Laser Interior Modification for Precise Solid Body Thickness Reduction
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Solution Overview
Problem
Current methods for reducing the thickness of solid bodies, such as semiconductor wafers or ingots, like polishing or sawing, result in material loss and tool wear, leading to high costs and inefficiencies.
Innovation Solution
A method and apparatus that expose the solid body to light waves of different wavelengths to determine thickness and transmittance variations, allowing for precise introduction of laser radiation to produce modifications within the solid body, enabling controlled thickness reduction without material loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If polishing or lapping is used to reduce thickness, then thickness reduction is achieved, but material is lost and tool wear occurs
Solution Approach 1:
The patent performs preliminary measurement of thickness and transmittance variations before the thickness reduction process. This allows the laser parameters to be pre-configured for precise modification at the desired depth without removing excess material, thereby resolving the contradiction between achieving thickness reduction and minimizing material loss.
Solution Approach 2:
The patent replaces mechanical polishing or lapping processes with optical laser radiation. The laser modifies the crystal structure or induces stress at specific depths without mechanical contact, eliminating both material loss and tool wear while achieving the desired thickness reduction.
2Weight of moving object
If sawing is used to separate solid body layers, then separation is achieved, but material loss and tool wear increase costs
Solution Approach 1:
The patent measures thickness and transmittance variations before separation to precisely determine where modifications should be made. This preliminary information enables the laser to create separation planes at exact locations without cutting through additional material, resolving the contradiction between separation capability and material loss.
Solution Approach 2:
The patent replaces mechanical sawing with optical laser radiation that modifies the solid body interior to enable separation. The laser creates stress or structural changes that allow clean separation without physical contact, eliminating material loss and tool wear associated with sawing.
3Productivity
If laser radiation is introduced without measurement, then modifications can be produced, but precision in modification depth is reduced
Solution Approach 1:
The patent uses light waves to measure transmittance variations and thickness, then feeds this information back to adjust laser parameters. This feedback loop ensures that modifications are produced at the precise desired depth by compensating for variations in solid body thickness and optical properties, resolving the contradiction between productivity and precision.
Solution Approach 2:
The patent changes laser parameters (energy, pulse duration, wavelength) based on measured thickness and transmittance variations. By dynamically adjusting these parameters according to real-time measurements, the system maintains high modification depth precision while efficiently producing modifications across the solid body.
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 precise thickness reduction with minimal material loss and reduced tool wear, improving efficiency and cost-effectiveness in semiconductor processing.
Implementation Method 1
exposing a volume portion of the solid body to light waves of different wavelengths via the first surface, wherein the light waves are partly reflected at the first surface and are partly coupled into the solid body and reflected at the second surface
Implementation Method 2
introducing laser radiation into the volume portion of the solid body via the first surface to produce at least one modification in the interior of the solid body at a predefined distance from the second surface
Data Source
AI summary
A method and apparatus are provided. In an example, a volume portion of the solid body is exposed to light waves of different wavelengths, wherein the light waves are partly reflected at surfaces of the solid body. Light parameters of the reflected light waves are at least partly acquired using a sensor device. Distance information and/or intensity information are/is ascertained from at least a portion of the acquired light parameters. A thickness and/or a transmittance of the solid body in the volume portion are/is determined based upon the distance information and/or the intensity information. Laser radiation is introduced into the volume portion to produce a modification in the interior of the solid body, wherein at least one laser parameter of the laser radiation is set at least depending on the thickness and/or the transmittance such that the modification is at a predefined distance from a surface of the solid body.