Non-Parallel Groove Orientation in Silicon Supporting Substrates
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Solution Overview
Problem
The existing method of manufacturing semiconductor devices, particularly BGA type devices, faces issues with fractures in the supporting substrate due to stress during the formation of grooves, leading to decreased yield as the dicing lines align with the cleavage planes of the silicon crystal lattice, causing unintended dicing and failure in forming protection films and bump electrodes.
Innovation Solution
The method involves attaching a supporting substrate made of single crystal silicon to the semiconductor substrate with an adhesive, forming grooves perpendicular to the dicing lines that are not parallel with the cleavage planes, and cutting the protection film and supporting substrate along these grooves to prevent cracking, ensuring the grooves are formed along directions that avoid the cleavage planes, thereby maintaining the integrity of the supporting substrate during and after processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If grooves are formed in the supporting substrate along dicing lines parallel to cleavage planes, then dicing can be easily performed, but the supporting substrate may crack and fracture due to stress during groove formation
Solution Approach 1:
The patent applies asymmetry by intentionally designing the groove direction to be non-parallel to the cleavage planes of the single crystal silicon supporting substrate. This asymmetric orientation prevents the groove from aligning with the natural weak planes of the crystal lattice, thereby avoiding stress concentration and fracture while still enabling effective dicing separation.
Solution Approach 2:
The patent changes the critical parameter of groove orientation angle relative to the cleavage planes. By adjusting this angular parameter so that grooves are formed at non-parallel directions to the cleavage planes, the substrate's mechanical strength is preserved during the grooving process while maintaining the ability to perform subsequent dicing operations.
2Ease of manufacture
If dicing lines are aligned with cleavage planes of the silicon crystal lattice, then dicing can be performed more easily, but unintended dicing occurs and yield decreases
Solution Approach 1:
The patent introduces asymmetry in the dicing line design by making the dicing lines non-parallel to the cleavage planes of the single crystal silicon supporting substrate. This asymmetric configuration prevents unintended dicing along the cleavage planes while still achieving clean separation, thereby improving device yield without sacrificing dicing effectiveness.
Solution Approach 2:
The patent modifies the angular parameter of dicing lines relative to the crystal lattice structure. By changing the orientation angle so that dicing lines are not parallel to the cleavage planes, the patent eliminates the harmful effect of unintended dicing while maintaining the beneficial ease of dicing separation.
3Shape
If grooves are formed perpendicular to the front surface along dicing lines, then chip size package structure is achieved, but fractures occur in the supporting substrate during groove formation
Solution Approach 1:
The patent applies asymmetry by orienting the grooves at non-parallel directions to the cleavage planes of the supporting substrate. This asymmetric groove configuration maintains the vertical chip size package structure while preventing stress-induced fractures during the grooving process by avoiding alignment with the crystal lattice's weak planes.
Solution Approach 2:
The patent changes the orientation parameter of grooves relative to the cleavage planes. By adjusting this angular parameter to be non-parallel, the patent preserves the desired chip size package geometry while eliminating manufacturing defects caused by stress concentration along cleavage planes.
Data Source
AI summary
The invention prevents a fracture parallel to a cleavage plane of a supporting substrate along a groove formed in the supporting substrate before dicing. A supporting substrate is attached to a front surface of a semiconductor substrate formed with an electronic device with an adhesive layer being interposed therebetween. In this supporting substrate, dicing lines are not parallel with cleavage planes which are perpendicular to the front surface of supporting substrate, i.e., a fifth cleavage plane and a sixth cleavage plane crossing perpendicularly thereto. A groove is then formed in the supporting substrate from the front surface to the middle thereof in the direction perpendicular to the front surface, along the dicing lines inside an opening provided in the semiconductor substrate. This groove is not parallel with the fifth cleavage plane and the sixth cleavage plane. After given processes, dicing is performed to the layered body of layers from the semiconductor substrate to the supporting substrate along the dicing lines.