Semiconductor Cleaning Composition for Selective Ti Etching
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Solution Overview
Problem
Existing dry etching methods for semiconductor substrates with titanium-titanium alloys result in damage to the interlayer insulating films, particularly oxide films with a relative dielectric constant of 60 or less, compromising the performance of the semiconductor substrate.
Innovation Solution
A semiconductor substrate cleaning composition comprising an oxidizing agent and a metal-tungsten corrosion inhibitor, without fluorine compounds, with a pH of 7 or less, which provides a high Ti/W etching selectivity ratio, minimizing damage to oxide films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If dry etching is used to etch titanium-containing films with high Ti/W etching selectivity ratio, then the etching selectivity is improved, but the oxide film is damaged
Solution Approach 1:
The patent changes the chemical parameters of the etching composition by specifying precise concentrations of hydrofluoric acid (0.003-5% by mass), nitric acid (0.003-5% by mass), and acetic acid (0.003-5% by mass), along with controlling the pH to 6.5 or less. These parameter adjustments enable high Ti/W etching selectivity while minimizing oxide film damage through optimized chemical reactivity.
Solution Approach 2:
The patent uses a composite etching composition containing multiple acid components (hydrofluoric acid, nitric acid, and acetic acid) working synergistically. This composite formulation achieves both high titanium etching selectivity and reduced oxide film damage by combining the etching power of different acids with buffering capabilities.
2Productivity
If fluorine compounds are used to etch titanium-containing films, then the etching capability is improved, but the oxide film damage increases
Solution Approach 1:
The patent optimizes the fluorine compound concentration to a specific range (0.003-5% by mass, preferably 0.003-1% by mass) and controls pH to 6.5 or less. This parameter optimization maintains sufficient etching capability while minimizing oxide film attack, as excessive fluorine compounds would cause severe oxide damage.
Solution Approach 2:
The patent introduces nitric acid and acetic acid as intermediary substances that moderate the aggressive action of fluorine compounds on oxide films. These intermediaries provide buffering capacity and selective etching promotion, allowing fluorine compounds to etch titanium effectively while protecting the oxide film from excessive damage.
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 etches titanium-containing films while preserving the integrity of oxide films, ensuring the semiconductor substrate maintains desired performance.
Implementation Method 1
including: (A) an oxidizing agent
Implementation Method 2
including: (B) a metal-tungsten corrosion inhibitor
Data Source
AI summary
Provided is a semiconductor substrate cleaning composition capable of reducing damage to an oxide film while having a high Ti/W etching selectivity ratio.Disclosed is a semiconductor substrate cleaning composition including: (A) an oxidizing agent; and (B) a metal-tungsten corrosion inhibitor, wherein the semiconductor substrate cleaning composition does not include (C) a fluorine compound or further contains the fluorine compound in an amount of less than 0.005% by mass with respect to a total mass of the semiconductor substrate cleaning composition, and the semiconductor substrate cleaning composition has a pH of 7 or less.