Dual Laser Beam Cross-Section Preparation
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Solution Overview
Problem
Current methods for forming cross-sections of semiconductor structures, such as 3D MEMS and multiple stacked ICs, are inefficient due to the need for lengthy processing times, especially when inspecting buried features, which hinders quality assurance and process control in the semiconductor industry.
Innovation Solution
A processing system combining focused ion beam technology with laser ablation using two laser beams, where the first and second laser beams are directed at common impingement locations with angles greater than 10 degrees, allowing for the creation of a pre-prepared surface region with low surface roughness, enabling rapid focused ion beam preparation of cross-sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional single-laser ablation is used to prepare cross-sections, then the processing can be performed with simpler equipment, but the surface roughness is high and processing time is excessive
Solution Approach 1:
The patent divides the laser ablation process into two distinct stages using two separate laser beams: a first laser beam for initial material removal and a second laser beam for surface smoothing. This segmentation allows each laser to be optimized for its specific function, achieving low surface roughness while managing equipment complexity through modular design
Solution Approach 2:
The first laser beam performs preliminary material removal to create a pre-prepared surface region, which then serves as the substrate for the second laser beam to perform precise surface smoothing. This preliminary action reduces the workload for the second laser and enables achievement of low surface roughness within reasonable processing time
2Productivity
If conventional cross-section preparation methods are used, then equipment simplicity is maintained, but processing time becomes excessively long for modern semiconductor structures
Solution Approach 1:
The two laser beams operate in a continuous sequence on the same processing region, with the second laser beam following the first to perform surface smoothing immediately after material removal. This continuous action eliminates idle time between preparation stages and maintains high productivity throughout the process
Solution Approach 2:
The first laser beam performs preliminary material removal to create a pre-prepared surface region, which then serves as the substrate for the second laser beam to perform precise surface smoothing. This preliminary action reduces the workload for the second laser and enables achievement of low surface roughness within reasonable processing time
3Manufacturing precision
If laser beams with small angle between incidence directions are used, then optical system complexity is reduced, but surface roughness cannot be sufficiently minimized
Solution Approach 1:
The patent employs asymmetric angle configuration for the two laser beams, with the first laser beam incident at a first angle and the second laser beam incident at a second angle greater than the first angle. This asymmetric arrangement optimizes the surface smoothing effect by creating favorable stress distribution and material removal patterns, achieving low surface roughness while maintaining manageable optical system complexity
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 reduces the time required for cross-section preparation, allowing for efficient inspection of large exposed areas, particularly beneficial for modern semiconductor structures, by creating a pre-prepared surface region that facilitates quick and precise focused ion beam processing.
Implementation Method 1
forming the pre-prepared surface region by laser ablation of a processing region of the object with a first and a second laser beam
Implementation Method 2
a focused ion beam system for forming the cross-section from a pre-prepared surface region of the object
Data Source
AI summary
A processing system for forming a cross-section of an object. The processing system comprises a focused ion beam system for forming the cross-section from a pre-prepared surface region of the object and a laser and a light optical system for forming the pre-prepared surface region by laser ablation of a processing region of the object with a first and a second laser beam. The light optical system is configured to direct the first and the second laser beams onto common impingement locations of a common scanning line in the processing region for scanning the first laser beam and for scanning the second laser beam. For each of the impingement locations, an angle between a first incidence direction along an axis of the first laser beam and a second incidence direction along an axis of the second laser beam is greater than 10 degrees, measured in a stationary coordinate system.