Sputtering Shield Gas Flow Target Redeposition
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Solution Overview
Problem
Sputtering equipment faces premature target replacement due to disturbances like flakes and particles, leading to unscheduled downtime, primarily caused by target redeposition and plasma concentration issues.
Innovation Solution
The implementation of a sputtering apparatus with a front gas injection shield and an enhanced plasma shield that directs gas flow over the target surface, using textured gas channels and adjustable shield configurations to prevent redeposition and optimize plasma confinement, thereby reducing target imperfections and improving thin film formation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sputtering process is carried out with high plasma concentration, then thin film deposition efficiency is improved, but target redeposition increases causing flakes and particles
Solution Approach 1:
A gas flow system is introduced as an intermediary between the plasma and target surface. The gas flow (typically inert gas like argon) carries sputtered material away from the target surface and directs it toward the substrate, preventing redeposition while maintaining high plasma concentration for efficient deposition.
Solution Approach 2:
The harmful redeposited material is extracted from the target surface region by the gas flow before it can settle back onto the target. This removes the source of flakes and particles that would otherwise form and cause target degradation.
2Reliability
If target replacement is performed frequently to maintain quality, then target quality is improved, but unscheduled downtime increases
Solution Approach 1:
The gas flow system performs preliminary action by continuously clearing sputtered material from the target surface during operation, preventing the formation of flakes and particles before they can accumulate and cause target failure. This proactive approach extends target life and prevents unscheduled downtime.
3Reliability
If gas flow rate is increased to prevent redeposition, then target quality is improved, but deposition efficiency decreases
Solution Approach 1:
The system optimizes gas flow parameters (rate, pressure, composition) to achieve the minimum effective flow needed to prevent redeposition without excessively reducing the flux of sputtered material reaching the substrate. This balancing act maintains both target quality and deposition efficiency.
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 extends the lifespan of the target by minimizing redeposition and maintaining target quality, reducing unscheduled downtime and enhancing the efficiency and quality of thin film deposition.
Implementation Method 1
front gas injection shield and an enhanced plasma shield that directs gas flow over the target surface
Implementation Method 2
enhanced plasma shield that directs gas flow over the target surface, using textured gas channels and adjustable shield configurations to prevent redeposition and optimize plasma confinement
Implementation Method 3
Electrons in the chamber strike and ionize an inert gas, forming positive ions
Implementation Method 4
The positive ions are then attracted to the negative target. When the ions strike the target, the ions transfer energy to the target material, causing material from the target surface to eject
Implementation Method 5
sputtering is a process carried out in a vacuum chamber that is filled with selected gasses. The sputtering process causes a substrate to be coated with a material from a target located within the sputtering equipment
Data Source
AI summary
A sputtering apparatus includes a sputtering cathode and a target overlying the sputtering cathode. A shield overlies the target and forms an aperture configured to direct sputtering particles onto a substrate. The shield includes a lower shield portion overlying the target, a channel outlet overlying the lower shield portion, and an upper shield portion overlying the channel. In some embodiments the shield includes a first shield and a second shield. The first shield includes a front gas injection outlet. The second shield overlies the first shield and forms the aperture. In various embodiments, the second shield is operable to adjust plasma confinement between the first shield and the second shield.