Tilting Substrate Support for PVD Deposition Uniformity
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Solution Overview
Problem
Physical vapor deposition (PVD) chambers face challenges in achieving uniformity of deposition across large substrates, particularly for extreme ultraviolet (EUV) reflective elements, where small non-uniformities can lead to significant defects due to the stringent requirements of EUV lithography, such as EUV mask blanks and reflective elements.
Innovation Solution
The solution involves a method where a substrate is supported on a rotating substrate support within a PVD chamber, with the substrate and/or target being tilted to improve uniformity, and a computer-readable storage medium is used to control the rotation and plasma generation for precise deposition, ensuring full-cycle substrate support rotation and dynamic rotation speed profiles to compensate for non-uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the substrate is large in size, then the coating area increases, but the deposition uniformity deteriorates due to thickness non-uniformity exceeding error tolerance
Solution Approach 1:
The substrate support is tilted at a specific angle (e.g., 15-30 degrees) relative to the target, creating an asymmetric geometry that causes the deposition plume to distribute more uniformly across the substrate surface. This asymmetric orientation compensates for the natural radial non-uniformity of PVD deposition, allowing large substrates to achieve thickness uniformity within error tolerances.
Solution Approach 2:
The substrate support rotates during deposition to dynamically redistribute material flux across the substrate surface. This rotation, combined with the tilted orientation, ensures that all regions of the large substrate receive comparable amounts of deposited material over time, achieving uniform thickness across the entire coating area.
2Manufacturing precision
If the substrate support rotates, then deposition uniformity improves, but the system complexity increases due to additional control requirements
Solution Approach 1:
The rotation and tilting functions are merged into a single substrate support mechanism, allowing both motions to be controlled by one integrated assembly. This reduces overall system complexity compared to having separate rotation and tilting mechanisms, while still achieving the deposition uniformity benefits of both motions.
Solution Approach 2:
The substrate support is tilted at an optimized angle (e.g., 15-30 degrees) that maximizes deposition uniformity while minimizing the required rotation speed and control precision. This parameter optimization reduces the complexity of the control system by lowering the performance requirements for rotation control.
3Manufacturing precision
If the target is tilted, then deposition uniformity across the substrate improves, but the manufacturing complexity increases
Solution Approach 1:
The target is mounted on a tilting mechanism that allows dynamic adjustment of the target angle during deposition. This dynamic tilting capability enables optimization of the deposition geometry for different substrate sizes and shapes, achieving uniform layer thickness while maintaining ease of manufacture through a single adjustable parameter rather than fixed complex geometry.
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 thickness non-uniformity across the substrate, meeting the stringent specifications for EUV mask blanks by ensuring uniform deposition of multilayer stacks, such as Mo/Si layers, with non-uniformity reduced from 0.29% to 0.18%.
Implementation Method 1
supporting a substrate having an exposed substrate surface in a physical vapor deposition process chamber on a substrate support; producing a plume of deposition material from a target
Implementation Method 2
applying power to cathode within the physical vapor deposition chamber to generate a plasma within the processing system to form a first layer of material on the substrate
Data Source
AI summary
A physical vapor deposition chamber comprising a tilting substrate support is described. Methods of processing a substrate are also provided comprising tilting at least one of the substrate and the target to improve the uniformity of the layer on the substrate from the center of the substrate to the edge of the substrate. Process controllers are also described which comprise one or more process configurations causing the physical deposition chamber to perform the operations of rotating a substrate support within the physical deposition chamber and tilting the substrate support at a plurality of angles with respect to a horizontal axis.