Wafer Polishing with Self-Positioning Round Edge
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Solution Overview
Problem
Current wafer polishing methods for the outer circumferential area are complex and require precise control, making them difficult to execute accurately and efficiently, especially when the width of the polishing area is small, such as 2 mm or less, due to the need for a completely round polishing member and precise positioning.
Innovation Solution
A method and apparatus that includes a disk-shaped polishing member with a completely round edge formed by a cutting tool, allowing for accurate positioning and polishing of the outer circumferential area by moving the polishing member in two directions: parallel and perpendicular to the wafer surface, ensuring only the specified area is polished.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If accurate positioning control is implemented to polish only the outer circumferential area, then polishing precision is improved, but device complexity and operation difficulty increase
Solution Approach 1:
The polishing member is designed to self-position on the wafer through its geometric shape (completely round outer circumferential edge) and the wafer's rotation, eliminating the need for complex external positioning control systems. The shape itself provides the positioning function.
Solution Approach 2:
The polishing member features a completely round outer circumferential edge (circular arc shape) that naturally conforms to the wafer's circular geometry. This curved geometry enables automatic centering and positioning without complex control mechanisms.
2Manufacturing precision
If a completely round polishing member is formed to polish the outer circumferential area, then polishing precision is improved, but manufacturing complexity increases
Solution Approach 1:
The completely round outer circumferential edge of the polishing member is formed in advance during manufacturing. This preliminary shaping allows the polishing member to automatically self-position during operation, simplifying the overall system while maintaining high precision.
3Manufacturing precision
If the polishing member is moved with high accuracy to polish only the outer circumferential area, then polishing precision is improved, but operation complexity increases
Solution Approach 1:
The polishing member performs its own positioning function through its geometric design. The completely round outer edge automatically aligns with the wafer's circular shape during rotation, eliminating the need for complex external positioning operations.
Solution Approach 2:
The circular arc shape of the polishing member's outer circumferential edge matches the wafer's geometry, enabling natural self-alignment and simplifying the operation to basic rotation and pressure application without complex movement control.
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 and easy polishing of the outer circumferential area of wafers, particularly effective for small widths, with high reproducibility and simplified operation, improving die strength by removing strain layers effectively.
Implementation Method 1
polishing the ground surface of the wafer by using a disk-shaped polishing member containing abrasive grains
Data Source
AI summary
A wafer polishing method, in which the outer circumferential edge of a polishing member is first cut by a cutting tool fixed to a table base, thereby forming the polishing member into a completely round shape and also positioning the polishing member in a Y direction at a Y-directional reference position of the table base. Thereafter, a polishing unit is once lifted in the condition where the table base remains still at the reference position. Thereafter, the table base is horizontally moved toward a column in the Y direction to thereby position the polishing member in the Y direction so that only a peripheral portion of the wafer is polished by the polishing member. At this time, the horizontal travel of the table base is preliminarily obtained from the Y-directional positional relation between the cutting tool and the wafer held on a chuck table and from the width of the peripheral portion to be polished. Finally, the polishing unit is lowered to make the lower surface of the polishing member into pressure contact with the peripheral portion of the wafer, thus polishing only the peripheral portion.