Transparent Workpiece Laser Division With Suppressed Nonlinear Propagation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laser-based methods for dividing semiconductor wafers face challenges in achieving precise and efficient separation due to non-linear propagation effects outside the beam convergence zone, leading to incomplete energy coupling and increased thermal damage.
Innovation Solution
The method involves optimizing the duration of energy input and spatial beam shaping to suppress non-linear propagation, ensuring that the energy deposition is controlled and localized within the beam convergence zone, thereby minimizing damage and achieving a uniform weakening along the desired separating line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If short pulse duration laser radiation is used to achieve precise localization of energy deposition, then manufacturing precision is improved, but non-linear propagation effects outside the beam convergence zone increase causing energy coupling loss and thermal damage
Solution Approach 1:
The patent optimizes the pulse duration parameter within a specific range (10-1000 fs) to balance two competing requirements: short enough to achieve precise spatial localization of energy deposition through non-linear absorption, but long enough to suppress non-linear propagation effects outside the beam convergence zone. This parameter optimization resolves the contradiction by finding the optimal window where both precision and energy efficiency are achieved simultaneously.
2Productivity
If high peak intensity laser radiation is used to achieve rapid material modification, then productivity is improved, but non-linear effects outside the beam convergence zone increase preventing effective energy coupling
Solution Approach 1:
The patent carefully selects and optimizes the pulse duration parameter (10-1000 fs) to achieve the desired peak intensity for rapid material modification while preventing excessive non-linear propagation. By controlling the temporal profile of the laser pulse, the system maintains high peak power for efficient processing speed while avoiding the harmful non-linear effects that would cause energy loss and reduce coupling efficiency.
3Device complexity
If laser radiation propagation is allowed to proceed without suppression of non-linear effects, then device complexity is reduced, but manufacturing precision deteriorates due to disturbed energy deposition
Solution Approach 1:
The patent achieves suppression of non-linear propagation effects not through complex additional optical components or active control systems, but by optimizing the pulse duration parameter itself. This simple yet effective approach maintains relatively low device complexity while significantly improving manufacturing precision and uniformity of material modification throughout the workpiece volume.
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 results in a high-quality break line with minimized chipping and material stresses, allowing for efficient separation of both thin and thick semiconductor wafers with improved edge quality and reduced thermal impairment.
Implementation Method 1
creating a beam convergence zone in the volume of the workpiece in which the intensity of the laser radiation exceeds a threshold value for non-linear absorption
Implementation Method 2
In the beam convergence zone, multiphoton processes occur accordingly, e.g. in the form of multiphoton ionization or avalanche ionization, which lead to the formation of a plasma
Implementation Method 3
In the beam convergence zone, multiphoton processes occur accordingly, e.g. in the form of multiphoton ionization or avalanche ionization, which lead to the formation of a plasma
Implementation Method 4
This is therefore also referred to as 'optical breakdown'
Implementation Method 5
multiphoton processes occur accordingly, e.g. in the form of multiphoton ionization or avalanche ionization, which lead to the formation of a plasma
Implementation Method 6
spatially localized, reproducibly small amounts of energy are introduced into the material
Data Source
AI summary
The invention relates to a method for dividing a transparent workpiece (1) by means of pulsed laser radiation (2) by way of creating a beam convergence zone (3) in the volume of the workpiece, in which the intensity of the laser radiation (2) exceeds a threshold value for non-linear absorption, wherein the beam convergence zone (3) and the workpiece (1) are moved relative to each other, thereby creating a two-dimensional weakening in the workpiece (1) extending along a predetermined separating line (4), and wherein the workpiece (1) is subsequently divided along the separating line (4). The invention proposes that by selecting the duration of the energy input generated by the non-linear absorption of the pulsed laser radiation and by spatial beam shaping, non-linear propagation of the laser radiation (2) in the volume (1) of the workpiece outside the beam convergence zone (3) is suppressed.