Titanium Layer Etchant Composition for Selective Semiconductor Etching
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Solution Overview
Problem
Conventional etchant compositions for titanium-containing metal layers in semiconductor manufacturing cause over-etching and damage to other layers, leading to reliability issues and reduced productivity.
Innovation Solution
An etchant composition comprising polyvalent phosphonic acid, inorganic base, sulfonic acid-based polymer compound, and hydrogen peroxide, with specific weight ratios and pH control, to selectively etch titanium-containing metal layers without affecting adjacent layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional etchant compositions (fluoric acid, periodic acid, sulfuric acid) are used to etch titanium layer, then etching efficiency is improved, but other metal layers are simultaneously etched causing damage to quality
Solution Approach 1:
The patent changes the chemical composition parameters of the etchant by replacing conventional acids (fluoric, periodic, sulfuric) with a novel combination containing hydrofluoric acid at specifically controlled low concentrations (0.01-5 wt%), combined with organic acids (acetic, formic, propionic) and buffer substances. This parameter change achieves selective etching of titanium layer while protecting other metal layers from damage.
2Manufacturing precision
If buffer substances or highly concentrated hydrogen peroxide are used to selectively etch titanium layer, then selectivity is improved, but over-etching and damage to other layers still occur
Solution Approach 1:
The patent creates a composite etchant formulation combining multiple acid types (hydrofluoric, acetic, formic, propionic) with buffer substances (ammonium fluoride, sodium fluoride, potassium fluoride) and hydrogen peroxide at controlled concentrations. This composite approach achieves high etching selectivity for titanium while preventing over-etching and damage to other layers through synergistic interactions among components.
3Manufacturing precision
If etching process is made more aggressive to remove titanium residues, then cleaning effect is improved, but over-etching increases affecting adjacent layers
Solution Approach 1:
The patent incorporates buffer substances (ammonium fluoride, sodium fluoride, potassium fluoride) that provide chemical feedback control during etching. These buffers maintain stable pH and fluoride ion concentration, automatically regulating etching aggressiveness to remove titanium residues effectively while preventing excessive etching that would damage adjacent layers.
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 provides rapid etching with minimal over-etching and residue formation, ensuring stable etching characteristics and protecting the quality of other layers, thereby enhancing semiconductor device reliability and productivity.
Implementation Method 1
hydrogen peroxide (10 to 30 wt%)
Implementation Method 2
hydrogen peroxide (10 to 30 wt%)
Implementation Method 3
a polyvalent phosphonic acid or a salt thereof, an inorganic base, a sulfonic acid-based polymer compound
Data Source
AI summary
Provided are an etchant composition for a titanium-containing metal layer, and a method using the same, which may selectively etch the titanium-containing metal layer without affecting the quality of other films during a process of manufacturing semiconductor and display devices, and thus, may increase productivity and reliability with improved etching characteristics in a semiconductor manufacturing process.