Post-CMP Cleaning Compositions for Semiconductor Wafer Defect Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional post-CMP cleaning processes are inadequate in removing contaminants from semiconductor substrates, leading to defects and diminished device performance in advanced node semiconductor manufacturing.
Innovation Solution
The use of cleaning compositions comprising organic acids, anionic polymers, and nonionic surfactants, applied as both polisher rinse and post-CMP compositions, to effectively remove residues and contaminants from semiconductor substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional post-CMP cleaning solutions are used, then the cleaning process is simple, but contaminants are not effectively removed from the wafer surface
Solution Approach 1:
The patent employs composite cleaning compositions that integrate multiple components working synergistically: organic acids (e.g., citric acid, gluconic acid) for chemical dissolution, anionic polymers (e.g., polyacrylic acid, polyvinylphosphonic acid) for binding metal ions and organic residues, and nonionic surfactants (e.g., polysorbates) for emulsifying organic contaminants. This composite approach achieves superior contaminant removal compared to single-component solutions while maintaining manageable formulation complexity.
Solution Approach 2:
The patent optimizes multiple parameters of the cleaning composition including pH level (typically adjusted to acidic range using organic acids), concentration of active ingredients, molecular weight distribution of polymers, and surfactant type and concentration. By carefully controlling these parameters, the composition achieves effective contaminant removal without excessive complexity in formulation or application.
2Manufacturing precision
If deionized water rinsing is used after CMP, then water miscible components are removed, but contaminants such as particulate abrasive and organic residue remain on the surface
Solution Approach 1:
The patent applies cleaning composition to the wafer surface before the traditional post-CMP cleaning step, performing preliminary chemical and mechanical action to loosen and remove contaminants. This preliminary treatment includes organic acid-based dissolution of metal ions, polymer-based binding and removal of organic residues, and surfactant-based emulsification of hydrophobic contaminants. By performing this action beforehand, the subsequent rinsing and drying steps more effectively remove remaining contaminants, reducing overall process time while improving surface cleanliness.
Solution Approach 2:
The cleaning composition acts as an intermediary substance that facilitates contaminant removal between the CMP process and final wafer inspection. The organic acids, anionic polymers, and nonionic surfactants work together as a mediating system that transfers contaminants from the wafer surface into the cleaning solution, enabling their subsequent removal without requiring complex mechanical scrubbing or extended process time.
3Reliability
If traditional post-CMP cleaning is used, then the process is straightforward, but it is insufficient to adequately remove contaminants from polished wafers in advanced node semiconductor manufacturing
Solution Approach 1:
The patent uses composite cleaning compositions containing organic acids (citric acid, gluconic acid, lactic acid), anionic polymers (polyacrylic acid, polyvinylphosphonic acid, polyethylene glycol), and nonionic surfactants (polysorbates, polyethylene glycol monostearate). This multi-component formulation synergistically addresses different contaminant types: acids dissolve metal ions, anionic polymers bind organic residues, and nonionic surfactants emulsify hydrophobic contaminants, thereby reducing wafer defectivity while maintaining reasonable process simplicity.
Solution Approach 2:
The patent tailors the cleaning composition to address specific local contamination issues on the wafer surface. Different regions of the wafer may have different contamination profiles from CMP processing, and the formulation can be adjusted to optimize for specific contaminant types (metal ions, organic residues, particulate matter). This localized optimization approach improves reliability without requiring overly complex universal formulations.
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 compositions significantly reduce wafer defects, making the substrates suitable for further processing and enhancing chip manufacturing yield.
Implementation Method 1
The cleaning composition can include at least one chelating agent... which can be selected from the group consisting of carboxylic acids, amino acids, or a combination thereof
Implementation Method 2
at least one first organic acid... at least one second organic acid... which can be selected from the group consisting of carboxylic acids, amino acids, or a combination thereof
Implementation Method 3
at least one anionic polymer... which can have a weight average molecular weight ranging from at least about 250 g/mol to at most about 500,000 g/mol
Implementation Method 4
anionic polymer... which can be selected from the group consisting of poly(4-styrenylsulfonic) acid (PSSA), polyacrylic acid (PAA), poly(vinylphosphonic acid) (PVPA), or a mixture thereof
Implementation Method 5
at least one nonionic surfactant... which can be selected from the group consisting of polyoxyalkylene alkyl ether, polyoxyalkylene alkenyl ether, polyoxyalkylene glycol, polyoxyalkylene monoalkylate, polyoxyalkylene dialkylate, bispolyoxyalkylene alkylamide, sorbitan fatty acid ester, or a combination thereof
Implementation Method 6
at least one nonionic surfactant... which can be selected from the group consisting of polyoxyalkylene alkyl ether, polyoxyalkylene alkenyl ether, polyoxyalkylene glycol, polyoxyalkylene monoalkylate, polyoxyalkylene dialkylate, bispolyoxyalkylene alkylamide, sorbitan fatty acid ester, or a combination thereof
Implementation Method 7
CMP is a process used to planarize/flatten a wafer surface by removing material using abrasion-based physical processes concurrently with surface-based chemical reactions
Data Source
AI summary
The present disclosure relates to cleaning compositions that can be used to clean semiconductor substrates. These cleaning compositions can be used to remove defects arising from previous processing steps on these semiconductor substrates. These cleaning compositions can remove the defects/contaminants from the semiconductor substrates and thereby make the substrates appropriate for further processing. Such cleaning compositions can include use of a polisher rinse composition, use of a post-CMP composition, or use of a combination of the polisher rinse composition and the post-CMP composition.