Multi-Laser Wafer Dicing With Feedback Alignment Control
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Solution Overview
Problem
Current wafer dicing technologies face challenges in achieving high productivity and efficient cutting processes, particularly when using laser-based methods that require precise alignment and control of laser beams to form cracks and modified areas within the wafer.
Innovation Solution
The proposed solution involves an apparatus for dicing a wafer that includes a stage for moving the wafer and a plurality of laser heads arranged in a specific configuration. Each laser head is equipped with an optical system, a height sensor, and a camera, allowing for precise emission of laser beams along multiple cutting lines as the stage moves. This configuration enables improved alignment and control of the laser beams, enhancing the dicing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single laser head is used for wafer dicing, then the device complexity is low, but the productivity is insufficient
Solution Approach 1:
The patent divides the single laser head into multiple laser heads (first laser head and second laser head) arranged at different positions. Each laser head independently emits laser beams to form cracks along different cutting lines, enabling parallel processing and significantly improving wafer dicing productivity.
Solution Approach 2:
The patent combines multiple laser heads and their corresponding optical systems into a single integrated apparatus. The multiple laser heads work simultaneously on the same wafer, merging their cutting capabilities to achieve high-speed parallel dicing while maintaining a unified control system.
2Productivity
If multiple laser heads are used to increase productivity, then the cutting speed improves, but the alignment precision becomes more difficult to maintain
Solution Approach 1:
The patent incorporates height sensors and cameras that continuously monitor the wafer surface topography and provide feedback to the control system. This feedback enables real-time adjustment of laser beam positions and focal depths, ensuring precise alignment even when processing multiple cutting lines simultaneously, thus maintaining manufacturing precision while achieving high productivity.
Solution Approach 2:
The patent configures each laser head with its own optical system specifically optimized for its designated cutting line. The optical systems include adjustable focal lengths and positioning mechanisms tailored to the specific requirements of each cutting path, ensuring that each laser beam maintains optimal precision for its local task while contributing to overall high throughput.
3Ease of manufacture
If laser beams are focused deeply into the wafer to form cracks, then the cutting effectiveness improves, but the control precision becomes more challenging
Solution Approach 1:
The height sensors measure the actual wafer surface height at each cutting position and provide feedback to the control system. Based on this feedback, the system automatically adjusts the focal length and positioning of each optical system to ensure the laser beam focuses at the precise required depth inside the wafer, maintaining both crack formation efficiency and focal point accuracy.
Solution Approach 2:
The patent employs dynamically adjustable optical systems with variable focal lengths for each laser head. These optical systems can be real-time adjusted based on wafer thickness variations and positioning, enabling the laser beams to maintain accurate focus at different depths across the wafer surface, thus achieving both effective crack formation and precise focal control.
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 significantly improves the productivity of the wafer dicing process by allowing for faster and more precise cutting, reducing the time required to cut the wafer and enhancing overall efficiency.
Implementation Method 1
a plurality of laser heads above the stage along the first direction, and as the stage moves the wafer in the first direction, the plurality of laser heads are configured to emit a plurality of laser beams onto the wafer
Implementation Method 2
The wafer may be cut by focusing the laser beam onto and/or into the interior of a wafer to form a crack and a modified area inside the wafer
Data Source
AI summary
An apparatus for dicing a wafer includes a stage configured to receive a wafer, and move the wafer in a first direction, and a plurality of laser heads above the stage along the first direction, and as the stage moves the wafer in the first direction, the plurality of laser heads are configured to emit a plurality of laser beams onto the wafer along a plurality of cutting lines, the plurality of cutting lines extending in the first direction and each cutting line spaced apart from other cutting lines in a second direction, the second direction perpendicular to the first direction.