Printed Carrier Substrate for Wafer Bow Correction During Thinning
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Solution Overview
Problem
Semiconductor wafers exhibit intrinsic compressive and tensile stresses due to processing steps, leading to mechanical bending and increased risk of breakage during thinning, which hampers further processing and vacuum suction.
Innovation Solution
A method involving the application of a water-insoluble first layer on the semiconductor wafer using printing technology, cured with UV radiation or sintering, to create a mechanically stable carrier substrate that offsets existing stresses and allows for controlled wafer bow correction, with optional openings for contact area exposure and a planarizing layer to distribute mechanical pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the semiconductor wafer is ground very thin toward the end of manufacturing processes, then the wafer thickness is reduced to meet specifications, but the wafer exhibits high mechanical bending and increased risk of breakage due to intrinsic stresses
Solution Approach 1:
A carrier substrate is applied to the front side of the semiconductor wafer before the final thinning process. This preliminary action provides mechanical support during grinding, preventing the thin wafer from bending or breaking due to intrinsic stresses. The carrier substrate is removed after thinning is complete, having served its stabilizing function throughout the critical processing steps.
Solution Approach 2:
The carrier substrate acts as an intermediary element between the processing equipment and the fragile thin semiconductor wafer. It provides the necessary mechanical strength and stability during handling and processing, while being removable afterward to leave the final thin wafer product. The carrier substrate mediates between the conflicting requirements of thinness and mechanical stability.
2Volume of moving object
If the semiconductor wafer is ground very thin, then the wafer meets thickness specifications, but vacuum suction during further processing becomes impossible
Solution Approach 1:
The carrier substrate is applied in advance to the wafer surface, creating a thick composite structure that enables effective vacuum suction during processing. This preliminary action ensures that vacuum hold-down can be achieved even though the actual semiconductor wafer will be very thin. The carrier substrate provides the necessary thickness for vacuum cup engagement before the final thinning occurs.
3Reliability
If a carrier substrate is applied to stabilize the wafer, then mechanical stability is improved, but the complexity of the manufacturing process increases
Solution Approach 1:
The carrier substrate is applied and then removed (taken out) after serving its stabilizing function. This extraction approach allows the process to benefit from the carrier substrate's mechanical support during critical steps, while the carrier substrate itself is not part of the final product. The added complexity is temporary and confined to specific process steps, rather than being permanent.
Solution Approach 2:
The carrier substrate application focuses on specific areas of the wafer where mechanical support is most needed, such as the front side with contact areas. This localized approach rather than comprehensive coverage reduces material usage and process complexity while still achieving the necessary mechanical stability for handling and processing.
4Adaptability or versatility
If openings are produced in the carrier substrate to expose contact areas, then testability is maintained, but the manufacturing precision requirements increase
Solution Approach 1:
The carrier substrate has different properties in different locations: areas with openings have different characteristics than areas without openings. The openings are precisely positioned only where contact areas need to remain accessible for testing, while other areas maintain full coverage for mechanical support. This local differentiation achieves testability without compromising overall structural integrity.
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 stabilizes semiconductor wafers for subsequent processing, enables safe thinning, and maintains contactability of metallization surfaces, reducing the risk of breakage and allowing for precise stress management, thus facilitating efficient and process-safe semiconductor component manufacturing.
Implementation Method 1
the curing of the at least one first layer with the aid of UV radiation
Implementation Method 2
the curing of the at least one first layer with the aid of UV radiation, thermally or with the aid of sintering
Implementation Method 3
the curing of the at least one first layer with the aid of UV radiation, thermally or with the aid of sintering
Implementation Method 4
openings of the at least one first layer, which partially expose the contact areas, are produced with the aid of a laser
Data Source
AI summary
A method for manufacturing a carrier substrate on a semiconductor wafer that includes a front side and a rear side, the front side being situated opposite the rear side, the front side representing a structured semiconductor wafer side including contact areas. The method includes the following steps: applying at least one first layer to the front side with the aid of printing technology, the at least one first layer including a first material that is water-insoluble, and curing the at least one first layer with the aid of UV radiation, thermally or with the aid of sintering.