Wafer Shield Ring Self-Alignment for Edge Deposition Control
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Solution Overview
Problem
In semiconductor wafer processing, existing shielding components often fail to maintain precise alignment with the wafer center, leading to uneven shielding and deposition defects due to eccentricity, which results in unwanted deposition on the edges and sides of the wafer.
Innovation Solution
The apparatus includes a pedestal with an annular edge step and a wafer pocket, a side ring with a centripetal slant bevel, and a shadow ring with a matching slant bevel, allowing for automatic alignment of the shielding component with the wafer center through a lifting mechanism that ensures precise contact and alignment during deposition processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a shielding component is used to cover the edge of the wafer, then deposition on the edge and side of the wafer is prevented, but the center of the shielding component becomes eccentric to the center of the wafer, resulting in uneven shielding and reduced effectiveness
Solution Approach 1:
The shielding component performs self-alignment through its own geometric features. The V-shaped groove on the bottom surface of the shielding component fits with the corresponding V-shaped protrusion on the wafer pocket, allowing the shielding component to automatically position itself concentrically with the wafer center without requiring external alignment mechanisms.
Solution Approach 2:
The V-shaped groove and protrusion structure acts as an intermediary alignment mechanism between the shielding component and the wafer pocket. This geometric interface ensures precise concentric alignment by providing a mechanical guide that forces the shielding component into the correct position relative to the wafer center during installation.
2Measurement precision
If manual alignment of the shielding component is attempted, then alignment precision may be improved, but the operation becomes more complex and time-consuming
Solution Approach 1:
The system eliminates the need for manual alignment operations by incorporating self-aligning geometric features. The V-shaped groove and protrusion automatically guide the shielding component into correct alignment with the wafer center, simplifying the installation process to a simple drop-in operation without requiring complex adjustment procedures.
3Stability of the object's composition
If the shielding component is fixed rigidly, then positioning stability is improved, but any misalignment cannot be compensated, leading to eccentricity
Solution Approach 1:
The V-shaped groove and protrusion structure serves as a mechanical intermediary that provides both stability and alignment. Once the shielding component is positioned, the geometric fit ensures it remains firmly held in the correct concentric position, providing both the stability needed for reliable shielding and the alignment accuracy to prevent eccentricity.
Data Source
AI summary
This application relates to an apparatus and method for processing a wafer. In an embodiment of this application, an apparatus for processing a wafer includes: a heater including a pedestal, where a top portion of the pedestal includes an annular edge step and a wafer pocket recessed relative to the annular edge step to accommodate a wafer; a side ring, including an outer portion and a top portion, where the outer portion surrounds an outer side wall of the pedestal, and the top portion covers an outer portion of the annular edge step and includes a centripetal slant bevel; and a shadow ring, a bottom portion thereof including a slant bevel matching the centripetal slant bevel of the top portion of the side ring.