Semiconductor Circumferential Embedded Structure Crack-Stop
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Solution Overview
Problem
Conventional die separation methods in semiconductor manufacturing, such as mechanical dicing, often result in cracks that can propagate into semiconductor devices, affecting device reliability and requiring a better trade-off between cost and reliability.
Innovation Solution
A method involving laser irradiation to form a circumferential embedded structure of polycrystalline semiconductor material around the central portion of a semiconductor die, which acts as a crack-stop structure during die separation, suppressing crack propagation and serving as gettering sites for impurity atoms and recombination centers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mechanical dicing is used for die separation, then high throughput and ease of implementation are achieved, but cracks propagate into semiconductor devices reducing reliability
Solution Approach 1:
The patent applies preliminary action by forming a circumferential embedded structure around the active region before the dicing process. This structure is created through laser irradiation that transforms single-crystal semiconductor material into polycrystalline material, generating mechanical stress that forms a crack-stop barrier. By preparing this protective structure in advance, the patent prevents crack propagation during mechanical dicing while maintaining high throughput production capabilities.
2Ease of manufacture
If conventional laser dicing is used, then die separation is achieved, but the laser wavelength must be absorbed by semiconductor material limiting process flexibility
Solution Approach 1:
The patent applies parameter changes by utilizing laser wavelengths at which the semiconductor substrate is highly transparent rather than absorbed. This allows the laser beam to be focused inside the semiconductor wafer at a controlled depth, enabling precise formation of the embedded structure. The wavelength parameter is specifically selected to achieve transparency, providing flexibility in process design and adaptability to different semiconductor materials and thicknesses.
3Productivity
If stealth dicing with focused laser inside wafer is used, then die separation is achieved, but mechanical stress causes perpendicular cracks towards wafer surfaces
Solution Approach 1:
The patent applies local quality by creating a circumferential embedded structure that selectively modifies only the region surrounding the active area of the semiconductor die. The laser irradiation is focused to transform single-crystal material into polycrystalline material in a specific环形 zone, while leaving the central active region and surrounding areas unchanged. This localized transformation creates a crack-stop barrier precisely where needed, preventing perpendicular crack propagation towards wafer surfaces while maintaining dicing efficiency.
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
The embedded structure effectively prevents crack propagation into the active region of the semiconductor die, enhancing device reliability and allowing for increased dicing saw feed rates while maintaining area efficiency.
Implementation Method 1
Around the focal point the laser beam melts the semiconductor material, which recrystallizes in polycrystalline form
Implementation Method 2
the laser beam melts the semiconductor material, which recrystallizes in polycrystalline form with high density dislocations
Implementation Method 3
The mechanical stress effects that perpendicular cracks can develop towards the wafer front and back surfaces. In this way the stress induced by local transformation of the single-crystal semiconductor material into polycrystalline semiconductor material facilitates die separation
Data Source
AI summary
A circumferential embedded structure is formed by laser irradiation in a semiconductor substrate, which is of a semiconductor material. The embedded structure includes a polycrystalline structure of the semiconductor material, and surrounds a central portion of a semiconductor die. The semiconductor die including the embedded structure is separated from the semiconductor substrate.