TiN Etching Composition for Selective Semiconductor Layer Removal
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Solution Overview
Problem
The challenge in semiconductor manufacturing is maintaining high etching selectivity of etching target layers to prevent damage and ensure reliability and electrical properties, particularly in the presence of different materials like titanium nitride, copper, and aluminum oxide.
Innovation Solution
An etching composition comprising 20-30% oxidizer, 1-10% ammonium phosphate buffer, 3-10% alkyl ammonium hydroxide pH adjustor, 0.1-10% benzotriazole corrosion inhibitor, 0.1-3% chelating agent, and 15-25% solubilizer, with a pH of 7-9, is used to selectively etch titanium nitride while protecting other layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional etching compositions are used, then etching process can be performed, but etching selectivity between different layers is insufficient causing damage to non-target layers
Solution Approach 1:
The patent modifies the chemical composition parameters of the etching solution by incorporating specific buffers (ammonium phosphate, HEPES, MOPS, TAPS, or TES) at controlled concentrations (1-10 wt%), pH adjustors (alkyl ammonium hydroxides) at 3-10 wt%, and corrosion inhibitors (benzotriazole derivatives) at 0.1-10 wt%. These parameter changes create a chemically controlled environment that enhances etching selectivity while protecting non-target layers from damage.
Solution Approach 2:
The patent introduces buffer substances as intermediary components that mediate between the etching agent and the semiconductor layers. These buffers act as chemical mediators that control the etching reaction kinetics, allowing selective removal of target material while preventing excessive etching or damage to adjacent non-target layers through controlled chemical interaction.
2Reliability
If etching selectivity is increased to protect non-target layers, then reliability improves, but etching rate may decrease
Solution Approach 1:
The patent optimizes multiple compositional parameters simultaneously: buffer concentration (1-10 wt%), pH adjustor concentration (3-10 wt%), corrosion inhibitor concentration (0.1-10 wt%), and oxidizer concentration (20-30 wt%). This multi-parameter optimization achieves a balance where sufficient etching rate is maintained while ensuring high selectivity and reliability through controlled chemical reactions.
Solution Approach 2:
The patent creates a composite etching solution formulation combining multiple functional components: buffers for pH stabilization, pH adjustors for acidity control, corrosion inhibitors for protective film formation, oxidizers for etching action, chelating agents for metal ion complexation, and solubilizers for homogeneous mixing. This composite formulation achieves both high etching rate and high reliability through synergistic interaction of components.
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 selectivity for titanium nitride over copper and aluminum oxide, improving manufacturing yield and reducing damage to non-target materials.
Implementation Method 1
an etching composition includes about 20 wt % to about 30 wt % of an oxidizer
Implementation Method 2
a buffer including at least one among ammonium phosphate and a material represented by Formula 1 below; and a pH adjustor including alkyl ammonium hydroxide, wherein the etching composition may have a pH of 7 to 9
Data Source
AI summary
According to the inventive concept, an etching composition includes about 20 wt % to about 30 wt % of an oxidizer, a buffer including at least one among ammonium phosphate and a material represented by Formula 1, and a pH adjustor including alkyl ammonium hydroxide, wherein the etching composition may have a pH of 7 to 9.