Tertiary Amine Etching Composition for Selective TiN and WC Removal
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Solution Overview
Problem
Existing etching technologies fail to achieve high etching rates and selectivity for removing layers containing titanium or tungsten on low dielectric constant materials like silica or polyimide, especially when co-existing with metal underlayers such as aluminum, cobalt, copper, nickel, or ruthenium.
Innovation Solution
An etching composition comprising a tertiary amine compound, an oxidizing agent, and optionally an alkali compound, organic solvent, and chelating agent, which selectively targets and oxidizes titanium nitride or tungsten carbide, enhancing etching rates and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional etching methods are used to remove titanium nitride or tungsten carbide layers, then etching can be performed, but the etching rate is low and etching selectivity is poor when metal underlayers are present
Solution Approach 1:
The patent changes the chemical parameters of the etching composition by incorporating specific oxidizing agents (hydrogen peroxide, ammonium persulfate, ammonium peroxodisulfate) and tertiary amine compounds to achieve both high etching rate and high etching selectivity. This parameter modification enables the etching solution to selectively attack titanium nitride and tungsten carbide while minimizing damage to metal underlayers, thereby resolving the contradiction between productivity and manufacturing precision.
Solution Approach 2:
The patent uses a composite etching composition containing multiple components including oxidizing agents, tertiary amine compounds, and optional additives (chelating agents, surfactants, organic solvents). This composite formulation synergistically enhances both etching rate and etching selectivity, allowing effective removal of titanium nitride/tungsten carbide layers while protecting underlying metal structures, thus simultaneously improving productivity and manufacturing precision.
2Productivity
If stronger etching agents are used to increase etching rate, then productivity improves, but damage to adjacent metals and low dielectric constant materials increases
Solution Approach 1:
The patent applies local quality by designing an etching composition with selective chemical affinity. The oxidizing agents and tertiary amine compounds are specifically chosen to target titanium nitride and tungsten carbide layers while having minimal effect on adjacent metals (aluminum, cobalt, copper, nickel, manganese, ruthenium) and low dielectric constant materials (silica, polyimide). This selective action increases etching rate without proportionally increasing damage to surrounding structures, thus improving productivity while controlling harmful effects.
Solution Approach 2:
The tertiary amine compounds act as intermediaries that facilitate the action of oxidizing agents on titanium nitride and tungsten carbide while protecting other materials. The chelating agents and surfactants also serve as intermediaries to modulate the chemical interaction between the etching solution and various materials in the structure, enabling high etching rate while minimizing collateral damage to adjacent metals and low-k materials.
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 composition achieves high etching rates and selectivity for titanium nitride and tungsten carbide, while minimizing oxidation of adjacent metals, thereby facilitating efficient manufacturing of electronic components.
Implementation Method 1
an etching method using an SC-1 solution (NH4OH:H2O2:deionized water=1:1:5) is well known
Implementation Method 2
the etching composition including: an amine compound containing a tertiary amine; and an oxidizing agent
Data Source
AI summary
An etching composition which selectively removes an etching target, the etching composition including an amine compound containing a tertiary amine, and an oxidizing agent. The etching composition may also contain at least one of an alkali compound, an organic solvent, water, a chelating agent, and a surfactant.