Grinding Tool Coolant Flow Control for Semiconductor Wafer Processing
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Solution Overview
Problem
Existing grinding technologies face challenges in maintaining constant grinding conditions and extending the service life of grinding tools due to non-constant surface damage and inadequate cooling, particularly with varying grinding tool wear.
Innovation Solution
The method adjusts the coolant flow rate based on the grinding tooth height of the tool, reducing it as the tooth height decreases, ensuring constant cooling and preventing aquaplaning, while maintaining a minimum flow rate to prevent premature tool replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a constant coolant flow rate is used during grinding, then cooling is maintained, but the service life of the grinding tool is reduced due to inadequate cooling as tooth height decreases
Solution Approach 1:
The coolant flow rate is made dynamic rather than constant, being automatically adjusted based on the grinding tooth height. As the tooth height decreases due to wear, the system reduces the coolant flow rate proportionally, optimizing cooling effectiveness throughout the tool's service life and preventing premature replacement.
Solution Approach 2:
The system incorporates feedback control where the actual grinding tooth height is measured and used to regulate the coolant flow rate. This closed-loop control ensures that cooling is always appropriate to the current tool condition, extending service life while maintaining effective cooling.
2Duration of action of stationary object
If the coolant flow rate is reduced as grinding tooth height decreases, then cooling is optimized for tool wear, but aquaplaning may occur at very low flow rates
Solution Approach 1:
The system changes the coolant flow rate parameter dynamically based on grinding tooth height, reducing it as the tool wears. This parameter adjustment optimizes cooling efficiency throughout the tool's life while maintaining sufficient flow to prevent aquaplaning, balancing tool longevity with process stability.
3Temperature
If a high coolant flow rate is used throughout the grinding process, then cooling is effective, but material is removed too quickly reducing productivity
Solution Approach 1:
The coolant flow rate is dynamically adjusted to match the grinding tooth height, which correlates with material removal capacity. As the tool wears and removes less material, the system proportionally reduces coolant flow, preventing excessive cooling that would reduce productivity while maintaining effective cooling when the tool is fresh.
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
This approach achieves consistent surface damage and extends the service life of grinding tools by optimizing coolant delivery in relation to tool wear, preventing aquaplaning and ensuring effective cooling throughout the grinding process.
Implementation Method 1
a supply of coolant is delivered into a contact region between a semiconductor wafer and the at least one grinding tool
Implementation Method 2
guided substantially free from constraining forces axially between a water cushion (hydrostatic principle) or air cushion (aerostatic principle) acting on the front and back sides
Implementation Method 3
guided substantially free from constraining forces axially between a water cushion (hydrostatic principle) or air cushion (aerostatic principle) acting on the front and back sides
Implementation Method 4
mechanical processing steps which remove material. Edge rounding is carried out by grinding or polishing
Data Source
AI summary
Semiconductor wafers are processed so as to remove material on one or both sides by means of at least one grinding tool, with coolant supplied into a contact region between the semiconductor wafer and the at least one grinding tool, characterized in that the coolant flow rate is set as a function of a grinding tooth height of the at least one grinding tool and this coolant flow rate is reduced as the grinding tooth height decreases.