Bipolar Electrostatic Chuck Edge Uniformity Tunability
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Solution Overview
Problem
In semiconductor manufacturing, the decreasing feature size of transistor structures leads to challenges in process uniformity, particularly at the edge of substrates, resulting in yield issues and defects due to non-uniform film deposition and electrostatic chucking, which causes arcing and plasma instability.
Innovation Solution
The use of an electrostatic chuck with two bipolar electrodes and one annular electrode allows for better tunability of ion flux and reduced voltage, minimizing arcing and plasma instability by enabling fine, localized process control and reducing electrostatic charge effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional electrostatic chuck with single electrode is used, then the structure is simple, but the process uniformity at substrate edge deteriorates
Solution Approach 1:
The electrostatic chuck is divided into multiple independent electrodes (first electrode, second electrode, and annular electrode) that can be controlled separately. This segmentation allows different regions of the substrate to experience different electrostatic forces, enabling independent optimization of edge and center regions to achieve uniform film deposition across the entire substrate.
Solution Approach 2:
The patent applies different voltages to different electrodes to create localized electrostatic fields. The first and second electrodes can be adjusted to provide stronger holding force at the substrate edge, while the annular electrode controls the overall chucking. This local quality adjustment compensates for edge effects and achieves uniform process conditions across the substrate surface.
2Force
If higher voltage is applied to electrostatically chuck the wafer, then the chucking force increases, but arcing and wafer defects increase
Solution Approach 1:
By dividing the electrostatic chucking function across multiple electrodes, each electrode can operate at lower individual voltages while collectively providing sufficient total chucking force. This segmentation of voltage application reduces the risk of arcing that occurs when a single electrode must operate at very high voltage to achieve the same holding force.
Solution Approach 2:
The patent changes the electrical parameters by applying different voltages to different electrodes rather than using a single high voltage. This parameter distribution approach maintains the necessary electrostatic holding force while operating below the arcing threshold, thereby preventing wafer defects caused by electrical discharge.
3Productivity
If plasma is ignited at the same time as wafer chucking, then the process starts efficiently, but plasma instability occurs due to electrostatic charge
Solution Approach 1:
The patent applies preliminary action by fully establishing the electrostatic chucking force on the wafer before initiating plasma generation. The multiple electrodes are configured to provide stable holding force in advance, which prevents electrostatic charge buildup during plasma ignition. This preliminary stabilization of the electrostatic field eliminates plasma instability that would otherwise occur during simultaneous chucking and ignition.
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 configuration enhances film uniformity, reduces wafer defects, and allows for stable plasma ignition after the wafer is chucked, improving processing reliability and reducing operational costs.
Implementation Method 1
the first electrode and the second electrode have opposite voltages when the first power source delivers voltage to the first electrode
Implementation Method 2
plasma-enhanced chemical vapor deposition (PECVD) process is a chemical process wherein electro-magnetic energy is applied to at least one precursor gas or precursor vapor to transform the precursor into a reactive plasma
Implementation Method 3
The electrode configuration may allow for better tunability of ion flux near the edge of the wafer
Data Source
AI summary
Embodiments of the present technology may include an electrostatic chuck. The chuck may include a top surface, defining a recessed portion of the chuck. The recessed portion of the chuck may be configured to support a substrate. The chuck may further include a first electrode and a second electrode. The first electrode and the second electrode may be disposed within the chuck. The first electrode and the second electrode may be substantially coplanar. In addition, the chuck may include a third electrode. The third electrode may be disposed within the chuck. Furthermore, the third electrode may have an annular shape. The third electrode may be separated from the first electrode and the second electrode. In addition, the third electrode may be substantially parallel to the first electrode and the second electrode. Systems and methods including the electrostatic chuck are also described.