Electrostatic Chuck Protection via Impurity-Doped Layer
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Solution Overview
Problem
The adherence of foreign materials such as phosphorus or carbon on the electrostatic chuck surface in semiconductor manufacturing processes leads to reduced adsorption performance, affecting heat conduction and substrate holding, potentially resulting in defective products due to contamination and increased substrate temperature.
Innovation Solution
An impurity-doped layer formation apparatus and electrostatic chuck protection method that shields the chuck surface during process suspension periods to prevent foreign material transfer, using a barrier like a shutter member or dummy substrate to prevent adherence of volatile substances like phosphorus or carbon, and removes the barrier for process execution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the electrostatic chuck surface is exposed during process suspension period, then the substrate can be quickly loaded and unloaded, but foreign materials including phosphorus or carbon transfer from the process chamber surface to the chuck surface, degrading chuck performance
Solution Approach 1:
A protective film is formed on the electrostatic chuck surface before the process suspension period begins. This preliminary protective layer prevents foreign materials from adhering to the chuck surface during suspension, eliminating the need to clean or replace the chuck between processes and maintaining consistent adsorption performance.
Solution Approach 2:
The protective film acts as an intermediary layer between the electrostatic chuck surface and foreign materials in the process chamber. This film prevents direct contact and adhesion between the chuck surface and contaminants like phosphorus or carbon, thereby preserving the chuck's adsorption performance during process suspension.
2Reliability
If the electrostatic chuck surface is shielded during process suspension period, then foreign material adherence is prevented, but the complexity of the apparatus increases due to additional shielding mechanisms
Solution Approach 1:
The protective film serves as a simple intermediary layer that can be applied directly to the chuck surface without requiring complex mechanical shielding structures. This film-based approach prevents foreign material adhesion while adding minimal structural complexity to the apparatus.
Solution Approach 2:
The protective film is a thin, easily applied coating that can be formed quickly and removed or replaced without significant cost or complexity. This disposable-like protective layer simplifies the overall system compared to permanent mechanical shielding mechanisms.
3Reliability
If foreign materials adhere to the electrostatic chuck surface, then the chuck performance degrades requiring frequent maintenance, but maintaining high chuck performance requires continuous cleaning or replacement operations
Solution Approach 1:
The protective film is applied to the electrostatic chuck surface before the process suspension period begins, proactively preventing foreign material adhesion. This preliminary protection eliminates the need for subsequent cleaning or maintenance operations, saving time and maintaining consistent chuck performance across multiple process cycles.
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
Effectively suppresses degradation of electrostatic chuck performance by preventing contamination, maintaining proper heat conduction and substrate holding, thereby reducing the likelihood of defective products and extending the operational interval between maintenance cycles.
Implementation Method 1
an electrostatic chuck accommodated in the process chamber and including a chuck surface for holding the substrate
Implementation Method 2
configured to shield the chuck surface at least for a certain duration during a process suspension period, in order to suppress transfer of foreign materials including phosphorus or carbon from a surface of the process chamber to the chuck surface
Implementation Method 3
a process chamber configured to perform a process of forming an impurity-doped layer including phosphorus or carbon on a substrate
Data Source
AI summary
An electrostatic chuck protection method includes providing an exposed chuck surface with a protective surface for preventing adherence of foreign materials including a substance exhibiting volatility in a vacuum environment, and removing the protective surface in order to perform a process of forming a substrate electrostatically held on the chuck surface with a surface layer including a substance having volatility in a vacuum chamber. The protective surface may be provided when a low vacuum pumping mode of operation is performed in a vacuum environment surrounding the chuck surface.