Laser Buffer Material for Oblique Angle Substrate Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing laser-based material separation techniques face challenges in achieving efficient separation with non-zero angles of incidence, as they often result in decreased focal energy density and poor quality separation surfaces due to index mismatch and energy loss.
Innovation Solution
Incorporating a buffer material with a refractive index closer to that of the substrate at the entry surface, which reduces energy loss and allows for the formation of laser-induced channels at higher draft angles without increasing laser power, using a pulsed laser system to create channels through the substrate thickness for zero-kerf separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If laser beam impinges substrate at oblique angle to create draft angle, then separation surface quality improves with draft angle >= 20 degrees, but focal energy density decreases due to index mismatch
Solution Approach 1:
A buffer material with refractive index intermediate between air and substrate is introduced at the entry surface. This intermediary material reduces the index mismatch when the laser beam enters the substrate at oblique angles, thereby maintaining focal energy density while enabling the formation of laser-induced channels that produce separation surfaces with draft angles of 20 degrees or greater.
2Manufacturing precision
If laser power is increased to maintain focal energy density at oblique angles, then separation quality improves, but energy consumption increases
Solution Approach 1:
The refractive index parameter of the medium at the entry surface is changed by introducing buffer material. This parameter change allows the laser system to maintain effective focal energy density at oblique incidence angles without increasing laser power, thereby achieving high-quality separation surfaces with draft angles >= 20 degrees while avoiding increased energy consumption.
3Manufacturing precision
If post-processing operations such as grinding are used to improve separation surface quality, then surface finish improves, but manufacturing complexity and time increase
Solution Approach 1:
The laser-induced channel formation process inherently produces separation surfaces with draft angles of 20 degrees or greater and smooth finishes through the self-organized damage mechanism. This self-service capability eliminates the need for additional post-processing operations such as grinding, thereby achieving high surface quality while reducing manufacturing complexity and process time.
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
Enables efficient separation of substrates into smooth, high-quality portions with draft angles greater than or equal to 20 degrees, maintaining focal energy density and preventing material removal, thus achieving zero-kerf separation without post-processing.
Implementation Method 1
Incorporating a buffer material with a refractive index closer to that of the substrate at the entry surface, which reduces energy loss
Implementation Method 2
a laser configured to produce a pulsed laser beam... produce a plurality of laser-induced channels extending at least partially through the thickness of the substrate
Implementation Method 3
laser-induced channels extending at least partially through the thickness of the substrate along a process path defined along an entry surface
Data Source
AI summary
A laser system includes a buffer material at an entry surface of a substrate in which laser-induced channels are formed. The laser beam propagates through the buffer material and impinges the substrate with a central axis of the laser beam at an oblique angle of incidence. The buffer material has a refractive index that may be closer to that of the substrate than is the refractive index of the atmosphere, such as air, in which the laser system operates. The buffer material facilitates forming laser-induced channels at relative large angles with respect to the substrate surface by attenuating energy loss or other effects on the laser beam that are normally caused by the mismatch in refractive index between the environment and the substrate in the absence of the buffer material.