Wafer Chamfer Removal with Dual Cutting Units
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
During the removal of chamfered portions on disk-shaped wafers, cutting swarf adheres to the wafer's surface and devices, leading to potential defects in bonding and device damage due to improper removal and drying.
Innovation Solution
A dual dicer cutting apparatus with two cutting units and liquid supply nozzles is used to remove the chamfered portion, where the second cutting unit positions adjacent to the first, creating a liquid barrier to prevent swarf from moving towards the center and ensuring effective cleaning of the front surface, preventing adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cutting liquid is continuously supplied to cool the cutting blade and remove cutting swarf, then the cutting blade is cooled and cutting swarf is removed from the cutting point, but the cutting swarf spreads on the upper surface of the wafer and adheres firmly to devices during drying
Solution Approach 1:
The patent extracts and removes the cutting swarf from the wafer surface by directing the cutting liquid flow to carry swarf away from the device areas. The liquid flow path is designed to extract swarf from the cutting zone and transport it to a safe discharge location, preventing adhesion to devices.
Solution Approach 2:
The cutting liquid acts as an intermediary medium that not only cools the cutting blade but also serves as a transport carrier for cutting swarf. By controlling the liquid flow, the swarf is carried away from the wafer surface and devices, resolving the adhesion problem while maintaining the cooling function.
2Device complexity
If a single cutting unit is used to remove the chamfered portion, then the structure is simple, but cutting swarf cannot be effectively prevented from moving toward the center of the wafer
Solution Approach 1:
The patent divides the cutting operation into two separate cutting units positioned at different locations. The first cutting unit removes the chamfered portion while the second cutting unit, positioned adjacent to the first, creates a liquid barrier that segments the flow path and prevents swarf from migrating toward the wafer center.
Solution Approach 2:
The patent uses hydraulic principles by utilizing the cutting liquid flow to create a barrier effect. The second cutting unit's liquid supply creates a fluid barrier that directs swarf away from the center, using hydraulic flow control to manage swarf movement without mechanical contact.
3Manufacturing precision
If the chamfered portion is removed before grinding, then sharp edge formation is prevented, but cutting swarf may adhere to the wafer surface and cause defects
Solution Approach 1:
The patent performs preliminary cleaning action during the chamfer removal process itself. By incorporating the second cutting unit that supplies cutting liquid to create a barrier and wash away swarf, the cleaning action is performed preliminarily before the wafer proceeds to grinding, preventing subsequent adhesion issues.
Solution Approach 2:
The patent converts the potentially harmful cutting swarf into a beneficial flushing medium. The cutting liquid that would normally just cool the blade is instead utilized to actively transport and remove swarf from critical areas, turning the cooling function into a dual-purpose cooling and cleaning system.
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 method effectively prevents cutting swarf from adhering to the wafer's center and devices, ensuring clean processing and preventing sharp edge formation, while allowing for smooth progression to grinding without defects.
Implementation Method 1
a cutting liquid is continuously supplied to a processing point and a surface of the cutting blade, to remove cutting swarf and to cool the cutting blade
Implementation Method 2
a cutting liquid is continuously supplied to a processing point and a surface of the cutting blade, to remove cutting swarf
Data Source
AI summary
A processing method for a wafer having a chamfered portion at a peripheral edge includes a holding step of holding the wafer by a holding table, and a chamfer removing step of rotating the holding table while causing a first cutting blade to cut into the peripheral edge of the wafer while supplying a cutting liquid from a first cutting liquid supply nozzle to cut the peripheral edge of the wafer. In the chamfer removing step, a second cutting unit is positioned at a position adjacent to the first cutting unit at such a height that a second cutting blade does not make contact with the wafer and on the side of the center of the wafer as compared to the first cutting unit, and the cutting liquid is supplied from a second cutting liquid supply nozzle.