Semiconductor Chip Anti-Collision Recesses for Crack-Free Laser Dicing
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Solution Overview
Problem
Mechanical cutting of semiconductor substrates often results in defects such as cracks in semiconductor chips due to collisions during the cutting process, which can damage the integrated circuit areas.
Innovation Solution
The method involves forming anti-collision recesses with rounded internal sidewalls in the cut area adjacent to the corners of integrated circuit areas on the semiconductor substrate, followed by laser irradiation to create a modified portion and subsequent polishing to separate the chips along cracks, thereby preventing collisions and defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical cutting is used to separate semiconductor chips, then cutting speed and productivity are improved, but cut surfaces become broken and defects such as cracks occur
Solution Approach 1:
The patent replaces the mechanical cutting system with a laser-based cutting system. The laser beam irradiates the semiconductor substrate to form a modified portion along the cut line, eliminating mechanical contact and thus preventing mechanical damage to the cut surfaces while maintaining high cutting speed.
Solution Approach 2:
The laser irradiation causes phase transition in the semiconductor material along the cut line, forming a modified portion that facilitates clean separation. This phase transition mechanism enables precise cutting without mechanical force, resolving the contradiction between cutting speed and surface quality.
2Manufacturing precision
If laser cutting is used to improve cut surface quality, then manufacturing precision is improved, but the process complexity increases
Solution Approach 1:
The patent applies preliminary action by forming anti-collision recesses with rounded internal sidewalls in regions adjacent to corners of IC areas before laser cutting. This preliminary structural modification prevents collision between adjacent chips during separation, simplifying the overall process while maintaining high cut surface quality.
Solution Approach 2:
The patent applies local quality by providing different structures in different regions: anti-collision recesses with rounded sidewalls are formed only in corner regions adjacent to IC areas, while the rest of the substrate undergoes standard laser cutting. This localized approach improves precision where needed without unnecessarily complicating the entire process.
3Reliability
If anti-collision recesses with rounded internal sidewalls are formed, then reliability is improved by suppressing cracks, but device complexity increases
Solution Approach 1:
The anti-collision recesses with rounded internal sidewalls are formed only in specific regions adjacent to corners of IC areas, not throughout the entire substrate. This localized structural modification improves reliability by preventing collision-induced cracks at critical locations while minimizing the increase in overall device complexity.
Solution Approach 2:
The rounded internal sidewalls of the anti-collision recesses serve as a cushioning structure that absorbs and distributes mechanical stress during chip separation. This beforehand cushioning prevents stress concentration that would otherwise cause cracks, improving reliability without requiring complex additional components.
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 approach effectively suppresses the occurrence of cracks and defects during the cutting process, improving the reliability and quality of semiconductor chips by providing a buffer space and reducing mechanical stress on the corners, leading to smoother cut surfaces and increased productivity.
Implementation Method 1
forming a modified portion in the semiconductor substrate by irradiating a cut line of the cut area with a laser
Implementation Method 2
polishing the inactive surface of the semiconductor substrate
Data Source
AI summary
A method of manufacturing a semiconductor chip includes preparing a semiconductor substrate having an active surface on which a device layer is provided and an inactive surface opposite to the active surface, the device layer having a integrated circuit (IC) areas and a cut area provided between adjacent IC areas; forming anti-collision recesses in regions of the cut area that are adjacent to corners of the IC areas, each of the anti-collision recesses having rounded internal sidewalls, each of the rounded internal sidewalls corresponding to a respective corner of the adjacent corners; forming a modified portion in the semiconductor substrate by irradiating a cut line of the cut area with a laser; polishing the inactive surface of the semiconductor substrate, wherein cracks propagate from the modified portion in a vertical direction of the semiconductor substrate; and separating the IC areas from each other along the cracks to form semiconductor chips.