Structured Carrier Substrate for Wafer Bow Compensation
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Solution Overview
Problem
Semiconductor wafers with intrinsic tensile and compressive stresses due to different material thicknesses and trench structuring lead to uncontrollable wafer bow, making further processing difficult or impossible, especially as wafers thin.
Innovation Solution
A structured carrier substrate with different materials of varying properties is applied to the front side of the semiconductor wafer, compensating for mechanical stress regions through localized stress induction by materials with specific modulus of elasticity and curing behaviors, arranged alternately or in point-like fashion to adjust stress levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If different materials with different thicknesses are applied to compensate mechanical stress regions, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent applies different materials with different stress properties to specific mechanical stress regions on the wafer front side. By printing materials selectively in different locations based on the local stress state (tensile or compressive), the solution addresses wafer bow locally rather than uniformly, improving flatness while avoiding unnecessary complexity in regions that don't require compensation.
Solution Approach 2:
The carrier substrate is divided into multiple regions with different printed materials arranged in different patterns (stripes, points, or alternating layers). This segmentation allows each region to be optimized independently for its specific stress compensation needs, achieving overall wafer flatness through localized adjustments rather than a single complex uniform structure.
2Reliability
If multiple materials with different properties are used for stress compensation, then reliability is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent replaces traditional mechanical stress compensation methods (such as physical carrier substrates or mechanical pressing) with a printing-based material deposition system. This substitution allows for precise, programmable material placement that adapts to the specific stress map of each wafer, improving reliability while maintaining ease of manufacture through automated printing processes.
Solution Approach 2:
The patent varies multiple parameters of the printed materials including material type, thickness, and spatial distribution pattern to optimize stress compensation. By changing these parameters based on the specific stress conditions detected on each wafer, the system achieves high reliability compensation while using a flexible manufacturing process that can adapt to different wafer configurations.
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
This approach reliably reduces distortions and curvatures, enabling further processing by compensating internal mechanical stress, allowing for a flat and relaxed layer system for power semiconductor devices.
Implementation Method 1
the material properties comprise a modulus of elasticity and a shrinkage behavior or a swelling behavior
Implementation Method 2
the material properties comprise a modulus of elasticity and a shrinkage behavior or a swelling behavior
Implementation Method 3
the different curing behavior induces stresses and elongations into the semiconductor surface
Implementation Method 4
A structured carrier substrate that has different materials with different material properties is arranged on the front side, wherein the different materials are arranged on the different mechanical stress regions
Data Source
AI summary
A semiconductor wafer having a front side and a rear side, the front side is opposite the rear side. The front side has different mechanical stress regions. A structured carrier substrate that has different materials with different material properties is arranged on the front side, wherein the different materials are arranged on the different mechanical stress regions.