Semiconductor Wafer Reinforcement Structure for Stability
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Solution Overview
Problem
Semiconductor wafers with thinned central portions face challenges in stability and liquid management, leading to warping and contamination issues during processing due to the accumulation of excess liquids and stress concentrations from mechanical processing.
Innovation Solution
Incorporating a reinforcement structure with radially oriented perforations and elevated areas on the wafer rim, allowing fluid flow and preventing liquid accumulation, along with a chuck design that aligns with the wafer's perforations to facilitate liquid bypass and secure holding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a thinned central portion is formed by grinding, then the device formation area is increased, but warping and stress concentrations occur reducing stability
Solution Approach 1:
The annular rim is segmented into multiple discrete reinforcement structures (ridges or protrusions) distributed around the circumference. This segmentation allows the rim to provide localized support points that counteract warping forces while maintaining the overall thinned geometry for device formation.
Solution Approach 2:
The reinforcement structures are strategically positioned only at the annular rim region where mechanical support is needed, while the central portion remains thinned for device formation. This local differentiation of structural quality allows simultaneous optimization of both stability and device area.
2Stability of the object's composition
If the annular rim is made thicker to increase stability, then warping is reduced, but liquid accumulation increases causing contamination
Solution Approach 1:
The continuous annular rim is divided into discrete segmented structures with gaps between them. These gaps create channels that allow liquids to drain through the rim region, preventing accumulation while the raised portions maintain structural stability.
Solution Approach 2:
The annular rim is designed with a porous or perforated structure containing multiple openings or channels. This porous configuration enables liquid penetration and drainage through the rim, eliminating liquid accumulation and contamination risks while preserving mechanical support function.
3Strength
If reinforcement structures are added to increase radial bending resistance, then wafer stability improves, but device area is reduced
Solution Approach 1:
The reinforcement is provided through discrete segmented structures positioned at the annular rim rather than a continuous thickened rim. This segmentation concentrates reinforcement material only where mechanically necessary, maximizing bending resistance while minimizing encroachment on the central device formation area.
Solution Approach 2:
The wafer structure employs a composite configuration with a thinned central region for devices and a reinforced annular rim for structural support. This composite design allows each region to be optimized for its specific function without compromising the other.
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
Enhances the radial bending resistance and stability of the wafer, prevents liquid accumulation, and supports precise processing by enabling effective liquid management and contamination reduction during semiconductor processing.
Implementation Method 1
The reinforcement structure provides one or more passages for a fluid flow between an inner face of said one reinforcement structure towards an outer face of the reinforcement structure
Data Source
AI summary
A semiconductor wafer (12) with a thinned central portion (2) has a first side (3) and a second side (4) and at least one reinforcement structure for increasing the radial bending resistance of the semiconductor wafer (12). The reinforcement structure provides at least one passage (10) for a fluid flow between an inner face (9) of said one reinforcement structure towards an outer face (8) of the reinforcement structure. The passages (10) are manufactured in a z-direction coming from above the semiconductor wafer (12) in a direction which is essentially perpendicular to the surface, e.g. to the first side (3), of the semiconductor wafer (12).