Wafer Separation Facility Using Laser-Guided Crack Detachment
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Solution Overview
Problem
Traditional wafering processes for semiconductor materials result in material loss, surface roughness, and subsurface damage due to kerf losses and high-temperature spalling methods, which require additional polishing and grinding steps, and are limited in control over wafer thickness and surface quality.
Innovation Solution
A manufacturing system that includes an analysis device for determining individual properties of donor substrates, a laser device for creating modifications, and a release device for generating mechanical stresses to separate wafers with precise control, using recipe-based process control and higher-level process control to adapt to variations in substrate properties and reduce material loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If diamond- or slurry-based wire sawing processes are used for wafering, then material can be separated from the donor substrate, but material loss occurs due to kerf losses and surface roughness and subsurface damage are caused
Solution Approach 1:
The patent replaces the mechanical wire sawing process with a laser-based modification process. The laser creates modifications in the crystal structure that guide crack propagation, eliminating the need for mechanical cutting. This substitution resolves the contradiction by avoiding both kerf losses (material loss) and the surface damage caused by mechanical contact, achieving kerf-free separation with superior surface quality
Solution Approach 2:
The patent utilizes phase transitions in the crystal structure through laser heating. The laser induces localized melting and rapid cooling, creating modified zones that act as crack initiation sites. This phase transition mechanism enables precise control over crack propagation paths, achieving clean separation without the material loss and surface damage associated with mechanical sawing
2Loss of substance
If high-temperature spalling methods are used to separate crystalline materials, then kerf gap losses and damage below the surface can be reduced, but diffusion of unwanted chemical components through the material increases
Solution Approach 1:
The patent changes the temperature parameter from high-temperature spalling to room temperature or low-temperature laser processing. By using laser modifications to create stress concentrations that guide crack propagation, the process achieves kerf-free separation without the thermal diffusion problems. This parameter change resolves the contradiction by maintaining the benefit of reduced material loss while eliminating the harmful chemical diffusion
Solution Approach 2:
The patent replaces thermal spalling with a laser-modification-and-crack-propagation mechanism. Instead of using high temperatures to induce separation, the laser creates localized modifications that serve as crack initiation sites, and mechanical stress is then applied to propagate cracks along desired paths. This substitution eliminates thermal diffusion while maintaining kerf-free separation
3Productivity
If conventional spalling methods are used for wafer separation, then material can be separated along crystal planes, but additional polishing or grinding steps are required to reduce surface roughness
Solution Approach 1:
The patent extracts the surface finishing step from the overall wafer production process by achieving near-final surface quality directly through the laser-modification crack propagation method. The laser creates modifications that guide cracks along precise paths, producing smooth separation surfaces that eliminate or minimize the need for subsequent polishing or grinding. This extraction reduces process complexity while maintaining high productivity
Solution Approach 2:
The patent replaces subsequent mechanical polishing or grinding operations with a laser-based modification process. The laser creates controlled modifications that guide crack propagation to produce smooth surfaces directly, eliminating the need for additional mechanical finishing steps. This substitution reduces device complexity and process steps while maintaining efficient wafer separation
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
The system enables efficient, low-stress separation of wafers with precise geometric dimensions, reducing the need for additional polishing and grinding, and minimizing material loss by accurately controlling the separation process based on individual substrate properties.
Implementation Method 1
a laser device (12) for generating modifications (14) inside the at least one respective donor substrate (4) to form a detachment zone (16) inside the at least one respective donor substrate (4)
Implementation Method 2
The laser device is operated for processing the specific donor substrate depending on the donor substrate process data of that specific donor substrate
Implementation Method 3
a release device for generating mechanical stresses within the at least one respective donor substrate to trigger and/or guide a crack for separating at least one wafer (2) from a donor substrate (4)
Implementation Method 4
at least one analysis device for determining at least one individual property, in particular the doping, of the respective donor substrates (4)
Data Source
Figure 1a~1d
Figure 2
Figure 3
AI summary
The invention relates to a production facility (40) for detaching wafers (2) from donor substrates (4). According to the invention, the production facility comprises at least one analysis device (6) for determining at least one individual property, particularly the doping, of the respective donor substrate (4), a data device (10) for producing donor substrate process data for individual donor substrates (4), wherein the donor substrate process data comprise analysis data of the analysis device (6), and the analysis data describe at least the individal property of the donor substrate (4), a laser device (12) for producing modifications (14) inside the donor substrate (4) in order to form a region of detachment (16) inside the respective donor substrate (4), wherein the laser device (12) can be operated according to the donor substrate process data of a concrete donor substrate (4) for the machining of the concrete donor substrate (4), and a detachment device (18) for producing mechanical voltages inside the respective donor substrate (4) for triggering and/or guiding a crack for separating respectively at least one wafer (2) from a donor substrate (4).