Extended PVD Chamber for Uniform Tantalum TSV Deposition
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Solution Overview
Problem
The challenge in semiconductor manufacturing is the non-uniform deposition of barrier layer materials, such as tantalum, on the sides and bottoms of through silicon vias (TSVs) due to their small diameter and increased depth, which affects the quality and density of integrated circuits.
Innovation Solution
A modified physical vapor deposition (PVD) chamber with enhanced design features, including dual magnet source compensation, additional electromagnets, and a specific configuration of grounding loops, is used to achieve uniform tantalum deposition on TSVs, ensuring better step coverage and film uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If physical vapor deposition (PVD) is used to deposit barrier layer materials on TSVs, then the deposition process can be performed, but the barrier layer materials are not sputtered uniformly on the sides and bottoms of the TSVs due to small diameter and increased depth
Solution Approach 1:
The magnetron source is divided into multiple independent magnet sections (e.g., three separate magnets instead of one large magnet), allowing each section to be independently controlled and optimized for different regions of the target, thereby achieving uniform deposition on high aspect ratio TSV structures
Solution Approach 2:
The patent employs a rotating magnetron source where magnets rotate around the target, dynamically changing the sputtering pattern over time. This rotational motion ensures that all areas of the target receive equivalent exposure, achieving uniform deposition on vertical TSV walls that would otherwise be difficult to coat evenly
2Productivity
If the TSV diameter is reduced and depth is increased to increase circuit density, then more structures can be packed per area, but the barrier layer materials are not sputtered uniformly on the TSV sides and bottoms
Solution Approach 1:
The patent transitions from conventional planar deposition geometry to a three-dimensional rotating magnetron configuration. The rotation adds a temporal dimension to the deposition process, allowing uniform coating on vertical surfaces by cycling through different angular positions, thereby enabling uniform barrier layers on high aspect ratio TSVs required for increased circuit density
3Reliability
If conventional PVD chamber design is used, then the chamber can operate, but the step coverage of barrier layers on TSVs is insufficient
Solution Approach 1:
The magnetron source incorporates rotating magnets that continuously change their position relative to the target during deposition. This dynamic motion ensures that sputtered material is deposited uniformly on vertical TSV walls, achieving superior step coverage and conformal barrier layers that are critical for device reliability
Solution Approach 2:
The rotating magnetron source acts as an intermediary mechanism between the sputtering target and the TSV structures. By introducing controlled rotation, it mediates the deposition process to achieve uniform material distribution on complex three-dimensional TSV surfaces, thereby improving step coverage without requiring fundamental changes to the PVD chamber architecture
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 solution improves tantalum barrier step coverage by over two times without compromising throughput or film performance, enabling cost-effective TSV metallization for next-generation semiconductor devices and facilitating 3D packaging.
Implementation Method 1
a magnetron assembly in the source including dual magnets, a first magnet of the dual magnets rotates about a central axis at a first radius and a second magnet of the dual magnets rotates about the central axis at a second radius
Implementation Method 2
Methods and apparatus for deposition of tantalum film on TSVs may comprise a PVD process chamber with a source and a chamber body
Implementation Method 3
an RF power source configured to supply greater than 0 kW to approximately 3 kW of RF bias power to the substrate support assembly, wherein the RF power source is configured to supply approximately 1.9 kW of RF bias power to the substrate support assembly, wherein the RF power source supplies RF bias power at a frequency of approximately 13.65 MHz
Implementation Method 4
a DC power source configured to supply approximately 38 kW to approximately 60 kW of DC power to a target of the source
Data Source
AI summary
An apparatus leverages a physical vapor deposition (PVD) process chamber with a wafer-to-target distance of approximately 400 millimeters to deposit tantalum film on through silicon via (TSV) structures. The PVD process chamber includes a source that is configured with dual magnet source compensation. The PVD chamber also includes an upper electromagnet assembly exterior to the chamber body in close proximity to the source, a magnetron assembly in the source including dual magnets with dual radius trajectories, a shield within the chamber body, and a plurality of grounding loops that are symmetrically spaced about a periphery of a substrate support assembly and are configured to provide an RF ground return path between the substrate support assembly and the shield.