Silicon Substrate Laser Processing with Polarization Angle Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing substrate processing methods face challenges in accurately forming spaces with various shapes, particularly through holes tilted with respect to the thickness direction of silicon substrates, limiting design flexibility.
Innovation Solution
The method involves converging laser light at a silicon substrate with a polarization angle of 45° or greater between the laser light's moving direction and polarization direction, allowing fractures to extend more accurately and facilitating the joining of adjacent modified spots, enabling reliable anisotropic etching along modified regions to form complex shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the laser light is converged at a small angle between moving direction and polarization direction, then the fracture extension in lateral direction is suppressed, but the fracture extension in incident direction is insufficient
Solution Approach 1:
The patent changes the polarization angle parameter from small angles to 45° or greater, which fundamentally alters the fracture extension behavior. This parameter change enables fractures to extend sufficiently in both the incident direction and lateral direction, simultaneously achieving precise fracture control and the ability to form various shapes including tilted through holes.
2Adaptability or versatility
If the laser light is converged to form modified spots along a tilted line, then the design freedom is improved, but the fractures from adjacent modified spots fail to join properly
Solution Approach 1:
By changing the polarization angle to 45° or greater, the patent enables fractures to extend in multiple directions including lateral direction. This ensures that when modified spots are formed along tilted lines, the fractures from adjacent modified spots can reliably join together, maintaining structural integrity while achieving design freedom for various shapes.
3Manufacturing precision
If the laser light is converged with high polarization angle, then fractures extend more in lateral direction, but energy efficiency may be reduced
Solution Approach 1:
The patent identifies 45° or greater as the optimal polarization angle range that balances fracture extension effectiveness with energy utilization. At this angle, fractures extend sufficiently in both incident and lateral directions to form accurate three-dimensional spaces, while avoiding excessive energy waste that would occur at much larger angles.
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 allows for the accurate formation of variously shaped spaces, including tilted through holes, by enhancing the extension and joining of fractures from modified spots, thereby improving the etching process and design freedom in silicon substrates.
Implementation Method 1
a laser light L is converged at a silicon substrate 11, so as to form a plurality of modifies spots S within the silicon substrate 11 along a predetermined line 12
Implementation Method 2
the laser light L is converged at the silicon substrate 11 such that the moving direction of the laser light L and the direction of polarization of the laser light L form an angle of 45° or greater therebetween
Implementation Method 3
When the silicon substrate 11 is anisotropically etched, the etching reliably advances along the modified region 7
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A substrate processing method for forming a space extending along a predetermined line in a silicon substrate includes a first step of converging a laser light which is an elliptically-polarized light having an ellipticity other than 1 at the substrate so as to form a plurality of modified spots within the substrate along the line and produce a modified region including the modified spots, and a second step of anisotropically etching the substrate so as to advance an etching selectively along the modified region and form the space in the substrate. In the first step, the light is converged at the substrate such that a moving direction of the light with respect to the substrate and a direction of polarization of the light form an angle of 45° or greater therebetween, and the modified spots are made align in one row along the line.