Pulsed DC Sputtering of Dielectric Targets to Prevent Arcing
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Solution Overview
Problem
Existing methods for depositing dielectric films in PVD chambers face challenges in preventing excessive charge accumulation on dielectric targets, which can lead to arcing and damage to the film, substrate, and chamber components.
Innovation Solution
A vapor deposition apparatus and method that utilize a pulsed DC power supply to the dielectric target, creating a plasma in the process gap between the target and the substrate support, thereby preventing charge accumulation and reducing the risk of arcing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If DC power is applied to the dielectric target to generate plasma, then the sputtering rate is enhanced, but charge accumulation occurs on the dielectric target causing arcing and damage
Solution Approach 1:
The patent applies periodic pulsed DC power to the dielectric target instead of continuous DC power. The power is applied in cycles with an ON time (e.g., 1-100 microseconds) and an OFF time (e.g., 1-100 microseconds), creating a duty cycle between 1-90%. This periodic action allows charge to dissipate during the OFF period while maintaining plasma generation during the ON period, thereby preventing charge accumulation while preserving sputtering rate.
2Productivity
If high power density is applied to increase deposition efficiency, then the sputtering rate increases, but excessive heat is generated causing target temperature rise and potential damage
Solution Approach 1:
The pulsed DC power application provides periodic high power density during the ON time to maintain high sputtering rate and deposition efficiency, followed by an OFF time that allows the target to cool down. This periodic cycling prevents excessive heat accumulation while maintaining high average deposition efficiency. The duty cycle and pulse width can be optimized to balance between deposition rate and temperature control.
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
The use of pulsed DC power effectively prevents charge accumulation on the dielectric target, reducing the occurrence of arcing and enhancing the consistency and quality of the dielectric film deposition process.
Implementation Method 1
applying power to a dielectric target within a vacuum chamber to generate a plasma in a process gap between the dielectric target and a substrate support
Implementation Method 2
pulsing the power applied to the dielectric target to prevent charge accumulation
Data Source
AI summary
A vapor deposition system and methods of operation thereof are disclosed. The vapor deposition system includes a vacuum chamber; a dielectric target within the vacuum chamber, the dielectric target having a front surface and a thickness; a substrate support within the vacuum chamber, the substrate support having a front surface spaced from the front surface of the dielectric target to form a process gap; and a signal generator connected to the dielectric target to generate a plasma in the vacuum chamber, the signal generator comprises a power source, the power source configured to prevent charge accumulation in the dielectric target. The method includes applying power to a dielectric target within a vacuum chamber to generate a plasma in a process gap between the dielectric target and a substrate support and pulsing the power applied to the dielectric target to prevent charge accumulation.