Wafer Edge Polishing Roller Mechanism for Step Recess Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional polishing apparatuses fail to form a stable step-shaped recess in the edge portion of wafers due to uneven polishing rates and pressure distribution, resulting in an inclined bottom surface and unstable profile.
Innovation Solution
A polishing apparatus comprising a substrate rotating device, a first roller with a circumferential surface to press the polishing tape against the edge portion, and a second roller with a tape stopper surface to restrict the tape's movement, ensuring line contact and uniform polishing rates, along with a detection system to adjust the rollers and maintain tape width consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a polishing tape is pressed against the edge portion of the wafer using a conventional pressing member, then the wafer edge can be polished, but the polishing rate varies between outer and inner regions causing an inclined bottom surface
Solution Approach 1:
The pressing member is segmented into a first roller for pressing the polishing tape and a second roller for restricting tape movement. This segmentation allows independent control of pressing force and tape position, enabling uniform polishing rate across the entire contact surface while maintaining operational simplicity through modular design.
Solution Approach 2:
The second roller acts as an intermediary element between the polishing tape and the wafer edge. By restricting the tape's movement in the radial direction through this intermediary component, the system achieves uniform polishing pressure distribution without complicating the overall operation.
2Reliability
If the pressing member is slightly inclined with respect to the wafer surface, then the polishing process can be performed, but the polishing-pressure distribution changes significantly making it difficult to obtain a stable recess profile
Solution Approach 1:
The first and second rollers are configured to be substantially parallel to each other, creating an equipotential pressing surface. This geometric arrangement ensures uniform polishing-pressure distribution across the wafer edge regardless of minor inclinations, achieving stable recess profiles without requiring complex pressure control mechanisms.
3Manufacturing precision
If the polishing tape contact length with the outer region is longer than with the inner region, then the polishing process can proceed, but the polishing rate difference creates an inclined bottom surface and vertical surface
Solution Approach 1:
The second roller with its tape stopper surface provides localized control at the inner edge of the polishing tape contact area. This local quality enhancement ensures that the polishing tape maintains consistent contact length with both outer and inner regions of the wafer edge, producing vertical side walls and a flat bottom surface while preserving overall polishing efficiency.
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 solution achieves a stable step-shaped recess with a right-angled cross section, uniform polishing rates, and reduced pressure concentration, leading to a consistent and perpendicular polishing profile.
Implementation Method 1
a first roller 51 having a first circumferential surface 51a configured to press a polishing tape 38 against the edge portion of the substrate
Implementation Method 2
The polishing tape 505 contacts the edge portion of the rotating wafer W while advancing at a predetermined speed... to form a stepped-shape recess 510 in the edge portion of the wafer W
Implementation Method 3
a second roller 54 having a second circumferential surface 54a in contact with the first circumferential surface 51a, the second roller having a tape stopper surface that restricts movement of the polishing tape in a direction away from the rotation axis
Data Source
AI summary
A polishing apparatus capable of forming a step-shaped recess having a right-angled cross section in an edge portion of a substrate, such as a wafer, is disclosed. The polishing apparatus includes: a substrate rotating device configured to rotate the substrate about a rotation axis; a first roller having a first circumferential surface configured to press a polishing tape against the edge portion of the substrate; and a second roller having a second circumferential surface in contact with the first circumferential surface. The second roller has a tape stopper surface that restricts movement of the polishing tape in a direction away from the rotation axis. The tape stopper surface is located radially outward of the first circumferential surface.