Wafer Shield Tunnel Cleaving for Thick Chip Division
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Solution Overview
Problem
Existing chip manufacturing methods for thick wafers face challenges in productivity due to the need for multi-stage modified layers, and they often result in processing defects like chippings and cracks due to high dividing forces and loads.
Innovation Solution
A chip manufacturing method that forms shield tunnels with fine pores and amorphous regions along planned division lines on a wafer by moving the wafer and a focal point of a laser beam relative to each other, and then divides the wafer along these lines using an external force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multi-stage modified layers are formed to divide thick wafers, then division capability is improved, but productivity deteriorates due to multiple irradiation steps
Solution Approach 1:
The invention transitions from forming multiple horizontal modified layers to forming vertical shield tunnels that penetrate through the entire wafer thickness. This dimensional change allows a single laser irradiation process to achieve complete division capability, eliminating the need for multiple irradiation steps and thereby improving productivity while maintaining division effectiveness.
Solution Approach 2:
The shield tunnels are pre-formed with fine pores and amorphous regions along the planned division lines before the actual division process. This preliminary action creates predetermined weak points that guide the division process, allowing complete through-divisions to be achieved more efficiently than forming multiple sequential modified layers.
2Manufacturing precision
If high dividing force is applied to divide the wafer, then division completeness is improved, but processing defects increase due to chippings and cracks
Solution Approach 1:
The shield tunnels with fine pores and amorphous regions are formed in advance along the division lines, creating predetermined separation paths. These pre-formed structures act as stress guides that direct the division force along the intended paths, reducing random stress distribution and minimizing chippings and cracks during the division process.
Solution Approach 2:
The shield tunnels contain fine pores that create controlled weak points in the wafer structure. These porous regions serve as stress release zones that accommodate division forces, allowing complete division while reducing the transmission of harmful stresses to surrounding areas, thereby minimizing processing defects.
3Manufacturing precision
If conventional laser irradiation is used, then modified layers are formed, but the number of irradiation steps increases for thick wafers
Solution Approach 1:
Instead of forming multiple modified layers at different depths through sequential irradiation, the invention forms vertical shield tunnels that extend through the entire wafer thickness in a single irradiation process. This dimensional approach reduces the number of irradiation steps from multiple to one, significantly reducing processing time.
Solution Approach 2:
The laser irradiation process creates continuous shield tunnels that extend uninterrupted through the wafer thickness. This continuous action eliminates the need for multiple discrete irradiation steps, maintaining productive laser action throughout the entire process and reducing total irradiation time.
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 improves productivity by reducing the number of laser irradiations required and decreases the load applied during division, thereby reducing the occurrence of processing defects such as chippings and cracks.
Implementation Method 1
forming shield tunnels each having a fine pore and an amorphous region surrounding the fine pore along the planned division line by relatively moving a wafer and a focal point of a laser beam
Implementation Method 2
forming shield tunnels each having a fine pore and an amorphous region surrounding the fine pore
Data Source
AI summary
A chip manufacturing method for manufacturing a chip includes: forming shield tunnels each having a fine pore and an amorphous region surrounding the fine pore along the planned division line, by relatively moving the wafer and a focal point of a laser beam having a wavelength transmissive to the wafer in a condition in which the focal point is positioned inside the wafer; and dividing the wafer along the planned division line where the shield tunnels are formed by applying an external force to the wafer. Forming the shield tunnels includes: shaping the laser beam into a shape having a longitudinal direction and a transverse direction; and irradiating the wafer with the laser beam along the planned division line in a state where the longitudinal direction is set to intersect an extending direction of the planned division line.