CMP Sludge Recycling via Roasting and Acid Leaching
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Solution Overview
Problem
The semiconductor chemical mechanical polishing (CMP) sludge is treated as general industrial waste and is not being reused, leading to resource wastage and lack of environmental benefits.
Innovation Solution
A method involving drying, roasting, soaking in acid solutions, solid-liquid separation, concentration, cleaning, and dehydration to recycle CMP sludge into refractory and ceramic materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If CMP sludge is treated as general industrial waste and disposed of through burial or incineration, then the waste management problem is solved, but the resources contained in the sludge are wasted and there are no environmental protection benefits
Solution Approach 1:
The patent applies the discarding and recovering principle by transforming the disposal approach from simple waste removal to resource recovery. The CMP sludge is processed through drying, roasting, and acid leaching to extract valuable metal components (copper, zinc, lead, etc.) and recover silica-rich solid residue. This principle directly addresses the contradiction by recovering substances that would otherwise be lost, turning waste into reusable resources while eliminating the need for traditional disposal methods.
Solution Approach 2:
The patent employs parameter changes by altering the physical and chemical state of the sludge through controlled processing parameters. The drying step removes moisture (changing from 30-80% water content to solid state), the roasting step applies high temperature (800-1200°C) to transform the sludge structure, and the acid leaching step changes the chemical composition by dissolving metal oxides. These parameter changes enable the separation and recovery of valuable components, resolving the resource waste problem.
2Loss of substance
If a multi-step recycling process including drying, roasting, soaking, separating, concentrating, cleaning, and dehydrating is implemented, then resource reuse is achieved, but the process complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the complex recycling process into distinct sequential stages: drying (moisture removal), roasting (high-temperature treatment), soaking/leaching (acid treatment for metal extraction), separating (solid-liquid separation), concentrating (metal recovery from solution), cleaning (solid residue washing), and dehydrating (final drying). Each stage performs a specific function and can be independently optimized or operated, making the overall complex process more manageable and controllable while achieving comprehensive resource recovery.
3Loss of substance
If high-temperature roasting at 800-1200°C is applied to the sludge, then the material structure is transformed for better recyclability, but the energy consumption increases
Solution Approach 1:
The patent applies preliminary action by performing a drying step before the high-temperature roasting process. The drying step removes 30-80% of the water content from the fresh sludge, transforming it into a solid or semi-solid state. This preliminary moisture removal significantly reduces the energy required for the subsequent roasting step, as less energy is needed to evaporate water. The drying-pre-roasting sequence optimizes energy utilization while achieving the necessary material transformation for recyclability.
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 recycled CMP sludge is reused as refractory and ceramic materials, maximizing resource utilization and providing environmental benefits.
Implementation Method 1
drying: drying out the CMP sludge into a condition of solid, wherein the drying temperature is 100° C. ̃200° C.
Implementation Method 2
roasting: putting the solid sludge obtained in step (1) into a high-temperature furnace for roasting, wherein the roasting temperature is 800° C. ̃1200° C.
Implementation Method 3
soaking: putting the solid sludge obtained after roasting in step (2) into a reaction tank and adding a impregnating liquid for stirring, wherein the impregnating liquid is implemented as a single ingredient solution of inorganic acid or organic acid
Implementation Method 4
separating: performing a solid-liquid separation to a reaction product in step (3) to obtain a solid and a liquid, wherein the separation method is allowed to be one of heat drying, freeze drying, filtration, centrifugation, sedimentation, etc.
Implementation Method 5
separating: performing a solid-liquid separation to a reaction product in step (3) to obtain a solid and a liquid, wherein the separation method is allowed to be one of heat drying, freeze drying, filtration, centrifugation, sedimentation, etc.
Implementation Method 6
concentrating: performing a concentration reaction on the liquid separated in step (4) through a concentration system to obtain a copper sulfate aqueous solution by-product
Implementation Method 7
cleaning: taking out the solid sludge obtained by the separation treatment in step (4) and adding water for washing
Implementation Method 8
dehydrating: dehydrating a product obtained in step (6) to obtain solid and liquid, wherein the dehydration method is allowed to be one of heat drying, freeze drying, filtration, centrifugation, etc.
Data Source
AI summary
The present invention relates to a semiconductor chemical mechanical polishing sludge recycling method, which comprises the following steps: (1) drying out the CMP sludge into a condition of solid; (2) putting the solid sludge obtained in step (1) into a high-temperature furnace for roasting; (3) putting the solid sludge obtained in step (2) into a reaction tank and adding a impregnating liquid for soaking, (4) performing a solid-liquid separation in step (3) to obtain a solid and a liquid, (5) performing a concentration reaction on the liquid separated in step (4) to obtain a copper sulfate aqueous solution by-product; (6) taking out the solid sludge obtained in step (4) and adding water for washing; (7) dehydrating a product obtained in step (6); (8) obtaining the solid dehydrated is the goods, and a sum of silicon dioxide and aluminum oxide on a dry basis is greater than 94%.