Semiconductor Metallization with Slit Recesses for Laser Dicing
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Solution Overview
Problem
The separation of semiconductor wafers into chips using laser dicing is hindered by metal materials, which scatter laser light and reduce process reliability, leading to potential clamping or fraying of metal layers, thereby affecting chip quality and separation efficiency.
Innovation Solution
Designing metallization layers with slit-shaped recesses or gaps to minimize the intersection length of metal layers with the cutting line, allowing for efficient laser dicing by reducing the length of metal encountered by the cutting line and promoting clean separation of semiconductor wafers into chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If laser dicing is used to separate semiconductor wafers into chips, then cutting waste is avoided and dry cutting is achieved, but metal materials scatter laser light and reduce process reliability
Solution Approach 1:
The metal layer is segmented by introducing slit-shaped recesses that divide the continuous metal layer into multiple sections. This segmentation reduces the length of metal material intersecting the laser cutting line, allowing the laser to pass through more effectively and maintain high separation efficiency while improving process reliability by reducing metal scattering.
Solution Approach 2:
The metal layer is designed with non-uniform local quality through slit-shaped recesses, creating regions of different metal density along the cutting path. The recesses are strategically positioned to minimize metal intersection at critical cutting zones while maintaining continuous metallization where electrical connectivity is required, thus resolving the contradiction between cutting efficiency and process reliability.
2Stability of the object's composition
If metal layers are present in cut regions, then electrical connectivity is maintained, but laser light scattering increases and causes clamping or fraying of metal layers
Solution Approach 1:
The continuous metal layer is segmented into multiple sections by slit-shaped recesses. These recesses create gaps that reduce laser light scattering during dicing while the remaining metal sections maintain electrical connectivity. The segmentation prevents clamping and fraying by reducing the total metal volume intersecting the cutting line.
Solution Approach 2:
The metal layer structure is optimized with local quality variations through strategically positioned slit-shaped recesses. In regions where electrical connectivity is critical, the metal remains continuous or nearly continuous. In regions where laser cutting occurs, the recesses reduce metal presence to minimize scattering and disruption, thus maintaining overall metallization stability while preventing harmful metal layer disruption.
3Productivity
If the cutting line intersects metal layers, then separation can be achieved, but the length of metal intersection reduces breakage strength and increases running costs
Solution Approach 1:
The metal layer is segmented by slit-shaped recesses that reduce the continuous metal length intersecting the cutting line. This segmentation maintains separation capability while significantly reducing the total metal-material interaction length, thereby improving breakage strength of the separated chips and reducing laser running costs due to less energy dissipation on metal scattering.
4Reliability
If slit-shaped recesses are introduced in metal layers, then laser dicing reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The metal layer is segmented by introducing slit-shaped recesses that can be formed using standard semiconductor fabrication techniques such as photolithography and etching. While this segmentation increases structural complexity, the recesses are designed with simple geometries and standardized dimensions that can be integrated into existing manufacturing processes, thus improving dicing reliability without excessive increase in manufacturing complexity.
Solution Approach 2:
The metallization structure is optimized with local quality variations through slit-shaped recesses positioned only in specific regions where laser cutting occurs. The recesses are not introduced throughout the entire metal layer but only where needed to improve dicing reliability, thus minimizing the increase in manufacturing complexity while achieving the desired reliability improvement.
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 enhances the reliability and quality of the chip separation process by reducing metal layer disruption and maintaining continuous metallization, ensuring high-speed dicing with superior breakage strength and low running costs.
Implementation Method 1
separating a semiconductor wafer into at least two semiconductor units by dicing the semiconductor wafer with a laser beam
Data Source
AI summary
A semiconductor device and method. One embodiment provides a semiconductor substrate having a plurality of cut regions. A metal layer is located within a cut region. The metal layer includes a recess, the recess having a slit-like shape.