Electromagnet Array for Uniform Sputtering Erosion
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Solution Overview
Problem
Conventional sputtering techniques, such as those using rotating magnet modules, often result in uneven target erosion patterns and under-erosion at the center of the target, leading to non-uniform deposition in semiconductor manufacturing.
Innovation Solution
A controllable electromagnet array is used to apply static or sweeping magnetic fields, dynamically adjusting to address localized over- and under-erosion by generating an eddy current and measuring impedance variations to determine erosion features, ensuring uniform target erosion and deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a rotating magnet module is used to apply a sweeping magnetic field over the target, then target erosion is promoted, but uneven circular erosion patterns (racetracks) are created and under-erosion occurs at the center of the target
Solution Approach 1:
The patent replaces the mechanical rotating magnet module with an electromagnet array that can be controlled electronically. The electromagnet array includes multiple electromagnets arranged in a pattern that corresponds to the racetrack erosion pattern, allowing independent control of each electromagnet to create uniform erosion without the mechanical complexity of rotation mechanisms.
Solution Approach 2:
The patent applies different magnetic field strengths to different locations on the target by using an array of electromagnets with independently controllable currents. Each electromagnet can be adjusted to provide the appropriate local magnetic field strength to achieve uniform erosion across the entire target surface, including the center region that was previously under-eroded.
2Measurement precision
If impedance variations are measured to determine erosion features, then erosion monitoring is achieved, but additional measurement and control systems are required
Solution Approach 1:
The patent implements a feedback control system where impedance sensors continuously monitor the electrical impedance of each electromagnet, which correlates with the erosion state of the target at that location. The controller uses this impedance information to automatically adjust the current through each electromagnet, creating a closed-loop feedback system that maintains uniform erosion without requiring complex external measurement and control systems.
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 achieves uniform target erosion and deposition, improving the quality of semiconductor manufacturing by dynamically addressing uneven erosion patterns and enhancing the uniformity of material layers on substrates.
Implementation Method 1
A gas is introduced into the sputtering chamber, where the gas is ignited to form a plasma. The gas ions in the plasma are drawn to the target by an electric field across the target, the back plate and the substrate. With sufficient energies, gas ions can dislodge atoms off of the target, allowing the dislodged target atoms to be deposited on the substrate.
Implementation Method 2
controllable electromagnet array, which can be used to apply a static or sweeping magnetic field. The electromagnet array also can be used to generate an eddy current and determine erosion features of a target by measuring an impedance variation.
Data Source
AI summary
Sputtering systems and methods are provided. In an embodiment, a sputtering system includes a chamber configured to receive a substrate, a sputtering target positioned within the chamber, and an electromagnet array over the sputtering target. The electromagnet array includes a plurality of electromagnets.