One-Side Polishing Pad Displacement Tracking During Wafer Polishing
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Solution Overview
Problem
Conventional methods struggle to accurately measure the dynamic displacement of polishing pads during one-side polishing of workpieces, particularly due to the inability to capture the behavior of the polishing pad recovering its deformation after pressure is relieved.
Innovation Solution
A one-side polishing apparatus equipped with a surface displacement measurement section and a polishing liquid removal mechanism, such as air blowing, to measure the dynamic displacement of the polishing pad during polishing, allowing for precise tracking of the pad's displacement behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional measurement methods are used to determine polishing pad physical properties, then static properties can be measured, but dynamic displacement during actual polishing cannot be captured
Solution Approach 1:
The patent transitions from static measurement to dynamic measurement by positioning the displacement measurement section to monitor the polishing pad during actual polishing operations. The measurement section captures real-time displacement data as the pad rotates and contacts the workpiece, enabling observation of dynamic viscoelastic behavior rather than just static properties.
Solution Approach 2:
The patent introduces a displacement measurement section as an intermediary device that indirectly measures pad properties through displacement monitoring. This mediator captures the pad's dynamic behavior during polishing without interfering with the polishing process itself, solving the problem of measuring dynamic characteristics during actual operation.
2Productivity
If the polishing pad is pressed against the workpiece during polishing, then polishing action occurs, but the recovery behavior of the pad after pressure release cannot be measured
Solution Approach 1:
The displacement measurement section operates continuously during the polishing process, maintaining measurement capability throughout the entire polishing cycle including both the pressing phase and the recovery phase. This continuous monitoring ensures that no information about pad recovery behavior is lost, capturing the complete dynamic response of the pad material.
Solution Approach 2:
The measurement system provides feedback on pad displacement during pressing and recovery, enabling observation of the viscoelastic recovery behavior. This feedback mechanism allows the system to capture how the pad returns to its original shape after pressure is released, preserving information about the material's dynamic properties.
3Manufacturing precision
If polishing liquid is supplied to the polishing pad during polishing, then polishing effectiveness is maintained, but measurement accuracy of the exposed top surface is reduced
Solution Approach 1:
The patent divides the polishing pad surface into two functional zones: a covered region where polishing liquid is supplied for effective polishing, and an exposed region where displacement measurement occurs. This segmentation allows the measurement section to monitor pad dynamics on a dry surface while the polishing process continues elsewhere on the pad, maintaining both measurement accuracy and polishing effectiveness.
Solution Approach 2:
The exposed top surface acts as an intermediary measurement zone that indirectly reflects the dynamic behavior of the polishing pad without being contaminated by polishing liquid. This intermediary area provides a clean optical path for displacement measurement while the polishing liquid performs its function on the covered portion of the pad.
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 accurate measurement of the polishing pad's dynamic displacement, providing insights into its viscoelastic properties and improving the understanding of polishing processes.
Implementation Method 1
a surface displacement measurement section that can measure displacement of an exposed top surface
Implementation Method 2
the polishing liquid removal section is configured to be capable of blowing air onto the exposed top surface
Implementation Method 3
the viscoelasticity of the polishing pad has an effect on the distribution of the amount of polishing
Implementation Method 4
it was not possible to measure the behavior of the polishing pad recovering its deformation after the wafer is pressed against the same
Data Source
AI summary
The one-side polishing apparatus for a workpiece of the present disclosure further comprises a surface displacement measurement section that can measure displacement of an exposed top surface, which is a top surface of the polishing pad that is not covered by the polishing head. The method for one-side polishing of a workpiece of the present disclosure polishes, in the polishing process, one side of the workpiece while measuring displacement of the exposed upper surface by the surface displacement measurement section that can measure the displacement of the exposed upper surface. The method for manufacturing silicon wafers of the present disclosure uses the method for one-side polishing of a workpiece as described above.