Adaptive Wafer Separation Using Donor Substrate Property Analysis
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Solution Overview
Problem
Conventional wafering methods for semiconductor materials, such as sawing with diamond or slurry-based wire saws, result in kerf loss, surface roughness, and damage, necessitating additional polishing and grinding steps, while stress-based spalling techniques suffer from limited control over wafer thickness and prominent Wallner lines, increasing surface roughness and material loss.
Innovation Solution
A production facility equipped with an analysis device for determining substrate properties, a laser device for generating modifications, and a separating device for mechanical stress induction, allowing for precise control of the separation process and reduction of material loss through formula-based process management and adaptive processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sawing processes with diamond or slurry-based wire saws are used, then wafering can be performed, but kerf loss occurs and surface roughness increases requiring additional polishing and grinding steps
Solution Approach 1:
The patent replaces mechanical sawing processes with a stress-based separation method. A stress layer is applied to the substrate surface, and controlled cracking is induced through thermal or mechanical stress, eliminating the need for diamond or slurry-based wire saws and their associated kerf losses.
Solution Approach 2:
The patent utilizes phase transitions in the stress layer material (such as polymer stress layers) through thermal cycling. The stress layer is heated above its glass transition temperature and then cooled, inducing contraction stresses that propagate cracks along predetermined paths to separate wafers without mechanical contact.
2Ease of manufacture
If sawing processes are used, then wafering can be performed, but surface roughness increases requiring additional polishing and grinding steps
Solution Approach 1:
The patent replaces mechanical sawing with stress-induced crack propagation. This substitution eliminates the mechanical contact that causes surface roughness and damage, resulting in cleaner separation surfaces that require minimal or no additional polishing and grinding.
Solution Approach 2:
The patent converts the potentially harmful uncontrolled cracking into a beneficial controlled process. By carefully designing the stress layer and controlling the stress application, the crack propagation is guided along precise predetermined paths, creating clean separation surfaces rather than random damage.
3Loss of substance
If spalling processes are used, then kerf loss is reduced, but control over wafer thickness is limited and Wallner lines increase surface roughness
Solution Approach 1:
The patent applies a stress layer to the substrate surface before the separation process. This preliminary action creates a predetermined crack path that guides the subsequent crack propagation, enabling precise control over wafer thickness and separation location that is not achievable with conventional spalling methods.
Solution Approach 2:
The patent controls crack propagation by changing stress parameters (temperature, stress magnitude, stress layer properties). By adjusting these parameters, the crack depth and propagation path can be precisely controlled to achieve the desired wafer thickness, overcoming the limitations of conventional spalling.
4Loss of substance
If spalling processes are used, then kerf loss is reduced, but prominent Wallner lines occur increasing surface roughness
Solution Approach 1:
The patent converts the potentially harmful uncontrolled crack propagation into a beneficial controlled process. By using a stress layer with specific properties and controlled thermal or mechanical stress, the crack propagation is guided smoothly along predetermined paths, eliminating the chaotic Wallner lines that characterize conventional spalling.
Solution Approach 2:
The patent utilizes phase transitions in the stress layer material to control crack propagation. The stress layer is heated above its glass transition temperature and then cooled, inducing controlled contraction that propagates cracks smoothly along predetermined paths rather than creating the chaotic Wallner lines of conventional spalling.
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 facility enables accurate and efficient separation of wafers with reduced material loss and surface roughness, minimizing the need for additional polishing and grinding steps, and improves the control over wafer thickness and surface quality.
Implementation Method 1
a laser device for generating modifications inside the donor substrates in order to form a separating region inside the respective donor substrate
Implementation Method 2
generating modifications inside the donor substrates... generating mechanical stresses inside the respective donor substrate
Implementation Method 3
a separating device for generating mechanical stresses inside the respective donor substrate in order to initiate and/or guide a crack in order to separate respectively at least one wafer from a donor substrate
Data Source
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 individual 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).