CMP Slurry Composition for Selective Polishing of Mixed Films
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Solution Overview
Problem
Existing chemical mechanical polishing (CMP) processes struggle to effectively remove defects and minimize material loss in integrated circuit manufacturing, particularly when dealing with different materials like polysilicon and silicon nitride films, leading to surface roughness and thickness deviations.
Innovation Solution
A slurry composition comprising polishing particles, a nonionic polymer inhibitor for polysilicon, and an anionic polymer inhibitor for silicon nitride, selectively bonded to each film, is used to minimize material loss and planarize the surface during CMP, thereby reducing surface roughness and thickness deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional CMP slurry is used to polish multiple different materials, then the polishing process can be applied to various films, but the surface roughness increases and thickness deviations occur due to inability to selectively protect different materials
Solution Approach 1:
The slurry composition incorporates different inhibitors with specific affinities for different materials (polysilicon, silicon nitride, copper). Each inhibitor selectively adsorbs onto its target material surface, providing localized protection during polishing. This enables the single slurry to adaptively protect different materials based on local chemical characteristics, resolving the contradiction between versatility and precision.
Solution Approach 2:
The invention adjusts the chemical composition parameters of the slurry by incorporating multiple inhibitors with different molecular structures and binding characteristics. The nonionic polymer protects polysilicon, while the anionic polymer protects silicon nitride and copper. By changing the chemical parameters of the slurry composition, it achieves selective interaction with different materials, maintaining both adaptability and manufacturing precision.
2Reliability
If polishing is performed to remove surface defects, then surface quality improves, but unnecessary material loss occurs leading to thickness variations
Solution Approach 1:
The inhibitors in the slurry perform preliminary protective action by selectively adsorbing onto the target film surfaces before polishing begins. This pre-formed protective layer prevents excessive material removal during the polishing process, allowing defect removal while minimizing unnecessary thickness loss, thus resolving the contradiction between surface quality improvement and material conservation.
Solution Approach 2:
The inhibitors act as intermediary substances between the polishing particles and the target films. They mediate the interaction by selectively binding to specific materials and modulating the polishing rate. This intermediary action enables controlled material removal for defect elimination while preventing excessive polishing, balancing surface quality and thickness preservation.
3Device complexity
If a single slurry composition is used for polishing polysilicon and silicon nitride films, then the process is simplified, but selective protection of different materials cannot be achieved
Solution Approach 1:
The slurry composition achieves multi-functionality by incorporating multiple inhibitors that can selectively interact with different materials. The nonionic polymer provides protection for polysilicon, while the anionic polymer protects silicon nitride and copper. This universal slurry composition can handle multiple material types in a single polishing step, simplifying the process while maintaining material-specific protection capabilities.
Solution Approach 2:
The invention creates a composite slurry system combining polishing particles with multiple types of inhibitors having different chemical characteristics. This composite composition enables selective protection of different materials through the synergistic action of various inhibitors, achieving both process simplification and material-specific adaptability.
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 slurry composition effectively removes defects while minimizing unnecessary loss of target films, improving surface smoothness and reducing thickness variations, enhancing manufacturing yield and reliability of integrated circuit devices.
Implementation Method 1
a first inhibitor, which includes a nonionic polymer selectively bonded to a polysilicon layer
Implementation Method 2
a second inhibitor, which includes an anionic polymer selectively bonded to the silicon nitride film
Implementation Method 3
treating a surface of the target structure by a chemical mechanical polishing (CMP) process
Data Source
AI summary
A slurry composition is used to treat a surface of a target structure including at least one of a first polishing target film and a second polishing target film, which include different materials from each other, by a chemical mechanical polishing (CMP) process. The slurry composition includes: polishing particles; a first inhibitor including a nonionic polymer to selectively bond to the first polishing target film; and a second inhibitor including an anionic polymer to selectively bond to the second polishing target film. A method of manufacturing an integrated circuit device includes: forming, on a substrate, a target structure including at least one of a first polishing target film and a second polishing target film; applying the slurry composition onto the target structure; and treating a surface of the target structure by a CMP process while the slurry composition covers the target structure.