Titanium Etchant Composition with 5-Aminotetrazole Corrosion Inhibitor
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Solution Overview
Problem
Current semiconductor manufacturing processes lack an effective method for selectively removing titanium-containing layers without damaging adjacent metal layers, which are crucial for forming reliable semiconductor devices.
Innovation Solution
A titanium etchant composition comprising fluoride as a titanium remover, 5-aminotetrazole as a corrosion inhibitor, and deionized water, applied at specific temperatures to selectively remove titanium-containing layers while protecting metal layers with higher ionization energies, such as nickel, copper, tin, and silver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional etchant composition is used to remove titanium-containing layers, then titanium removal capability is improved, but adjacent metal layers (nickel, copper, tin, silver) are damaged or corroded
Solution Approach 1:
The patent introduces 5-aminotetrazole as an intermediary substance that selectively interacts with titanium. This corrosion inhibitor acts as a mediator that allows the etchant to remove titanium while protecting other metal layers through selective chemical bonding - the 5-aminotetrazole forms protective complexes with titanium ions, enabling selective etching without damaging adjacent metals with higher ionization energies
Solution Approach 2:
The patent modifies the chemical parameters of the etchant composition by incorporating 5-aminotetrazole at specific concentrations (0.001-5 wt%). This parameter change alters the chemical selectivity of the etchant, enabling it to distinguish between titanium and other metal layers based on their different ionization energies, thereby achieving selective removal of titanium only
2Object-affected harmful factors
If the etching process is made more selective to protect metal layers, then damage to adjacent metal layers is reduced, but etching efficiency and processing time are worsened
Solution Approach 1:
The patent optimizes the concentration parameter of 5-aminotetrazole in the etchant composition. By controlling the inhibitor concentration within the range of 0.001-5 wt%, the patent achieves a balance between selectivity and etching speed - enough inhibitor to protect metal layers but not so much as to completely stop the etching process, thereby maintaining high productivity while ensuring layer protection
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 effectively removes titanium-containing layers with minimal damage to other metal layers, ensuring reliable semiconductor device formation and potentially reducing processing time due to enhanced etching efficiency.
Implementation Method 1
The titanium remover may include fluoride. The titanium remover may include at least one of ammonium fluoride, ammonium bifluoride, tetramethyl ammonium fluoride, and hydrofluoric acid.
Implementation Method 2
The 5-aminotetrazole may be included in an amount of about 0.001 wt % to about 5 wt %, based on a total weight of the titanium etchant composition. The titanium etchant composition may be formulated to be simultaneously applied to an exposed surface of a titanium-containing layer and a material layer not containing titanium and to selectively remove the titanium-containing layer.
Data Source
AI summary
A titanium etchant composition and a method of forming a semiconductor device using the same, the titanium etchant composition including a titanium remover; a corrosion inhibitor; and a deionized water; wherein the corrosion inhibitor includes 5-aminotetrazole.