Bipolar Electrostatic Chucking for Multi-Pressure Substrate Flatness
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Solution Overview
Problem
In semiconductor manufacturing, substrate bowing caused by material stresses leads to non-uniform heating and deposition, which is challenging to address with existing electrostatic chucking methods, especially during multi-pressure processes where vacuum chucking is insufficient and monopolar chucking requires plasma presence.
Innovation Solution
A bipolar electrostatic chuck with coplanar or concentric electrodes and a floating power supply that can reverse polarity, combined with vacuum chucking, to securely hold substrates and minimize defects by adjusting voltage and pressure during processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum chucking is used to hold the substrate, then the substrate can be secured during processing, but the chucking becomes insufficient during multi-pressure processes where plasma is not present
Solution Approach 1:
The electrostatic chuck is divided into multiple independent electrode regions (first electrode and second electrode) that can be controlled separately. This segmentation allows different chucking modes (monopolar and bipolar) to be implemented within a single chuck structure, enabling adaptation to various processing conditions without requiring multiple separate chucks.
Solution Approach 2:
The chucking voltage polarity is made dynamically switchable between monopolar (single polarity) and bipolar (opposite polarities) modes. This dynamic control allows the system to adapt to different pressure conditions: using vacuum chucking at low pressure and electrostatic chucking at higher pressure, thereby resolving the contradiction between reliable substrate holding and adaptability across pressure conditions.
2Stability of the object's composition
If monopolar electrostatic chucking is used to maintain substrate flatness, then substrate stability is improved, but electrical discharge risks increase during plasma processing
Solution Approach 1:
Instead of using the traditional monopolar electrostatic chucking configuration, the patent employs bipolar electrostatic chucking where the first and second electrodes have opposite polarities. This inversion of the conventional approach creates a more balanced electric field distribution that maintains substrate flatness while reducing electrical discharge risks during plasma processing by preventing excessive charge accumulation on the substrate surface.
3Stability of the object's composition
If high chucking voltage is applied to maintain substrate flatness, then substrate stability is improved, but non-uniform deposition increases due to substrate bowing
Solution Approach 1:
The electrostatic chuck employs localized electrode regions (first and second electrodes with distinct polarities) that can independently influence different areas of the substrate. This local quality control allows for precise adjustment of electric field distribution across the substrate surface, maintaining uniform flatness without inducing the substrate bowing that occurs with high-voltage monopolar chucking, thereby ensuring uniform deposition.
Solution Approach 2:
The patent changes the fundamental parameter of electrostatic chucking from monopolar to bipolar configuration. This parameter change creates a more balanced electric field that maintains substrate flatness through moderate voltage application rather than high voltage, preventing substrate bowing and ensuring uniform deposition across the substrate surface.
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 solution maintains substrate flatness and stability across multiple processing operations, reducing non-uniform deposition and electrical discharge risks, while enabling effective chucking at various pressures and temperatures.
Implementation Method 1
a bipolar electrostatic chuck with coplanar or concentric electrodes... to securely hold substrates
Implementation Method 2
activating a vacuum port defined by the body of the electrostatic chuck... sub-atmospheric chemical vapor deposition is carried out
Implementation Method 3
the power supply is configured to selectively reverse the polarity of a chucking voltage to at least one of the electrodes
Implementation Method 4
plasma is struck in the interior of the semiconductor processing chamber and plasma-enhanced processing of the semiconductor substrate is carried out
Data Source
AI summary
Exemplary semiconductor processing systems include a processing chamber, a power supply, and a chuck disposed at least partially within the processing chamber. The chuck includes a chuck body defining a vacuum port. The chuck also includes first and second coplanar electrodes embedded in the chuck body and connected to the power supply. In some examples, coplanar electrodes include concentric electrodes defining a concentric gap in between. Exemplary semiconductor processing methods may include activating the power supply for the electrostatic chuck to secure a semiconductor substrate on the body of the chuck and/or activating the vacuum port defined by the body of the electrostatic chuck. Some processing can be carried out at increased pressure, while other processing can be carried out at reduced pressure with increased chucking voltage.