Wafer Notch Polishing Sequence for Improved Local Flatness
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Solution Overview
Problem
The existing wafer manufacturing methods that adjust notch depth to improve flatness near the notch often result in notch depths that are unusable in subsequent steps, and fail to enhance flatness without altering the notch shape.
Innovation Solution
A method involving polishing the principal surfaces, mirror-polishing the notch chamfered portion, and then the outer-periphery chamfered portion, with finish-polishing performed last, to improve the flatness near the notch without changing the notch shape, specifically by reversing the order of the polishing steps compared to prior methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the notch depth is adjusted to improve flatness near the notch, then the flatness of the part near the notch is improved, but the notch depth becomes unusable in subsequent steps
Solution Approach 1:
The polishing process is divided into distinct segments: notch chamfered portion polishing, outer-periphery chamfered portion polishing, and finish polishing of principal surfaces. Each segment addresses specific areas independently, allowing the notch depth to remain unchanged while improving flatness through targeted polishing of surrounding regions.
Solution Approach 2:
Different polishing treatments are applied to different locations: the notch chamfered portion receives mirror polishing, the outer-periphery chamfered portion receives mirror polishing, and the principal surfaces receive finish polishing. This localized approach improves flatness near the notch without altering the notch depth, maintaining its usability.
2Manufacturing precision
If the notch depth is adjusted to improve flatness near the notch, then the flatness of the part near the notch is improved, but the shape of the notch is changed
Solution Approach 1:
The invention applies polishing treatments selectively to specific regions (notch chamfered portion, outer-periphery chamfered portion, and principal surfaces) while deliberately excluding the notch itself from depth-altering operations. This preserves the original notch shape while improving the flatness of surrounding areas through controlled material removal from chamfered portions.
Solution Approach 2:
The polishing process is segmented into distinct operations that target different areas with different polishing parameters. The notch chamfered portion is polished separately from the principal surfaces, allowing independent control of each region's surface quality without affecting the notch depth or overall shape.
3Manufacturing precision
If mirror polishing is performed on the notch chamfered portion before finish polishing, then the flatness near the notch is improved, but the polishing process complexity increases
Solution Approach 1:
The polishing process is divided into three sequential segments: (1) mirror polishing of the notch chamfered portion, (2) mirror polishing of the outer-periphery chamfered portion, and (3) finish polishing of the principal surfaces. This segmentation allows each operation to be optimized independently while maintaining a systematic workflow that improves flatness without excessive complexity.
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 effectively improves the flatness of the wafer near the notch without altering the notch shape, as demonstrated by reduced edge roll-off amounts and enhanced surface smoothness, as shown in the comparative examples.
Implementation Method 1
polishing principal surfaces of the wafer; mirror-polishing a notch chamfered portion of the notch; mirror-polishing an outer-periphery chamfered portion of an outer periphery of the wafer; and finish-polishing one of the principal surfaces of the wafer
Data Source
AI summary
A manufacturing method of a wafer with a notch includes: polishing principal surfaces of the wafer; mirror-polishing a notch chamfered portion of the notch; mirror-polishing an outer-periphery chamfered portion of an outer peripheral portion of the wafer; and finish-polishing one of principal surfaces of the wafer, the finish-polishing being performed after performing the mirror-polishing of the notch chamfered portion, the polishing of the principal surfaces, and the mirror-polishing of the outer-periphery chamfered portion in this order.