Pulsed Sputter Gun Ionization Duty Cycle Control
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Solution Overview
Problem
Current full-substrate PVD tools face challenges in achieving high metal ionization without damaging smaller diameter sputter guns, which are necessary for efficient semiconductor processing and combinatorial processing capabilities.
Innovation Solution
A sputter processing tool with multiple sputter guns connected to a pulsed power source with a duty cycle less than 30% and a substrate support biased with a synchronized pulsed power source, allowing for high metal ionization while minimizing gun damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high power is applied to the sputter gun to achieve high metal ionization, then step coverage is improved, but the sputter gun is damaged
Solution Approach 1:
The patent applies pulsed DC power to the sputter gun instead of continuous power, creating periodic on/off cycles. During the on-phase, high power is delivered to achieve high metal ionization and improved step coverage. During the off-phase, the gun rests and cools, preventing cumulative thermal damage. This periodic action allows the system to achieve the benefits of high power while avoiding its harmful effects.
Solution Approach 2:
The patent changes the temporal parameters of power delivery by introducing duty cycle control. Instead of maintaining constant high power, the system varies the average power through duty cycle adjustment (ratio of on-time to total cycle time). This parameter change allows optimization of both ionization quality and gun longevity by controlling the temporal distribution of energy input.
2Productivity
If smaller diameter sputter guns are used for combinatorial processing, then processing efficiency is improved, but the guns are more susceptible to damage from high power
Solution Approach 1:
Smaller diameter sputter guns used in combinatorial processing are more susceptible to thermal damage. The pulsed DC operation with controlled duty cycle provides periodic rest periods that allow these smaller guns to dissipate heat and recover, enabling them to withstand the high peak powers needed for effective deposition without suffering cumulative damage.
Solution Approach 2:
The patent makes the power delivery dynamic rather than static. By adjusting the duty cycle and pulse frequency, the system can adapt the average power load to match the thermal capacity of smaller guns while maintaining high peak power capability. This dynamic control enables the use of smaller, more efficient guns without sacrificing their longevity.
3Manufacturing precision
If continuous high power is applied to achieve high metal ionization, then deposition quality is improved, but energy consumption increases
Solution Approach 1:
The pulsed DC power system delivers high power only during the on-phase of each cycle, with the off-phase providing energy recovery time. This periodic operation achieves high metal ionization and deposition quality during the active phase while reducing average power consumption through the duty cycle, thereby lowering overall energy requirements.
Solution Approach 2:
While the power is pulsed, the system maintains continuous deposition capability by ensuring the pulse frequency is sufficient to sustain the deposition process without interruption. The useful action of material deposition continues throughout the process, with the pulsed power providing the necessary ionization bursts while allowing energy recovery during off-phases.
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 enables high metal ionization with reduced average power consumption, preventing sputter gun damage and enhancing step coverage on semiconductor wafers, thereby improving processing efficiency and productivity.
Implementation Method 1
Sputtering is a common physical vapor deposition method, where atoms or molecules are ejected from a target material by high-energy particle bombardment and then deposited onto the substrate
Implementation Method 2
the substrate is biased
Data Source
AI summary
In one aspect of the invention, a process chamber is provided. The chamber includes a plurality of sputter guns with a target affixed to one end of each of the sputter guns. Each of the plurality of sputter guns is coupled to a first power source. The first power source is operable to provide a pulsed power supply to each of the plurality of sputter guns. The pulsed power supply has a duty cycle that is less than 30%. A substrate support disposed at a distance from the plurality of sputter guns is included. The substrate support is coupled to a second power source. The second power source is operable to bias a substrate disposed on the substrate support, wherein the duty cycle of the second power source is synchronized with a duty cycle of the first power source. A method of performing a deposition process is also included.