Sealed CMP Cleaning Tank for In-Line SPM Particle Removal
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Solution Overview
Problem
The existing chemical mechanical polishing (CMP) systems face challenges in integrating sulfuric peroxide mixture (SPM) cleaning processes within single-wafer processing platforms due to issues such as cross-contamination, temperature fluctuations, and inefficient use of chemicals, which are exacerbated by the need for separate tanks and frequent opening of lids, leading to increased costs and reduced throughput.
Innovation Solution
A system and method for in-line SPM cleaning that processes substrates individually or in batches using a cleaning tank with a stationary lid and conveyor system, allowing for controlled chemical exposure and minimal exposure of the tank contents, combined with a robot system for efficient transfer and processing of substrates through multiple tanks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If SPM cleaning is performed in a separate wet bench apparatus with batch processing, then cerium oxide particulates can be effectively removed from substrates, but the process requires frequent opening of tank lids causing steam and sulfuric vapor escape, temperature changes, bath concentration changes, and cross-contamination risks
Solution Approach 1:
The patent integrates the SPM cleaning process into the single-wafer CMP polishing platform by merging the cleaning tank with the existing polishing chamber. The cleaning tank is positioned within the polishing platform housing, allowing the substrate to be transferred from the polishing station to the cleaning station without leaving the sealed environment. This integration eliminates the need for separate wet bench apparatus and frequent lid openings, thereby maintaining process stability while achieving effective cerium oxide removal.
Solution Approach 2:
The patent maintains a controlled atmosphere within the cleaning tank by keeping it sealed during the SPM cleaning process. The tank is equipped with a lid that remains closed throughout processing, preventing steam and sulfuric vapor escape. This sealed environment acts as an inert atmosphere that protects against cross-contamination and maintains consistent temperature and bath concentration, thereby improving reliability without compromising cleaning effectiveness.
2Productivity
If SPM cleaning is integrated into a single-wafer processing platform, then throughput is maintained and cross-contamination is reduced, but the tank lid must be opened frequently for batch processing causing temperature fluctuations and chemical waste
Solution Approach 1:
The patent combines batch processing capability with single-wafer platform throughput by integrating multiple substrate holders within the cleaning tank. Multiple substrates can be processed simultaneously in batch mode within the sealed tank, eliminating the need for frequent lid openings. This approach maintains the throughput benefits of single-wafer processing while reducing chemical waste through minimized exposure to the external environment.
Solution Approach 2:
The patent enables continuous processing by maintaining the cleaning tank in a sealed state throughout the SPM cleaning operation. The lid remains closed, allowing the chemical bath to work continuously on multiple substrates without interruption or exposure. This continuity prevents temperature fluctuations and minimizes chemical waste by eliminating the need to open and close the lid repeatedly, thereby resolving the contradiction between throughput and chemical loss.
3Manufacturing precision
If separate tanks are used for SPM cleaning, then cleaning effectiveness is maintained, but device complexity increases and costs increase due to additional equipment and frequent lid operations
Solution Approach 1:
The patent merges the SPM cleaning functionality into the existing single-wafer CMP polishing platform by integrating the cleaning tank within the platform housing. This integration eliminates the need for a separate wet bench apparatus, thereby reducing device complexity and associated costs. The cleaning tank shares the same controlled environment and substrate handling infrastructure as the polishing station, achieving effective cerium oxide removal without requiring additional standalone equipment.
Solution Approach 2:
The patent creates a multi-functional platform that combines both CMP polishing and SPM cleaning capabilities within a single integrated system. The cleaning tank is designed to work seamlessly with the polishing station, allowing the same substrate holder and transfer mechanism to be used for both processes. This universality reduces device complexity by eliminating redundant equipment while maintaining cleaning effectiveness through the integrated design.
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
Enables efficient and cost-effective SPM cleaning within a single-wafer processing platform by minimizing chemical waste, reducing cross-contamination, and maintaining throughput, while allowing for flexible batch processing of substrates.
Implementation Method 1
a mixture of sulfuric acid and hydrogen peroxide (i.e., sulfuric peroxide mixture (SPM)) can be used in the removal or dissolution of cerium oxide particulates from the surfaces of a substrate after polishing
Implementation Method 2
The slurry of abrasive particles can include cerium oxide particulates and other additives which contribute to the polishing process. To remove these particulates, the substrates can be subjected to a cleaning process that can include the use of harsh oxidizing solvents.
Data Source
AI summary
A substrate cleaning system to remove particulates from multiple substrates includes a cleaning tank for applying a cleaning liquid to substrates, a rinse tank for applying a rinsing liquid to substrates, and a robot system. The cleaning tank includes a stationary lid, an input lid, and an output lid. The input and output lids allow a substrate carrier designed to carry an individual substrate to access an inner volume of the cleaning tank for processing. A transport system moves the substrate in the substrate carrier through the inner volume of the cleaning tank by creating a series of gaps between substrates to allow proper processing. The robot system transports substrates through the input and output lids of the cleaning tank, and transports substrates into the rinse tank.