PVD Target Assembly Dark Space Shield Gap Control
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Solution Overview
Problem
In physical vapor deposition (PVD) chambers, the distance between the target and the dark space shield is critical in controlling plasma irregularities and arc events, which can negatively impact deposition quality.
Innovation Solution
A target assembly with a plate and target configuration, where the target is bonded to a supporting surface with a specific diameter and groove, and a dark space shield with an inner wall defining a controlled gap of 0.040 to 0.090 inches between the target and shield, to reduce arcing and enhance deposition symmetry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the distance between the target and dark space shield is not precisely controlled, then the structure is simpler to assemble, but plasma irregularities and arc events increase, degrading deposition quality
Solution Approach 1:
The patent introduces a dark space shield as an intermediary component between the target and chamber wall. The shield's inner wall is positioned at a precise distance (0.040-0.090 inches) from the target edge, creating a controlled dark space region that prevents plasma irregularities and arc events, thereby improving deposition quality without requiring complex adjustment mechanisms
Solution Approach 2:
The patent specifies a precise parameter range for the gap distance between the target edge and dark space shield inner wall (0.040-0.090 inches). By controlling this critical dimension parameter, the system achieves optimal plasma confinement and prevents arcing, resolving the contradiction between precision requirements and assembly simplicity
2Manufacturing precision
If the target diameter extends beyond the supporting surface diameter, then the target can be properly positioned relative to the dark space shield, but the mounting structure becomes more complex
Solution Approach 1:
The patent creates a localized protrusion where the target diameter extends beyond the supporting surface diameter. This local geometric feature ensures proper positioning of the target relative to the dark space shield, allowing precise gap control (0.040-0.090 inches) without requiring complex mounting structures or adjustment mechanisms throughout the entire assembly
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 solution effectively reduces arcing and improves deposition symmetry and uniformity by optimizing the spacing between the target and dark space shield, leading to improved PVD processing outcomes.
Implementation Method 1
a power source coupled to the chamber body to form a plasma within the chamber body
Implementation Method 2
In a physical vapor deposition (PVD) chamber
Data Source
AI summary
Embodiments of apparatus for physical vapor deposition are provided. In some embodiments, a target assembly for use in a substrate processing system to process a substrate includes a plate having a first side and an opposing second side, wherein the second side comprises a target supporting surface extending from the second side in a direction normal to the second side, wherein the target supporting surface has a first diameter and is bounded by a first edge; and a target having a first side bonded to the target supporting surface, wherein a diameter of the target is greater than the first diameter of the target supporting surface.