Semiconductor Slurry Recycling via Shear Aggregates
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Solution Overview
Problem
Current recycling methods for semiconductor wafer polishing slurry are inefficient due to aggregate formation, filter clogging, and contamination risks, limiting the reuse of used slurry and increasing operational costs.
Innovation Solution
A recycling method and apparatus that uses a shearing force imparting device, such as a micro-bubble generator, to break up aggregates in the used slurry, combined with a dispersant to inhibit aggregation and a foreign substances removing device to prevent contamination, allowing for the effective recycling of a large amount of slurry in a short time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If used-slurry is subjected to filtration to remove aggregates, then foreign substances can be removed, but filter clogging occurs frequently requiring replacement
Solution Approach 1:
The patent applies preliminary action by adding a dispersant to the used-slurry before filtration to prevent aggregate formation. This pre-treatment step ensures that aggregates do not form during the filtration process, thereby preventing filter clogging and eliminating the need for frequent filter replacements while maintaining reliable slurry recycling
Solution Approach 2:
The patent uses a dispersant as an intermediary substance that mediates between the slurry components. The dispersant adsorbs onto aggregate surfaces and provides steric or electrostatic repulsion, preventing aggregate formation and ensuring smooth filtration without clogging, thus resolving the contradiction between effective foreign substance removal and filter maintenance
2Quantity of substance
If ultrasonic beam is emitted to break up aggregates, then slurry can be recycled, but only peripheral area is affected and large amount of slurry requires long processing time
Solution Approach 1:
The patent introduces a dispersant as an intermediary chemical agent that acts throughout the entire slurry volume. Unlike ultrasonic treatment which only affects peripheral areas, the dispersant distributes uniformly throughout the slurry and prevents aggregate formation systemically, enabling rapid processing of large volumes without time constraints
Solution Approach 2:
The patent replaces the mechanical ultrasonic treatment system with a chemical dispersant-based system. This substitution eliminates the limitation of ultrasonic waves being confined to peripheral areas, as the dispersant chemically acts throughout the entire slurry volume simultaneously, dramatically reducing processing time for large quantities
3Stability of the object's composition
If dispersant is added to inhibit aggregation, then slurry stability improves, but additional chemical substances are introduced
Solution Approach 1:
The patent applies parameter changes by carefully controlling the dispersant concentration within an optimal range. By adjusting this parameter, the system achieves stable slurry composition with minimal dispersant addition, preventing both aggregate formation and excessive chemical substance introduction, thus resolving the contradiction between stability improvement and chemical consumption
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 method enables the stable and efficient recycling of a large volume of used slurry by breaking up aggregates and preventing filter clogging, ensuring high-quality semiconductor wafer production with reduced operational costs.
Implementation Method 1
breaking up aggregates in such a manner that the whole of the used-slurry, subjected to the dispersant addition step, is passed through a shearing force imparting device to impart shearing force to aggregates contained in the slurry by the shearing force imparting device
Implementation Method 2
adding a dispersant to a recovered used-slurry to inhibit aggregation of the slurry
Data Source
AI summary
A recycling method of slurry for use in wafer polishing for reusing slurry used in a polishing process of semiconductor wafer, comprises the steps of: adding a dispersant to a recovered used-slurry to inhibit aggregation of the slurry; breaking up aggregates in such a manner that the whole of the used slurry, subjected to the dispersant addition step, is passed through a shearing force imparting device to impart shearing force to the aggregates contained in the slurry by the shearing force imparting device, thereby breaking up the aggregates; and removing foreign substances in the slurry subjected to the aggregate breakup step, by means of a foreign substances removing device. According to the method, a large amount of used-slurry can be processed in a short time.