Wafer Edge Chamfer Removal With Cutting and Mirror Polishing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The chamfered portion on wafers, when not completely removed during processing, can cause contamination in subsequent steps and chipping of device chips during dicing, posing a risk to operators and damaging the devices.
Innovation Solution
A method involving a processing apparatus with a cutting blade to remove the chamfered portion and a polishing blade to create a mirror surface, ensuring complete removal of the chamfered portion and preventing contamination or chipping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the chamfered portion is removed by laser processing to form a modified layer, then the sharp edge is eliminated, but the chamfered portion may not be completely removed, causing contamination or chipping
Solution Approach 1:
The chamfered portion removal is divided into two distinct stages: first, laser processing creates a modified layer to eliminate the sharp edge, then mechanical cutting completes the removal of the chamfered portion. This segmentation ensures both safety and complete removal without contamination.
Solution Approach 2:
The laser processing is performed as a preliminary action before mechanical cutting. The laser creates a modified layer that weakens the chamfered portion, making it easier to remove completely in the subsequent mechanical cutting step, while ensuring no sharp edges remain.
2Reliability
If mechanical cutting is used to remove the chamfered portion, then complete removal is achieved, but the cut surface becomes rough and requires additional polishing
Solution Approach 1:
The processing is segmented into three distinct operations: laser processing to create a modified layer, mechanical cutting to remove the chamfered portion, and polishing to finish the cut surface. Each operation focuses on a specific aspect, ensuring complete removal and high surface quality.
Solution Approach 2:
The process maintains continuous useful action by seamlessly transitioning from laser processing to mechanical cutting to polishing. Each step builds on the previous one, with the laser-modified material facilitating easier mechanical removal, which in turn creates a surface ready for polishing, eliminating idle time and ensuring complete removal with high surface quality.
3Reliability
If multiple processing steps are added to ensure complete removal and surface quality, then reliability and surface finish improve, but process complexity increases
Solution Approach 1:
The laser processing unit and mechanical cutting unit are merged into an integrated processing system that can perform both operations in sequence on the same wafer. The polishing step is also combined in the same system, allowing all three operations to be completed without moving the wafer between different equipment, thus reducing overall process complexity while maintaining high reliability.
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 removes the chamfered portion and polishes the cut surface to a mirror finish, preventing contamination and chipping of device chips, thus enhancing the reliability and safety of the wafer processing.
Implementation Method 1
a focusing point of a laser beam, having a wavelength transmissive to the wafer, is positioned on the inner side of the chamfered portion and the laser beam is applied thereto
Implementation Method 2
cutting means including a rotatable cutting blade configured to cut the chamfered portion of the wafer
Implementation Method 3
polishing means including a rotatable polishing blade configured to polish a surface from which the chamfered portion has been removed
Data Source
AI summary
A method of processing a wafer for solving problems where a chamfered portion is not completely removed from an outer periphery of the wafer. This method includes: preparing a processing apparatus, including a chuck table, cutting means including a rotatable cutting blade, and polishing means including a rotatable polishing blade; holding the wafer on the chuck table; removing the chamfered portion by rotating the chuck table, with the cutting blade being positioned on the outer peripheral surplus region of the wafer, and with the cutting blade rotating; and polishing a cut surface, from which the chamfered portion has been removed, into a mirror surface by rotating the chuck table, with the polishing blade being positioned on the outer periphery of the wafer that is held on the chuck table in a state where the chamfered portion has been removed, and with the polishing blade rotating.