Sputtering Apparatus Pulse Cycle Shifting for Discharge Stability
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Solution Overview
Problem
Existing sputtering apparatuses face challenges in stabilizing electric discharge and maintaining uniform film quality due to synchronization issues between voltage control and pulse cycles, leading to uneven film deposition and premature target material consumption.
Innovation Solution
A sputtering apparatus with a pulsing unit that measures and controls electric current to maintain a prescribed value, shifting the pulse cycle from the DC power supply control cycle to stabilize electric discharge and minimize positional variations during target material consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage control cycle and pulse cycle are synchronized, then control precision is improved, but electric discharge stability deteriorates and film quality uniformity worsens
Solution Approach 1:
The patent applies periodic pulse action to the DC power supply, where the pulse cycle is deliberately set to be different from the voltage control cycle. This periodic pulsing of electric current to the target material stabilizes plasma generation and improves electric discharge stability, while the voltage control cycle maintains control precision. The key is that the pulse frequency and voltage control frequency are kept distinct to avoid synchronization issues that would cause discharge instability.
2Loss of substance
If erosion position is moved by rotating magnets, then target material utilization is improved, but film quality uniformity deteriorates due to uneven reaction
Solution Approach 1:
The patent introduces dynamic control of the magnetic field by rotating the magnets, which moves the erosion position across the target material surface. This dynamic adjustment improves target material utilization by preventing localized depletion. The rotation speed is controlled to ensure uniform erosion distribution, thereby maintaining film quality uniformity while enhancing material usage efficiency.
3Device complexity
If pulse cycle matches voltage control cycle, then control simplicity is improved, but film deposition stability deteriorates
Solution Approach 1:
The patent employs two different periodic cycles: the voltage control cycle for power supply adjustment and the pulse cycle for current pulsing to the target. By setting these cycles to be different, the system achieves stable film deposition. The voltage control cycle maintains simplicity in control logic, while the distinct pulse cycle ensures deposition stability by preventing synchronization-related fluctuations in plasma generation.
4Productivity
If target material is consumed during long-term deposition, then productivity is improved, but film quality uniformity deteriorates due to positional relationship changes
Solution Approach 1:
The patent implements dynamic adjustment mechanisms including magnet rotation and substrate position control. During long-term deposition, as the target material is consumed, the magnetic field rotation continues to move the erosion position, and the substrate position can be adjusted to maintain optimal spacing. This dynamic compensation ensures uniform film quality is preserved throughout extended deposition periods, enabling high productivity without sacrificing quality consistency.
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 approach stabilizes electric discharge and maintains high and uniform film quality, allowing for stable deposition of high-quality films over extended periods without premature target material exhaustion.
Implementation Method 1
plasma is generated in the vacuum chamber by applying voltage from a DC power supply to the target material
Implementation Method 2
the target material is sputtered out by pulsed plasma generated inside the vacuum chamber and reaches the substrate, thereby depositing a thin film
Implementation Method 3
stabilizes electric discharge and maintains high and uniform film quality
Data Source
AI summary
A sputtering apparatus has a vacuum chamber capable of arranging a target material and a substrate therein so as to face each other, a DC power supply capable of electrically being connected to the target material, and a pulsing unit pulsing electric current flowing in the target material from the DC power supply, in which plasma is generated in the vacuum chamber to form a thin film on the substrate, including an ammeter measuring electric current flowing in the pulsing unit from the DC power supply, a power supply controller performing feedback control of the DC power supply so that a current value measured by the ammeter becomes a prescribed value and a pulse controller indicating a pulse cycle shifted from a control cycle of the DC power supply by the power supply controller to the pulsing unit.