Dry Etching Stable Metals Ru Ta Using Interhalogen Compounds
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Solution Overview
Problem
Existing dry etching methods for materials containing stable metal elements like Ru or Ta face challenges in removing these materials without damaging the substrate or chamber, particularly due to the need for high-temperature fluorine gas exposure, which can impair semiconductor devices and equipment.
Innovation Solution
A plasma-less dry etching method using a fluorine-containing interhalogen compound to form a solid reaction product with the metal element at low temperatures (0° C. to 100° C.), followed by evaporation in an inert gas atmosphere or vacuum, allowing for the removal of the metal element without high-temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fluorine-containing gas is used for dry etching of Ru or Ta at high temperature, then etching capability is improved, but substrate damage and chamber corrosion increase
Solution Approach 1:
The invention changes the temperature parameter from high temperature to low temperature range (0°C to 100°C) for the etching process. By using fluorine-containing interhalogen compounds at these lower temperatures, the etching capability for Ru and Ta is maintained while the harmful effects on substrate and chamber are significantly reduced, directly resolving the technical contradiction between etching effectiveness and damage prevention
Solution Approach 2:
The invention employs an inert gas atmosphere during the etching process to prevent unwanted chemical reactions and reduce oxidation. This inert environment protects the substrate from damage while allowing selective etching of Ru and Ta, thereby reducing both substrate damage and chamber corrosion while maintaining productivity
2Productivity
If wet etching with strong acid solution is used, then Ru or Ta material removal is improved, but device characteristic impairment increases
Solution Approach 1:
The invention substitutes the wet chemical etching process with a dry etching process using fluorine-containing interhalogen compounds. This replacement eliminates the need for liquid acid solutions that cause indiscriminate reactions, thereby maintaining material removal efficiency while preserving device characteristics through more controlled and selective etching
Solution Approach 2:
The fluorine-containing interhalogen compound acts as an intermediary substance that enables selective removal of Ru and Ta without the harsh effects of strong acid solutions. This intermediary approach allows effective material removal while avoiding the collateral damage to device characteristics that occurs with conventional wet etching
3Productivity
If plasma excitation is used for dry etching, then etching performance is improved, but device magnetic properties deteriorate
Solution Approach 1:
The invention changes the physical state parameter of the etching gas from plasma-excited to non-excited molecular state. By using fluorine-containing interhalogen compounds in their molecular form rather than plasma form, the etching performance is maintained through chemical reactivity while the harmful effects on magnetic properties are eliminated, as the non-plasma process does not disrupt the magnetic material structure
4Productivity
If RF power source is used for plasma generation, then etching capability is improved, but manufacturing cost increases
Solution Approach 1:
The invention substitutes the plasma generation system requiring RF power sources with a simpler thermal or chemical activation process. By using fluorine-containing interhalogen compounds that can react at lower temperatures without plasma excitation, the need for expensive RF power equipment is eliminated, thereby maintaining etching capability while significantly reducing manufacturing costs
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
This method effectively etches stable metal elements like Ru or Ta without damaging the substrate or chamber, achieving selective etching with minimal impact on silicon-based materials and reducing equipment corrosion.
Implementation Method 1
bringing a processing gas containing a fluorine-containing interhalogen compound into contact with a material containing a specific metal element at a reaction temperature of 0° C. to 100° C., thereby forming a reaction product of the specific metal element and the fluorine-containing interhalogen compound as a solid product
Implementation Method 2
evaporating the solid product by heating the solid product in an inert gas atmosphere or vacuum atmosphere at a temperature higher than the reaction temperature of the first step
Data Source
AI summary
Disclosed is a dry etching method which includes: a first step of bringing a processing gas containing a fluorine-containing interhalogen compound into contact with a material containing a specific metal element at a reaction temperature of 0° C. to 100° C., thereby forming a reaction product of the specific metal element and the fluorine-containing interhalogen compound as a solid product; and a second step of evaporating the solid product by heating the solid product in an inert gas atmosphere or vacuum atmosphere at a temperature higher than the reaction temperature of the first step, wherein the specific metal element is one or more kinds of elements selected from the group consisting of Ru, Ta, and Nb.