PVD Deposition Uniformity via Offset Cathode and Dynamic Rotation
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Solution Overview
Problem
Physical vapor deposition (PVD) chambers face challenges in achieving uniformity of layer thickness for large substrates, particularly in extreme ultraviolet (EUV) lithography, where small feature sizes and high reflectivity requirements demand precise control to prevent non-uniformity exceeding error tolerance limits.
Innovation Solution
Implementing a rotating substrate support with a specific rotation speed and process window time to complete whole number rotations, combined with a cathode configuration where the radial center is offset from the substrate support's rotational axis, and using a dynamic rotation speed profile to compensate for non-uniform deposition, ensuring full-cycle substrate support rotation and precise starting position control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rotating substrate support is used to improve deposition uniformity, then layer thickness uniformity is improved, but device complexity increases due to precise rotation control requirements
Solution Approach 1:
The substrate support rotation speed is dynamically adjusted during the deposition process. The system transitions from a static rotation speed approach to a dynamic one where the rotation speed varies based on the angular position of the substrate support, allowing compensation for non-uniform deposition patterns while managing system complexity through controlled adaptability
Solution Approach 2:
The rotation speed parameter is changed as a function of angular position. By modifying the rotation speed parameter dynamically during deposition, the system achieves uniform layer thickness across the substrate surface, addressing the manufacturing precision requirement while using parameter control rather than mechanical complexity
2Manufacturing precision
If the cathode radial center is offset from the substrate support rotational axis to compensate for non-uniform deposition, then deposition uniformity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The system intentionally introduces asymmetry by offsetting the cathode radial center from the substrate support rotational axis. This asymmetric configuration compensates for non-uniform deposition patterns. The patent manages the associated measurement precision requirements through dynamic rotation speed adjustment and whole-number rotation control, balancing the asymmetry benefit with controllable positioning requirements
Solution Approach 2:
The system uses feedback control to manage the starting position precision requirements. By monitoring the angular position and ensuring whole-number rotations are completed within the process window, the system compensates for the asymmetric cathode configuration, maintaining deposition uniformity while managing measurement precision demands
3Manufacturing precision
If whole number of rotations are completed in process window time to ensure uniformity, then layer thickness control is improved, but productivity decreases due to extended process time
Solution Approach 1:
The substrate support performs periodic rotations at controlled speeds to complete whole numbers of rotations within the process window. This periodic action ensures uniform material deposition from all angles while managing process time. The system optimizes the rotation speed and number of rotations to balance precision requirements with productivity constraints
Solution Approach 2:
The rotation speed is dynamically optimized to complete the required whole number of rotations within the process window time. By adjusting the rotation speed dynamically rather than using fixed speeds, the system achieves both precise layer thickness control and improved productivity by minimizing the process time while maintaining uniformity requirements
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 significantly reduces layer thickness non-uniformity across the substrate, meeting stringent specifications for EUV reflective elements by ensuring equal material deposition from all angles and compensating for non-horizontal effects, thereby improving the overall uniformity of multilayer stacks.
Implementation Method 1
exposing the substrate to a physical vapor deposition process for the process window time (t) to form a first layer of material on the substrate
Implementation Method 2
applying power to cathode within the processing system, the cathode having a radial center that is offset relative to the rotational axis of the substrate support to generate a plasma within the processing system
Data Source
AI summary
A physical vapor deposition chamber comprising a rotating substrate support having a rotational axis, a first cathode having a radial center positioned off-center from a rotational axis of the substrate support is disclosed. A process controller comprising one or more process configurations selected from one or more of a first configuration to determine a rotation speed (v) for a substrate support to complete a whole number of rotations (n) around the rotational axis of the substrate support in a process window time (t) to form a layer of a first material on a substrate, or a second configuration to rotate the substrate support at the rotation speed (v).