PVD Magnet Spacing Control for Target Voltage Drift
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Solution Overview
Problem
Target voltage drift due to target erosion in physical vapor deposition (PVD) chambers affects deposition rate and film properties, and conventional compensation methods are not suitable for maintaining consistent process parameters.
Innovation Solution
The method involves energizing a target in a PVD processing chamber with magnets and adjusting their distance based on an inverse target voltage curve determined using a third-order polynomial to maintain constant target voltage, independent of target quality and performance consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional compensation methods are used to maintain constant deposition rate, then deposition rate control is attempted, but target voltage drift cannot be effectively controlled and process consistency deteriorates
Solution Approach 1:
The system implements feedback control by continuously monitoring target voltage and using this information to adjust magnet spacing. The controller measures the actual target voltage during sputtering and compares it to the desired voltage, then automatically adjusts the magnet-to-target distance to maintain constant voltage, creating a closed-loop control system that ensures process consistency
Solution Approach 2:
The invention changes the physical parameter of magnet spacing to control target voltage. By adjusting the distance between magnets and target, the magnetic field strength at the target surface is modified, which directly influences plasma density and ionization rate, thereby controlling target voltage and eliminating drift
2Stability of the object's composition
If magnet spacing is adjusted to control target voltage, then target voltage stability is improved, but system complexity increases
Solution Approach 1:
The system performs self-adjustment by using the measured target voltage to automatically control magnet spacing without requiring external manual intervention. The controller autonomously calculates the required spacing adjustment based on the inverse cubic relationship and executes the positioning, making the system self-regulating
Solution Approach 2:
The invention replaces complex mechanical voltage control mechanisms with an electromagnetic field-based approach. Instead of using mechanical means to directly control voltage, the system uses magnetic field adjustment (through magnet spacing) to indirectly control voltage, leveraging electromagnetic principles for more precise and reliable control
3Duration of action of stationary object
If target erosion is allowed to proceed naturally, then target life is extended, but deposition rate and film properties deteriorate due to voltage drift
Solution Approach 1:
The system takes preliminary action to counteract the harmful effects of target erosion before they can degrade process quality. By proactively adjusting magnet spacing in response to voltage changes, the system prevents deposition rate variations and film property deterioration, countering the natural degradation process
Solution Approach 2:
The invention introduces dynamic adjustment of magnet spacing to compensate for target erosion. Instead of using fixed magnet positioning, the system continuously adapts the magnet-to-target distance based on real-time voltage measurements, creating a dynamic control system that maintains optimal conditions throughout target life
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 maintains a substantially constant target voltage, increasing operable target life from 1200 to 2000 kilowatt hours and ensures consistent deposition rate and film properties by controlling ion energy and plasma density.
Implementation Method 1
a plurality of magnets configured to produce a magnetic field within the plasma processing chamber
Implementation Method 2
energizing a target disposed at a distance from a plurality of magnets disposed within a processing volume of a processing chamber
Implementation Method 3
physical vapor deposition (PVD) chamber
Data Source
AI summary
Methods and apparatus for processing a substrate are provided. In some embodiments, a method for processing a substrate includes: energizing a target disposed at a distance from a plurality of magnets disposed within a processing volume of a processing chamber, and moving the plurality of magnets either away from or closer to the target at a predetermined distance based on an inverse target voltage curve that is determined using a third order polynomial.