Semiconductor Wafer Cleaning Composition Using Quaternary Ammonium Hydroxides
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Solution Overview
Problem
Conventional post-chemical mechanical polishing (CMP) cleaning compositions for semiconductor wafers are inadequate in effectively removing contaminants while minimizing corrosion, leading to residual contaminants and surface roughness that can impact wafer performance.
Innovation Solution
A cleaning composition comprising quaternary ammonium hydroxides, organic amines, and metal inhibitors such as purines and azoles, which regulate pH and enhance the solubility of contaminants, effectively removing CMP residues and preventing metal dissolution, thereby reducing surface roughness and corrosion defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CMP cleaning compositions are used, then the cleaning process is simple, but the cleaning effectiveness is insufficient and corrosion occurs
Solution Approach 1:
The cleaning composition uses a composite formulation combining quaternary ammonium hydroxides (surface cleaning agents), organic amines (contaminant solubilizers), and metal inhibitors (corrosion preventors). This multi-component composite approach addresses multiple cleaning challenges simultaneously while maintaining composition stability through synergistic interactions between components.
Solution Approach 2:
The composition regulates pH to specific ranges (pH 10-14) using quaternary ammonium hydroxides, and controls concentrations of various components to optimize cleaning effectiveness while minimizing corrosion. The dialkylhydroxylamines provide antioxidant properties that stabilize the composition under these controlled parameter conditions.
2Reliability
If stronger cleaning agents are used to remove contaminants, then cleaning effectiveness improves, but metal corrosion increases
Solution Approach 1:
Metal inhibitors act as intermediaries between the strong cleaning agents (quaternary ammonium hydroxides and organic amines) and the metal surfaces. These inhibitors form protective complexes with metal ions, preventing direct corrosive interactions while allowing the cleaning agents to effectively remove contaminants. The purines and azoles specifically coordinate with copper and other metal ions to prevent dissolution.
Solution Approach 2:
The composition converts potentially harmful strong bases and cleaning agents into beneficial cleaning tools by adding metal inhibitors that neutralize their corrosive effects. The dialkylhydroxylamines provide antioxidant protection that further mitigates harmful oxidation reactions, transforming a corrosive cleaning process into a protective one.
3Reliability
If pH is increased to enhance cleaning, then contaminant solubility improves, but metal dissolution increases
Solution Approach 1:
Metal inhibitors serve as intermediaries that bind to metal ions at elevated pH levels, preventing their dissolution into the cleaning solution. The purines and azoles form stable complexes with metal ions, allowing the high pH environment to maintain contaminant solubility while the inhibitors prevent metal loss through coordination chemistry.
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 significantly reduces post-CMP defects, achieving low surface roughness and minimizing metal loss, ensuring improved semiconductor wafer performance by effectively cleaning contaminants and protecting metal surfaces.
Implementation Method 1
one or more quaternary ammonium hydroxides in an amount effective to regulate the pH of the composition to a pH of from about 10 to about 14
Implementation Method 2
one or more organic amines, and one or more metal inhibitors selected from purines, azoles, and combinations thereof
Implementation Method 3
enhance the solubility of contaminants, effectively removing CMP residues
Data Source
Figure 1A~2B
Figure 3~4
Figure 5
AI summary
The invention provides a composition for cleaning contaminants from semiconductor wafers following chemical-mechanical polishing. The cleaning composition contains one or more quaternary ammonium hydroxides, one or more organic amines, one or more metal inhibitors, and water. The invention also provides methods for using the cleaning composition.