CMP Slurry Composition with Cationic Film Protection
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Solution Overview
Problem
Chemical mechanical polishing (CMP) processes can cause corrosion of underlying conductive layers due to reactive slurry interactions, leading to performance and reliability issues in integrated circuits.
Innovation Solution
A slurry composition is developed that includes a cationic surfactant with a nitrogen atom, which forms a hydrophobic film on the exposed surfaces of conductive layers, preventing corrosion by repelling the slurry and maintaining the integrity of the underlying layers during polishing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a reactive slurry is used for polishing conductive layers, then polishing effectiveness is improved, but corrosion of underlying conductive layers occurs
Solution Approach 1:
A cationic surfactant is introduced as an intermediary substance in the slurry composition. This surfactant adsorbs onto the conductive layer surface to form a protective film that mediates between the reactive slurry and the underlying conductive layer, preventing direct corrosive interaction while allowing the polishing process to proceed effectively
Solution Approach 2:
The slurry composition is modified by adding cationic surfactants and adjusting pH levels to create a chemically modified environment. This parameter change transforms the slurry from a purely reactive system to one that forms protective surface films, thereby reducing corrosion while maintaining polishing capability
2Manufacturing precision
If polishing slurry contacts underlying conductive layers, then material removal is achieved, but material loss and integrity degradation occur
Solution Approach 1:
The cationic surfactant in the slurry performs preliminary protective action by adsorbing onto the conductive layer surface before the abrasive particles can cause excessive material removal or before corrosive chemicals can attack the underlying layers. This pre-formed protective layer prevents both over-removal and corrosion
Solution Approach 2:
The surfactant acts as a protective intermediary that allows controlled material removal while preventing uncontrolled material loss. It creates a selective barrier that permits necessary polishing action while blocking harmful corrosive effects on the underlying conductive layers
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 use of a cationic surfactant in the slurry composition effectively blocks the conductive layer from corrosion, enhancing the stability and reliability of the CMP process by reducing material loss and ensuring consistent polishing performance.
Implementation Method 1
forms a hydrophobic film on the exposed surfaces of conductive layers, preventing corrosion by repelling the slurry
Implementation Method 2
A slurry composition is developed that includes a cationic surfactant with a nitrogen atom
Data Source
AI summary
A slurry composition, a polishing method and an integrated circuit are provided. The slurry composition includes a slurry and at least one cationic surfactant having at least one nitrogen atom in the molecule. The slurry includes at least one liquid carrier, at least one abrasive and at least one pH adjusting agent, and has a pH of less than 7.0. The polishing method includes using the slurry composition with the cationic surfactant to polish a conductive layer. The integrated circuit comprises a block layer comprising the cationic surfactant between a sidewall of the conductive plug and an interlayer dielectric layer.