Reactive Sputtering Target Age Compensation via Gas Pressure Adjustment
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Solution Overview
Problem
In industrial reactive sputtering processes, the deposition rate varies significantly due to target age, leading to unstable coating conditions and unacceptable changes in film deposition, particularly in prolonged operations where target mass reduction causes erosion and alters sputtering characteristics.
Innovation Solution
Adjusting the partial pressure of the reactive gas based on the target weight maintains constant sputtering characteristics and deposition rates within acceptable ranges, while keeping the sputtering power density constant, effectively stabilizing the process across different target ages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If reactive sputtering is performed with constant power density, then the sputtering process is simple to operate, but the deposition rate varies significantly with target age
Solution Approach 1:
The invention changes the operating parameters from constant power density to constant deposition rate by dynamically adjusting reactive gas partial pressure and power density based on target weight measurements. This resolves the contradiction by maintaining operational simplicity through automated feedback control while achieving deposition rate stability despite target erosion.
Solution Approach 2:
The invention implements a feedback control system that continuously monitors target weight and adjusts reactive gas partial pressure and power density accordingly. This feedback mechanism maintains constant deposition rate despite changing target conditions, resolving the stability issue while keeping the system easy to operate through automated control.
2Productivity
If target erosion is allowed to proceed, then material is deposited on substrate, but sputtering characteristics change undesirably
Solution Approach 1:
The invention dynamically changes operating parameters (reactive gas partial pressure and power density) as functions of target weight to compensate for erosion effects. This allows continuous film deposition while maintaining stable sputtering characteristics by adjusting parameters to offset the changing target conditions.
Solution Approach 2:
The invention applies preliminary anti-action by measuring target weight and proactively adjusting operating parameters before significant deviations in sputtering characteristics occur. This prevents undesirable changes by compensating for erosion effects in advance, allowing continuous productivity while maintaining process stability.
3Manufacturing precision
If magnetic field strength is increased to improve coating quality, then coating quality improves, but target erosion increases
Solution Approach 1:
The invention compensates for increased target erosion caused by strong magnetic fields by dynamically adjusting reactive gas partial pressure and power density based on target weight. This allows maintaining high coating quality from strong magnetic fields while compensating for the accelerated erosion through parameter optimization.
Solution Approach 2:
The invention converts the harmful effect of increased target erosion into a manageable parameter by measuring target weight and using it to optimize operating conditions. The erosion, rather than being a detrimental side effect, becomes information that guides parameter adjustment to maintain both coating quality and process stability.
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 method ensures that the sputtering characteristics and deposition rates remain within ±10% or less of predefined values, even as the target ages, achieving stable and reproducible film deposition in industrial production contexts, particularly when using HIPIMS techniques.
Implementation Method 1
Target material from the target surface is sputtered by collision of ions (essentially ions from an ionized non-reactive gas), which are attracted to the target surface through the application of a magnetic field. Thus, the sputtering process at the target leads to erosion of the target surface and consequently to a change of the target weight.
Implementation Method 2
Target material from the target surface is sputtered by collision of ions (essentially ions from an ionized non-reactive gas), which are attracted to the target surface through the application of a magnetic field.
Implementation Method 3
In the case of reactive sputtering processes the species obtained from the target react with the reactive gas present in the coating chamber for forming the film on the substrate surface to be coated.
Data Source
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AI summary
The present invention relates to a method for performing reactive sputtering processes maintaining the sputtering characteristic at the target as well as the deposition rate constant, or at least in a for the industrial production context acceptable range, independent on the target age.