Post-CMP Cleaning Composition for Low Tungsten and Molybdenum Etch
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Solution Overview
Problem
Existing post-CMP removal compositions unintentionally remove unacceptable levels of tungsten and/or molybdenum from microelectronic device surfaces, leading to faults and pattern defects, especially in highly integrated semiconductor devices.
Innovation Solution
A composition comprising water, a sulfonated polymer, a sulfonated alkyl amine compound, a chelating agent, and an organic compound with a quaternary amine, maintained at a pH of less than about 7, is used to remove residue while inhibiting tungsten and molybdenum corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If post-CMP removal compositions are used to remove residue from microelectronic device surfaces, then cleaning effectiveness is improved, but unacceptable levels of tungsten and/or molybdenum are unintentionally removed leading to faults and pattern defects
Solution Approach 1:
The patent modifies the chemical parameters of the removal composition by controlling pH levels and selecting specific chemicals (chelating agents, sulfonated polymers, organic acids) to change how the composition interacts with different materials. This allows selective removal of residue while preserving tungsten and molybdenum films through parameter optimization
Solution Approach 2:
The patent introduces intermediary substances such as chelating agents and sulfonated polymers that mediate between the removal composition and the device surface. These intermediaries selectively bind to and remove particles and residue while forming protective complexes with tungsten and molybdenum to prevent their removal
2Manufacturing precision
If higher pH removal compositions are used, then residue removal capability is improved, but tungsten and molybdenum corrosion increases
Solution Approach 1:
The patent systematically changes the pH parameter from high to low (acidic) ranges, and further optimizes by selecting specific organic acids and controlling their concentrations. This parameter change fundamentally alters the chemical behavior toward metals, reducing corrosion while maintaining residue removal through alternative mechanisms
Solution Approach 2:
The patent converts potentially harmful acidic conditions into beneficial selective removal action. By using weak organic acids and chelating agents, the harmful corrosive effect is transformed into a selective chemical interaction that removes residue while protecting metal films through complex formation
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 residue while minimizing the etch rate of tungsten and molybdenum, ensuring a cleaner surface for subsequent processing and reducing defects.
Implementation Method 1
a sulfonated polymer, a sulfonated alkyl amine compound, or a combination thereof
Implementation Method 2
a chelating agent
Implementation Method 3
new additives are needed to inhibit tungsten and/or molybdenum corrosion (providing a lower etch rate and lower roughness)
Implementation Method 4
The surface is polished (more specifically, planarized) by coupling a physical process such as abrasion with a chemical process such as oxidation or chelation
Implementation Method 5
a chemical process such as oxidation or chelation
Data Source
AI summary
The invention provides a composition comprising (a) water, (b) a sulfonated polymer, a sulfonated alkyl amine compound, or a combination thereof, (c) a chelating agent, and (d) an organic compound comprising a quaternary amine, wherein the composition has a pH of less than about 7. The invention also provides a method for removing residue from a surface of a microelectronic device substrate comprising contacting the surface of the microelectronic device substrate with the compositions described herein.