Wafer Dicing Sequence to Control Crack Extension in Laminates
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Solution Overview
Problem
The existing chip manufacturing methods face challenges in reliably dividing wafers with laminates on the front surface of substrates due to abnormal extension of cracks caused by changes in crystal orientation, leading to processing defects and reduced productivity from repeated wafer inversion during the processing steps.
Innovation Solution
A chip manufacturing method that forms modified layers along planned dividing lines using a first laser beam with a wavelength transmitted through the substrate, followed by grinding the back surface, and then forms laser-processed grooves in the laminate using a second laser beam with a wavelength absorbed by the substrate, reducing the need for repeated wafer inversion and minimizing abnormal crack extension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser-processed grooves are formed in the laminate before modified layers are formed, then the wafer can be divided along streets, but the crystal orientation of the substrate changes due to thermal effect, causing cracks to avoid the grooves and processing defects to occur
Solution Approach 1:
The patent applies preliminary action by forming modified layers in the substrate before forming laser-processed grooves in the laminate. This sequence ensures that cracks extend along the pre-formed modified layers rather than being deflected by subsequent laser processing, thereby preventing processing defects while maintaining wafer division accuracy
Solution Approach 2:
The patent inverts the conventional processing sequence by forming modified layers first and then forming laser-processed grooves, rather than the traditional approach of forming grooves first. This inversion resolves the contradiction by ensuring crack extension follows the modified layers without being affected by thermal effects from prior laser processing
2Reliability
If the processing sequence is changed to form modified layers after laser-processed grooves, then abnormal crack extension is suppressed, but the wafer needs to be inverted twice during processing, decreasing productivity
Solution Approach 1:
The patent uses preliminary action by forming modified layers before laser-processed grooves, which suppresses abnormal crack extension. This sequence eliminates the need for wafer inversion between these steps, as both operations can be performed with the back surface exposed upward, thereby improving productivity while maintaining reliability
3Adaptability or versatility
If the wafer is inverted multiple times during processing, then different surfaces can be accessed for different operations, but the number of inversions increases, reducing productivity
Solution Approach 1:
The patent applies preliminary action by forming modified layers with the back surface exposed upward before forming laser-processed grooves. This allows both operations to be performed in the same wafer orientation, eliminating the need for inversion and improving processing speed while maintaining the versatility to perform different operations
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 allows for reliable division of wafers along planned lines while reducing the number of times the wafer needs to be inverted, thereby improving productivity and minimizing processing defects.
Implementation Method 1
forming a modified layer along the planned dividing lines and forming a crack extending from the modified layer to a front surface side of the substrate by applying, along the planned dividing lines, a first laser beam having a wavelength transmitted through the substrate
Implementation Method 2
a grinding step of thinning the wafer to a predetermined thickness by grinding the back surface side of the substrate exposed in the modified layer forming step
Implementation Method 3
forming a laser-processed groove in the laminate by applying, along the planned dividing lines, a second laser beam having a wavelength absorbed by the substrate
Data Source
AI summary
A chip manufacturing method includes a modified layer forming step of forming a modified layer and a crack by applying, along planned dividing lines, a first laser beam having a wavelength transmitted through a substrate of a wafer including the substrate and a laminate in a state in which the back surface side of the substrate is exposed and a condensing point of the first laser beam is positioned within the substrate from the back surface side of the substrate, a grinding step of thinning the wafer to a predetermined thickness by grinding the back surface side of the substrate exposed in the modified layer forming step, and a laser-processed groove forming step of forming a laser-processed groove in the laminate by applying, along the planned dividing lines, a second laser beam having a wavelength absorbed by the substrate, from the front surface side of the wafer.