Wafer Notch Processing for Stable Back Grinding Alignment
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Solution Overview
Problem
During the back grinding process, wafers become excessively thin, leading to damage, particularly at the notch portion formed for alignment, which can result in recognition errors and processing issues.
Innovation Solution
A wafer processing method that involves preparing and aligning a wafer with a notch portion, then using a notch wheel to process a specific region of the notch portion to a preset thickness, ensuring the notch wheel's center remains outside the wafer for stable and precise processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If back grinding process is performed to reduce wafer thickness, then the number of stacked wafer layers increases and semiconductor performance improves, but the wafer becomes too thin and damage occurs particularly at the notch portion
Solution Approach 1:
The notch portion is processed before the back grinding process to reduce its thickness in advance. This preliminary action prevents the notch from becoming too thin during subsequent back grinding, thereby avoiding wafer damage while still allowing the main wafer body to be thinned to the desired specifications for increased stacking layers
Solution Approach 2:
Instead of uniformly thinning the entire wafer, the invention applies selective thinning only to the notch portion using a notch wheel. This local quality approach ensures the notch has sufficient thickness to prevent damage during back grinding, while the rest of the wafer can be processed to achieve the target thickness for optimal device performance and stacking
2Reliability
If the notch portion is processed to prevent damage, then wafer reliability improves, but additional processing steps are required
Solution Approach 1:
The notch portion processing is integrated as a preliminary step before back grinding, ensuring the notch is pre-conditioned to withstand subsequent processing. This approach, while adding a processing step, prevents defects that would require rework or lead to wafer rejection, thereby improving overall process efficiency
Solution Approach 2:
A dedicated notch wheel is introduced as an intermediary tool specifically for processing the notch portion. This specialized component allows precise control over notch thinning without affecting the main wafer body, enabling reliable notch preparation while maintaining simplicity in the overall processing workflow
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 method prevents damage to the wafer during back grinding, enhances processing stability, and reduces recognition errors by forming an inclined surface for alignment, thereby improving the overall processing yield.
Implementation Method 1
processing the notch portion so that a certain region of the notch portion has a preset thickness using a notch wheel
Data Source
AI summary
A wafer processing method is provided. The method includes preparing a wafer having a notch portion at one side thereof, aligning the wafer by analyzing image information of the notch portion captured by a vision camera, and processing the notch portion using a notch wheel so that a certain region of the notch portion has a preset thickness.