Plasma Sputtering Device with Expanding Tube and Curved Magnetic Field
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Solution Overview
Problem
Current plasma sputtering devices face challenges in generating high-density plasma downstream of the plasma source, controlling ion energy to prevent substrate damage, and efficiently forming thin films on large-diameter substrates, particularly when using magnetic targets or reactive gases.
Innovation Solution
A plasma sputtering device with an insulating tube of expanding inner diameter, equipped with a high frequency antenna and static magnetic field generators, uses a curved magnetic field to direct ions to the target while suppressing ion damage to the substrate, and includes a mechanism to raise the target temperature for optimal film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high density plasma is generated near the target to increase sputtering speed, then productivity is improved, but ion damage to the substrate increases
Solution Approach 1:
The device is divided into two independent functional sections: a plasma generation section (with RF coil and magnetic field application mechanism) and an ion attraction section (with substrate stage and independent power supply). This segmentation allows plasma to be generated at high density near the target while ions are attracted separately to the substrate, enabling high sputtering speed without proportionally increasing ion damage.
Solution Approach 2:
A magnetic field application mechanism is introduced as an intermediary to control and guide plasma and ion behavior. The magnetic field confines plasma near the target surface during generation, then directs ion flow toward the substrate in a controlled manner, decoupling the relationship between plasma density and ion damage intensity.
2Quantity of substance
If magnetron sputtering method is used to confine plasma, then plasma density is improved, but it becomes difficult to use magnetic targets
Solution Approach 1:
By separating plasma generation from ion attraction functions, the device eliminates the conflict between magnetron plasma confinement and magnetic target usage. The plasma generation section can use any target type (magnetic or non-magnetic) without relying on leakage flux confinement, as plasma is generated and maintained by RF excitation and independent magnetic field application.
Solution Approach 2:
The invention changes the fundamental parameters of plasma generation from magnetron-based (relying on target material properties) to RF-based (independent of target material). This allows the system to handle magnetic targets effectively while maintaining high plasma density through RF power coupling and magnetic field control.
3Device complexity
If plasma generation and ion attraction are performed simultaneously through common power supply, then device complexity is reduced, but independent control of ion flux and energy is lost
Solution Approach 1:
The power supply system is segmented into two independent units: an RF power supply for plasma generation and a separate DC power supply for ion attraction. This segmentation enables independent control of plasma density (via RF power) and ion flux/energy (via DC power), providing precise process control despite increased device complexity.
Solution Approach 2:
The independent power supplies enable dynamic and flexible control of sputtering parameters. Operators can adjust plasma generation and ion attraction independently in real-time, optimizing ion flux and energy for different substrate materials and film requirements without being constrained by a fixed common power supply configuration.
4Productivity
If substrate is exposed directly to plasma to achieve high sputtering efficiency, then film formation speed is improved, but ion damage to substrate increases
Solution Approach 1:
The spatial separation of plasma generation (near target) and ion attraction (at substrate) allows the substrate to be exposed to plasma for efficient film formation while independent control prevents excessive ion damage. The magnetic field application mechanism further optimizes this by guiding plasma flow and ion directionality.
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 configuration enables high-speed, high-quality film formation with reduced substrate damage, maintaining high-density plasma downstream and allowing for uniform film deposition on large substrates, even with magnetic targets, by controlling ion flux and energy.
Implementation Method 1
When high density plasma is generated inside such a cylindrical insulating tube by a high frequency electromagnetic field
Implementation Method 2
a static magnetic field application mechanism
Implementation Method 3
ions in the plasma are taken into a target member, and particles scattered as a result of ion bombardment are deposited on the surface of a substrate
Implementation Method 4
it is difficult to suppress of loss of plasma into the inner wall of the insulating tube
Data Source
AI summary
A plasma sputtering device including one or a plurality of plasma generating devices each including an insulating tube having an expanding inner diameter and having a gas injection port formed in an end portion or a side portion thereof, a first electromagnet or a permanent magnet group which can apply a static magnetic field, and a high frequency antenna; a second electromagnet which is disposed in a region downstream of the plasma generating device(s) and which can form a curved magnetic force line structure; a target mechanism which includes a permanent magnet embedded therein and a cooling mechanism and which can apply a DC or high frequency voltage; a substrate stage facing the target mechanism; a second permanent magnet group around the substrate stage; and a heat insulating mechanism between a target material and the target mechanism.