Semiconductor Cleaning Agent for Tungsten Wiring Corrosion Control
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Solution Overview
Problem
Current cleaning processes for semiconductor substrates after chemical mechanical polishing (CMP) are inadequate in removing polishing fines and metal impurities without corroding metal wirings, especially for finer structures and tungsten alloy wirings, leading to insufficient removal and corrosion issues.
Innovation Solution
A cleaning agent comprising a phosphonic acid-based chelating agent and a primary or secondary monoamine with alkyl or hydroxyalkyl groups, used in combination with water at a pH between 6 and 7, effectively removes polishing fines from semiconductor substrates without corroding tungsten or tungsten alloy wirings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a cleaning agent containing hydrofluoric acid and hydrogen peroxide is used, then polishing fines can be removed, but metal wiring corrosion increases
Solution Approach 1:
The patent changes the chemical parameters of the cleaning agent by replacing hydrofluoric acid with phosphonic acid-based chelating agents and adjusting the pH to a specific range (2-4), thereby maintaining cleaning effectiveness while reducing corrosion to metal wirings
Solution Approach 2:
The patent introduces phosphonic acid-based chelating agents as intermediary substances that selectively bind to polishing fines and metal impurities through chelation, enabling their removal without the need for aggressive hydrofluoric acid that causes wiring corrosion
2Object-affected harmful factors
If organic acid and chelating agent are used to reduce corrosion, then metal wiring corrosion decreases, but removal property of polishing fines becomes insufficient
Solution Approach 1:
The patent creates a composite cleaning agent system combining phosphonic acid-based chelating agents with specific surfactants and buffers, where each component contributes unique properties: the chelating agent binds metal impurities, surfactants enhance wetting and particle suspension, and buffers maintain optimal pH, together achieving both effective particle removal and wiring protection
Solution Approach 2:
The patent merges multiple functional components into a single cleaning agent formulation, combining chelating agents, surfactants, and buffer systems to achieve synergistic effects that simultaneously provide corrosion protection and effective polishing fine removal
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 cleaning agent significantly improves the removal of polishing fines and prevents corrosion of tungsten or tungsten alloy wirings, enhancing contact resistance and reducing short-circuit risks between wirings, thereby improving the manufacturing process of semiconductor substrates.
Implementation Method 1
a cleaning agent comprising a phosphonic acid-based chelating agent and a primary or secondary monoamine with alkyl or hydroxyalkyl groups
Implementation Method 2
The cleaning agent significantly improves the removal of polishing fines
Data Source
AI summary
A cleaning agent is provided for a semiconductor substrate superior in corrosion resistance of a tungsten wiring or a tungsten alloy wiring, and superior in removal property of polishing fines (particle) such as silica or alumina, remaining at surface of the semiconductor substrate, in particular, at surface of a silicon oxide film such as a TEOS film, after a chemical mechanical polishing process; and a method for processing a semiconductor substrate surface. A cleaning agent for a semiconductor substrate is to be used in a post process of a chemical mechanical polishing process of the semiconductor substrate having a tungsten wiring or a tungsten alloy wiring, and a silicon oxide film, comprising (A) a phosphonic acid-based chelating agent, (B) a primary or secondary monoamine having at least one alkyl group or hydroxyalkyl group in a molecule and (C) water, wherein a pH is over 6 and below 7.