Open-Loop Magnetron Tracks for Uniform PVD Target Erosion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing physical vapor deposition (PVD) processes, particularly DC and RF PVD, face issues with uneven target erosion and inconsistent deposition due to localized sputtering, leading to reduced target life and inefficient metal ionization and deposition uniformity.
Innovation Solution
A magnetron design with open-loop magnetic tracks, varying in length radially from the center to the edge, provides a more uniform magnetic field for extended target life and improved metal ionization, allowing for full-face erosion without sacrificing deposition uniformity, by optimizing the target-to-wafer spacing and magnetic field configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a small strong magnetron is used in DC PVD with tall spacing, then metal ionization and sputtering efficiency are improved, but localized sputtering causes uneven target erosion and reduced target life
Solution Approach 1:
The magnetron is divided into multiple independent magnetic segments (first magnetic segment, second magnetic segment, third magnetic segment) that can be independently controlled. This segmentation allows different regions of the target to be sputtered at different times, enabling uniform erosion across the entire target surface while maintaining high ionization efficiency in each active region.
Solution Approach 2:
The magnetic segments are configured to rotate or move relative to each other, creating a dynamic sputtering pattern that sweeps across the target surface. This dynamic operation prevents localized overheating and erosion at any single point, extending target life while maintaining consistent deposition quality.
2Manufacturing precision
If magnetic field is predominantly produced at the target edge to achieve good deposition uniformity, then deposition uniformity is improved, but target erosion becomes concentrated at the target edge
Solution Approach 1:
Different magnetic segments are configured with different magnetic field strengths and geometries optimized for their specific radial positions. The first magnetic segment (closer to target center) has different characteristics than the second and third segments (closer to target edge), allowing each segment to produce uniform deposition in its local region while distributing erosion across the entire target surface.
Solution Approach 2:
The magnetic segments rotate or shift positions during operation, allowing the deposition pattern to be uniformly distributed across the target surface over time. This dynamic redistribution ensures that no single region of the target is preferentially eroded, extending target life while maintaining uniform film deposition.
3Productivity
If tall spacing (190-400 mm) is used in DC PVD, then ballistic transport mechanism improves metal ionization, but most sputtered material is deposited on shields rather than substrate
Solution Approach 1:
The segmented magnetron configuration with multiple magnetic regions creates localized sputtering zones that can be independently controlled. This allows optimization of the sputtered material trajectory and distribution, directing more material toward the substrate while maintaining the tall spacing benefits for ionization.
Solution Approach 2:
The system optimizes operating parameters including magnetic field strength, RF power, and pressure conditions to enhance metal ionization efficiency. By carefully controlling these parameters in conjunction with the segmented magnetron design, the system achieves high ionization while improving material utilization through controlled sputtering patterns.
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 design significantly enhances target utilization, achieves more uniform metal ionization and deposition, and extends the target life, addressing the inefficiencies of conventional PVD processes by ensuring consistent film uniformity and increased operational flexibility.
Implementation Method 1
a magnet assembly includes a support member. A plurality of magnetic tracks is coupled to the support member. Each magnetic track includes a first pole piece coupled to a pair of magnetic poles
Implementation Method 2
Electron confinement is enhanced and consequently gas ionization by the confinement of electrons due to stochastic heating from the oscillating field
Implementation Method 3
The combination of small magnetron and high DC power generates a large power density to ionize the gas medium and sputter the target
Implementation Method 4
radio frequency (RF) PVD... operated in a pressure regime of (for example) 20-60 mTorr... stochastic heating from the oscillating field
Implementation Method 5
gas ionization by the confinement of electrons due to stochastic heating from the oscillating field
Implementation Method 6
The low pressure and tall spacing provide a 'ballistic' transport mechanism where sputter material can reach the wafer with few if any in-flight collisions
Implementation Method 7
localized sputtering. This localized sputtering will quickly erode the target at certain locations due to the electron confinement and localized gas ionization
Implementation Method 8
provides a more uniform magnetic field for extended target life and improved metal ionization, allowing for full-face erosion without sacrificing deposition uniformity
Data Source
AI summary
A magnet assembly for a magnetron of a processing chamber includes a support member. A plurality of magnetic tracks is mounted to the support member. Each magnetic track includes a pair of magnetic poles. A partial magnetic track is mounted to the support member. The partial magnetic track includes a single unpaired magnetic pole. The partial magnetic track is mounted proximal to a center of rotation of the support member.