Composite Support Unit for Kerf-Free Wafer Detachment
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Solution Overview
Problem
Current methods for producing wafers, such as those used in microelectronics and photovoltaic technology, result in significant material loss and thickness variations due to kerf loss, curvature, and inefficient thermal contact, making them unsuitable for many applications and increasing production costs.
Innovation Solution
A method utilizing a composite structure of polymer-metal laminates with a stabilization layer having a higher modulus of elasticity than the receiving layer, allowing for controlled thermally induced stress to split wafers with reduced thickness variations and improved thermal contact, enabling more efficient and reproducible wafer production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If a polymer layer is used to generate thermal stresses for wafer detachment, then kerf-free wafer production is achieved, but significant thickness variations and curvature occur
Solution Approach 1:
The patent applies composite materials by combining a polymer layer with a stabilizing mesh structure (metal or ceramic) to create a hybrid support unit. The mesh provides rigid support to counteract thermal stress-induced curvature while the polymer enables kerf-free detachment through thermal expansion. This composite approach resolves the contradiction by maintaining both material efficiency and thickness uniformity.
Solution Approach 2:
The patent utilizes parameter changes by exploiting the glass transition temperature of the polymer material. By heating the polymer above its glass transition temperature, it becomes more compliant and allows for better thermal contact and stress distribution. This temperature parameter change enables the polymer to adapt its mechanical properties, reducing thickness variations during the detachment process.
2Temperature
If a thick polymer layer is used to support the wafer, then thermal contact is improved, but the wafer bends significantly and becomes difficult to handle
Solution Approach 1:
The patent combines polymer material with a stabilizing mesh structure to create a composite support unit. The mesh provides rigid support that prevents excessive wafer bending while the polymer maintains good thermal contact. This composite structure resolves the contradiction by balancing thermal contact quality with shape stability.
Solution Approach 2:
The patent segments the support function by dividing it between two materials: the polymer provides thermal contact and flexibility, while the mesh provides structural support and curvature control. This segmentation of functions allows each material to optimize its contribution without the drawbacks of using a single thick polymer layer.
3Manufacturing precision
If conventional sawing is used for wafer production, then manufacturing precision is maintained, but material loss increases significantly
Solution Approach 1:
The patent replaces the mechanical sawing system with a thermal stress-based detachment system. Instead of using a physical saw blade that removes material, the invention uses thermal expansion differences between the polymer and workpiece to generate stresses that detach wafers kerf-free. This substitution eliminates material loss while maintaining manufacturing precision through controlled thermal processes.
Solution Approach 2:
The patent exploits thermal expansion by using a polymer material with a coefficient of thermal expansion approximately two orders of magnitude higher than the workpiece. This large thermal expansion difference generates sufficient stress during cooling to detach the wafer without mechanical contact, achieving both kerf-free production and precise thickness control.
4Loss of substance
If polymer material is used for thermal stress generation, then kerf-free detachment is achieved, but thermal contact consistency deteriorates
Solution Approach 1:
The patent uses composite materials where the mesh structure provides a rigid, thermally conductive framework that ensures consistent thermal contact across the support unit. The polymer fills the spaces and provides additional thermal pathways, improving overall thermal contact consistency while maintaining kerf-free detachment capabilities.
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 method significantly reduces thickness fluctuations in wafers to less than 40% of the average thickness, enhances thermal contact, and facilitates easier handling and processing, addressing the limitations of previous methods by producing wafers with improved uniformity and reduced curvature.
Implementation Method 1
the stabilizing layer is at least partially designed such that it has a Young's modulus greater than the Young's modulus of the receiving layer
Implementation Method 2
applying an internal and/or external stress field to the composite structure in such a way that the solid layer is detached from the workpiece
Data Source
Figure 1a~1b
Figure 1c~1e
Figure 2I~2V
AI summary
The invention relates to a method for producing solid-state layers, in particular for use as wafers, having the following the steps: providing a workpiece (4) for detaching the solid-state layers, said workpiece (4) having at least one exposed surface; generating and/or providing a support unit for receiving at least one solid-state layer, said support unit being designed in a multilayered manner, wherein the support unit has a stabilizing layer (1), the stabilizing layer (1) is superimposed by a receiving layer (2) at least in some sections, said receiving layer (2) being designed to retain the solid-state layer, and the stabilizing layer (1) is designed in at least some sections so as to have an elastic modulus which is greater than the elastic modulus of the receiving layer (2); connecting the receiving layer (2) to the exposed surface of the workpiece (4) while forming a composite structure; and applying an inner and/or outer stress field to the composite structure such that the solid-state layer is detached from the workpiece (4) along a plane extending within the workpiece (4).