoroalkylamines, and the like. The mass concentration of potassium permanganate in the abovementioned oxidizing agent (A) is between 0.001% and 0.1%, inclusive, and the mass concentration of the abovementioned fluorine compound (B) is between 0.01% and 1%, inclusive.