Self-centering Process Shield Pin Alignment
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Solution Overview
Problem
Current physical vapor deposition (PVD) chambers face inaccuracies in aligning the process shield and target, which worsen with increasing RF energy frequencies, leading to plasma irregularities and arc events that negatively impact deposition quality.
Innovation Solution
The design incorporates an elongated annular process shield with a radially extending lip and pins to align the target atop the shield, featuring a beveled peripheral edge and concave sidewall, ensuring precise concentric placement and reducing arcing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate alignment features are used between target and process shield, then assembly flexibility is maintained, but alignment precision deteriorates
Solution Approach 1:
The alignment features are merged directly into the target structure itself, eliminating separate alignment components. The target includes integrated alignment features that directly engage with corresponding features on the process shield, ensuring precise alignment while maintaining assembly flexibility.
Solution Approach 2:
Alignment pins serve as intermediary elements between the target and process shield. These pins physically bridge the two components, providing a mechanical interface that ensures accurate concentric alignment while allowing for easy assembly and disassembly.
2Productivity
If RF energy frequency is increased to improve deposition efficiency, then productivity increases, but plasma irregularity increases due to alignment sensitivity
Solution Approach 1:
The patent replaces mechanical alignment adjustments with a precision-machined alignment feature system. The target and process shield include precisely machined surfaces and features that automatically ensure accurate alignment when assembled, eliminating the need for manual mechanical adjustments and ensuring consistent alignment at high RF frequencies.
3Ease of repair
If target and process shield are separately mounted to maintain modularity, then ease of repair is improved, but alignment accuracy deteriorates
Solution Approach 1:
The system maintains segmentation by allowing the target and process shield to be separate, removable components. However, each component includes integrated alignment features that ensure precise alignment when assembled, enabling both modularity for easy replacement and high alignment accuracy for reliable operation.
Data Source
AI summary
A process shield may include an elongated annular body having an outer surface and an inner surface; a lip extending radially outward from the outer surface of the body proximate a first end of the body such that a first portion of the body extends beyond the lip toward the first end; a plurality of openings in the lip; and a pin disposed in each of the plurality of openings to align the target assembly atop the process shield when the lid is placed atop the process shield, wherein the pin comprises an elongated body having a first surface with a beveled peripheral edge, wherein the first surface has a first diameter, a second surface opposing the first surface, wherein the second surface has a second diameter, and a sidewall, between the first surface and the second surface, wherein the sidewall has a concave portion having a third diameter.