Coolant Silicon Powder Removal by Coagulation in Diamond Wire Slicing
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Solution Overview
Problem
Existing methods for removing ultrafine silicon powder from coolant in monocrystalline silicon slicing are inefficient, costly, and environmentally harmful, leading to reduced wafer quality and increased pollution.
Innovation Solution
A method using an inorganic coagulation-inducing saline solution, prepared with calcium and magnesium salts in deionized water, is mixed with the waste coolant to agglomerate and precipitate silicon powder, allowing for its recovery and reuse of the coolant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a plate and frame filter press is used to remove silicon powder from coolant, then the coolant can be filtered, but the filter efficiency is low due to fine particles, high concentration, and coolant viscosity
Solution Approach 1:
The patent introduces an inorganic coagulation-inducing saline solution as an intermediary substance that modifies the physical-chemical properties of the coolant system. This saline solution acts as a mediator between the fine silicon powder particles and the filtration process, enabling effective removal by altering particle behavior through coagulation and precipitation mechanisms, thereby resolving the inefficiency of direct filtration of ultrafine particles
Solution Approach 2:
The patent changes the physical-chemical parameters of the coolant system by adding inorganic coagulation-inducing saline solution. This alters the aggregation state of silicon powder particles, transforming them from fine dispersed particles to larger agglomerates that can be efficiently removed through precipitation and simplified filtration, thus improving filter efficiency without increasing device complexity
2Productivity
If resin adsorption separation method is used to reduce ultrafine silicon powder content, then the powder content can be reduced, but the process becomes cumbersome and difficult to automate due to regeneration requirements
Solution Approach 1:
The patent extracts the complex regeneration step from the overall separation process by using inorganic coagulation-inducing saline solution that enables direct precipitation and filtration. This eliminates the need for resin regeneration operations, allowing the process to be simplified to a single-pass treatment that can be easily automated, thereby resolving the contradiction between removal efficiency and automation capability
Solution Approach 2:
The patent employs a disposable inorganic coagulation-inducing saline solution that performs its function in a single use and then is discarded or replaced. This eliminates the need for expensive, reusable resin materials that require complex regeneration cycles, enabling a simpler, more automatable process while maintaining high silicon powder removal efficiency
3Productivity
If resin adsorption is used for ultrafine silicon powder removal, then powder content can be reduced, but adsorption and agglomeration results are not ideal
Solution Approach 1:
The patent changes the physical-chemical parameters of the coolant system by introducing inorganic coagulation-inducing saline solution, which fundamentally alters the mechanism from adsorption to coagulation-precipitation. This parameter change enables more effective agglomeration of ultrafine silicon powder particles into larger aggregates that can be efficiently removed with higher removal quality, resolving the insufficient agglomeration performance of resin adsorption
Solution Approach 2:
The patent creates a composite system combining inorganic coagulation-inducing saline solution with the coolant containing silicon powder particles. This composite approach leverages the coagulation properties of the saline solution to enhance particle aggregation, achieving superior removal efficiency and quality compared to single-mechanism resin adsorption methods
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 effectively reduces silicon powder content in the coolant, enabling its reuse and recycling, while reducing environmental impact and costs, and simplifying the process.
Implementation Method 1
mixing the inorganic coagulation-inducing saline solution with a waste coolant of the coolant after the monocrystalline silicon slicing to obtain a mixture, and leaving the mixture to stand to carry out agglomeration and precipitation of the silicon powder
Implementation Method 2
leaving the mixture to stand to carry out agglomeration and precipitation of the silicon powder
Data Source
AI summary
The present disclosure provides a method for removing silicon powder in a coolant for monocrystalline silicon slicing with a diamond wire, including following steps: preparing an inorganic coagulation-inducing saline solution; mixing the inorganic coagulation-inducing saline solution with a waste coolant of the coolant after monocrystalline silicon slicing to obtain a mixture, and leaving the mixture to stand to carry out agglomeration and precipitation of the silicon powder. The inorganic coagulation-inducing saline solution has advantages of being inexpensive, non-toxic, easy to obtain, and achieving good agglomeration and precipitation. It is inexpensive to remove the silicon powder in the waste coolant for the monocrystalline silicon slicing with the diamond wire, and does not cause environmental pollution. The recovered silicon powder can be recycled and sold again, and the coolant can be reused for cutting after simple treatment.